A unit with valves for three phases, together with unit control equipment, essential protective and switching devices, DC storage capacitors, phase reactors and auxiliaries, if any, used for conversion.
A DC electrical connection point at the AC/DC converter. The AC/DC converter is electrically connected also to the AC side. The AC connection is inherited from the AC conducting equipment in the same way as any other AC equipment. The AC/DC converter DC terminal is separate from generic DC terminal to restrict the connection with the AC side to AC/DC converter and so that no other DC conducting equipment can be connected to the AC side.
An electrical connection point (AC or DC) to a piece of conducting equipment. Terminals are connected at physical connection points called connectivity nodes.
A wire or combination of wires, with consistent electrical characteristics, building a single electrical system, used to carry alternating current between points in the power system. For symmetrical, transposed three phase lines, it is sufficient to use attributes of the line segment, which describe impedances and admittances for the entire length of the segment. Additionally impedances can be computed by using length and associated per length impedances. The BaseVoltage at the two ends of ACLineSegments in a Line shall have the same BaseVoltage.nominalVoltage. However, boundary lines may have slightly different BaseVoltage.nominalVoltages and variation is allowed. Larger voltage difference in general requires use of an equivalent branch.
A rotating machine whose shaft rotates asynchronously with the electrical field. Also known as an induction machine with no external connection to the rotor windings, e.g. squirrel-cage induction machine.
Asynchronous machine whose behaviour is described by reference to a standard model expressed in either time constant reactance form or equivalent circuit form or by definition of a user-defined model. Parameter details: Asynchronous machine parameters such as Xl, Xs, etc. are actually used as inductances in the model, but are commonly referred to as reactances since, at nominal frequency, the PU values are the same. However, some references use the symbol L instead of X.
The electrical equations of all variations of the asynchronous model are based on the AsynchronousEquivalentCircuit diagram for the direct- and quadrature- axes, with two equivalent rotor windings in each axis. Equations for conversion between equivalent circuit and time constant reactance forms: Xs = Xm + Xl X’ = Xl + Xm x Xlr1 / (Xm + Xlr1) X’’ = Xl + Xm x Xlr1 x Xlr2 / (Xm x Xlr1 + Xm x Xlr2 + Xlr1 x Xlr2) T’o = (Xm + Xlr1) / (omega0 x Rr1) T’’o = (Xm x Xlr1 + Xm x Xlr2 + Xlr1 x Xlr2) / (omega0 x Rr2 x (Xm + Xlr1) Same equations using CIM attributes from AsynchronousMachineTimeConstantReactance class on left of ‘=’ and AsynchronousMachineEquivalentCircuit class on right (except as noted): xs = xm + RotatingMachineDynamics.statorLeakageReactance xp = RotatingMachineDynamics.statorLeakageReactance + xm x xlr1 / (xm + xlr1) xpp = RotatingMachineDynamics.statorLeakageReactance + xm x xlr1 x xlr2 / (xm x xlr1 + xm x xlr2 + xlr1 x xlr2) tpo = (xm + xlr1) / (2 x pi x nominal frequency x rr1) tppo = (xm x xlr1 + xm x xlr2 + xlr1 x xlr2) / (2 x pi x nominal frequency x rr2 x (xm + xlr1).
Parameter details: If X’’ = X’, a single cage (one equivalent rotor winding per axis) is modelled. The “p” in the attribute names is a substitution for a “prime” in the usual parameter notation, e.g. tpo refers to T’o. The parameters used for models expressed in time constant reactance form include: - RotatingMachine.ratedS (MVAbase); - RotatingMachineDynamics.damping (D); - RotatingMachineDynamics.inertia (H); - RotatingMachineDynamics.saturationFactor (S1); - RotatingMachineDynamics.saturationFactor120 (S12); - RotatingMachineDynamics.statorLeakageReactance (Xl); - RotatingMachineDynamics.statorResistance (Rs); - .xs (Xs); - .xp (X’); - .xpp (X’‘); - .tpo (T’o); - .tppo (T’’o).
AuxiliaryEquipment describe equipment that is not performing any primary functions but support for the equipment performing the primary function. AuxiliaryEquipment is attached to primary equipment via an association with Terminal.
A collection of power system resources (within a given substation) including conducting equipment, protection relays, measurements, and telemetry. A bay typically represents a physical grouping related to modularization of equipment.
Designates a connection point at which one or more model authority sets shall connect to. The location of the connection point as well as other properties are agreed between organisations responsible for the interconnection, hence all attributes of the class represent this agreement. It is primarily used in a boundary model authority set which can contain one or many BoundaryPoint-s among other Equipment-s and their connections.
A mechanical switching device capable of making, carrying, and breaking currents under normal circuit conditions and also making, carrying for a specified time, and breaking currents under specified abnormal circuit conditions e.g. those of short circuit.
Used to apply user standard names to TopologicalNodes. Associated with one or more terminals that are normally connected with the bus name. The associated terminals are normally connected by non-retained switches. For a ring bus station configuration, all BusbarSection terminals in the ring are typically associated. For a breaker and a half scheme, both BusbarSections would normally be associated. For a ring bus, all BusbarSections would normally be associated. For a ‘straight’ busbar configuration, normally only the main terminal at the BusbarSection would be associated.
A conductor, or group of conductors, with negligible impedance, that serve to connect other conducting equipment within a single substation. Voltage measurements are typically obtained from voltage transformers that are connected to busbar sections. A bus bar section may have many physical terminals but for analysis is modelled with exactly one logical terminal.
A Clamp is a galvanic connection at a line segment where other equipment is connected. A Clamp does not cut the line segment. A Clamp is ConductingEquipment and has one Terminal with an associated ConnectivityNode. Any other ConductingEquipment can be connected to the Clamp ConnectivityNode.
A set of thermal generating units for the production of electrical energy and process steam (usually from the output of the steam turbines). The steam sendout is typically used for industrial purposes or for municipal heating and cooling.
A set of combustion turbines and steam turbines where the exhaust heat from the combustion turbines is recovered to make steam for the steam turbines, resulting in greater overall plant efficiency.
Combination of conducting material with consistent electrical characteristics, building a single electrical system, used to carry current between points in the power system.
A curve of load versus time (X-axis) showing the active power values (Y1-axis) and reactive power (Y2-axis) for each unit of the period covered. This curve represents a typical pattern of load over the time period for a given day type and season.
A conductor, or group of conductors, with negligible impedance, that serve to connect other conducting equipment within a single substation and are modelled with a single logical terminal.
Control is used for supervisory/device control. It represents control outputs that are used to change the state in a process, e.g. close or open breaker, a set point value or a raise lower command.
A control area is a grouping of generating units and/or loads and a cutset of tie lines (as terminals) which may be used for a variety of purposes including automatic generation control, power flow solution area interchange control specification, and input to load forecasting. All generation and load within the area defined by the terminals on the border are considered in the area interchange control. Note that any number of overlapping control area specifications can be superimposed on the physical model. The following general principles apply to ControlArea: 1. The control area orientation for net interchange is positive for an import, negative for an export. 2. The control area net interchange is determined by summing flows in Terminals. The Terminals are identified by creating a set of TieFlow objects associated with a ControlArea object. Each TieFlow object identifies one Terminal. 3. In a single network model, a tie between two control areas must be modelled in both control area specifications, such that the two representations of the tie flow sum to zero. 4. The normal orientation of Terminal flow is positive for flow into the conducting equipment that owns the Terminal. (i.e. flow from a bus into a device is positive.) However, the orientation of each flow in the control area specification must align with the control area convention, i.e. import is positive. If the orientation of the Terminal flow referenced by a TieFlow is positive into the control area, then this is confirmed by setting TieFlow.positiveFlowIn flag TRUE. If not, the orientation must be reversed by setting the TieFlow.positiveFlowIn flag FALSE.
A control area generating unit. This class is needed so that alternate control area definitions may include the same generating unit. It should be noted that only one instance within a control area should reference a specific generating unit.
DC side of the current source converter (CSC). The firing angle controls the dc voltage at the converter, both for rectifier and inverter. The difference between the dc voltages of the rectifier and inverter determines the dc current. The extinction angle is used to limit the dc voltage at the inverter, if needed, and is not used in active power control. The firing angle, transformer tap position and number of connected filters are the primary means to control a current source dc line. Higher level controls are built on top, e.g. dc voltage, dc current and active power. From a steady state perspective it is sufficient to specify the wanted active power transfer (ACDCConverter.targetPpcc) and the control functions will set the dc voltage, dc current, firing angle, transformer tap position and number of connected filters to meet this. Therefore attributes targetAlpha and targetGamma are not applicable in this case. The reactive power consumed by the converter is a function of the firing angle, transformer tap position and number of connected filter, which can be approximated with half of the active power. The losses is a function of the dc voltage and dc current. The attributes minAlpha and maxAlpha define the range of firing angles for rectifier operation between which no discrete tap changer action takes place. The range is typically 10-18 degrees. The attributes minGamma and maxGamma define the range of extinction angles for inverter operation between which no discrete tap changer action takes place. The range is typically 17-20 degrees.
Instrument transformer used to measure electrical qualities of the circuit that is being protected and/or monitored. Typically used as current transducer for the purpose of metering or protection. A typical secondary current rating would be 5A.
Multi-purpose data points for defining a curve. The use of this generic class is discouraged if a more specific class can be used to specify the X and Y axis values along with their specific data types.
A cut separates a line segment into two parts. The cut appears as a switch inserted between these two parts and connects them together. As the cut is normally open there is no galvanic connection between the two line segment parts. But it is possible to close the cut to get galvanic connection. The cut terminals are oriented towards the line segment terminals with the same sequence number. Hence the cut terminal with sequence number equal to 1 is oriented to the line segment’s terminal with sequence number equal to 1. The cut terminals also act as connection points for jumpers and other equipment, e.g. a mobile generator. To enable this, connectivity nodes are placed at the cut terminals. Once the connectivity nodes are in place any conducting equipment can be connected at them.
An electrical connection point at a piece of DC conducting equipment. DC terminals are connected at one physical DC node that may have multiple DC terminals connected. A DC node is similar to an AC connectivity node. The model requires that DC connections are distinct from AC connections.
Indivisible operative unit comprising all equipment between the point of common coupling on the AC side and the point of common coupling - DC side, essentially one or more converters, together with one or more converter transformers, converter control equipment, essential protective and switching devices and auxiliaries, if any, used for conversion.
A modelling construct to provide a root class for containment of DC as well as AC equipment. The class differ from the EquipmentContaner for AC in that it may also contain DCNode-s. Hence it can contain both AC and DC equipment.
A wire or combination of wires not insulated from one another, with consistent electrical characteristics, used to carry direct current between points in the DC region of the power system.
An electrically connected subset of the network. DC topological islands can change as the current network state changes, e.g. due to: - disconnect switches or breakers changing state in a SCADA/EMS. - manual creation, change or deletion of topological nodes in a planning tool. Only energised TopologicalNode-s shall be part of the topological island.
The diagram being exchanged. The coordinate system is a standard Cartesian coordinate system and the orientation attribute defines the orientation. The initial view related attributes can be used to specify an initial view with the x,y coordinates of the diagonal points.
An object that defines one or more points in a given space. This object can be associated with anything that specializes IdentifiedObject. For single line diagrams such objects typically include such items as analog values, breakers, disconnectors, power transformers, and transmission lines.
This is used for grouping diagram object points from different diagram objects that are considered to be glued together in a diagram even if they are not at the exact same coordinates.
A point in a given space defined by 3 coordinates and associated to a diagram object. The coordinates may be positive or negative as the origin does not have to be in the corner of a diagram.
A reference to a style used by the originating system for a diagram object. A diagram object style describes information such as line thickness, shape such as circle or rectangle etc, and colour.
The diagram style refers to a style used by the originating system for a diagram. A diagram style describes information such as schematic, geographic, etc.
It represents the difference model header. The content is described by the Model class, the association role forwardDifferences and association role reverseDifferences. Both association roles may have one set of Statements.
IEEE type DEC1A discontinuous excitation control model that boosts generator excitation to a level higher than that demanded by the voltage regulator and stabilizer immediately following a system fault. Reference: IEEE 421.5-2005, 12.2.
IEEE type DEC2A model for discontinuous excitation control. This system provides transient excitation boosting via an open-loop control as initiated by a trigger signal generated remotely. Reference: IEEE 421.5-2005 12.3.
IEEE type DEC3A model. In some systems, the stabilizer output is disconnected from the regulator immediately following a severe fault to prevent the stabilizer from competing with action of voltage regulator during the first swing. Reference: IEEE 421.5-2005 12.4.
A manually operated or motor operated mechanical switching device used for changing the connections in a circuit, or for isolating a circuit or equipment from a source of power. It is required to open or close circuits when negligible current is broken or made.
Discontinuous excitation control function block whose behaviour is described by reference to a standard model or by definition of a user-defined model.
A conducting equipment used to represent a connection to ground which is typically used to compensate earth faults. An earth fault compensator device modelled with a single terminal implies a second terminal solidly connected to ground. If two terminals are modelled, the ground is not assumed and normal connection rules apply.
Describes an area having energy production or consumption. Specializations are intended to support the load allocation function as typically required in energy management systems or planning studies to allocate hypothesized load levels to individual load points for power flow analysis. Often the energy area can be linked to both measured and forecast load levels.
Generic user of energy - a point of consumption on the power system model. EnergyConsumer.pfixed, .qfixed, .pfixedPct and .qfixedPct have meaning only if there is no LoadResponseCharacteristic associated with EnergyConsumer or if LoadResponseCharacteristic.exponentModel is set to False.
The class represents equivalent branches. In cases where a transformer phase shift is modelled and the EquivalentBranch is spanning the same nodes, the impedance quantities for the EquivalentBranch shall consider the needed phase shift.
A class that groups electrical equivalents, including internal nodes, of a network that has been reduced. The ConnectivityNodes contained in the equivalent are intended to reflect internal nodes of the equivalent. The boundary Connectivity nodes where the equivalent connects outside itself are not contained by the equivalent.
Italian excitation system corresponding to IEEE (1968) type 2 model. It represents an alternator and rotating diodes and electromechanic voltage regulators.
Transformer fed static excitation system (static with ABB regulator). This model represents a static excitation system in which a gated thyristor bridge fed by a transformer at the main generator terminals feeds the main generator directly.
Modified IEEE DC2A direct current commutator exciter with speed input, one more leg block in feedback loop and without underexcitation limiters (UEL) inputs. DC type 2 excitation system model with added speed multiplier, added lead-lag, and voltage-dependent limits.
Static PI transformer fed excitation system ELIN (VATECH) - simplified model. This model represents an all-static excitation system. A PI voltage controller establishes a desired field current set point for a proportional current controller. The integrator of the PI controller has a follow-up input to match its signal to the present field current. A power system stabilizer with power input is included in the model.
Detailed excitation system ELIN (VATECH). This model represents an all-static excitation system. A PI voltage controller establishes a desired field current set point for a proportional current controller. The integrator of the PI controller has a follow-up input to match its signal to the present field current. Power system stabilizer models used in conjunction with this excitation system model: PssELIN2, PssIEEE2B, Pss2B.
IEEE 421.5-2005 type AC1A model. The model represents the field-controlled alternator-rectifier excitation systems designated type AC1A. These excitation systems consist of an alternator main exciter with non-controlled rectifiers. Reference: IEEE 421.5-2005, 6.1.
IEEE 421.5-2005 type AC2A model. The model represents a high initial response field-controlled alternator-rectifier excitation system. The alternator main exciter is used with non-controlled rectifiers. The type AC2A model is similar to that of type AC1A except for the inclusion of exciter time constant compensation and exciter field current limiting elements. Reference: IEEE 421.5-2005, 6.2.
IEEE 421.5-2005 type AC3A model. The model represents the field-controlled alternator-rectifier excitation systems designated type AC3A. These excitation systems include an alternator main exciter with non-controlled rectifiers. The exciter employs self-excitation, and the voltage regulator power is derived from the exciter output voltage. Therefore, this system has an additional nonlinearity, simulated by the use of a multiplier whose inputs are the voltage regulator command signal, Va, and the exciter output voltage, Efd, times KR. This model is applicable to excitation systems employing static voltage regulators. Reference: IEEE 421.5-2005, 6.3.
IEEE 421.5-2005 type AC4A model. The model represents type AC4A alternator-supplied controlled-rectifier excitation system which is quite different from the other types of AC systems. This high initial response excitation system utilizes a full thyristor bridge in the exciter output circuit. The voltage regulator controls the firing of the thyristor bridges. The exciter alternator uses an independent voltage regulator to control its output voltage to a constant value. These effects are not modelled; however, transient loading effects on the exciter alternator are included. Reference: IEEE 421.5-2005, 6.4.
IEEE 421.5-2005 type AC5A model. The model represents a simplified model for brushless excitation systems. The regulator is supplied from a source, such as a permanent magnet generator, which is not affected by system disturbances. Unlike other AC models, this model uses loaded rather than open circuit exciter saturation data in the same way as it is used for the DC models. Because the model has been widely implemented by the industry, it is sometimes used to represent other types of systems when either detailed data for them are not available or simplified models are required. Reference: IEEE 421.5-2005, 6.5.
IEEE 421.5-2005 type AC6A model. The model represents field-controlled alternator-rectifier excitation systems with system-supplied electronic voltage regulators. The maximum output of the regulator, VR, is a function of terminal voltage, VT. The field current limiter included in the original model AC6A remains in the 2005 update. Reference: IEEE 421.5-2005, 6.6.
IEEE 421.5-2005 type AC7B model. The model represents excitation systems which consist of an AC alternator with either stationary or rotating rectifiers to produce the DC field requirements. It is an upgrade to earlier AC excitation systems, which replace only the controls but retain the AC alternator and diode rectifier bridge. Reference: IEEE 421.5-2005, 6.7. Note, however, that in IEEE 421.5-2005, the [1 / sTE] block is shown as [1 / (1 + sTE)], which is incorrect.
IEEE 421.5-2005 type AC8B model. This model represents a PID voltage regulator with either a brushless exciter or DC exciter. The AVR in this model consists of PID control, with separate constants for the proportional (KPR), integral (KIR), and derivative (KDR) gains. The representation of the brushless exciter (TE, KE, SE, KC, KD) is similar to the model type AC2A. The type AC8B model can be used to represent static voltage regulators applied to brushless excitation systems. Digitally based voltage regulators feeding DC rotating main exciters can be represented with the AC type AC8B model with the parameters KC and KD set to 0. For thyristor power stages fed from the generator terminals, the limits VRMAX and VRMIN should be a function of terminal voltage: VT x VRMAX and VT x VRMIN. Reference: IEEE 421.5-2005, 6.8.
IEEE 421.5-2005 type DC1A model. This model represents field-controlled DC commutator exciters with continuously acting voltage regulators (especially the direct-acting rheostatic, rotating amplifier, and magnetic amplifier types). Because this model has been widely implemented by the industry, it is sometimes used to represent other types of systems when detailed data for them are not available or when a simplified model is required. Reference: IEEE 421.5-2005, 5.1.
IEEE 421.5-2005 type DC2A model. This model represents field-controlled DC commutator exciters with continuously acting voltage regulators having supplies obtained from the generator or auxiliary bus. It differs from the type DC1A model only in the voltage regulator output limits, which are now proportional to terminal voltage VT. It is representative of solid-state replacements for various forms of older mechanical and rotating amplifier regulating equipment connected to DC commutator exciters. Reference: IEEE 421.5-2005, 5.2.
IEEE 421.5-2005 type DC3A model. This model represents older systems, in particular those DC commutator exciters with non-continuously acting regulators that were commonly used before the development of the continuously acting varieties. These systems respond at basically two different rates, depending upon the magnitude of voltage error. For small errors, adjustment is made periodically with a signal to a motor-operated rheostat. Larger errors cause resistors to be quickly shorted or inserted and a strong forcing signal applied to the exciter. Continuous motion of the motor-operated rheostat occurs for these larger error signals, even though it is bypassed by contactor action. Reference: IEEE 421.5-2005, 5.3.
IEEE 421.5-2005 type DC4B model. These excitation systems utilize a field-controlled DC commutator exciter with a continuously acting voltage regulator having supplies obtained from the generator or auxiliary bus. Reference: IEEE 421.5-2005, 5.4.
IEEE 421.5-2005 type ST1A model. This model represents systems in which excitation power is supplied through a transformer from the generator terminals (or the unit’s auxiliary bus) and is regulated by a controlled rectifier. The maximum exciter voltage available from such systems is directly related to the generator terminal voltage. Reference: IEEE 421.5-2005, 7.1.
IEEE 421.5-2005 type ST2A model. Some static systems use both current and voltage sources (generator terminal quantities) to comprise the power source. The regulator controls the exciter output through controlled saturation of the power transformer components. These compound-source rectifier excitation systems are designated type ST2A and are represented by ExcIEEEST2A. Reference: IEEE 421.5-2005, 7.2.
IEEE 421.5-2005 type ST3A model. Some static systems utilize a field voltage control loop to linearize the exciter control characteristic. This also makes the output independent of supply source variations until supply limitations are reached. These systems utilize a variety of controlled-rectifier designs: full thyristor complements or hybrid bridges in either series or shunt configurations. The power source can consist of only a potential source, either fed from the machine terminals or from internal windings. Some designs can have compound power sources utilizing both machine potential and current. These power sources are represented as phasor combinations of machine terminal current and voltage and are accommodated by suitable parameters in model type ST3A which is represented by ExcIEEEST3A. Reference: IEEE 421.5-2005, 7.3.
IEEE 421.5-2005 type ST4B model. This model is a variation of the type ST3A model, with a proportional plus integral (PI) regulator block replacing the lag-lead regulator characteristic that is in the ST3A model. Both potential and compound source rectifier excitation systems are modelled. The PI regulator blocks have non-windup limits that are represented. The voltage regulator of this model is typically implemented digitally. Reference: IEEE 421.5-2005, 7.4.
IEEE 421.5-2005 type ST5B model. The type ST5B excitation system is a variation of the type ST1A model, with alternative overexcitation and underexcitation inputs and additional limits. The block diagram in the IEEE 421.5 standard has input signal Vc and does not indicate the summation point with Vref. The implementation of the ExcIEEEST5B shall consider summation point with Vref. Reference: IEEE 421.5-2005, 7.5.
IEEE 421.5-2005 type ST6B model. This model consists of a PI voltage regulator with an inner loop field voltage regulator and pre-control. The field voltage regulator implements a proportional control. The pre-control and the delay in the feedback circuit increase the dynamic response. Reference: IEEE 421.5-2005, 7.6.
IEEE 421.5-2005 type ST7B model. This model is representative of static potential-source excitation systems. In this system, the AVR consists of a PI voltage regulator. A phase lead-lag filter in series allows the introduction of a derivative function, typically used with brushless excitation systems. In that case, the regulator is of the PID type. In addition, the terminal voltage channel includes a phase lead-lag filter. The AVR includes the appropriate inputs on its reference for overexcitation limiter (OEL1), underexcitation limiter (UEL), stator current limiter (SCL), and current compensator (DROOP). All these limitations, when they work at voltage reference level, keep the PSS (VS signal from PSS) in operation. However, the UEL limitation can also be transferred to the high value (HV) gate acting on the output signal. In addition, the output signal passes through a low value (LV) gate for a ceiling overexcitation limiter (OEL2). Reference: IEEE 421.5-2005, 7.7.
Proportional/integral regulator excitation system. This model can be used to represent excitation systems with a proportional-integral (PI) voltage regulator controller.
General purpose rotating excitation system. This model can be used to represent a wide range of excitation systems whose DC power source is an AC or DC generator. It encompasses IEEE type AC1, AC2, DC1, and DC2 excitation system models.
Excitation system type RQB (four-loop regulator, r?gulateur quatre boucles, developed in France) primarily used in nuclear or thermal generating units. This excitation system shall be always used together with power system stabilizer type PssRQB.
Simple excitation system with generic characteristics typical of many excitation systems; intended for use where negative field current could be a problem.
Slovakian excitation system. UEL and secondary voltage control are included in this model. When this model is used, there cannot be a separate underexcitation limiter or VAr controller model.
A FaultIndicator is typically only an indicator (which may or may not be remotely monitored), and not a piece of equipment that actually initiates a protection event. It is used for FLISR (Fault Location, Isolation and Restoration) purposes, assisting with the dispatch of crews to ‘most likely’ part of the network (i.e. assists with determining circuit section where the fault most likely happened).
The fossil fuel consumed by the non-nuclear thermal generating unit. For example, coal, oil, gas, etc. These are the specific fuels that the generating unit can consume.
An overcurrent protective device with a circuit opening fusible part that is heated and severed by the passage of overcurrent through it. A fuse is considered a switching device because it breaks current.
Resistive and reactive components of compensation for generator associated with IEEE type 2 voltage compensator for current flow out of another generator in the interconnection.
A single or set of synchronous machines for converting mechanical power into alternating-current power. For example, individual machines within a set may be defined for scheduling purposes while a single control signal is derived for the set. In this case there would be a GeneratingUnit for each member of the set and an additional GeneratingUnit corresponding to the set.
General model for any prime mover with a PID governor, used primarily for combustion turbine and combined cycle units. This model can be used to represent a variety of prime movers controlled by PID governors. It is suitable, for example, for the representation of: gas turbine and single shaft combined cycle turbines diesel engines with modern electronic or digital governors steam turbines where steam is supplied from a large boiler drum or a large header whose pressure is substantially constant over the period under study simple hydro turbines in dam configurations where the water column length is short and water inertia effects are minimal. Additional information on this model is available in the 2012 IEEE report, Dynamic Models for Turbine-Governors in Power System Studies, 3.1.2.3 pages 3-4 (GGOV1).
General governor with frequency-dependent fuel flow limit. This model is a modification of the GovCT1 model in order to represent the frequency-dependent fuel flow limit of a specific gas turbine manufacturer.
Woodward™ gas turbine governor. [Footnote: Woodward gas turbines are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
Modified IEEE hydro governor-turbine. This model differs from that defined in the IEEE modelling guideline paper in that the limits on gate position and velocity do not permit ‘wind up’ of the upstream signals.
Hydro turbine and governor. Represents plants with straight-forward penstock configurations and hydraulic governors of the traditional ‘dashpot’ type. This model can be used to represent simple, Francis/Pelton or Kaplan turbines.
Detailed hydro unit - Francis model. This model can be used to represent three types of governors. A schematic of the hydraulic system of detailed hydro unit models, such as Francis and Pelton, is provided in the DetailedHydroModelHydraulicSystem diagram.
IEEE simplified hydro governor-turbine model. Used for mechanical-hydraulic and electro-hydraulic turbine governors, with or without steam feedback. Typical values given are for mechanical-hydraulic turbine-governor. Reference: IEEE Transactions on Power Apparatus and Systems, November/December 1973, Volume PAS-92, Number 6, Dynamic Models for Steam and Hydro Turbines in Power System Studies, page 1904.
IEEE hydro turbine governor model represents plants with straightforward penstock configurations and hydraulic-dashpot governors. Reference: IEEE Transactions on Power Apparatus and Systems, November/December 1973, Volume PAS-92, Number 6, Dynamic Models for Steam and Hydro Turbines in Power System Studies, page 1904.
Hydro turbine and governor. Represents plants with straightforward penstock configurations and ‘three term’ electro-hydraulic governors (i.e. WoodwardTM electronic). [Footnote: Woodward electronic governors are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
Detailed hydro unit - Pelton model. This model can be used to represent the dynamic related to water tunnel and surge chamber. The DetailedHydroModelHydraulicSystem diagram, located under the GovHydroFrancis class, provides a schematic of the hydraulic system of detailed hydro unit models, such as Francis and Pelton.
WoodwardTM electric hydro governor. [Footnote: Woodward electric hydro governors are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
WoodwardTM PID hydro governor. [Footnote: Woodward PID hydro governors are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
IEEE steam turbine governor model. Reference: IEEE Transactions on Power Apparatus and Systems, November/December 1973, Volume PAS-92, Number 6, Dynamic Models for Steam and Hydro Turbines in Power System Studies, page 1904.
Relationship between the generating unit’s gross active power output on the X-axis (measured at the terminals of the machine(s)) and the generating unit’s net active power output on the Y-axis (based on utility-defined measurements at the power station). Station service loads, when modelled, should be treated as non-conforming bus loads. There may be more than one curve, depending on the auxiliary equipment that is in service.
A hydro power station which can generate or pump. When generating, the generator turbines receive water from an upper reservoir. When pumping, the pumps receive their water from a lower reservoir.
A short section of conductor with negligible impedance which can be manually removed and replaced if the circuit is de-energized. Note that zero-impedance branches can potentially be modelled by other equipment types.
Specifies one limit value for a Measurement. A Measurement typically has several limits that are kept together by the LimitSet class. The actual meaning and use of a Limit instance (i.e., if it is an alarm or warning limit or if it is a high or low limit) is not captured in the Limit class. However the name of a Limit instance may indicate both meaning and use.
Specifies a set of Limits that are associated with a Measurement. A Measurement may have several LimitSets corresponding to seasonal or other changing conditions. The condition is captured in the name and description attributes. The same LimitSet may be used for several Measurements. In particular percentage limits are used this way.
Aggregate loads are used to represent all or part of the real and reactive load from one or more loads in the static (power flow) data. This load is usually the aggregation of many individual load devices and the load model is an approximate representation of the aggregate response of the load devices to system disturbances. Standard aggregate load model comprised of static and/or dynamic components. A static load model represents the sensitivity of the real and reactive power consumed by the load to the amplitude and frequency of the bus voltage. A dynamic load model can be used to represent the aggregate response of the motor components of the load.
Load whose behaviour is described by reference to a standard model or by definition of a user-defined model. A standard feature of dynamic load behaviour modelling is the ability to associate the same behaviour to multiple energy consumers by means of a single load definition. The load model is always applied to individual bus loads (energy consumers).
Generic non-linear dynamic (GNLD) load. This model can be used in mid-term and long-term voltage stability simulations (i.e., to study voltage collapse), as it can replace a more detailed representation of aggregate load, including induction motors, thermostatically controlled and static loads.
Aggregate induction motor load. This model is used to represent a fraction of an ordinary load as ‘induction motor load’. It allows a load that is treated as an ordinary constant power in power flow analysis to be represented by an induction motor in dynamic simulation. This model is intended for representation of aggregations of many motors dispersed through a load represented at a high voltage bus but where there is no information on the characteristics of individual motors. Either a ‘one-cage’ or ‘two-cage’ model of the induction machine can be modelled. Magnetic saturation is not modelled. This model treats a fraction of the constant power part of a load as a motor. During initialisation, the initial power drawn by the motor is set equal to Pfrac times the constant P part of the static load. The remainder of the load is left as a static load. The reactive power demand of the motor is calculated during initialisation as a function of voltage at the load bus. This reactive power demand can be less than or greater than the constant Q component of the load. If the motor’s reactive demand is greater than the constant Q component of the load, the model inserts a shunt capacitor at the terminal of the motor to bring its reactive demand down to equal the constant Q reactive load. If an induction motor load model and a static load model are both present for a load, the motor Pfrac is assumed to be subtracted from the power flow constant P load before the static load model is applied. The remainder of the load, if any, is then represented by the static load model.
Models the characteristic response of the load demand due to changes in system conditions such as voltage and frequency. It is not related to demand response. If LoadResponseCharacteristic.exponentModel is True, the exponential voltage or frequency dependent models are specified and used as to calculate active and reactive power components of the load model. The equations to calculate active and reactive power components of the load model are internal to the power flow calculation, hence they use different quantities depending on the use case of the data exchange. The equations for exponential voltage dependent load model injected power are: pInjection= Pnominal* (Voltage/cim:BaseVoltage.nominalVoltage) ** cim:LoadResponseCharacteristic.pVoltageExponent qInjection= Qnominal* (Voltage/cim:BaseVoltage.nominalVoltage) ** cim:LoadResponseCharacteristic.qVoltageExponent Where: 1) * means ‘multiply’ and ** is ‘raised to power of’; 2) Pnominal and Qnominal represent the active power and reactive power at nominal voltage as any load described by the voltage exponential model shall be given at nominal voltage. This means that EnergyConsumer.p and EnergyConsumer.q are at nominal voltage. 3) After power flow is solved: -pInjection and qInjection correspond to SvPowerflow.p and SvPowerflow.q respectively. - Voltage corresponds to SvVoltage.v at the TopologicalNode where the load is connected.
General static load. This model represents the sensitivity of the real and reactive power consumed by the load to the amplitude and frequency of the bus voltage.
The place, scene, or point of something where someone or something has been, is, and/or will be at a given moment in time. It can be defined with one or more position points (coordinates) in a given coordinate system.
A Measurement represents any measured, calculated or non-measured non-calculated quantity. Any piece of equipment may contain Measurements, e.g. a substation may have temperature measurements and door open indications, a transformer may have oil temperature and tank pressure measurements, a bay may contain a number of power flow measurements and a Breaker may contain a switch status measurement. The PSR - Measurement association is intended to capture this use of Measurement and is included in the naming hierarchy based on EquipmentContainer. The naming hierarchy typically has Measurements as leaves, e.g. Substation-VoltageLevel-Bay-Switch-Measurement. Some Measurements represent quantities related to a particular sensor location in the network, e.g. a voltage transformer (VT) or potential transformer (PT) at a busbar or a current transformer (CT) at the bar between a breaker and an isolator. The sensing position is not captured in the PSR - Measurement association. Instead it is captured by the Measurement - Terminal association that is used to define the sensing location in the network topology. The location is defined by the connection of the Terminal to ConductingEquipment. If both a Terminal and PSR are associated, and the PSR is of type ConductingEquipment, the associated Terminal should belong to that ConductingEquipment instance. When the sensor location is needed both Measurement-PSR and Measurement-Terminal are used. The Measurement-Terminal association is never used alone.
The current state for a measurement. A state value is an instance of a measurement from a specific source. Measurements can be associated with many state values, each representing a different source for the measurement.
Measurement quality flags. Bits 0-10 are defined for substation automation in IEC 61850-7-3. Bits 11-15 are reserved for future expansion by that document. Bits 16-31 are reserved for EMS applications.
MeasurementValueSource describes the alternative sources updating a MeasurementValue. User conventions for how to use the MeasurementValueSource attributes are defined in IEC 61970-301.
A Model is a collection of data describing instances, objects or entities, real or computed. In the context of CIM the semantics of the data is defined by profiles. Hence a model can contain equipment data, power flow initial values, power flow results etc. The Model class describes the header content that is the same for the FullModel and the DifferenceModel. A Model is identified by an rdf:about attribute. The rdf:about attribute uniquely describe the model data and not the CIMXML document. A new rdf:about identification is generated for created documents only when the model data has changed. A repeated creation of documents from unchanged model data shall have the same rdf:about identification as previous document generated from the same model data.
NonConformLoad represents loads that do not follow a daily load change pattern and whose changes are not correlated with the daily load change pattern.
An active power (Y1-axis) and reactive power (Y2-axis) schedule (curves) versus time (X-axis) for non-conforming loads, e.g., large industrial load or power station service (where modelled).
A non linear shunt compensator has bank or section admittance values that differ. The attributes g, b, g0 and b0 of the associated NonlinearShuntCompensatorPoint describe the total conductance and admittance of a NonlinearShuntCompensatorPoint at a section number specified by NonlinearShuntCompensatorPoint.sectionNumber.
A non linear shunt compensator bank or section admittance value. The number of NonlinearShuntCompenstorPoint instances associated with a NonlinearShuntCompensator shall be equal to ShuntCompensator.maximumSections. ShuntCompensator.sections shall only be set to one of the NonlinearShuntCompenstorPoint.sectionNumber. There is no interpolation between NonlinearShuntCompenstorPoint-s.
A value and normal value associated with a specific kind of limit. The sub class value and normalValue attributes vary inversely to the associated OperationalLimitType.acceptableDuration (acceptableDuration for short). If a particular piece of equipment has multiple operational limits of the same kind (apparent power, current, etc.), the limit with the greatest acceptableDuration shall have the smallest limit value and the limit with the smallest acceptableDuration shall have the largest limit value. Note: A large current can only be allowed to flow through a piece of equipment for a short duration without causing damage, but a lesser current can be allowed to flow for a longer duration.
A set of limits associated with equipment. Sets of limits might apply to a specific temperature, or season for example. A set of limits may contain different severities of limit levels that would apply to the same equipment. The set may contain limits of different types such as apparent power and current limits or high and low voltage limits that are logically applied together as a set.
Different from LimIEEEOEL, LimOEL2 has a fixed pickup threshold and reduces the excitation set-point by means of a non-windup integral regulator. Irated is the rated machine excitation current (calculated from nameplate conditions: Vnom, Pnom, CosPhinom).
The over excitation limiter model is intended to represent the significant features of OELs necessary for some large-scale system studies. It is the result of a pragmatic approach to obtain a model that can be widely applied with attainable data from generator owners. An attempt to include all variations in the functionality of OELs and duplicate how they interact with the rest of the excitation systems would likely result in a level of application insufficient for the studies for which they are intended. Reference: IEEE OEL 421.5-2005, 9.
Field voltage or current overexcitation limiter designed to protect the generator field of an AC machine with automatic excitation control from overheating due to prolonged overexcitation.
Power factor or VAr controller type 1 function block whose behaviour is described by reference to a standard model or by definition of a user-defined model.
Power factor or VAr controller type 2 function block whose behaviour is described by reference to a standard model or by definition of a user-defined model.
Power factor / reactive power regulator. This model represents the power factor or reactive power controller such as the Basler SCP-250. The controller measures power factor or reactive power (PU on generator rated power) and compares it with the operator’s set point. [Footnote: Basler SCP-250 is an example of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of this product.]
IEEE PF controller type 2 which is a summing point type controller making up the outside loop of a two-loop system. This controller is implemented as a slow PI type controller. The voltage regulator forms the inner loop and is implemented as a fast controller. Reference: IEEE 421.5-2005, 11.4.
IEEE VAR controller type 2 which is a summing point type controller. It makes up the outside loop of a two-loop system. This controller is implemented as a slow PI type controller, and the voltage regulator forms the inner loop and is implemented as a fast controller. Reference: IEEE 421.5-2005, 11.5.
A transformer phase shifting tap model that controls the phase angle difference across the power transformer and potentially the active power flow through the power transformer. This phase tap model may also impact the voltage magnitude.
Describes the tap model for an asymmetrical phase shifting transformer in which the difference voltage vector adds to the in-phase winding. The out-of-phase winding is the transformer end where the tap changer is located. The angle between the in-phase and out-of-phase windings is named the winding connection angle. The phase shift depends on both the difference voltage magnitude and the winding connection angle.
Describes a tap changer with a linear relation between the tap step and the phase angle difference across the transformer. This is a mathematical model that is an approximation of a real phase tap changer. The phase angle is computed as stepPhaseShiftIncrement times the tap position. The voltage magnitude of both sides is the same.
The non-linear phase tap changer describes the non-linear behaviour of a phase tap changer. This is a base class for the symmetrical and asymmetrical phase tap changer models. The details of these models can be found in IEC 61970-301.
Describes a symmetrical phase shifting transformer tap model in which the voltage magnitude of both sides is the same. The difference voltage magnitude is the base in an equal-sided triangle where the sides corresponds to the primary and secondary voltages. The phase angle difference corresponds to the top angle and can be expressed as twice the arctangent of half the total difference voltage.
Set of spatial coordinates that determine a point, defined in the coordinate system specified in ‘Location.CoordinateSystem’. Use a single position point instance to describe a point-oriented location. Use a sequence of position points to describe a line-oriented object (physical location of non-point oriented objects like cables or lines), or area of an object (like a substation or a geographical zone - in this case, have first and last position point with the same values).
Instrument transformer (also known as Voltage Transformer) used to measure electrical qualities of the circuit that is being protected and/or monitored. Typically used as voltage transducer for the purpose of metering, protection, or sometimes auxiliary substation supply. A typical secondary voltage rating would be 120V.
A power system resource (PSR) can be an item of equipment such as a switch, an equipment container containing many individual items of equipment such as a substation, or an organisational entity such as sub-control area. Power system resources can have measurements associated.
An electrical device consisting of two or more coupled windings, with or without a magnetic core, for introducing mutual coupling between electric circuits. Transformers can be used to control voltage and phase shift (active power flow). A power transformer may be composed of separate transformer tanks that need not be identical. A power transformer can be modelled with or without tanks and is intended for use in both balanced and unbalanced representations. A power transformer typically has two terminals, but may have one (grounding), three or more terminals. The inherited association ConductingEquipment.BaseVoltage should not be used. The association from TransformerEnd to BaseVoltage should be used instead.
A PowerTransformerEnd is associated with each Terminal of a PowerTransformer. The impedance values r, r0, x, and x0 of a PowerTransformerEnd represents a star equivalent as follows. 1) for a two Terminal PowerTransformer the high voltage (TransformerEnd.endNumber=1) PowerTransformerEnd has non zero values on r, r0, x, and x0 while the low voltage (TransformerEnd.endNumber=2) PowerTransformerEnd has zero values for r, r0, x, and x0. Parameters are always provided, even if the PowerTransformerEnds have the same rated voltage. In this case, the parameters are provided at the PowerTransformerEnd which has TransformerEnd.endNumber equal to 1. 2) for a three Terminal PowerTransformer the three PowerTransformerEnds represent a star equivalent with each leg in the star represented by r, r0, x, and x0 values. 3) For a three Terminal transformer each PowerTransformerEnd shall have g, g0, b and b0 values corresponding to the no load losses distributed on the three PowerTransformerEnds. The total no load loss shunt impedances may also be placed at one of the PowerTransformerEnds, preferably the end numbered 1, having the shunt values on end 1. This is the preferred way. 4) for a PowerTransformer with more than three Terminals the PowerTransformerEnd impedance values cannot be used. Instead use the TransformerMeshImpedance or split the transformer into multiple PowerTransformers. Each PowerTransformerEnd must be contained by a PowerTransformer. Because a PowerTransformerEnd (or any other object) can not be contained by more than one parent, a PowerTransformerEnd can not have an association to an EquipmentContainer (Substation, VoltageLevel, etc).
Supports definition of one or more parameters of several different datatypes for use by proprietary user-defined models. This class does not inherit from IdentifiedObject since it is not intended that a single instance of it be referenced by more than one proprietary user-defined model instance.
IEEE 421.5-2005 type PSS1A power system stabilizer model. PSS1A is the generalized form of a PSS with a single input signal. Reference: IEEE 1A 421.5-2005, 8.1.
IEEE 421.5-2005 type PSS2B power system stabilizer model. This stabilizer model is designed to represent a variety of dual-input stabilizers, which normally use combinations of power and speed or frequency to derive the stabilizing signal. Reference: IEEE 2B 421.5-2005, 8.2.
IEEE 421.5-2005 type PSS3B power system stabilizer model. The PSS model PSS3B has dual inputs of electrical power and rotor angular frequency deviation. The signals are used to derive an equivalent mechanical power signal. This model has 2 input signals. They have the following fixed types (expressed in terms of InputSignalKind values): the first one is of rotorAngleFrequencyDeviation type and the second one is of generatorElectricalPower type. Reference: IEEE 3B 421.5-2005, 8.3.
IEEE 421.5-2005 type PSS4B power system stabilizer. The PSS4B model represents a structure based on multiple working frequency bands. Three separate bands, respectively dedicated to the low-, intermediate- and high-frequency modes of oscillations, are used in this delta omega (speed input) PSS. There is an error in the in IEEE 421.5-2005 PSS4B model: the Pe input should read -Pe. This implies that the input Pe needs to be multiplied by -1. Reference: IEEE 4B 421.5-2005, 8.4. Parameter details: This model has 2 input signals. They have the following fixed types (expressed in terms of InputSignalKind values): the first one is of rotorAngleFrequencyDeviation type and the second one is of generatorElectricalPower type.
Power system stabilizer type RQB. This power system stabilizer is intended to be used together with excitation system type ExcRQB, which is primarily used in nuclear or thermal generating units.
SiemensTM “H infinity” power system stabilizer with generator electrical power input. [Footnote: Siemens ‘H infinity’ power system stabilizers are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
Power system stabilizer part of an ABB excitation system. [Footnote: ABB excitation systems are an example of suitable products available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by IEC of these products.]
Dual input power system stabilizer, based on IEEE type 2, with modified output limiter defined by WECC (Western Electricity Coordinating Council, USA).
A tap changer that changes the voltage ratio impacting the voltage magnitude but not the phase angle across the transformer. Angle sign convention (general): Positive value indicates a positive phase shift from the winding where the tap is located to the other winding (for a two-winding transformer).
Reactive power rating envelope versus the synchronous machine’s active power, in both the generating and motoring modes. For each active power value there is a corresponding high and low reactive power limit value. Typically there will be a separate curve for each coolant condition, such as hydrogen pressure. The Y1 axis values represent reactive minimum and the Y2 axis values represent reactive maximum.
Specifies a set of equipment that works together to control a power system quantity such as voltage or flow. Remote bus voltage control is possible by specifying the controlled terminal located at some place remote from the controlling equipment. The specified terminal shall be associated with the connectivity node of the controlled point. The most specific subtype of RegulatingControl shall be used in case such equipment participate in the control, e.g. TapChangerControl for tap changers. For flow control, load sign convention is used, i.e. positive sign means flow out from a TopologicalNode (bus) into the conducting equipment. The attribute minAllowedTargetValue and maxAllowedTargetValue are required in the following cases: - For a power generating module operated in power factor control mode to specify maximum and minimum power factor values; - Whenever it is necessary to have an off center target voltage for the tap changer regulator. For instance, due to long cables to off shore wind farms and the need to have a simpler setup at the off shore transformer platform, the voltage is controlled from the land at the connection point for the off shore wind farm. Since there usually is a voltage rise along the cable, there is typical and overvoltage of up 3-4 kV compared to the on shore station. Thus in normal operation the tap changer on the on shore station is operated with a target set point, which is in the lower parts of the dead band. The attributes minAllowedTargetValue and maxAllowedTargetValue are not related to the attribute targetDeadband and thus they are not treated as an alternative of the targetDeadband. They are needed due to limitations in the local substation controller. The attribute targetDeadband is used to prevent the power flow from move the tap position in circles (hunting) that is to be used regardless of the attributes minAllowedTargetValue and maxAllowedTargetValue.
A shunt capacitor or reactor or switchable bank of shunt capacitors or reactors. A section of a shunt compensator is an individual capacitor or reactor. A negative value for bPerSection indicates that the compensator is a reactor. ShuntCompensator is a single terminal device. Ground is implied.
A facility for providing variable and controllable shunt reactive power. The SVC typically consists of a stepdown transformer, filter, thyristor-controlled reactor, and thyristor-switched capacitor arms. The SVC may operate in fixed MVar output mode or in voltage control mode. When in voltage control mode, the output of the SVC will be proportional to the deviation of voltage at the controlled bus from the voltage setpoint. The SVC characteristic slope defines the proportion. If the voltage at the controlled bus is equal to the voltage setpoint, the SVC MVar output is zero.
A collection of equipment for purposes other than generation or utilization, through which electric energy in bulk is passed for the purposes of switching or modifying its characteristics.
Shunt device, installed on the network, usually in the proximity of electrical equipment in order to protect the said equipment against transient voltage transients caused by lightning or switching activity.
The SvInjection reports the calculated bus injection minus the sum of the terminal flows. The terminal flow is positive out from the bus (load sign convention) and bus injection has positive flow into the bus. SvInjection may have the remainder after state estimation or slack after power flow calculation.
State variable for power flow. Load convention is used for flow direction. This means flow out from the TopologicalNode into the equipment is positive.
A generic device designed to close, or open, or both, one or more electric circuits. All switches are two terminal devices including grounding switches. The ACDCTerminal.connected at the two sides of the switch shall not be considered for assessing switch connectivity, i.e. only Switch.open, .normalOpen and .locked are relevant.
An electromechanical device that operates with shaft rotating synchronously with the network. It is a single machine operating either as a generator or synchronous condenser or pump.
All synchronous machine detailed types use a subset of the same data parameters and input/output variables. The several variations differ in the following ways: - the number of equivalent windings that are included; - the way in which saturation is incorporated into the model; - whether or not “subtransient saliency” (X’‘q not = X’’d) is represented. It is not necessary for each simulation tool to have separate models for each of the model types. The same model can often be used for several types by alternative logic within the model. Also, differences in saturation representation might not result in significant model performance differences so model substitutions are often acceptable.
Synchronous machine whose behaviour is described by reference to a standard model expressed in one of the following forms: - simplified (or classical), where a group of generators or motors is not modelled in detail; - detailed, in equivalent circuit form; - detailed, in time constant reactance form; or - by definition of a user-defined model. It is a common practice to represent small generators by a negative load rather than by a dynamic generator model when performing dynamics simulations. In this case, a SynchronousMachine in the static model is not represented by anything in the dynamics model, instead it is treated as an ordinary load. Parameter details: Synchronous machine parameters such as Xl, Xd, Xp etc. are actually used as inductances in the models, but are commonly referred to as reactances since, at nominal frequency, the PU values are the same. However, some references use the symbol L instead of X.
The electrical equations for all variations of the synchronous models are based on the SynchronousEquivalentCircuit diagram for the direct- and quadrature- axes. Equations for conversion between equivalent circuit and time constant reactance forms: Xd = Xad + Xl X’d = Xl + Xad x Xfd / (Xad + Xfd) X”d = Xl + Xad x Xfd x X1d / (Xad x Xfd + Xad x X1d + Xfd x X1d) Xq = Xaq + Xl X’q = Xl + Xaq x X1q / (Xaq + X1q) X”q = Xl + Xaq x X1q x X2q / (Xaq x X1q + Xaq x X2q + X1q x X2q) T’do = (Xad + Xfd) / (omega0 x Rfd) T”do = (Xad x Xfd + Xad x X1d + Xfd x X1d) / (omega0 x R1d x (Xad + Xfd) T’qo = (Xaq + X1q) / (omega0 x R1q) T”qo = (Xaq x X1q + Xaq x X2q + X1q x X2q) / (omega0 x R2q x (Xaq + X1q) Same equations using CIM attributes from SynchronousMachineTimeConstantReactance class on left of ‘=’ and SynchronousMachineEquivalentCircuit class on right (except as noted): xDirectSync = xad + RotatingMachineDynamics.statorLeakageReactance xDirectTrans = RotatingMachineDynamics.statorLeakageReactance + xad x xfd / (xad + xfd) xDirectSubtrans = RotatingMachineDynamics.statorLeakageReactance + xad x xfd x x1d / (xad x xfd + xad x x1d + xfd x x1d) xQuadSync = xaq + RotatingMachineDynamics.statorLeakageReactance xQuadTrans = RotatingMachineDynamics.statorLeakageReactance + xaq x x1q / (xaq+ x1q) xQuadSubtrans = RotatingMachineDynamics.statorLeakageReactance + xaq x x1q x x2q / (xaq x x1q + xaq x x2q + x1q x x2q) tpdo = (xad + xfd) / (2 x pi x nominal frequency x rfd) tppdo = (xad x xfd + xad x x1d + xfd x x1d) / (2 x pi x nominal frequency x r1d x (xad + xfd) tpqo = (xaq + x1q) / (2 x pi x nominal frequency x r1q) tppqo = (xaq x x1q + xaq x x2q + x1q x x2q) / (2 x pi x nominal frequency x r2q x (xaq + x1q) These are only valid for a simplified model where ‘Canay’ reactance is zero.
The simplified model represents a synchronous generator as a constant internal voltage behind an impedance (Rs + jXp) as shown in the Simplified diagram. Since internal voltage is held constant, there is no Efd input and any excitation system model will be ignored. There is also no Ifd output. This model should not be used for representing a real generator except, perhaps, small generators whose response is insignificant. The parameters used for the simplified model include: - RotatingMachineDynamics.damping (D); - RotatingMachineDynamics.inertia (H); - RotatingMachineDynamics.statorLeakageReactance (used to exchange jXp for SynchronousMachineSimplified); - RotatingMachineDynamics.statorResistance (Rs).
Synchronous machine detailed modelling types are defined by the combination of the attributes SynchronousMachineTimeConstantReactance.modelType and SynchronousMachineTimeConstantReactance.rotorType. Parameter details: The “p” in the time-related attribute names is a substitution for a “prime” in the usual parameter notation, e.g. tpdo refers to T’do. The parameters used for models expressed in time constant reactance form include: - RotatingMachine.ratedS (MVAbase); - RotatingMachineDynamics.damping (D); - RotatingMachineDynamics.inertia (H); - RotatingMachineDynamics.saturationFactor (S1); - RotatingMachineDynamics.saturationFactor120 (S12); - RotatingMachineDynamics.statorLeakageReactance (Xl); - RotatingMachineDynamics.statorResistance (Rs); - SynchronousMachineTimeConstantReactance.ks (Ks); - SynchronousMachineDetailed.saturationFactorQAxis (S1q); - SynchronousMachineDetailed.saturationFactor120QAxis (S12q); - SynchronousMachineDetailed.efdBaseRatio; - SynchronousMachineDetailed.ifdBaseType; - .xDirectSync (Xd); - .xDirectTrans (X’d); - .xDirectSubtrans (X’‘d); - .xQuadSync (Xq); - .xQuadTrans (X’q); - .xQuadSubtrans (X’‘q); - .tpdo (T’do); - .tppdo (T’‘do); - .tpqo (T’qo); - .tppqo (T’’qo); - .tc.
Describes behaviour specific to tap changers, e.g. how the voltage at the end of a line varies with the load level and compensation of the voltage drop by tap adjustment.
Defines the structure (in terms of location and direction) of the net interchange constraint for a control area. This constraint may be used by either AGC or power flow.
An electrically connected subset of the network. Topological islands can change as the current network state changes, e.g. due to: - disconnect switches or breakers changing state in a SCADA/EMS. - manual creation, change or deletion of topological nodes in a planning tool. Only energised TopologicalNode-s shall be part of the topological island.
For a detailed substation model a topological node is a set of connectivity nodes that, in the current network state, are connected together through any type of closed switches, including jumpers. Topological nodes change as the current network state changes (i.e., switches, breakers, etc. change state). For a planning model, switch statuses are not used to form topological nodes. Instead they are manually created or deleted in a model builder tool. Topological nodes maintained this way are also called ‘busses’.
A conducting connection point of a power transformer. It corresponds to a physical transformer winding terminal. In earlier CIM versions, the TransformerWinding class served a similar purpose, but this class is more flexible because it associates to terminal but is not a specialization of ConductingEquipment.
Turbine load controller model developed by WECC. This model represents a supervisory turbine load controller that acts to maintain turbine power at a set value by continuous adjustment of the turbine governor speed-load reference. This model is intended to represent slow reset ‘outer loop’ controllers managing the action of the turbine governor.
Simplified type UEL2 underexcitation limiter. This model can be derived from UnderexcLimIEEE2. The limit characteristic (look -up table) is a single straight-line, the same as UnderexcLimIEEE2 (see Figure 10.4 (p 32), IEEE 421.5-2005 Section 10.2).
Type UEL1 model which has a circular limit boundary when plotted in terms of machine reactive power vs. real power output. Reference: IEEE UEL1 421.5-2005, 10.1.
Type UEL2 underexcitation limiter which has either a straight-line or multi-segment characteristic when plotted in terms of machine reactive power output vs. real power output. Reference: IEEE UEL2 421.5-2005, 10.2 (limit characteristic lookup table shown in Figure 10.4 (p 32)).
IEEE voltage adjuster which is used to represent the voltage adjuster in either a power factor or VAr control system. Reference: IEEE 421.5-2005, 11.1.
Terminal voltage transducer and load compensator as defined in IEEE 421.5-2005, 4. This model is common to all excitation system models described in the IEEE Standard. Parameter details: If Rc and Xc are set to zero, the load compensation is not employed and the behaviour is as a simple sensing circuit. If all parameters (Rc, Xc and Tr) are set to zero, the standard model VCompIEEEType1 is bypassed. Reference: IEEE 421.5-2005 4.
Terminal voltage transducer and load compensator as defined in IEEE 421.5-2005, 4. This model is designed to cover the following types of compensation: reactive droop; transformer-drop or line-drop compensation; reactive differential compensation known also as cross-current compensation. Reference: IEEE 421.5-2005, 4.
Describes the translation of a set of values into a name and is intendend to facilitate custom translations. Each ValueAliasSet has a name, description etc. A specific Measurement may represent a discrete state like Open, Closed, Intermediate etc. This requires a translation from the MeasurementValue.value number to a string, e.g. 0->‘Invalid’, 1->‘Open’, 2->‘Closed’, 3->‘Intermediate’. Each ValueToAlias member in ValueAliasSet.Value describe a mapping for one particular value to a name.
Layers are typically used for grouping diagram objects according to themes and scales. Themes are used to display or hide certain information (e.g., lakes, borders), while scales are used for hiding or displaying information depending on the current zoom level (hide text when it is too small to be read, or when it exceeds the screen size). This is also called de-cluttering. CIM based graphics exchange supports an m:n relationship between diagram objects and layers. The importing system shall convert an m:n case into an appropriate 1:n representation if the importing system does not support m:n.
A collection of equipment at one common system voltage forming a switchgear. The equipment typically consists of breakers, busbars, instrumentation, control, regulation and protection devices as well as assemblies of all these.
Operational limit applied to voltage. The use of operational VoltageLimit is preferred instead of limits defined at VoltageLevel. The operational VoltageLimits are used, if present.
Parent class supporting relationships to wind turbines type 3 and type 4 and wind plant IEC and user-defined wind plants including their control models.
The grid protection model includes protection against over- and under-voltage, and against over- and under-frequency. Reference: IEC 61400-27-1:2015, 5.6.6.
Parent class supporting relationships to wind turbines type 1 and type 2 and their control models. Generator model for wind turbine of type 1 or type 2 is a standard asynchronous generator model.
Parent class supporting relationships to IEC wind turbines type 1 and type 2 including their control models. Generator model for wind turbine of IEC type 1 or type 2 is a standard asynchronous generator model. Reference: IEC 61400-27-1:2015, 5.5.2 and 5.5.3.
An unordered enumeration of phase identifiers. Allows designation of phases for both transmission and distribution equipment, circuits and loads. The enumeration, by itself, does not describe how the phases are connected together or connected to ground. Ground is not explicitly denoted as a phase. Residential and small commercial loads are often served from single-phase, or split-phase, secondary circuits. For the example of s12N, phases 1 and 2 refer to hot wires that are 180 degrees out of phase, while N refers to the neutral wire. Through single-phase transformer connections, these secondary circuits may be served from one or two of the primary phases A, B, and C. For three-phase loads, use the A, B, C phase codes instead of s12N. The integer values are from IEC 61968-9 to support revenue metering applications.
The unit multipliers defined for the CIM. When applied to unit symbols, the unit symbol is treated as a derived unit. Regardless of the contents of the unit symbol text, the unit symbol shall be treated as if it were a single-character unit symbol. Unit symbols should not contain multipliers, and it should be left to the multiplier to define the multiple for an entire data type. For example, if a unit symbol is ‘m2Pers’ and the multiplier is ‘k’, then the value is k(m**2/s), and the multiplier applies to the entire final value, not to any individual part of the value. This can be conceptualized by substituting a derived unit symbol for the unit type. If one imagines that the symbol ‘Þ’ represents the derived unit ‘m2Pers’, then applying the multiplier ‘k’ can be conceptualized simply as ‘kÞ’. For example, the SI unit for mass is ‘kg’ and not ‘g’. If the unit symbol is defined as ‘kg’, then the multiplier is applied to ‘kg’ as a whole and does not replace the ‘k’ in front of the ‘g’. In this case, the multiplier of ‘m’ would be used with the unit symbol of ‘kg’ to represent one gram. As a text string, this violates the instructions in IEC 80000-1. However, because the unit symbol in CIM is treated as a derived unit instead of as an SI unit, it makes more sense to conceptualize the ‘kg’ as if it were replaced by one of the proposed replacements for the SI mass symbol. If one imagines that the ‘kg’ were replaced by a symbol ‘Þ’, then it is easier to conceptualize the multiplier ‘m’ as creating the proper unit ‘mÞ’, and not the forbidden unit ‘mkg’.
The derived units defined for usage in the CIM. In some cases, the derived unit is equal to an SI unit. Whenever possible, the standard derived symbol is used instead of the formula for the derived unit. For example, the unit symbol Farad is defined as ‘F’ instead of ‘CPerV’. In cases where a standard symbol does not exist for a derived unit, the formula for the unit is used as the unit symbol. For example, density does not have a standard symbol and so it is represented as ‘kgPerm3’. With the exception of the ‘kg’, which is an SI unit, the unit symbols do not contain multipliers and therefore represent the base derived unit to which a multiplier can be applied as a whole. Every unit symbol is treated as an unparseable text as if it were a single-letter symbol. The meaning of each unit symbol is defined by the accompanying descriptive text and not by the text contents of the unit symbol. To allow the widest possible range of serializations without requiring special character handling, several substitutions are made which deviate from the format described in IEC 80000-1. The division symbol ‘/’ is replaced by the letters ‘Per’. Exponents are written in plain text after the unit as ‘m3’ instead of being formatted as ‘m’ with a superscript of 3 or introducing a symbol as in ‘m^3’. The degree symbol ‘°’ is replaced with the letters ‘deg’. Any clarification of the meaning for a substitution is included in the description for the unit symbol. Non-SI units are included in list of unit symbols to allow sources of data to be correctly labelled with their non-SI units (for example, a GPS sensor that is reporting numbers that represent feet instead of meters). This allows software to use the unit symbol information correctly convert and scale the raw data of those sources into SI-based units. The integer values are used for harmonization with IEC 61850.