This is a root class to provide common identification for all classes needing identification and naming attributes.

An AC electrical connection point to a piece of conducting equipment. Terminals are connected at physical connection points called connectivity nodes.

A two terminal and power conducting device of negligible impedance and length represented as zero impedance device that can be used to represent the conductor between connection points to substation conducting equipment on a substation bus.

Aggregates a set of line segments that are on the same tower, or in the same right-of-way, close enough that mutual coupling impedances between the lines need to be included in network analysis.

Describes the relationship of a line in a coupled group to the reference line in the group. (Reference line has a coupledLineNumber = 1.)

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 line segment is a conductor or combination of conductors, with consistent electrical characteristics along its length, building a single electrical system that carries alternating current between two points in the power system. The BaseVoltage at the two ends of a line segment 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. Line segment impedances can be either directly described in electrical terms or physical line detail can be provided from which impedances can be calculated. <b>Directly described impedances</b> For symmetrical, transposed three phase line segments, it is sufficient to use attributes of the line segment, which describe impedances and admittances for the entire length of the line segment. Additionally, line segment impedances can be computed by using line segment length and associated per length impedances. Unbalanced modeling of impedances is supported by the per length phase impedance matrix (PerLengthPhaseImpedance) in conjunction with phase-to-sequence number mapping supplied by either ACLineSegmentPhase or WirePosition. The sequence numbers are referenced by the row and column attributes of the per length phase impedance matrix. This method enables single-phase and two-phase line segments, and transpositions of phases, to be described using the same per length phase impedance matrix. The length of the line segment is used in the computation of total impedance values for the line segment. <b>Line detail characteristics</b> There are three approaches to providing line detail and all use WireAssembly to supply line positions: <ul> <li>Option 1 - WireAssembly supplies only line positions. ACLineSegmentPhase points to wire type and intraphase spacing and supplies the phase-to-sequence number mapping.</li> <li>Option 2 - WireAssembly supplies line position and, for each position, also supplies wire type and intraphase spacing. ACLineSegmentPhase supplies the phase-to-sequence number mapping.</li> <li>Option 3 - WireAssembly supplies line position and, for each position, also supplies wire type and intraphase spacing and phase. WireAssembly therefore supplies the phase-to-sequence number mapping and ACLineSegmentPhase is not needed.</li> </ul>

Represents a single wire of an alternating current line segment. A line segment phase represents one phase (or optionally the neutral) of an alternating current line segment. Under most circumstances there is not a line segment phase for the neutral. However, if a wire assembly is being used and it does not specify phase, a line segment phase must exist for each position in the assembly (including the neutral).

Combination of conducting material with consistent electrical characteristics, building a single electrical system, used to carry current between points in the power system.

A generic equivalent for an energy supplier on a transmission or distribution voltage level.

This class represents the zero sequence line mutual coupling.

Common type for per-length impedance electrical cataloguesimpedances.

Common type for per-length electrical catalogues describing line parameters.

Impedance and admittance parameters per unit length for n-wire unbalanced lines, in matrix form. The per length phase impedance matrix expresses impedance and admittance parameters per unit length for n-conductor unbalanced line segments. A phase impedance matrix contains both self impedances for each phase and mutual impedances between pairs of phases. The matrix is stored in symmetric lower triangular format where the diagonal entries represent self-impedances (and have the same value in row and column) and the off diagonal entries represent phase-to-phase impedances (and have different row and column values). The matrix can be use to express impedances for both non-coupled and coupled line segments. Coupled line segments share a single per length phase impedance matrix whose entries reflect the self and mutual impedances of all the phases of all the wires.

Sequence impedance and admittance parameters per unit length, for transposed linesline segments of 1, 2, or 3 phases. For 1-phase linesline segments, define x = x0 = xself. For 2-phase linesline segments, define x =xs xself -xm xmutual and x0 =xs xself +xm xmutual.

Impedance and conductance matrix element values. The diagonal elements are described by the elements having the same toPhase and fromPhase value and the off diagonal elements have different toPhase and fromPhase values. The matrix can also be stored in symmetric lower triangular format using the row and column attributes, which map to ACLineSegmentPhase.sequenceNumber. Per length phase impedance matrix entry describes impedance and conductance matrix element values for a specific row and column of the matrix. The phases to which each entry applies can be determined by means of the row and column attributes which bind to a sequence number provided in either ACLineSegmentPhase or WirePosition (which also specify phase). Due to physical symmetry that is reflected in the matrix, only the lower triangle of the matrix is populated with the row and column method. That is, the column attribute is always less than or equal to the row attribute.

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.

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.

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.

Voltage angle limit between two terminals. The association end OperationalLimitSet.Terminal defines one end and the host of the limit. The association end VoltageAngleLimit.AngleReferenceTerminal defines the reference terminal.

A control area power electronics unit. This class is needed so that alternate control area definitions may include the same power electronics unit. It should be noted that only one instance within a control area should reference a specific power electronics unit.

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 may 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.