Network modifications#

The powsybl-iidm-modification module gathers classes and methods used to modify the network easily.
Each modification must first be created with the right attributes or parameters and then applied on the network.
A NetworkModification offers a method to check whether or not its application would have an impact on the given network.

Scaling#

TODO

Topology modifications#

Powsybl provides classes that can be used to easily modify the topology of the network. This includes: the creation of network elements with automatic creation of switches with respect to the topology of the voltage level, the removal of network elements and their switches, the creation of T-pieces when connecting a line to another line, and the connection of a voltage level to a line. All these classes rely on a builder to create the modification and then apply it on the network.

Naming strategy#

The naming strategy aims at clarifying and facilitating the naming of the different network elements created via the different com.powsybl.iidm.modification.NetworkModification classes. Based on the name of the network element the user wishes to create (a VoltageLevel, a BranchFeederBay, etc.), all the other elements created during the NetworkModification will be given a name using this name as baseline and prefixes/suffixes according to the naming strategy chosen by the user. The naming strategy can be either the default one com.powsybl.iidm.modification.topology.DefaultNamingStrategy or a new implementation of the NamingStrategy interface.

Default naming strategy#

Default naming strategy is used if no other naming strategy is specified. The DefaultNamingStrategy implements a simple naming convention following the pattern: base name + separator + element type + optional index. The default implementation uses underscores as separators and appends element types and indices when necessary to ensure unique naming.

Custom strategies#

Other Naming strategies can be implemented based on the NamingStrategy interface. This allows for organization-specific naming conventions, different separator characters, or specialized formatting rules.

Naming strategies service loader#

The NamingStrategiesServiceLoader enables dynamic discovery of available naming strategies through Java’s ServiceLoader mechanism.

Network element creation#

Create feeder bay#

This class should be used to create any type of Injection. Injections are network elements with one terminal, such as loads, generators… It takes as input:

The InjectionAdder, already created with the right attributes. These attributes depend on the type of Injection.
The ID of the bus or busbar section (in BUS_BREAKER or NODE_BREAKER voltage levels respectively) to which the injection should be connected.
The position order of the injection: when adding an injection to a NODE_BREAKER voltage level, this integer will be used to create the ConnectablePosition extension that is used for visualization. It is optional for BUS_BREAKER voltage levels and will be ignored if specified.
Optionally, a name for the ConnectablePosition extension. By default, the ID of the injection will be used.
Optionally, the direction of the injection. It is also used to fill the ConnectablePosition extension. It indicates if the injection should be displayed at the top or at the bottom of the busbar section. By default, it is BOTTOM.
Optionally, a boolean logOrThrowIfIncorrectPositionOrder, that indicates what should happen if the position order is incorrect. This is mainly useful for voltage levels with NODE_BREAKER topology, since the ConnectablePosition extension is not created otherwise. The order position may be incorrect if
- it has already been taken on the busbar section,
- if it is higher or lower than the maximum or minimum available order positions for the busbar section,
- or if the order positions of other adjacent busbar sections do not allow any possible order positions. If the boolean is set to false, then the order position will be ignored and the ConnectablePostion extension will not be created, but the Injection will be created. If the boolean is set to true, the Injection will not be created, and either an exception will be thrown or a log will be returned, depending on the throwException boolean given when applying the modification.

When applying this modification on the network, the injection is added to the voltage level associated with the bus or busbar section. If the voltage level topology kind is BUS_BREAKER, then the injection is added to the voltage level and connected to the bus without any extension or switches. If the voltage level topology kind is NODE_BREAKER, then the injection is added to the voltage level and connected to the busbar section with a closed disconnector and a breaker. Additionally, open disconnectors will be created on every parallel busbar section. To know which busbar sections are parallel, the BusbarSectionPosition extension is used. The ConnectablePosition extension will also be created for the injection with the given data, unless there are no extensions yet in the voltage level.

Create Branch Feeder bays#

This class allows the creation of lines and two-winding transformers. It takes as input:

The BranchAdder, which should be created beforehand with the electrotechnical characteristics of the branch.
The ID of the bus or busbar section (in BUS_BREAKER or NODE_BREAKER voltage levels respectively) to which the side 1 of the branch should be connected.
The ID of the bus or busbar section (in BUS_BREAKER or NODE_BREAKER voltage levels respectively) to which the side 2 of the branch should be connected.
The position order of the branch on side 1. If the voltage level on side 1 of the branch is NODE_BREAKER, then this integer is used to create the ConnectablePosition extension for the branch that is used for visualization and for positioning connectables relative to each other.
It is optional for BUS_BREAKER voltage levels and will be ignored if specified.
The position order of the branch on side 2. It is the same but on the other side.
Optionally, a name for the feeder that will be added in the ConnectablePosition extension for side 1. This name is used for visualization. By default, it is the ID of the connectable.
Optionally, a name for the feeder for side 2.
Optionally, the direction of the feeder on side 1. This information will be used to fill the field in the ConnectablePosition extension and indicates the relative position of the branch with its busbar section on side 1. The default value is TOP.
Optionally, the direction on side 2.
Optionally, a boolean logOrThrowIfIncorrectPositionOrder1, that indicates what should happen if the position order is incorrect on side 1 of the branch. This is mainly useful for voltage levels with NODE_BREAKER topology, since the ConnectablePosition extension is not created otherwise. The order position may be incorrect if
- it has already been taken on the busbar section,
- if it is higher or lower than the maximum or minimum available order positions for the busbar section,
- or if the order positions of other adjacent busbar sections do not allow any possible order positions. If the boolean is set to false, then the order position will be ignored and the ConnectablePostion extension will not be created, but the Injection will be created. If the boolean is set to true, the Injection will not be created, and either an exception will be thrown or a log will be returned, depending on the throwException boolean given when applying the modification.
Optionally, a boolean logOrThrowIfIncorrectPositionOrder2, which is the same but for the side 2 of the branch.

When the modification is applied on the network, the branch is added to both voltage levels and connected on the bus or busbar section specified for both sides. For each side, if the voltage level topology kind is BUS_BREAKER, then the branch is added to the voltage level and connected to the bus without any extension or switches. If the voltage level topology kind is NODE_BREAKER, then the branch is added to the voltage level and connected to the busbar section with a closed disconnector and a breaker. Additionally, open disconnectors will be created on every parallel busbar section. To know which busbar sections are parallel, the BusbarSectionPosition extension is used. The ConnectablePosition extension will also be created for the branch with the given data, unless no extensions are already available in the voltage level.

Create Coupling Device#

This class allows the creation of coupling devices within a voltage level to couple some busbar sections. It takes as input:

The ID of one bus or busbar section (in BUS_BREAKER or NODE_BREAKER voltage levels respectively)
The ID of another bus or busbar section
Optionally, a prefix to be used when creating the switches of the coupling device.

Both buses or busbar sections must be within the same voltage level. If the voltage level has a BUS_BREAKER topology, then a new breaker is created between both buses.

If the voltage level has a NODE_BREAKER topology, then the coupling device is created between the two given buses or busbar sections as such: A closed disconnector will be created on both busbar sections. A closed breaker will be created between the two closed disconnectors. An open disconnector will be created on every parallel busbar section. To find the parallel busbar sections, the BusbarSectionPosition extension is used. The coupling device can be created between busbar sections that are parallel or not. If the two busbar sections are parallel and there are exactly two parallel busbar sections, then no open disconnectors are created.

Create Voltage Level Topology#

This class allows the creation of the topology inside a voltage level if it is meant to be symmetrical. The voltage level must already exist and does not have to be empty. When applied to a network, it will create buses or busbar sections in a matrix of aligned buses or busbar sections. In BUS_BREAKER topology, the buses will be separated by Breakers and in NODE_BREAKER, the switch type between each section must be specified. It takes as input:

The ID of the voltage level
The count of aligned buses or busbar sections. This integer indicates the “row” number of the matrix of buses or busbar sections.
The section count. This integer indicates the “column” number of the matrix of buses or busbar sections.
A list of switch kinds, for NODE_BREAKER voltage levels. This list indicates the switches that should be created between each busbar section. In the end, alignedBusesOrBusbarCount * sectionCount buses or busbar sections will be created, and they will be connected by section either by Breakers in BUS_BREAKER topology or by the switch specified by the list in NODE_BREAKER topology. The length of this list must be equal to the section count - 1.

Additional input can be provided:

The low-bus or busbar section index. This integer indicates the index of the first “row” of buses or busbar sections that should be created. If the voltage level is not empty, then the buses or busbar sections will be created starting from this index, so it can be below some already existing buses or busbar sections. By default, it is 1 (no bus or busbar section already in the voltage level).
The low-section index. This integer indicates the index of the first section of buses or busbar sections that should be created. If the voltage level is not empty, it is possible to create buses or busbar sections next to already existing ones. By default, it is 1 (no bus or busbar section already in the voltage level).
The bus or busbar section prefix ID is optional and used, if specified, as a prefix for the IDs of the created buses or busbar sections. This prefix is followed by the “row” index and the section number. If it is not specified, then the name of the voltage level is used as prefix.
The switch prefix ID is also optional.
The boolean connectExistingConnectables indicates whether existing connectables should be connected to the new topology if the busbar sections are created in a non-empty voltage level. If true, they will all be connected with an open switch of the same kind as the first switch that connects the connectable to the other busbar sections. If this boolean is true, the ConnectFeedersToBusbarSections modification will be called on the network.

Create Voltage Level Sections#

This class allows the creation of new busbar sections inside a voltage level in the NODE_BREAKER topology. The voltage level must already have been created, must already contains some busbar sections, and these busbar sections must have the extension BusbarSectionPosition, which indicate their position in the voltage level busbar sections matrix (busbarIndex and sectionIndex). When applied to a network, it will create new busbar sections before or after a reference busbar section.

It takes as input:

The ID of the reference busbar section
A boolean indicating if the new busbar section(s) must be created before(left) or after(right) the reference busbar section
A boolean indicating if a new busbar section must be created on all busbars, or only on the busbar of the reference busbar section
The switch kind of the new switch(es) that will be created left to the newly created busbar section :
- DISCONNECTOR means that only a DISCONNECTOR switch will be created
- BREAKER means that a BREAKER switch surrounded by two DISCONNECTOR switches will be created
The switch kind of the new switch(es) that will be created right to the newly created busbar section :
- DISCONNECTOR means that only a DISCONNECTOR switch will be created
- BREAKER means that a BREAKER switch surrounded by two DISCONNECTOR switches will be created
A boolean indicating if the new switches created left to the newly created busbar section(s) are fictitious
A boolean indicating if the new switches created right to the newly created busbar section(s) are fictitious
A boolean indicating if the new switches created left to the newly created busbar section(s) will be open
A boolean indicating if the new switches created right to the newly created busbar section(s) will be open
The switch prefix ID, used as a prefix for the IDs of the newly created switches.
The busbar section prefix ID, used as a prefix for the IDs of the newly created busbar sections. This prefix is followed by the busbar index and the section index, if the default naming strategy is used.

TODO: add single line diagrams

Connect feeders to busbar sections#

This class allows the connection of feeders to busbar sections in NODE_BREAKER topology. The ConnectablePosition extension must be available for each busbar section in the voltage level.

It takes as input:

A list of connectables that should be connected. None of them should be a BusbarSection.
A list of busbar sections. The connectables will be connected to these busbar sections if they are not already.
A boolean connectCouplingDevices indicating if the coupling devices of the voltage level should be connected to the busbar sections. If the busbar sections are not already connected on each side of the coupling device breaker, an open switch will be created.
A string couplingDeviceSwitchPrefixId that will be used, if the boolean connectCouplingDevices is true, in the naming strategy to determine the IDs of the new disconnectors.

When applied to a network, the network modification will loop through all the parallel busbar sections of each input busbar section to gather the switches that are connecting the feeders. Then, the feeders and coupling devices will be connected by a switch of the same kind as the first switch that connects the feeder to the other busbar sections. If all the feeders are already connected to the busbar sections, then the network modification will do nothing.

Let’s take an example. This is the voltage level before applying the modification:

If we apply the modification with both busbar sections, all the connectables and coupling devices, we will get:

If we want to only connect the two-winding transformers on busbar section bbs3, we can specify the right lists as input and we will get:

Network element removal#

The classes com.powsybl.iidm.modification.RemoveFeederBay, com.powsybl.iidm.modification.RemoveHvdcLine, com.powsybl.iidm.modification.RemoveVoltageLevel and com.powsybl.iidm.modification.RemoveSubstation allow to remove all types of elements from a network.

RemoveFeederBay#

This is the class to use to remove any Injection, Branch or Three-winding transformer. The builder should be used to create any instance of this class. Only the ID of the connectable to remove should be given as input. When applied to the network, the connectable will be removed, as well as all the switches connecting it to busbar sections. Note: Busbar sections are not allowed to be removed with this class.

RemoveHvdcLine#

This class should be used to remove a HVDC line. The input arguments are:

The ID of the HVDC line
If the HVDC line is an LCC, an optional list of IDs of the shunt compensators associated with this HVDC line that should also be removed. When applied to the network, the HVDC line is removed, as well as the two converter stations on each side and the switches connecting them to their voltage levels. If the list of shunt compensators is not empty, then they will also be removed along with their switches.

RemoveVoltageLevel#

This class is used to remove an entire voltage level. All the connectables, busbar sections, coupling devices of the voltage level are removed. The lines, two-winding transformers and three-winding transformers are also removed as well as their switches in other voltage levels. The builder to be used to initialize this class takes only the ID of the voltage level to be removed.

RemoveSubstation#

This class should be used to remove an entire substation. All the voltage levels of the substation with all their connectables are removed. The branches and three-winding transformers are also removed with their switches in the other substations. The builder takes the ID of the substation as input.

Moving a network element#

MoveFeederBay#

This class is used to move feeder bays of connectables (except BusOrBusBarSection connectables) from one place to another within a network.

This class allows to move a feeder bay from one busbar section to another within the network. The builder should be used to create any instance of this class. It takes as input:

The ID of the connectable whose feeder bay will be moved (connectableId). Note that BusOrBusBarSection connectables are not accepted.
The ID of the target bus or busbar section (targetBusOrBusBarSectionId) to which the feeder bay should be connected.
The ID of the target voltage level (targetVoltageLevelId) where the feeder bay will be moved to.
The terminal object that specifies which terminal of the connectable should be moved.

When the modification is applied on the network, the system identifies and updates all relevant switches and connections to move the feeder bay from its current position to the specified target place. This includes disconnecting from the original busbar section and reconnecting to the target busbar section. If the target voltage level topology kind is BUS_BREAKER, the connectable is connected to the target bus without additional switches. If the target voltage level topology kind is NODE_BREAKER, the appropriate disconnectors and breakers are created to connect the feeder bay to the target busbar section, maintaining the correct topology. This modification ensures that the connectivity of the network is preserved while moving the feeder bay to its new position.

Connect a line on a line or a voltage level on a line#

ConnectVoltageLevelOnLine#

TODO

RevertConnectVoltageLevelOnLine#

TODO

CreateLineOnLine#

TODO

RevertCreateLineOnLine#

TODO

ReplaceTeePointbyVoltageLevelOnLine#

TODO

Tripping#

Battery tripping#

TODO

Branch tripping#

TODO

Busbar section tripping#

TODO

Bus tripping#

TODO

Dangling line tripping#

TODO

Generator tripping#

TODO

Hvdc line tripping#

TODO

Line tripping#

TODO

Load tripping#

TODO

Shunt compensator tripping#

TODO

Static Var compensator tripping#

TODO

Switch tripping#

TODO

Three-winding transformer tripping#

TODO

Tie line tripping#

TODO

Two-winding transformer tripping#

TODO

Other modifications#

List#

This modification is used to apply a list of any Powsybl NetworkModification.

Class: NetworkModificationList

Area interchange#

This modification is used to update the target of an area interchange.

The target is in MW in load sign convention (negative for export, positive for import).
Providing Double.NaN removes the target.

Class: AreaInterchangeTargetModification

Battery#

This modification is used to update the target powers (active targetP and reactive targetV) of a battery.

Class: BatteryModification

Connection#

This modification is used to connect a network element to the closest bus or bus bar section.

It works on:

Connectable elements by connecting their terminals
HVDC lines, by connecting the terminals of their converter stations
Tie lines, by connecting the terminals of their underlying dangling lines

It is possible to specify a side of the element to connect. If no side is specified, the network modification will try to connect every side.

Class: ConnectableConnection

Dangling line#

This modification is used to update the active and reactive powers of the load part of a dangling line.

If relativeValue is set to true, then the new constant active power (P0) and reactive power (Q0) are set as the addition of the given values to the previous ones.
If relativeValue is set to false, then the new constant active power (P0) and reactive power (Q0) are updated to the new given values.

Class: DanglingLineModification

Disconnections#

Planned#

This modification is used to disconnect a network element from the bus or bus bar section to which it is currently connected. It should be used if the disconnection is planned. If it is not, UnplannedDisconnection should be used instead.

It works on:

Connectable elements.
HVDC lines, by disconnecting their converter stations
Tie lines, by disconnecting their underlying dangling lines

It is possible to specify a side of the element to connect. If no side is specified, the network modification will try to connect every side.

Class: PlannedDisconnection

Unplanned#

This modification is used to disconnect a network element from the bus or bus bar section to which it is currently connected. It should be used if the disconnection is unplanned. If it is not, PlannedDisconnection should be used instead.

It works on:

Connectable elements.
HVDC lines, by disconnecting their converter stations
Tie lines, by disconnecting their underlying dangling lines

It is possible to specify a side of the element to connect. If no side is specified, the network modification will try to connect every side.

Class: UnplannedDisconnection

Generator#

Modification#

This modification is used to apply a set of modifications on a generator.

The data to be updated are optional among:

minP, the minimum active power boundary in MW.
maxP, the maximum active power boundary in MW.
targetV, the target voltage value in kV.
targetQ, the target reactive power value in MVAR.
connected, the connection state of the generator terminal.
voltageRegulatorOn, to activate or deactivate the generator voltage regulator status. If true and the generator target voltage is not set then an acceptable value for the generator targetV is computed before activating.
The active power if targetP or deltaTargetP are given. An active power is determined by the new targetP if given, and if not then the deltaTargetP is considered instead and the new value of the generator targetP is the addition of the old generator value with the given delta target P value. Then, according to the given ignoreCorrectiveOperations parameter:
- If ignoreCorrectiveOperations is true, this determined active power is applied as the new generator target P value.
- If ignoreCorrectiveOperations is false, then the new active power will also depend on the limits and will be the minimum value between the generator maxP and the maximum value between the generator minP and the previously determined active power value. Besides, if the generator connection state has not been updated before within this NetworkModification then the generator is connected if necessary.

Class: GeneratorModification

Connection#

This modification is used to connect a given generator.

If the generator terminal is regulating then it will also set its target voltage if an acceptable value is found.

Class: ConnectGenerator

Set to local regulation#

This modification is used to set the generator regulating terminal to a local regulation.

The target voltage value is set to the same value for all the generators of the bus that are regulating locally. In case other generators are already regulating locally on the same bus, targetV value is determined by being the closest value to the voltage level nominal voltage among the regulating terminals. If no other generator is regulating on the same bus, targetV engineering unit value is adapted to the voltage level nominal voltage, but the per unit value remains the same.

Class:SetGeneratorToLocalRegulation

HVDC line#

This modification is used to modify a given HVDC line (and potentially its angle droop active power control extension).

Modify the HVDC line activePowerSetpoint if given, relatively to the existent activePowerSetpoint if relativeValue is true or as a replacement value if not.
Modify the convertersMode with the given one if set
Modify the angle droop active power control extension (if existing but will not crash if not found for the HVDC line):
- Enable or disable the AC emulation if acEmulationEnabled is provided
- Update the active power if p0 is provided
- Update the droop in MW/degree if droop is provided

Class: HvdcLineModification

Load#

Modification#

This modification updates the P and Q values of the load.

Class: LoadModification

Percent modification#

This modification is used to add or remove a percentage of the P and Q of the load. The percentage to add or remove for P and Q cannot be less than -100 (in percentage).

Class: PercentChangeLoadModification

Phase shifters#

Optimize tap modification#

This modification is used to find the optimal phase tap changer position of a given two-winding transformer phase shifter id.

A phase shifter optimization load flow is run with the configured load-flow-based-phase-shifter-optimizer to determine the optimal tap position.

Class: PhaseShifterOptimizeTap

Fixed tap modification#

This modification updates the phase tap changer of a given two-winding transformer phase shifter id.

It updates its tapPosition with the given value and set the phase tap changer as not regulating.

Class: PhaseShifterSetAsFixedTap

Shift tap modification#

This modification is used to update the phase tap changer of a given two-winding transformer phase shifter id.

It sets the phase tap changer as not regulating and updates its tapPosition by adjusting it with the given tapDelta applied on the current tap position. The resulting tap position is bounded by the phase tap changer lowest and highest possible positions.

Class: PhaseShifterShiftTap

Replace tie lines by lines#

This modification is used to replace all the tie lines of a network to simple lines built from the original tie line and its 2 dangline lines.

The two voltage levels are set from the tie line dangling lines terminal voltage levels (the first voltage level from the first dangling line and the second from the second one).
For each voltage level the topology kind is taken into account to create node (for NODE_BREAKER kind) or bus and connectable bus (for BUS_BREAKER kind)
The tie line id, name, r, x, b1, b2, g1, g2 are set in the new line
Active power limits, apparent power limits and current limits are set on each side of the line from the limits of the 2 dangling lines
Terminal active and reactive powers are set for both terminals from each dangling line active and reactive powers
Line properties are set from the merge of the tie line and its 2 dangling lines properties
Line aliases are set from the merge of the tie line and its 2 dangling lines aliases
If the tie line has a pairing key then it is added to the new line as a pairing key alias
The tie line and its dangling lines are removed from the network

Class: ReplaceTieLinesByLines

Shunt compensator#

This modification is used to (dis)connect a shunt compensator and/or change its section count in service.

If the modification connects the shunt compensator and its terminal is regulating then it will also set its target voltage if an acceptable value is found.

Class: ShuntCompensatorModification

Static var compensator#

This modification modifies the voltage and reactive power setpoints of a static var compensator, following a load convention.

Class: StaticVarCompensatorModification

Switch#

Close#

This modification is used to close a switch.

Class: CloseSwitch

Open#

This modification is used to open a switch.

Class: OpenSwitch

Transformers#

Three-winding transformers legs rated voltage#

This modification is used to modify the rated voltage of each leg of a three-winding transformer.

On each leg the new rated voltage is computed from the given common rated voltage multiplied by the ratio (leg old rated voltage / rated voltage of the three-winding transformer (the ratedU0 also used as nominal voltage) at the fictitious bus (in kV)).

Class: ThreeWindingsTransformerModification

Replace 1 three-winding transformer by 3 two-winding transformers#

This modification is used to replace all or a given list of ThreeWindingsTransformer by triplets of TwoWindingsTransformer.

For each ThreeWindingsTransformer to be replaced:

A new voltage level is created for the star node with nominal voltage of ratedU0.
Three TwoWindingsTransformers are created, one for each leg of the ThreeWindingsTransformer to transform.
The following attributes are copied from each leg to the new associated TwoWindingsTransformer:
- Electrical characteristics, ratio tap changers, and phase tap changers. No adjustments are required.
- Operational Loading Limits are copied to the non-star end of the two-winding transformers.
- Active and reactive powers at the terminal are copied to the non-star terminal of the two-winding transformer.
Aliases:
- Aliases for known CGMES identifiers (terminal, transformer end, ratio, and phase tap changer) are copied to the right TwoWindingsTransformer after adjusting the alias type.
- Aliases that are not mapped are recorded in the functional log.
Properties:
- Star bus voltage and angle are set to the bus created for the star node.
- The names of the operational limits are copied to the right TwoWindingsTransformer.
- The rest of the properties of the ThreeWindingsTransformer are transferred to all 3 TwoWindingsTransformer.
Extensions:
- Only IIDM extensions are copied: TransformerFortescueData, PhaseAngleClock, and TransformerToBeEstimated.
- CGMES extensions can not be copied, as they cause circular dependencies.
- Extensions that are not copied are recorded in the functional log.
All the controllers using any of the ThreeWindingsTransformer terminals as regulated terminal are updated.
New and removed equipment is recorded in the functional log.
Internal connections are created to manage the replacement.

Class: ReplaceThreeWindingsTransformersBy3TwoWindingsTransformers

Replace 3 two-winding transformers by 1 three-winding transformer#

This modification is used to replace all or a given list of TwoWindingsTransformer by ThreeWindingsTransformer.

In the list of TwoWindingsTransformer if only one of a triplet of TwoWindingsTransformer is given then the 3 TwoWindingsTransformer will be transformed to a ThreeWindingsTransformer.

Conditions to detect a triplet of TwoWindingsTransformer to transform:

BusbarSections and the three TwoWindingsTransformer are the only connectable equipment allowed in the voltage level associated with the star bus.
The three TwoWindingsTransformer must be connected to the star bus.
The star terminals of the two-winding transformers must not be regulated terminals for any controller.
Each TwoWindingsTransformer is well oriented if the star bus is located at the end 2.

Then a ThreeWindingsTransformer is created to replace them:

The following attributes are copied from each TwoWindingsTransformer to the new associated leg:
- Electrical characteristics, ratio tap changers, and phase tap changers. Adjustments are required if the TwoWindingsTransformer is not well oriented.
- Only the operational loading limits defined at the non-star end are copied to the leg.
- Active and reactive powers at the non-star terminal are copied to the leg terminal.
Aliases:
- Aliases for known CGMES identifiers (terminal, transformer end, ratio, and phase tap changer) are copied to the ThreeWindingsTransformer after adjusting the alias type.
- Aliases that are not mapped are recorded in the functional log.
Properties:
- Voltage and angle of the star bus are added as properties of the ThreeWindingsTransformer.
- Only the names of the transferred operational limits are copied as properties of the ThreeWindingsTransformer.
- All the properties of the first TwoWindingsTransformer are transferred to the ThreeWindingsTransformer, then those of the second that are not in the first, and finally, the properties of the third that are not in the first two.
- Properties that are not mapped are recorded in the functional log.
Extensions:
- Only IIDM extensions are copied: TransformerFortescueData, PhaseAngleClock, and TransformerToBeEstimated.
- CGMES extensions can not be copied, as they cause circular dependencies.
- Extensions that are not copied are recorded in the functional log.
All the controllers using any of the TwoWindingsTransformer terminals as regulated terminal are updated.
New and removed equipment is recorded in the functional log.
Internal connections are created to manage the replacement.

Class: Replace3TwoWindingsTransformersByThreeWindingsTransformers

Tap changers#

Phase tap changer position#

This modification is used to modify a phase tap changers tap position of a given PhaseTapChangerHolder (for two or three-winding transformer).

The new tap position can be either the one given in parameter or a relative position added to the existing one.
The PhaseTapChangerHolder can be from:

A two-winding transformers
A three-winding transformer with a single phase tap changer
A leg of a three-winding transformer

Class: PhaseTapPositionModification

Ratio tap changer position#

This modification is used to modify a ratio tap changers tap position of a given RatioTapChangerHolder (for two or three-winding transformer).

The RatioTapChangerHolder can be from:

A two-winding transformers
A three-winding transformer with a single phase tap changer
A leg of a three-winding transformer

Class: RatioTapPositionModification

VSC converter station#

This modification is used to modify the voltage and reactive power setpoints of a VSC converter station, following a generator convention.

Class: VscConverterStationModification