Getting started#

OpenLoadFlow sensitivity calculation engine implements PowSyBl core sensitivity API. Here is an example of Java code calculating generator active power to branch flow active power sensitivity for all lines of the IEEE 14 network:

    Network network = IeeeCdfNetworkFactory.create14();
    List<SensitivityFactor> factors = new ArrayList<>();
    for (Generator g : network.getGenerators()) {
        for (Line l : network.getLines()) {
            factors.add(new SensitivityFactor(SensitivityFunctionType.BRANCH_ACTIVE_POWER_1, l.getId(),
                                              SensitivityVariableType.INJECTION_ACTIVE_POWER, g.getId(), 
                                              false, ContingencyContext.all()));
        }
    }
    List<Contingency> contingencies = network.getLineStream().map(l -> Contingency.line(l.getId())).collect(Collectors.toList());
    SensitivityAnalysisParameters parameters = new SensitivityAnalysisParameters();
    SensitivityAnalysisResult result = SensitivityAnalysis.run(network, factors, contingencies, parameters);

As we can see in this example for each sensitivity factor that we want to compute we need to specify the variable type and the function type. Not all combinations of variable and function types are allowed / implemented in OpenLoadFlow. Some are supported only in DC mode, some others only in AC. Here is a table to summarize supported use cases:

Function \ Variable

INJECTION_ACTIVE_POWER

INJECTION_REACTIVE_POWER

TRANSFORMER_PHASE

BUS_TARGET_VOLTAGE

HVDC_LINE_ACTIVE_POWER*

TRANSFORMER_PHASE_1

TRANSFORMER_PHASE_2

TRANSFORMER_PHASE_3

BRANCH_ACTIVE_POWER_1

AC + DC

N/A

AC + DC

N/A

AC + DC

AC + DC

AC + DC

AC + DC

BRANCH_CURRENT_1

AC

AC

AC

AC

AC

AC

AC

AC

BRANCH_REACTIVE_POWER_1

N/A

AC

N/A

AC

N/A

N/A

N/A

N/A

BRANCH_ACTIVE_POWER_2

AC + DC

N/A

AC + DC

N/A

AC + DC

AC + DC

AC + DC

AC + DC

BRANCH_CURRENT_2

AC

AC

AC

AC

AC

AC

AC

AC

BRANCH_REACTIVE_POWER_2

N/A

AC

N/A

AC

N/A

N/A

N/A

N/A

BRANCH_ACTIVE_POWER_3

AC + DC

N/A

AC + DC

N/A

AC + DC

AC + DC

AC + DC

AC + DC

BRANCH_CURRENT_3

AC

AC

AC

AC

AC

AC

AC

AC

BRANCH_REACTIVE_POWER_3

N/A

AC

N/A

AC

N/A

N/A

N/A

N/A

BUS_VOLTAGE

N/A

AC

N/A

AC

N/A

N/A

N/A

N/A

BUS_REACTIVE_POWER

N/A

AC

N/A

AC

N/A

N/A

N/A

N/A

*HVDC_LINE_ACTIVE_POWER is used to compute the sensitivity according to the active power set point of the HVDC. That is why it is not supported for HVDCs that are in AC emulation mode: an exception is thrown if the user asks a sensitivity according to an HVDC link with AC emulation (and if hvdcAcEmulation parameter is enabled).

Input function types#

Branch sensitivity functions :#

BRANCH_ACTIVE_POWER_#, BRANCH_REACTIVE_POWER_# or BRANCH_CURRENT_# are associated to branch objects (lines, transformers, boundary lines, tie lines). The # index corresponding to the side of the studied branch.

  • If it is a line, a tie line, or a two windings transformer : The side is 1 or 2.

  • If it is a three windings transformer : The side is 1, 2 or 3 corresponding to the studied leg of the transformer.

  • If it is a boundary line : The side is 1 (network side) or 2 (boundary side). Note that if the boundary line is paired, only side 1 (network side) can be specified, and the sensitivity function is computed at the corresponding tie line side.

Bus sensitivity functions :#

BUS_VOLTAGE or BUS_REACTIVE_POWER are associated to the bus of the given network element.