Monitoring#

CASTOR has a monitoring module that can be used apart from the RAO to monitor Angles and/or Voltages:

Introduction#

In the OpenRAO CRAC, the user can define angle or/and voltage constraints on network elements.
These are constraints that ensure that the angle/voltage values on given network elements do not exceed a given threshold.
OpenRAO allows modelling these constraints in VoltageCnec and AngleCnec objects.
However, modelling the impact of remedial actions on angle/voltage values is highly complex and non-linear. This is why CASTOR does not inherently support angle/voltage constraints.
The Monitoring package allows monitoring angle/voltage values after a RAO has been run.

Monitoring

The Java API#

You can easily call the monitoring module using the JAVA API:

Build a MonitoringInput object using the MonitoringInputBuilder:

For angle monitoring :

MonitoringInput monitoringInput = new MonitoringInput.MonitoringInputBuilder().withCrac(crac).withNetwork(network).withRaoResult(raoResult).withPhysicalParameter(PhysicalParameter.ANGLE).withScalableZonalData(scalableZonalData).build();

For voltage monitoring :

MonitoringInput monitoringInput = new MonitoringInput.MonitoringInputBuilder().withCrac(crac).withNetwork(network).withRaoResult(raoResult).withPhysicalParameter(PhysicalParameter.VOLTAGE).build();

With:

PhysicalParameter.VOLTAGE to start voltage monitoring and PhysicalParameter.ANGLE to start angle monitoring
crac: the CRAC object used for the RAO, and containing VoltageCnecs/ AngleCnecs to be monitored.
network: the network to be monitored.
raoResult: the RaoResult object containing selected remedial actions (that shall be applied on the network before monitoring angle/voltage values)
scalableZonalData for redispatching in case of angle monitoring

Run the monitoring algorithm using the constructed object’s following method:

public RaoResult runAngleAndUpdateRaoResult(String loadFlowProvider, LoadFlowParameters loadFlowParameters, int numberOfLoadFlowsInParallel, monitoringInput)

With:

loadFlowProvider: the name of the load-flow computer to use. This should refer to a PowSyBl load flow provider implementation
loadFlowParameters: the PowSyBl LoadFlowParameters object to configure load-flow computation.
numberOfLoadFlowsInParallel: the number of contingencies to monitor in parallel, allowing a maximum utilization of your computing resources (set it to your number of available CPUs).
monitoringInput as built above in step 1.

Here is a complete example while augmenting rao result by voltage monitoring result then augmenting the outcome by angle monitoring result:

Crac crac = ...
Network network = ...
RaoResult raoResult = Rao.find(...).run(...)
LoadFlowParameters loadFlowParameters = ..
        
MonitoringInput voltageMonitoringInput = new MonitoringInput.MonitoringInputBuilder().withCrac(crac).withNetwork(network).withRaoResult(raoResult).withPhysicalParameter(PhysicalParameter.VOLTAGE).build();
RaoResult raoResultWithVoltageMonitoring = Monitoring.runVoltageAndUpdateRaoResult("OpenLoadFlow", loadFlowParameters, 2, voltageMonitoringInput);

MonitoringInput angleMonitoringInput = new MonitoringInput.MonitoringInputBuilder().withCrac(crac).withNetwork(network).withRaoResult(raoResultWithVoltageMonitoring).withPhysicalParameter(PhysicalParameter.ANGLE).withScalableZonalData(scalableZonalData).build();
RaoResult raoResultWithVoltageAndAngleMonitoring = Monitoring.runAngleAndUpdateRaoResult("OpenLoadFlow", loadFlowParameters, 2, angleMonitoringInput);

The monitoring result#

The method presented above generates a new RAO result object, which is equivalent to the initial one, augmented by the relevant results of the angle monitoring or voltage monitoring :

The computation status of the RAO is updated
The activated network actions are updated
The angle & margin values for angle CNECs are updated in case of angle monitoring
The voltage & margin values for voltage CNECs are updated in case of voltage monitoring

The monitoring algorithm#

Here is a detailed description of how the monitoring algorithm operates:

Apply optimal preventive remedial actions from RaoResult on the network
From the CRAC, get the set of states on which AngleCnecs/VoltageCnecs exist
For each of these states, monitor angles/voltages:
- Use a new copy of the network
- If the state is not preventive,
  - apply the contingency on the network
  - from the RaoResult, apply on the network the optimal remedial actions decided by the RAO (automatic and curative)
- Compute load-flow
  - If it diverges, return the following content for this state, then move on to the next state:
    - If PhysicalParameter is ANGLE : the angles of the angle CNECs equal to NaN
    - If PhysicalParameter is Voltage : the max and min values of the voltage CNECs equal to NaN
    - no applied remedial actions
    - status FAILURE
- Compute the angles/voltages for all angle/voltage CNECs (1) :
  - If PhysicalParameter is ANGLE: angle values are the maximum phase difference between the 2 voltage levels Angle in degrees = 180 / pi * (max(angle on buses of exporting voltage level) - min(angle on buses of importing voltage level))
  - If PhysicalParameter is VOLTAGE: voltage values are the min and max voltages on the voltage level buses
- Compare the angles/voltages to their thresholds.
- Compute and save each cnec security status (SECURE, HIGH_CONSTRAINT, LOW_CONSTRAINT, HIGH_AND_LOW_CONSTRAINTS, FAILURE) depending on the position of the angle/voltage value(s) regarding the Angle/Voltage Thresholds
- For the Angle/Voltage Cnecs that have an angle/voltage overshoot (negative margin), get the associated remedial actions
  - If the Angle/Voltage Cnec has no associated RA, then the constraint cannot be remedied: move on to the next Angle/Voltage Cnec.
  - If the state is preventive, do not apply any PRA (it would be incoherent with the RAO results). Move on to the next state.
  - For every RA:
    - If the remedial action is not a network action, do not apply it (if it’s a RangeAction, we cannot know which set-point to use). Move on to the next RA.
    - If the RA is a network action, apply it on the network (2).
- If PhysicalParameter is ANGLE and there is any injection-set-point RA applied, create and apply the re-dispatch that shall compensate the loss of generation / load (3):
  - The amount of power to re-dispatch is the net sum (generation - load) of power generations & loads affected by the RAs, before changing the set-points
  - Exclude from the re-dispatching all the generators & loads that were modified by an injection-set-point RA, since they should not be affected
- If no RA was applied, keep Cnec results from (4) and move on to the next state
- If any RA was applied, recompute the load-flow
  - If it diverges, return the following content for this state, then move on to the next state:
    - the angles of the Angle/Voltage Cnecs equal to what was computed in step (1)
    - no applied remedial actions
    - security FAILURE
  - If it converges Re-compute all angle/voltage values and create a Cnec result, with updated angles/voltages, list of applied remedial actions in (2), and new cnec status after comparing the new angle/voltage value(s) to their thresholds
Assemble all the Angle/Voltage Cnec results in one overall result

Monitoring algorithm

The output logs#

In the logs, the start and end of different steps are logged:

Start and end of the ‘angle/voltage’ monitoring algorithm
Start and end of the monitoring of each state (preventive or post-contingency)
Start and end of each load-flow computation

Also, the following information is logged:

Applied remedial actions to relieve ‘angle/voltage’ constraints
At the end of each state monitoring, the list of remaining ‘angle/voltage’ constraints
At the end of the monitoring algorithm, the list of remaining ‘angle/voltage constraints

Example 1 - ANGLE Monitoring:
In this example, a curative constraint (after contingency “Co-1”) induces the implementation of a CRA, but this CRA is not enough to solve the constraint.

INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- ANGLE monitoring [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Using base network 'urn:uuid:4f4a3f29-6892-49ea-bfc1-92051973c799+urn:uuid:9e7050a8-960b-4e1a-8e34-7f56bc2b2a7b' on variant 'InitialState'
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'ANGLE' Monitoring at state 'Co-1 - curative' [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Applied the following remedial action(s) in order to reduce constraints on CNEC "AngleCnec1": RA-1
INFO  c.p.o.commons.logs.RaoBusinessLogs - Redispatching 108.0 MW in BE [start]
WARN  c.p.o.commons.logs.RaoBusinessWarns - Redispatching failed: asked=108.0 MW, applied=0.0 MW
INFO  c.p.o.commons.logs.RaoBusinessLogs - Redispatching 108.0 MW in BE [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Redispatching 150.0 MW in NL [start]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Redispatching 150.0 MW in NL [end]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'ANGLE' Monitoring at state 'Co-1 - curative' [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Some ANGLE Cnecs are not secure:
INFO  c.p.o.commons.logs.RaoBusinessLogs - AngleCnec AngleCnec1 (with importing network element _d77b61ef-61aa-4b22-95f6-b56ca080788d and exporting network element _8d8a82ba-b5b0-4e94-861a-192af055f2b8) at state Co-1 - curative has an angle of 5°.
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'ANGLE' Monitoring at state 'Co-2 - curative' [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'ANGLE' Monitoring at state 'Co-2 - curative' [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - All ANGLE Cnecs are secure.
INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- ANGLE monitoring [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Some ANGLE Cnecs are not secure:
INFO  c.p.o.commons.logs.RaoBusinessLogs - AngleCnec AngleCnec1 (with importing network element _d77b61ef-61aa-4b22-95f6-b56ca080788d and exporting network element _8d8a82ba-b5b0-4e94-861a-192af055f2b8) at state Co-1 - curative has an angle of 5°.

Example 2 - VOLTAGE Monitoring:
In this example, a constraint exists in preventive (it cannot be solved because OpenRAO cannot implement PRAs to solve voltage constraints), and another one in curative (but implementing the CRA does not solve it).

INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- VOLTAGE monitoring [start]
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'preventive' [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
WARN  c.p.o.commons.logs.RaoBusinessWarns - VOLTAGE Cnec vcPrev is constrained in preventive state, it cannot be secured.
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'preventive' [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Some VOLTAGE Cnecs are not secure:
INFO  c.p.o.commons.logs.RaoBusinessLogs - Network element VL1 at state preventive has a min voltage of 400 kV and a max voltage of 400 kV.
INFO  c.p.o.commons.logs.TechnicalLogs - Using base network 'phaseShifter' on variant 'InitialState'
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'co - curative' [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Applied the following remedial action(s) in order to reduce constraints on CNEC "vc": Open L1 - 2
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'co - curative' [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Some VOLTAGE Cnecs are not secure:
INFO  c.p.o.commons.logs.RaoBusinessLogs - Network element VL1 at state co - curative has a min voltage of 400 kV and a max voltage of 400 kV.
INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- VOLTAGE monitoring [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Some VOLTAGE Cnecs are not secure:
INFO  c.p.o.commons.logs.RaoBusinessLogs - Network element VL1 at state co - curative has a min voltage of 400 kV and a max voltage of 400 kV.
INFO  c.p.o.commons.logs.RaoBusinessLogs - Network element VL1 at state preventive has a min voltage of 400 kV and a max voltage of 400 kV.

Example 3 - VOLTAGE Monitoring:
In this example, a curative constraint (after contingency “co”) is solved by a CRA.

INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- VOLTAGE monitoring [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Using base network 'phaseShifter' on variant 'InitialState'
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'co - curative' [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - Applied the following remedial action(s) in order to reduce constraints on CNEC "vc": Close L1 - 1
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [start]
INFO  c.p.o.commons.logs.TechnicalLogs - Load-flow computation [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - -- 'VOLTAGE' Monitoring at state 'co - curative' [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - All VOLTAGE Cnecs are secure.
INFO  c.p.o.commons.logs.RaoBusinessLogs - ----- VOLTAGE monitoring [end]
INFO  c.p.o.commons.logs.RaoBusinessLogs - All VOLTAGE Cnecs are secure.