Time-coupled constraints

Generator constraints

Generators have physical and mechanical constraints that can be taken in account by the RAO to ensure a more realistic behavior.

To see the mathematical formulation of these constraints, please refer to the dedicated linear problem page.

Lead time

The lead time corresponds to the time elapsed between the moment when the generator gets a start-up order and the moment its power reaches it minimal operational power (\(P_{\min}\)).

Lag time

The lag time corresponds to the time required by the generator to reach complete shutdown from its \(P_{\min}\)

Power gradients

When operated above its \(P_{\min}\), a generator can be restricted by power gradients that limit the amount of MW its power can vary between two consecutive timestamps. These gradients can be defined upward and/or downward.

Shut Down allowed

This is a boolean to indicate if a generator can be shutdown. If no value is defined, value will be set to true, meaning that the generator can be shutdown.

Start Up Allowed

This is a boolean to indicate if a generator can be started up from standstill. If no value is defined, value will be set to true, meaning that generator can be started up.

JSON API

Generator constraints

Field name	Type	Status	Unit	Description
generatorId	string	Mandatory	-	Id of the generator on which the constraints apply.
leadTime	number	Optional	hours	Lead time of the generator, in hours. Must be positive.
lagTime	number	Optional	hours	Lag time of the generator, in hours. Must be positive.
upwardPowerGradient	number	Optional	MW/h	Upward power gradient for the generator’s power variation, in MW/h. Must be positive.
downwardPowerGradient	number	Optional	MW/h	Downward power gradient for the generator’s power variation, in MW/h. Must be negative.
isShutDownAllowed	boolean	Optional	-	Indicate if RA RD can be shutdown. Default value : true
isStartUpAllowed	boolean	Optional	-	Indicates if RA RD can be started up . Default value : true

Comprehensive example

{
  "type": "OpenRAO Time-Coupled Constraints",
  "version": "1.0",
  "generatorConstraints": [
    {
      "generatorId": "generator-1",
      "leadTime": 1.15,
      "lagTime": 2.0,
      "upwardPowerGradient": 100.0,
      "downwardPowerGradient": -50.0,
      "shutDownAllowed": false
    },
    {
      "generatorId": "generator-2"
    },
    {
      "generatorId": "generator-3",
      "leadTime": 0.5,
      "lagTime": 4.0,
      "downwardPowerGradient": -1000.0,
      "shutDownAllowed": true,
      "startUpAllowed": false
    }
  ]
}

Import

TimeCoupledConstraints timeCoupledConstraints = JsonTimeCoupledConstraints.read(getClass().getResourceAsStream("/time-coupled-constraints.json"));

Import Time-Coupled Constraints JSON from ICS data

// read ICS data
InputStream staticIcs = new FileInputStream("path/to/ics/static.csv");
InputStream seriesIcs = new FileInputStream("path/to/ics/series.csv");
InputStream gskIcs = new FileInputStream("path/to/ics/gsk.csv");
IcsData icsData = new IcsDataImporter.read(staticIcs, seriesIcs, gskIcs);

// Create Generator Constraints
Set<GeneratorConstraints> generatorConstraintsSet = new HashSet<>();
TimeCoupledConstraints timeCoupledConstraints = new TimeCoupledConstraints();
// Warning: in exemple we use a default generator id per node
icsData.getRedispatchingActions().forEach(raId -> generatorConstraintsSet.addAll(icsData.createGeneratorConstraints(raId, getDefaultGeneratorIdPerNode(raId))));
generatorConstraintsSet.forEach(constraint -> timeCoupledConstraints.addGeneratorConstraints(constraint));

// Write Time-Coupled Constraints JSON
OutputStream outputStream = Files.newOutputStream(Path.of("output.json"));
JsonTimeCoupledConstraints.write(timeCoupledConstraints, outputStream);
TimeCoupledConstraints timeCoupledConstraints = JsonTimeCoupledConstraints.read(icsData);