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Version: 0.23.0

Protection Relays

Protection Relay Functions, Schemes, and Systems​

Each protection relay in the CIM model is implemented in a ProtectionRelayFunction, which is composed of a collection of Sensors, thresholds that determine the conditions that activate the relay, the time limits for each condition before activation, and the ProtectedSwitches to open when the relay is activated.

ProtectionRelayFunctions may be grouped into ProtectionRelaySchemes, each of which belong to a ProtectionRelaySystem. A ProtectionRelaySystem is a physical piece of equipment containing a suite of ProtectionRelayFunctions, such as a circuit breaker panel. They typically comprise two schemes: main and failsafe.

Here is a contrived example of such a system modelled using the Evolve SDK:

import com.zepben.evolve.cim.iec61970.base.auxiliaryequipment.CurrentTransformer;
import com.zepben.evolve.cim.iec61970.base.domain.UnitSymbol;
import com.zepben.evolve.cim.iec61970.base.protection.CurrentRelay;
import com.zepben.evolve.cim.iec61970.base.protection.ProtectionRelayScheme;
import com.zepben.evolve.cim.iec61970.base.protection.ProtectionRelaySystem;
import com.zepben.evolve.cim.iec61970.base.protection.RelaySetting;
import com.zepben.evolve.cim.iec61970.base.wires.Breaker;

class ProtectionExample {
    public static void main(String[] args) {
        // Breakers for stove, bathroom, and washer are for individual outlets,
        // whereas the failsafe breaker can disconnect all appliances from power.
        Breaker stoveBreaker = new Breaker("stoveBreaker");
        Breaker bathroomBreaker = new Breaker("bathroomBreaker");
        Breaker washerBreaker = new Breaker("washerBreaker");
        Breaker failsafeBreaker = new Breaker("failsafeBreaker");

        CurrentTransformer stoveCT = new CurrentTransformer("stoveCT");
        CurrentTransformer bathroomCT = new CurrentTransformer("bathroomCT");
        CurrentTransformer washerCT = new CurrentTransformer("washerCT");
        CurrentTransformer failsafeCT = new CurrentTransformer("failsafeCT");

        CurrentRelay stoveCR = new CurrentRelay("stoveCR");
        stoveCR.addProtectedSwitch(stoveBreaker);
        stoveBreaker.addRelayFunction(stoveCR);
        stoveCR.addSensor(stoveCT);
        stoveCT.addRelayFunction(stoveCR);
        stoveCR.addThreshold(new RelaySetting(UnitSymbol.A, 50));
        stoveCR.addTimeLimit(0.5);

        CurrentRelay bathroomCR = new CurrentRelay("bathroomCR");
        bathroomCR.addProtectedSwitch(bathroomBreaker);
        bathroomBreaker.addRelayFunction(bathroomCR);
        bathroomCR.addSensor(bathroomCT);
        bathroomCT.addRelayFunction(bathroomCR);
        bathroomCR.addThreshold(new RelaySetting(UnitSymbol.A, 20));
        bathroomCR.addTimeLimit(0.1);

        CurrentRelay washerCR = new CurrentRelay("washerCR");
        washerCR.addProtectedSwitch(washerBreaker);
        washerBreaker.addRelayFunction(washerCR);
        washerCR.addSensor(washerCT);
        washerCT.addRelayFunction(washerCR);
        washerCR.addThreshold(new RelaySetting(UnitSymbol.A, 20));
        washerCR.addTimeLimit(0.5);

        CurrentRelay failsafeCR = new CurrentRelay("failsafeCR");
        failsafeCR.addProtectedSwitch(failsafeBreaker);
        failsafeBreaker.addRelayFunction(failsafeCR);
        failsafeCR.addSensor(failsafeCT);
        failsafeCT.addRelayFunction(failsafeCR);
        failsafeCR.addThreshold(new RelaySetting(UnitSymbol.A, 90));
        failsafeCR.addTimeLimit(1.0);

        ProtectionRelayScheme mainScheme = new ProtectionRelayScheme("mainScheme");
        mainScheme.addFunction(stoveCR);
        mainScheme.addFunction(bathroomCR);
        mainScheme.addFunction(washerCR);
        stoveCR.addScheme(mainScheme);
        bathroomCR.addScheme(mainScheme);
        washerCR.addScheme(mainScheme);

        ProtectionRelayScheme failsafeScheme = new ProtectionRelayScheme("failsafe");
        failsafeScheme.addFunction(failsafeCR);
        failsafeCR.addScheme(failsafeScheme);

        ProtectionRelaySystem system = new ProtectionRelaySystem("system");
        system.addScheme(mainScheme);
        system.addScheme(failsafeScheme);
        mainScheme.setSystem(system);
        failsafeScheme.setSystem(system);
    }
}

For brevity, this example excludes modelling of connectivity between the sensors and breakers.

Grounds and Ground Disconnectors​

To aid in modelling protection systems, our network data model also supports explicit modelling of grounds and ground disconnectors:

import com.zepben.evolve.cim.iec61970.base.core.IdentifiedObject;
import com.zepben.evolve.cim.iec61970.base.core.Terminal;
import com.zepben.evolve.cim.iec61970.base.wires.Ground;
import com.zepben.evolve.cim.iec61970.base.wires.GroundDisconnector;
import com.zepben.evolve.cim.iec61970.base.wires.Junction;
import com.zepben.evolve.services.network.NetworkService;

class GroundExample {
    public static void main(String[] args) {
        // junction --- ground disconnector --- ground
        NetworkService networkService = new NetworkService();

        Ground ground = new Ground("ground");
        Terminal groundTerminal = new Terminal("ground-t1");
        ground.addTerminal(groundTerminal);

        GroundDisconnector gd = new GroundDisconnector("gd");
        Terminal gdTerminal1 = new Terminal("gd-t1");
        Terminal gdTerminal2 = new Terminal("gd-t2");
        gd.addTerminal(gdTerminal1);
        gd.addTerminal(gdTerminal2);

        Junction junction = new Junction("junction");
        Terminal junctionTerminal = new Terminal("junction-t1");
        junction.addTerminal(junctionTerminal);

        networkService.connect(junctionTerminal, gdTerminal1);
        networkService.connect(gdTerminal2, groundTerminal);

        for (IdentifiedObject io: new IdentifiedObject[]{ground, groundTerminal, gd, gdTerminal1, gdTerminal2, junctionTerminal}) {
            networkService.tryAdd(io);
        }
    }
}

Series Compensators​

The Evolve SDK also supports modelling series compensators, which are series capacitors and reactors or an AC transmission line without charging susceptance.

import com.zepben.evolve.cim.iec61970.base.core.IdentifiedObject;
import com.zepben.evolve.cim.iec61970.base.core.Terminal;
import com.zepben.evolve.cim.iec61970.base.wires.AcLineSegment;
import com.zepben.evolve.cim.iec61970.base.wires.SeriesCompensator;
import com.zepben.evolve.services.network.NetworkService;

class SeriesCompensatorExample {
    public static void main(String[] args) {
        // AC line 1 --- series compensator -- AC line 2
        NetworkService networkService = new NetworkService();

        AcLineSegment acls1 = new AcLineSegment("acls1");
        Terminal acls1Terminal1 = new Terminal("acls1-t1");
        Terminal acls1Terminal2 = new Terminal("acls1-t2");
        acls1.addTerminal(acls1Terminal1);
        acls1.addTerminal(acls1Terminal2);

        AcLineSegment acls2 = new AcLineSegment("acls2");
        Terminal acls2Terminal1 = new Terminal("acls2-t1");
        Terminal acls2Terminal2 = new Terminal("acls2-t2");
        acls2.addTerminal(acls2Terminal1);
        acls2.addTerminal(acls2Terminal2);

        SeriesCompensator sc = new SeriesCompensator("sc");
        // dummy (likely unrealistic) values
        sc.setR(1.0);
        sc.setR0(1.5);
        sc.setX(123.0);
        sc.setX0(125.0);
        sc.setVaristorVoltageThreshold(10);
        sc.setVaristorRatedCurrent(5);
        Terminal scTerminal1 = new Terminal("sc-t1");
        Terminal scTerminal2 = new Terminal("sc-t2");
        sc.addTerminal(scTerminal1);
        sc.addTerminal(scTerminal2);

        networkService.connect(acls1Terminal2, scTerminal1);
        networkService.connect(scTerminal2, acls2Terminal1);

        for (IdentifiedObject io: new IdentifiedObject[]{
            acls1, acls1Terminal1, acls1Terminal2, acls2, acls2Terminal1, acls2Terminal2, sc, scTerminal1, scTerminal2
        }) {
            networkService.tryAdd(io);
        }
    }
}