Method and a device for compensation of the consumption of reactive power by an industrial load

A method for compensating a reactive power consumption of an industrial load, supplied from a three-phase electric AC network including a first compensation device for controllable consumption of reactive power and a second compensation device for generation of reactive power, both of said first and second compensation devices being connected to the AC network in a parallel connection with the industrial load, the first compensation device comprising a thyristor-controlled reactor for each of the phases of the AC network, the method comprising:

• sensing an amplitude value for a voltage for each of the thyristor-controlled reactors, said voltage representing a voltage across a respective thyristor-controlled reactor;
• forming a voltage mean value as a mean value of said amplitude values;
• forming an amplitude deviation for each of the thyristor-controlled reactors as a difference of the voltage mean value and the amplitude value associated with the respective thyristor-controlled reactor;
• forming a separate control order for phase-angle control of each of the thyristor-controlled reactors, said control order being dependent on the amplitude deviation for the respective thyristor-controlled reactor;
• and
• determining a total consumption of reactive power by the industrial load and the second compensation device, said control order being further dependent on the total consumption of reactive power by the industrial load and the second compensation device.

A device for compensating a reactive power consumption of an industrial load, supplied from a three-phase electric AC network, said device comprising:

• a first compensation device for controllable consumption of reactive power;
• a second compensation device for generation of reactive power, both of said first and second compensation devices being connected to the AC network in a parallel connection with the industrial load, the first compensation device including a thyristor-controlled reactor for each of the phases of the AC network;
• voltage-measuring devices for each of the thyristor-controlled reactors and for sensing of amplitude values for a voltage which represents a voltage across a respective thyristor-controlled reactor;
• current-measuring devices for each of the thyristor-controlled reactors for sensing of the respective current at the industrial load;
• control equipment for each of the thyristor-controlled reactors, which is supplied with measured values of the sensed amplitude values for voltages and currents, the control equipment including means for determining an instantaneous consumption of reactive power by the industrial load;
• and
• a control device for each of the thyristor-controlled reactors which forms a control order dependent on the sensed amplitude values for voltages and currents for the thyristor-controlled reactors and supplies the control order to the respective thyristor-controlled reactor, the control equipment including,
• means for forming a voltage mean value as the a mean value of said amplitude values for voltage,
• means for forming, for each of the thyristor-controlled reactors, an amplitude deviation as a difference of the voltage mean value and the amplitude value associated with the thyristor-controlled reactor, and
• means for forming, for each of the thyristor-controlled reactors, a separate control order in dependence on the amplitude deviation for the respective thyristor-controlled reactor.

A device for the compensating a reactive power consumption of an industrial load, supplied from a three-phase electric AC network, said first and second device comprising:

• a first compensation device for controllable consumption of reactive power;
• a second compensation device for generation of reactive power, both of said compensation devices being connected to the AC network in a parallel connection with the industrial load, the first compensation device including a thyristor-controlled reactor for each of the phases of the AC network;
• voltage-measuring devices for each of the thyristor-controlled reactors and for sensing of amplitude values for a voltage which represents a voltage across a respective thyristor-controlled reactor;
• current-measuring devices for each of the thyristor-controlled reactors for sensing currents flowing to the parallel connection that is constituted by the industrial load and the second compensation device;
• and
• control equipment for each of the thyristor-controlled reactors, which is supplied with measured values of the sensed amplitude values for voltages and currents, the control equipment including means for determining a total consumption of reactive power by the industrial load and the second compensation device;
• and
• a control device for each of the thyristor-controlled reactors which forms a control order dependent on the sensed amplitude values for voltages and currents for the thyristor-controlled reactors and supplies the control order to the respective thyristor-controlled reactor, the control equipment including,
• means for forming a voltage mean value as the a mean value of said amplitude values for voltage,
• means for forming, for each of the thyristor-controlled reactors, an amplitude deviation as a difference of the voltage mean value and the amplitude value associated with the thyristor-controlled reactor, and
• means for forming, for each of the thyristor-controlled reactors, a separate control order in dependence on the amplitude deviation for the respective thyristor-controlled reactor.

A device for compensating a reactive power consumption of an industrial load, supplied from a three-phase electric AC network, said device comprising:

• a first compensation device configured to control consumption of reactive power;
• a second compensation device configured to generate reactive power, both of said first and second compensation devices being connected to the AC network in a parallel connection with the industrial load, the first compensation device including a thyristor-controlled reactor for each of the phases of the AC network;
• voltage-measuring devices for each of the thyristor-controlled reactors and configured to sense amplitude values for a voltage which represents a voltage across a respective thyristor-controlled reactor;
• current-measuring devices for each of the thyristor-controlled reactors and configured to sense the respective current at the industrial load;
• control equipment for each of the thyristor-controlled reactors which is supplied with measured values of the sensed amplitude values for voltages and currents, the control equipment configured to determine the instantaneous consumption of reactive power by the load;
• and
• a control device for each of the thyristor-controlled reactors and configured to form a control order dependent on the sensed amplitude values for voltages and currents for the thyristor-controlled reactors and to supply the control order to the thyristor-controlled reactors, the control equipment including,
• a voltage mean value forming device configured to form a voltage mean value as a mean value of said amplitude values for voltage,
• an amplitude deviation forming device configured to form, for each of the thyristor-controlled reactors, an amplitude deviation as a difference of the voltage mean value and the amplitude value associated with the thyristor-controlled reactor, and
• a control order forming device for each of the thyristor-controlled reactors and configured to form a separate control order dependent on the amplitude deviation for the respective thyristor-controlled reactor.

A device for compensating a reactive power consumption of an industrial load, supplied from a three-phase electric AC network, said device comprising:

• a first compensation device configured to control consumption of reactive power;
• a second compensation device configured to generate reactive power, both of said first and second compensation devices being connected to the AC network in a parallel connection with the industrial load, the first compensation device including a thyristor-controlled reactor for each of the phases of the AC network;
• voltage-measuring devices for each of the thyristor-controlled reactors and configured to sense amplitude values for a voltage which represents a voltage across a respective thyristor-controlled reactor;
• current-measuring devices for each of the thyristor-controlled reactors and configured to sense currents flowing to the parallel connection that is constituted by the industrial load and the second compensation device;
• control equipment for each of the thyristor-controlled reactors which is supplied with measured values of the sensed amplitude values for voltages and currents, and the control equipment is configured to determine the total consumption of reactive power by the load and the second compensation device;
• and
• a control device for each of the thyristor-controlled reactors and configured to form a control order dependent on the sensed amplitude values for voltages and currents for the thyristor-controlled reactors and to supply the control order to the thyristor-controlled reactors, the control equipment including,
• a voltage mean value forming device configured to form a voltage mean value as a mean value of said amplitude values for voltage,
• an amplitude deviation forming device configured to form, for each of the thyristor-controlled reactors, an amplitude deviation as a difference of the voltage mean value and the amplitude value associated with the thyristor-controlled reactor, and
• a control order forming device for each of the thyristor-controlled reactors and configured to form a separate control order dependent on the amplitude deviation for the respective thyristor-controlled reactors.