Advanced cross current compensation system and method for enhancing reactive current sharing in power generation having multiple generators

A system for controlling a power generation system having two or more generators connected in parallel operation with each generator having a terminal voltage and supplying a generator reactive power output at a generator output to a common load, each generator having a generator field control input coupled to an automatic voltage regulator (AVR) that receives a generator field voltage from a generator field voltage source, the power generation system also having a parallel cross-current compensation element (CCC) coupled to the output of each generator for receiving reactive current and to the AVR and for providing a reactive current compensation input to the AVR responsive to the received reactive current, the system comprising:

• a proportional-integral PI controller;
• a memory for storing executable instructions;
• an input for receiving a reactive current of a controlled generator selected to be controlled from among the two or more generators, a first generator reactive current from the output of a first generator, and a second generator reactive current from an output of a second generator;
• a processor coupled to the memory and configured for executing the stored executable instructions including determining an average generator reactive current by averaging the received first and second generator reactive currents, and determining a difference reactive current that is a difference between the received reactive current and the determined average generator reactive current;
• a proportional-integral PI controller configured for receiving the determined difference reactive current, and determining an adjusted reactive current compensation value;
• and
• providing the determined adjusted reactive current compensation value as an input to the AVR associated with the controlled generator.

A method of controlling a power generation system having two or more generators connected in parallel operation with each generator having a terminal voltage and supplying a generator reactive power output at a generator output to a common load, each generator having a generator field control input coupled to an automatic voltage regulator (AVR) and that receives a generator field voltage from a generator field voltage source, the power generation system also having a parallel cross-current compensation element (CCC) coupled to the output of each generator for receiving reactive current from the generator and coupled to the AVR for providing a reactive current compensation to the AVR, the method comprising:

• (a) in a control system having a proportional-integral PI controller, a memory storing executable instructions, an input, an output coupled to the parallel cross-current compensation element, and a processor coupled to the memory and operable for executing the stored executable instructions, performing the operations of:
• receiving at the input a reactive current of a controlled generator that is selected to be controlled from among the two or more generators;
• receiving at the input a first generator reactive current from a first generator;
• receiving a second generator reactive current from a second generator;
• determining an average generator reactive current by averaging the received first and second generator reactive currents;
• determining a difference reactive current that is a difference between the received reactive current and the determined average generator reactive current;
• and
• generating an adjusted reactive current compensation value responsive to the received determined difference reactive current;
• and
• (b) in an automatic voltage regulator (AVR) coupled to the at least one of the first and second generators:
• receiving the adjusted reactive current compensation value;
• and
• generating an adjusted generator control input to generator field control input of the controlled generator responsive to the received adjusted reactive current compensation;
• in the controlled generator:
• receiving the adjusted generator control input;
• and
• adjusting an operation of the generator in response to the received adjusted generator control.

A system for controlling a power generation system having two or more generators connected in parallel operation with each generator having an output, a terminal voltage and supplying a generator reactive power output via the output to a common load, each generator having a generator field control input, the power generation system comprising:

• an automatic voltage regulator (AVR) with a generator reference voltage associated with each of the two or more generators, each AVR having an input and having an output that is coupled to the generator field control input of the associated generator;
• a parallel cross-current compensation element CCC coupled to an input of each AVR of the two or more generators and configured for receiving reactive current from its associated generator and providing reactive current compensation to its associated AVR;
• and
• a control system for each of the two or more generators, each control system having a proportional-integral PI controller, a memory, a processor, a first input, a second input, an control output, and executable instructions, each control system being configured for receiving at the first input, the reactive current of its associated generator, generator, and a second generator reactive current from an output of a second different one of the two or more generators;
• the executable instructions for each control system configured for performing the operation of determining an average generator reactive current by averaging the received reactive current of its associated generator and the received reactive of the second generator, and determining a difference reactive current that is a difference between the received reactive currents and the determined average generator reactive current,
• the proportional-integral PI controller being configured for:
• receiving the determined difference reactive current and generating an adjusted reactive current compensation value as a function of the received difference reactive current;
• receiving the determined difference reactive current from the control system;
• and
• generating an adjusted reactive current compensation value responsive to the received determined difference reactive current;
• the automatic voltage regulator (AVR) being configured for:
• receiving a reference voltage from a reference voltage source;
• receiving current compensation from the parallel cross-current compensation element CCC;
• receiving the determined adjusted reactive current compensation value from the control system;
• and
• generating an adjusted generator control input responsive to the received adjusted reactive current compensation value, the received reference voltage, and the received current compensation;
• wherein the controlled generator is configured for:
• receiving the adjusted generator control input from the AVR;
• and
• adjusting an operation of the generator in response to the received adjusted generator control input.