Multi generator synchronization system
AssigneeGoogle Inc.
InventorsKrishnanjan Gubba Ravikumar, Mahipathi Reddy Appannagari
Life of this patent
Estimating the term…
Abstract
The present disclosure contemplates a method for synchronizing a large number of generators on an AC bus simultaneously by closing the generator breakers when the generators are rotating but de-energized. Then excitation is raised for each generator simultaneously, causing the generators to synchronize as voltage increases, without large transient current surges that can damage the machines. In order to safely maximize the rate at which excitation is raised, initial excitation can be controlled using current regulation, specifically controlling excitation current instead of voltage. Once a predetermined voltage is reached, a control scheme can be switched to a voltage regulation mode, which brings the generator to the final desired voltage.
Claims15
A method for performing startup of two or more synchronous machines, the method comprising:
- mechanically rotating each of the synchronous machines at a predetermined speed;
- electrically connecting each of the synchronous machines to a power distribution bus, wherein the power distribution bus is de-energized when each of the synchronous machines are electrically connected;
- raising an excitation of each synchronous machine to achieve synchronized operation by:
- applying a field current to an exciter of the synchronous machine using a field current regulator to achieve a target field current;
- monitoring an output voltage of the synchronous machine;
- in response to the output voltage reaching a predetermined voltage threshold, activating a voltage regulator of the synchronous machine to determine an input to the field current regulator, wherein the voltage regulator and the field current regulator are configured to adjust the excitation to achieve a desired field voltage;
- and
- transmitting, through a communication link and to at least one other synchronous machine of the two or more synchronous machines, a switchover command that instructs the at least one other synchronous machine to activate a voltage regulator of the at least one other synchronous machine;
- monitoring, by each other synchronous machine, the communication link for the switchover command;
- and
- in response to receiving the switchover command, activating the voltage regulator of the other synchronous machine regardless of the output voltage of the other synchronous machine.
A system comprising two or more generator systems, each generator system comprising:
- a synchronous machine;
- an excitation control system including a voltage regulator and a field current regulator;
- an exciter configured to supply excitation current to the synchronous machine;
- and
- a controller, wherein the controller is configured to cause the generator system to perform operations for performing startup of two or more synchronous machines, the operations comprising:
- mechanically rotating each of the synchronous machines at a predetermined speed;
- electrically connecting each of the synchronous machines to a power distribution bus, wherein the power distribution bus is de-energized when each of the synchronous machines are electrically connected;
- raising an excitation of each synchronous machine to achieve synchronized operation by:
- applying a field current to an exciter of the synchronous machine using a field current regulator to achieve a desired field current;
- monitoring an output voltage of the synchronous machine;
- in response to the output voltage reaching a predetermined voltage threshold, activating a voltage regulator of the synchronous machine to determine an input to the field current regulator, wherein the voltage regulator and the field current regulator are configured to adjust the excitation to achieve a desired field voltage;
- and
- transmitting, through a communication link and to at least one other synchronous machine, a switchover command that instructs the at least one other synchronous machine to activate a voltage regulator of the at least one other synchronous machine;
- monitoring, by each other synchronous machine, the communication link for the switchover command;
- and
- in response to receiving the switchover command, activating the voltage regulator of the other synchronous machine regardless of the output voltage of the other synchronous machine.
A non-transitory computer-readable storage medium coupled to one or more processors and having instructions stored thereon which, when executed by the one or more processors, cause a generator system to startup a synchronous machine of the generator system, by causing the generator system to perform operations, the operations comprising:
- mechanically rotating each of the synchronous machines at a predetermined speed;
- electrically connecting each of the synchronous machines to a power distribution bus wherein the power distribution bus is de-energized when each of the synchronous machines are electrically connected;
- raising an excitation of each synchronous machine to achieve synchronized operation by:
- applying a field current to an exciter of the synchronous machine using a field current regulator to achieve a desired field current;
- monitoring an output voltage of the synchronous machine;
- in response to the output voltage reaching a predetermined threshold, activating a voltage regulator of the synchronous machine to determine an input to the field current regulator, wherein the voltage regulator and the field current regulator are configured to adjust the excitation to achieve a desired field voltage;
- and
- transmitting, through a communication link and to at least one other synchronous machine, a switchover command that instructs the at least one other synchronous machine to activate a voltage regulator of the at least one other synchronous machine;
- monitoring, by each other synchronous machine, the communication link for the switchover command;
- and
- in response to receiving the switchover command, activating the voltage regulator of the other synchronous machine regardless of the output voltage of the other synchronous machine.
Dependencies are inferred from the claim text.