Method for Protecting an Electrical Power System

Patent metadata

Field	Value
Publication number	US-2018302011-A1
Application number	US-201715490079-A
Country	US
Kind code	A1
Filing date	Apr 18, 2017
Priority date	Apr 18, 2017
Publication date	Oct 18, 2018
Grant date	—

Abstract

The present disclosure is directed to a method for protecting an electrical power system connected to a power grid. The electrical power system includes at least one cluster of electrical power subsystems. Each of the electrical power subsystems defines a stator power path and a converter power path for providing power to the power grid. The converter power path includes a partial power transformer. The electrical power system further includes a subsystem switch configured with each of the electrical power subsystems and a cluster transformer connecting each cluster of electrical power subsystems to the power grid. A cluster switch is configured with the cluster transformer. A controller is communicatively coupled to each of the plurality of electrical power subsystems. Thus, the controller monitors the electrical power system for faults, and if a fault is detected in the cluster, sends, via one of the subsystem switches or the power converters, a block signal to the cluster switch.

First claim

1 . An electrical power system connected to a power grid, comprising:
at least one cluster of electrical power subsystems, each of the electrical power subsystems comprising a power converter electrically coupled to a generator having a generator rotor and a generator stator, each of the electrical power subsystems defining a stator power path and a converter power path for providing power to the power grid, the converter power path comprising a partial power transformer; a subsystem switch configured with each of the electrical power subsystems; a cluster transformer connecting each cluster of electrical power subsystems to the power grid; a cluster switch communicatively coupled to the cluster transformer; and, a controller communicatively coupled to each of the plurality of electrical power subsystems, the controller configured to perform one or more operations, the operations comprising:
monitoring the electrical power system for faults; and,
if a fault is detected in the cluster, sending, via one of the subsystem switches or the power converters, a block signal to the cluster switch, the block signal comprising a signal that instructs the cluster switch to not trip in response to the fault being detected.

2 . The electrical power system of claim 1 , wherein the partial power transformer comprises at least one of a two-winding transformer or a three-winding transformer.

3 . The electrical power system of claim 1 , wherein the subsystem switches and the cluster switch comprise subsystem relays and a cluster relay, respectively.

4 . The electrical power system of claim 3 , wherein the subsystem relays and the cluster relay comprise differential relays configured to isolate the fault in one of the electrical power subsystems.

5 . The electrical power system of claim 1 , wherein monitoring the electrical power system for faults further comprises monitoring the stator power path of each of the electrical power systems for electrical faults.

6 . The electrical power system of claim 5 , wherein, if the subsystem switch is unable to clear the fault, the controller is further configured to drop the block signal.

7 . The electrical power system of claim 1 , wherein the generator of each of the electrical power subsystems comprises a doubly-fed induction generator (DFIG).

8 . The electrical power system of claim 1 , wherein the electrical power system comprises a wind farm, and wherein the electrical power subsystems comprise wind turbine power systems.

9 . An electrical power system connected to a power grid, comprising:
at least one cluster of electrical power subsystems, each of the electrical power subsystems comprising a power converter electrically coupled to a generator having a generator rotor and a generator stator, each of the electrical power subsystems defining a stator power path and a converter power path for providing power to the power grid, the converter power path comprising a partial power transformer; a subsystem switch configured with each of the electrical power subsystems; a cluster transformer connecting each cluster of electrical power subsystems to the power grid; a cluster switch communicatively coupled to the cluster transformer; and, a controller communicatively coupled to each of the plurality of electrical power subsystems, the controller configured to perform one or more operations, the operations comprising:
monitoring the electrical power system for faults; and,
if a fault is detected in the cluster, sending, via the cluster switch, a trip signal to at least one of the subsystem switches or one of the power converters of the electrical power subsystems to disconnect at least one of the electrical power subsystems from the power grid, the trip signal comprising a signal that instructs at least one of the subsystem switches or one of the power converters to disconnect at least one of the electrical power subsystems from the power grid.

10 . The electrical power system of claim 9 , wherein the partial power transformer comprises at least one of a two-winding transformer or a three-winding transformer.

11 . The electrical power system of claim 9 , wherein the subsystem switches and the cluster switch comprise subsystem relays and a cluster relay, respectively.

12 . The electrical power system of claim 9 , wherein monitoring the electrical power system for faults further comprises monitoring at least one of the cluster transformer for electrical faults or the stator power path of each of the electrical power systems for electrical faults.

13 . The electrical power system of claim 12 , wherein, if an electrical fault is detected, sending, via the cluster switch, the trip signal to each of the subsystem switches or each of the power converters to disconnect each of the electrical power subsystems from the power grid.

14 . A method for protecting an electrical power system, the electrical power system having a plurality of clusters of electrical power subsystems with a cluster transformer connecting each cluster of electrical power subsystems to a power grid, each of the electrical power subsystems having a power converter electrically coupled to a generator with a generator rotor and a generator stator, each of the electrical power subsystems defining a stator power path and a converter power path for providing power to the power grid, the converter power path containing a partial power transformer, the method comprising:
monitoring the electrical power system for faults; upon detection of a fault in one of the clusters of electrical power subsystems, determining a location of the fault; if the fault is located within one of the electrical power subsystems, sending, via a subsystem switch electrically coupled with the electrical power subsystem experiencing the fault or a power converter of the electrical power subsystem experiencing the fault, a block signal to a cluster switch electrically coupled to the cluster transformer associated with the cluster experiencing the fault, the block signal comprising a signal that instructs the cluster switch to not trip in response to the fault being detected; and, if the fault is located outside of the electrical power subsystems, sending, via the cluster switch, a trip signal to each subsystem switch or each power converter within the cluster experiencing the fault, the trip signal comprising a signal that instructs each subsystem switch or each power converter within the cluster experiencing the fault to disconnect from the power grid.

15 . The method of claim 14 , wherein the subsystem switches and the cluster switch comprise subsystem relays and a cluster relay, respectively.

16 . The method of claim 15 , wherein the subsystem relays and the cluster relay comprise differential relays configured to isolate the fault in one of the electrical power subsystems.

17 . The method of claim 14 , wherein monitoring the electrical power system for faults further comprises monitoring the stator power path of each of the electrical power systems for electrical faults.

18 . The method of claim 17 , wherein, if the subsystem switch is unable to clear the fault, dropping the block signal and communicating the dropped signal to a controller.

19 . The method of claim 17 , wherein monitoring the electrical power system for faults further comprises monitoring the cluster transformer for electrical faults.

20 . The method of claim 14 , wherein the electrical power system comprises a wind farm, and wherein the electrical power subsystems co

Assignees

• Gen Electric

Inventors

• Ganireddy Govardhan
• Bollenbecker John Leo
• Burra Rajni
• Wagoner Robert Gregory
• Klodowski Anthony Michael

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02H7/262

  involving transmissions of switching or blocking orders · CPC title

• H02P9/007 Primary

  Control circuits for doubly fed generators · CPC title

• F03D9/257

  the wind motor being part of a wind farm · CPC title

• H02P29/032

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title