Method and apparatus for controlling reactive power of wind turbine, and wind farm

Patent metadata

Field	Value
Publication number	US-12366227-B2
Application number	US-202017780010-A
Country	US
Kind code	B2
Filing date	Jun 10, 2020
Priority date	Nov 26, 2019
Publication date	Jul 22, 2025
Grant date	Jul 22, 2025

Abstract

Methods and apparatuses for controlling reactive power of a wind turbine, and a wind farm are provided. An exemplary method includes: obtaining operation data of single wind turbines in a wind turbine group at the current time point; determining the total maximum capacitive reactive capacity and total minimum inductive reactive capacity, satisfying a safety constraint condition at the next time point, of the wind turbine group; calculating a deviation value of a wind turbine group reactive instruction at the current time point; and updating the wind turbine group reactive instruction on the basis of the acquired, determined, and calculated data so as to perform reactive power control.

First claim

The invention claimed is:

1. A method for controlling reactive power of a wind turbine group, comprising:
acquiring operation data of each wind turbine in the wind turbine group at a current moment in response to a reactive power command of the wind turbine group, wherein the reactive power command of the wind turbine group comprises a reactive power command of each wind turbine at the current moment;
determining a total maximum capacitive reactive power capability and a total minimum inductive reactive power capability of the wind turbine group meeting a safety constraint condition at a next moment, based on an estimated system impedance at a grid-connected point at the current moment, the operation data of each wind turbine at the current moment, and boundaries of a voltage safety range, wherein the next moment is a moment after the current moment in a next control period;
calculating a reactive power command deviation of the wind turbine group at the current moment, based on the reactive power command of each wind turbine at the current moment and the operation data of each wind turbine at the current moment; and
updating the reactive power command of the wind turbine group, based on the reactive power command deviation of the wind turbine group at the current moment, the total maximum capacitive reactive power capability and the total minimum inductive reactive power capability of the wind turbine group meeting the safety constraint condition at the next moment, and the operation data of each wind turbine at the current moment, to control reactive power of each wind turbine in the wind turbine group based on the updated reactive power command of the wind turbine group.

2. The method according to claim 1 , wherein the safety constraint condition comprises an impact of an actual reactive power of each wind turbine in the wind turbine group on an actual active power of the wind turbine at the current moment, an impact of the actual reactive power of each wind turbine in the wind turbine group on three-phase voltages at a grid side at the current moment, and an impact of the actual reactive power of each wind turbine in the wind turbine group on three-phase currents at the grid side at the current moment.

3. The method according to claim 1 , wherein the estimated system impedance at the grid-connected point at the current moment is acquired by:
determining the estimated system impedance at the grid-connected point at the current moment, based on three-phase voltages at a grid side and an actual reactive power of each wind turbine at the current moment.

4. The method according to claim 1 , wherein the determining a total maximum capacitive reactive power capability and a total minimum inductive reactive power capability of the wind turbine group meeting a safety constraint condition at a next moment comprises:
calculating, for each wind turbine, a maximum capacitive reactive power capability and a minimum inductive reactive power capability of the wind turbine meeting the safety constraint condition at the next moment, based on the estimated system impedance at the current moment, an actual reactive power and three-phase voltages at a grid-side of the wind turbine at the current moment, and the boundaries of the voltage safety range; and
calculating the total maximum capacitive reactive power capability and the total minimum inductive reactive power capability of the wind turbine group meeting the safety constraint condition at the next moment, based on maximum capacitive reactive power capabilities and minimum inductive reactive power capabilities of all wind turbines meeting the safety constraint condition at the next moment.

5. The method according to claim 4 , wherein
the operation data of each wind turbine at the current moment comprises three-phase currents at the grid side of each wind turbine at the current moment,
wherein, the calculating, for each wind turbine, a maximum capacitive reactive power capability and a minimum inductive reactive power capability of the wind turbine meeting the safety constraint condition at the next moment, based on the estimated system impedance at the current moment, an actual reactive power and three-phase voltages at a grid side of the wind turbine at the current moment, and the boundaries of the voltage safety range comprises:
calculating, for each wind turbine, a maximum real-time capacitive reactive power capability and a maximum real-time inductive reactive power capability of the wind turbine at the current moment, based on the estimated system impedance at the current moment, the actual reactive power and the three-phase voltages at the grid side of the wind turbine at the current moment, and the boundaries of the voltage safety range;
determining, for each wind turbine, a safety constraint condition for an impact of an actual reactive power of the wind turbine on an actual active power of the wind turbine at the current moment, a safety constraint condition for an impact of the actual reactive power of the wind turbine on the three-phase voltages at the grid side of the wind turbine at the current moment, and a safety constraint condition for an impact of the actual reactive power of the wind turbine on the three-phase currents at the grid side of the wind turbine at the current moment, based on the maximum real-time capacitive reactive power capability and the maximum real-time inductive reactive power capability of the wind turbine at the current moment; and
calculating, for each wind turbine, the maximum capacitive reactive power capability and the minimum inductive reactive power capability of the wind turbine meeting the safety constraint condition at the next moment, based on the calculated maximum real-time capacitive reactive power capability and the calculated maximum real-time inductive reactive power capability of the wind turbine at the current moment, the determined safety constraint condition for the impact of the actual reactive power of the wind turbine on the actual active power of the wind turbine at the current moment, the determined safety constraint condition for the impact of the actual reactive power of the wind turbine on the three-phase voltages at the grid side of the wind turbine at the current moment, and the determined safety constraint condition for the impact of the actual reactive power of the wind turbine on the three-phase currents at the grid side of the wind turbine at the current moment.

6. The method according to claim 5 , wherein the calculating, for each wind turbine, a maximum real-time capacitive reactive power capability and a maximum real-time inductive reactive power capability of the wind turbine at the current moment based on the estimated system impedance at the current moment, the actual reactive power and the three-phase voltages at the grid side of the wind turbine at the current moment, and the boundaries of the voltage safety range comprises:
calculating, for each wind turbine, an increasable capacitive reactive power and a reducible inductive reactive power of the wind turbine at the current moment, based on the estimated system impedance at the current moment, the actual reactive power and the three-phase voltages at the grid side of the wind turbine at the current moment, and the boundaries of the voltage safety range; and
calculating, for each wind turbine, the maximum real-time capacitive reactive power capability and the maximum real-time inductive reactive power capability of the wind turbine at the current moment based on the actual reactive power, the increasable capacitive reactive power and the reducible inductive reactive power of the wind turbine at the current moment.

7. The method according to claim 3 , wherein the determining the estimated system impedance at the

Assignees

• Xinjiang Goldwind Science & Tech Co Ltd

Inventors

• Yu Lianfu
• Xiao Di
• Bao Xianwen

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02J13/12

  Monitoring network conditions, e.g. electrical magnitudes or operational status · CPC title

• H02J3/16

  by adjustment of reactive power · CPC title

• Y02E40/30

  Reactive power compensation · CPC title

• F05B2270/337

  Electrical grid status parameters, e.g. voltage, frequency or power demand · CPC title