	US 12,306,225 B2
	Method for measuring degree of stability of generator and power transmission line, and electrical grid control system
Chen Guo, Beijing (CN); Zhaolei Wang, Beijing (CN); Chong Jiao, Beijing (CN); Xiaoyu Wang, Beijing (CN); Xin Liu, Beijing (CN); Liying Zhang, Beijing (CN); and Anmin Cai, Beijing (CN)
Assigned to HUANENG CLEAN ENERGY RESEARCH INSTITUTE, Beijing (CN)
Filed by HUANENG CLEAN ENERGY RESEARCH INSTITUTE, Beijing (CN)
Filed on Oct. 14, 2021, as Appl. No. 17/501,880.
Application 17/501,880 is a continuation of application No. PCT/CN2020/121252, filed on Oct. 15, 2020.
Claims priority of application No. 201911411792.0 (CN), filed on Dec. 31, 2019.
Prior Publication US 2022/0043041 A1, Feb. 10, 2022
Int. Cl. G01R 21/133 (2006.01); G01R 31/34 (2020.01); H02J 13/00 (2006.01)

CPC G01R 21/1331 (2013.01) [G01R 31/34 (2013.01); H02J 13/00002 (2020.01)]

14 Claims

1. A stability controlling system of a power plant grid, comprising:

an electrical acquisition device;

a monitoring device;

a load regulating device, configured to regulate a load of a generator; and

a high-speed communication network, configured to communicate a stability measuring and controlling system of the power plant grid with a wide area measurement system of a wide area power grid,

wherein the electrical acquisition device and the monitoring device are configured to determine a dynamic reactive power reserve target value, a capacitive dynamic reactive power reserve target value, an inductive dynamic reactive power reserve target value, a capacitive stability, an inductive stability and a stability of a power plant by:

S51: calculating a capacitive stability, an inductive stability, a stability, a dynamic reactive power reserve target value, an inductive dynamic reactive power reserve target value and a capacitive dynamic reactive power reserve target value of each synchronous generator in the power plant;

S52: determining the dynamic reactive power reserve target value, the capacitive dynamic reactive power reserve target value and the inductive dynamic reactive power reserve target value of the power plant;

S53: determining the capacitive stability, the inductive stability and the stability of the power plant; and

S54: reporting the dynamic reactive power reserve target value, the capacitive dynamic reactive power reserve target value, the inductive dynamic reactive power reserve target value, the capacitive stability, the inductive stability and the stability of the power plant to the wide area measurement system for providing a risk early warning for the wide area power grid,

wherein in S52, the dynamic reactive power reserve target value of the power plant is a sum of the dynamic reactive power reserve target values of all synchronous generators in the power plant; the capacitive dynamic reactive power reserve target value of the power plant is a sum of the capacitive dynamic reactive power reserve target values of all synchronous generators in the power plant; and the inductive dynamic reactive power reserve target value of the power plant is a sum of the inductive dynamic reactive power reserve target values of all synchronous generators in the power plant:

wherein in S53, the capacitive stability of the power plant is a minimum of the capacitive stabilities of all synchronous generators in the power plant: the inductive stability of the power plant is a minimum of the inductive stabilities of all synchronous generators in the power plant; and the stability of the power plant is a sum of the capacitive stability and the inductive stability of the power plant:

wherein calculating the capacitive stability, the inductive stability, the stability, the dynamic reactive power reserve target value, the inductive dynamic reactive power reserve target value and the capacitive dynamic reactive power reserve target value of each synchronous generator in the power plant comprises:

S11: collecting electrical quantities, and setting an alarm PQ curve of the synchronous generator:

S12: calculating a dynamic reactive power reserve, an inductive dynamic reactive power reserve and a capacitive dynamic reactive power reserve of the synchronous generator:

S13: calculating the dynamic reactive power reserve target value, the inductive dynamic reactive power reserve target value and the capacitive dynamic reactive power reserve target value of the synchronous generator:

S14: calculating the capacitive stability, the inductive stability and the stability of the synchronous generator; and

providing the dynamic reactive power reserve, the inductive dynamic reactive power reserve and the capacitive dynamic reactive power reserve of the synchronous generator, and the dynamic reactive power reserve target value, the inductive dynamic reactive power reserve target value and the capacitive dynamic reactive power reserve target value of the synchronous generator to a power plant grid for improving a stability of the power plant grid,

wherein in S13, the dynamic reactive power reserve target value, the inductive dynamic reactive power reserve target value and the capacitive dynamic reactive power reserve target value of the synchronous generator are calculated by:

calculating a segment length between a left intersection point of a horizontal line passing through a coordinated PQ point of the synchronous generator and the alarm PQ curve of the synchronous generator and a right intersection point of the horizontal line passing through the coordinated PQ point of the synchronous generator and the alarm PQ curve of the synchronous generator as the dynamic reactive power reserve target value of the synchronous generator;

calculating a segment length between the left intersection point of the horizontal line passing through the coordinated PQ point of the synchronous generator and the alarm PQ curve of the synchronous generator and the coordinated PQ point of the synchronous generator as the capacitive dynamic reactive power reserve target value of the synchronous generator; and

calculating a segment length between the right intersection point of the horizontal line passing through the coordinated PQ point of the synchronous generator and the alarm PQ curve of the synchronous generator and the coordinated PQ point of the synchronous generator as the inductive dynamic reactive power reserve target value of the synchronous generator, and

wherein in S14, the capacitive stability, the inductive stability and the stability of the synchronous generator are calculated by:

calculating a percentage of the capacitive dynamic reactive power reserve of the synchronous generator accounting for the dynamic reactive power reserve target value of the synchronous generator as the capacitive stability of the synchronous generator;

calculating a percentage of the inductive dynamic reactive power reserve of the synchronous generator accounting for the dynamic reactive power reserve target value of the synchronous generator as the inductive stability of the synchronous generator; and

calculating a percentage of the dynamic reactive power reserve of the synchronous generator accounting for the dynamic reactive power reserve target value of the synchronous generator as the stability of the synchronous generator.