Low-frequency surge detection and protection method and device for power system

Abstract

A detection and protection method for low frequency oscillation of a power system adopts changing track of tie line active power to detect the low frequency oscillation; condition one: the following criterions are satisfied at the same time, namely low frequency oscillation hard platen input, low frequency oscillation soft platen input, a device in starting state with |Pk-Peqv| more than Psetqd; condition two: the following criterions are satisfied at the same time: oscillating period is less than or equal to Tsetmax and more than or equal to Tsetmin, power oscillation range is more than or equal to an alarm threshold, oscillation number is more than or equal to alarm period number; alarm period number: oscillation number threshold fixed value of alarming; condition three: the following criterions are satisfied at the same time: oscillating period is less than or equal to Tsetmax and more than or equal to Tsetmin, power oscillation range is more than or equal to action threshold, oscillation number is more than or equal to action period number. The low frequency oscillation gives an alarm when the condition one and the condition two are satisfied at the same time; and the low frequency oscillation .performs protective action when the condition one and the condition three are satisfied at the same time.

Description

1. Technical field [0001] The invention relates to a new method for detecting low-frequency oscillations in electric power systems, in particular to a new method and device for detecting low-frequency oscillations by using the change track of tie line active power. This method is the first in China to detect the low-frequency oscillation of the power system by using the active power change trajectory of the tie-line of the large-area interconnected power grid. 2. Background technology [0002] With the implementation of my country's power construction policy of "power transmission from west to east, mutual aid between north and south, and regional networking", the situation of interconnection of major regions in the country has basically taken shape. Due to the relatively weak connection between the current large regions, low-frequency oscillations have occurred many times in the domestic power grid in recent years. The frequency of low-frequency oscillation is low, general...

AI Technical Summary

Problems solved by technology

Or use synchrophasor measurement technology to detect power angle changes between representative power plant units and analyze low-frequency oscillations. This method relies on the global satellite positioning system, which is affected by weather or human interference (such as when a war occurs), and the reliability is compared In addition, this method requires more equipment, the system is complex, and it is rarely used in actual engineering.

Images