A fault phase selection method for new energy electric field tie lines

Abstract

The invention relates to the technical field of fault phase selection, and more specifically relates to a fault phase selection method for a new energy electric field tie line. The method comprises the following steps: comparing a zero-sequence voltage value with a threshold by acquiring the voltage of each phase of a tie line relay location and a positive sequence voltage value, a negative sequence voltage value and a zero sequence voltage value thereof, and performing fault type judgment according to a comparison result; and comparing the negative sequence voltage value with the threshold, and performing phase comparison judgment on the three-phase positive and negative sequence voltage phasor sum in pairs, thereby realizing fault type judgment. The fault phase selection method for the new energy electric field tie line provided by the invention is applicable to the fault steady-state quantity phase selection of the new energy electric field tie line, and can meet the phase selectionrequirement of the new energy electric field tie line.

Description

technical field [0001] The present invention relates to the technical field of fault phase selection, and more specifically, to a fault phase selection method for new energy electric field tie lines. Background technique [0002] With the improvement of new energy power generation technologies such as wind power and photovoltaic power generation, new energy power plants, as green energy, have been widely used in power grids. Due to the large difference between the short-circuit current characteristics of the new energy power supply and the traditional synchronous generator, the traditional fault phase selection element cannot operate correctly, which will seriously affect the operation performance of the distance protection of the tie line and the automatic reclosing switch, endangering the new energy station. and grid security. [0003] Traditional phase selection methods include sudden phase selection and steady-state phase selection. Among them, the sudden phase selectio...

AI Technical Summary

Problems solved by technology

Due to the large difference between the short-circuit current characteristics of the new energy power supply and the traditional synchronous generator, the traditional fault phase selection element cannot operate correctly, which will seriously affect the performance of the tie line distance protection and automatic reclosing, endangering the new energy station. and network security

[0003] The traditional phase selection method includes sudden phase selection and steady state phase selection. Among them, the sudden phase selection element can only be used in a short time after a fault, and cannot solve the problem of phase selection during fault transition and fault development, so it needs to be combined with steady state phase selection. Used in conjunction with quantity selection

However, the traditional phase selection method is mainly based on the assumption that the power supply is a synchronous generator, and the positive and negative sequence current branch coefficients are approximately equal after a fault. However, the special short-circuit current characteristics of the new energy power supply make the above assumption no longer applicable, resulting in the selection phase error

To solve this problem, the improved phase selection methods include: phase selection method based on positive sequence current compensation (Huang Tao, Lu Yuping. Improved current mutation phase selection element suitable for doubly-fed wind farms [J]. Power Grid Technology, 2015, 39( 10): 2959-2964.), but it is only applicable to the wind farm after the action of the crowbar. , Xiao Fan, Wang Youhuai, Zhang Zhe, Yin Xianggen. Applicable to double-fed wind farm tie-line fault phase selection method [J]. Electric Power System Automation: 2018, 3:1-7), but mainly for phase selection method of sudden change Improvement, can not solve the problems faced by steady-state measurement phase selection, and is only applicable to double-fed wind farms

In summary, the current research on fault phase selection methods for new energy electric fields is limited, especially in the aspect of steady-state fault phase selection, and no effective improvement method has been proposed.

Images