Method for protecting circuit interphase fault voltage phase based on fault overall-process transient characteristic

Abstract

The invention discloses a method for protecting a circuit interphase fault voltage phase based on a fault overall-process transient characteristic. Whether a protection device transmits an action skip signal or not is determined according to whether the phase angle by which the fault inter-phase voltage before a circuit interphase short circuit fault occurs is ahead of the fault inter-phase voltage at a power transmission circuit protection setting range falls in the action characteristic zone (90 degrees and 270 degrees). The voltage before the circuit fault does not need to be memorized and a relay is used for protecting hardware without needing to set a voltage maintaining circuit before the circuit fault. An action characteristic circle corresponding to the method for protecting the circuit interphase fault voltage passes the third quadrant and the origin of coordinates is in the action characteristic circle. Thus, an action characteristic of the method is free of protection dead zones when an outlet interphase short circuit fault is protected and misoperation is avoided when a backward outlet interphase short circuit fault occurs. According to the method for protecting the circuit interphase fault voltage based on the fault overall-process transient characteristic, the action characteristic is the transient action characteristic in the whole circuit interphase short circuit fault process and the strong capacities of resisting influences of transition resistance and loaded currents are achieved.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a phase-to-phase fault voltage phase protection method based on the transient characteristics of the whole fault process. Background technique [0002] The power frequency variation distance protection constitutes the distance protection by reflecting the sudden change of the working voltage amplitude. This method has the advantages of being less affected by the operation mode of the power system and having a strong ability to resist transition resistance. However, since the mutation of the working voltage amplitude used in this method only exists in the initial stage of the fault, it cannot be used as a backup protection for high-voltage transmission lines. [0003] Impedance distance protection reflects the fault distance according to the measured impedance to distinguish whether the fault point is inside or outside the protection zone. Impedance...

AI Technical Summary

Problems solved by technology

Since the origin of the coordinates is located on the boundary of the action characteristic circle, there is a possibility of misoperation for a phase-to-phase short-circuit fault at the outlet in the opposite direction, and the larger the transition resistance is, the easier the protection is to malfunction when there is a short-circuit fault between phases at the outlet in the opposite direction, which seriously threatens the safe and stable operation of the power grid.

Images