A Relay Protection Method for Interphase Faults of Lines Based on Voltage Drop Phase Characteristics

Abstract

The invention discloses a line inter-phase fault relay protection method based on voltage drop phase characteristics. Fault inter-phase voltage, fault inter-phase current and fault inter-phase negative-sequence current of a transmission line protection and installation portion are utilized to calculate voltage drop from an inter-phase short circuit fault point to a transmission line protection setting range and per unit length transmission line voltage drop, whether an angle of the voltage drop from the inter-phase short circuit fault point to the transmission line protection setting range leading the per unit length transmission line voltage drop is within the range of -90 degrees to 90 degrees or not is judged. If the angle is within the range of -90 degrees to 90 degree, a protection device sends out motion trip signals. The method considers influences of inter-phase short circuit fault point voltage in algorithm design, utilizes the voltage drop phase characteristics of transmission line way side to achieve relay protection of transmission line inter-phase short circuit faults, eliminates influences of transition resistance and load current on protection motion performance, and is suitable for the relay protection of whole fault process of the transmission line inter-phase short circuit faults.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a method for relay protection of line phase-to-phase faults based on voltage drop phase characteristics. Background technique [0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection. If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a short-circuit fault between phases in the protection zone of the transmission line; Impedance distance protection action is overridden during short circuit fault. [0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause impedance distance protection to malfunction or refuse to operate. The impact of heavy-load cu...

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Problems solved by technology

[0002] The additional impedance generated by the transition resistance will seriously affect the action performance of the impedance distance protection

If the additional impedance generated by the transition resistance is resistive and inductive, it is easy to cause the impedance distance protection to refuse to operate when there is a short-circuit fault between phases in the protection zone of the transmission line; When short-circuit fault occurs, the action of impedance distance protection exceeds

[0003] High / super / extreme voltage AC transmission lines are often also heavy-duty transmission lines. Heavy-load currents will cause the impedance distance protection to malfunction or refuse to operate. The influence of heavy-load currents on the performance of impedance distance protection cannot be ignored.

Under the condition of overload transmission, the line has no faults. The measured impedance of the traditional distance protection will seriously deviate from the actual measured impedance due to the influence of the overload current, which will easily lead to the misoperation of the traditional distance protection, resulting in the expansion of the power grid blackout range, and even causing a large number of load transfers to threaten other power transmission. The normal operation of the line has brought huge potential safety hazards to the safety of the power grid

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