Relay protection method for line-phase fault based on transition resistance measurement

Abstract

The invention discloses a relay protection method based on a transition resistance actually measured line interphase fault. According to the method, firstly, the fault interphase voltage and the fault phase current at the two ends of a power transmission line are firstly measured; the active exchange power of the power transmission line and the consumption active power of the power transmission line are calculated; the active exchange power of the power transmission line is used for subtracting the consumption active power of the power transmission line to obtain the active power consumed by the transition resistance of a interphase short circuit fault of the power transmission line; according to the physical characteristic that the active power consumed by the transition resistance of the interphase short circuit fault point of the power transmission line equals to the product of squared absolute values of the fault interphase current vector sum at the two ends of the power transmission line and the transition resistance, the transition resistance of the phase short circuit fault point of the power transmission line is calculated; then, whether the transition resistance of the interphase short circuit fault point of the power transmission line is greater than 50 Ohm or not, which can be judged. The method has the advantages that the system impedance parameter does not need to be used in an algorithm model, and the action performance is not influenced by the system operation mode.

Description

technical field [0001] The invention relates to the technical field of electric power system relay protection, in particular to a relay protection method for phase-to-phase faults of lines based on transition resistance measurement. Background technique [0002] Relay protection is the first line of defense to ensure the safe and stable operation of the power grid, and its accurate and fast action is crucial to isolating faults and preventing accidents from spreading. The traditional backup protection is based on local electrical quantities, which need to be coordinated with offline preset values ​​to ensure the selectivity of protection actions. The outstanding problems of this mode are that the protection setting is complex and the action delay is long, which has been difficult to meet the security and stability requirements of modern complex power grids. In the case of large-scale power flow transfer, the remote backup protection is prone to chain malfunctions, which wil...

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Problems solved by technology

The electrical quantity involved in the calculation of this method is the fault component, which is only applicable to the relay protection within two weeks after the fault of the transmission line; the operation performance of this method is seriously affected by the transition resistance. When the transition resistance is large, the protection will refuse to operate. It is impossible to isolate the faulty line from the grid in time; this method is related to the impedance parameters of the system, and is affected by the operation mode of the system in principle

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