Parallel multi-loop power transmission line zero sequence parameter positive sequence on-line testing method

Abstract

A parallel multi-loop power transmission line zero sequence parameter positive sequence on-line testing method is disclosed and belongs to the field of parallel multi-loop line coupling parameter testing. According to the method, steady-state data is used for testing positive sequence impedance and admittance of a loop line being tested, a ratio of impedance of parallel multi-loop lines and a ratio of admittance of the parallel multi-loop lines are calculated in the same environment, own impedance (own admittance) Z<->ii and mutual impedance (mutual admittance) Z<->ij are estimated and are finally presented in a formula defined in the description, errors can be effectively suppressed, and zero sequence coupled impedance and admittance of the parallel multi-loop power transmission lines can be tested indirectly on line. Via use of the testing method put forward in the invention, special-purpose zero sequence operation is not required, normal system operation cannot be affected, specifically effects exerted on an impedance testing method by soil resistivity is taken into account, fault tolerance capability and anti-interference capability of the method can be guaranteed, a parallel multi-loop power transmission line parameter testing method can be simplified, and testing efficiency, flexibility and operability can be improved.

Description

technical field [0001] The invention belongs to the field of zero-sequence coupling parameter testing of parallel multi-circuit transmission lines. The present invention proposes an online test method for zero-sequence coupling parameters of parallel multi-circuit transmission lines. The method only needs the voltage and current at both ends of a group of parallel multi-circuit transmission lines during normal operation to measure the positive-sequence impedance of the test loop. Calculate the ratio of each impedance and each admittance of parallel multi-circuit lines under the same environment, establish the relationship between each corresponding physical quantity, and realize the indirect online test of zero-sequence coupling impedance and admittance of parallel multi-circuit transmission lines. The present invention proposes to express the relationship between self impedance and mutual impedance (self admittance and mutual admittance) by the ratio of physical quantities be...

AI Technical Summary

Problems solved by technology

The existing perturbation method is simple to operate but the test accuracy is not high; the existing incremental method has a large amount of measurement, complicated operation, and a large amount of calculation, which needs to solve n(n+1) / 2 complex number equations. Very complicated

[0004] The existing multi-loop synchronous zero-sequence test method can only obtain the overall average equivalent zero-sequence coupling parameters, but cannot obtain the actual phase domain parameters. It needs at least (n-1) synchronous zero-sequence of all parallel loops operation, which is difficult to operate in engineering practice

It is almost impossible to achieve under the normal operation of all parallel loops

Once all the parallel loops (even if there is only one loop) are out of sync, it will cause a large error

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