Distributing capacitance current and transition resistance influence resisting line one-end fault ranging method

Abstract

The invention belongs to the electrical power system domain, specially relates to the line single end fault distance measuring method of the anti- distributed capacity electric current and the transition resistance influence. Including: surveys the transformer substation protection installment place fault phase voltage, the phase current, the zero sequence voltage, the zero sequence electric current and the negative sequence electric current as the input value; using the fault voltage cross zero time to measure the resistance characteristic which is not influence by transition resistance, from the protected line begin end start, computing the measure voltage real part computed value of the fault point voltage cross zero point time, compared with the measured value of the measure voltage real part, computing the error; and taking the delta-S as the step size, in turn computing the setting range which is protected by the send tripping signal, if cannot obtain the protect tripping signal, searching the total track length which is protected, taking the minimum point as the fault point. The invention method is not influenced by the distributed capacity electric current and transition resistance, does not have the false root problem of solving equation method and non convergence question of the iterative method, and has the very high practical value.

Description

technical field [0001] The invention belongs to the field of power systems, and in particular relates to a line single-end fault distance measurement method that is resistant to the influence of distributed capacitive current and transition resistance. Background technique [0002] The transmission line is responsible for the important task of transmitting electric energy, and its failure directly threatens the safe operation of the power system. In particular, China's voltage level is developing from ultra-high voltage (represented by 500kV) to ultra-high voltage (represented by 1000kV), and the capacity of transmission lines is further increased. The stability of the power system and ensuring the safe and stable operation of the system are of great significance. [0003] Fault location methods are divided into two types from the perspective of using electrical quantities: single-ended method and double-ended method. The double-ended method requires the use of electrical ...

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Problems solved by technology

The hyperbolic tangent function characteristic determines that its ability to resist transition resistance is very poor, and the additional measurement impedance brought by transition resistance will seriously affect the accuracy of fault location

The improvement scheme of the traditional impedance method: if the reactance component is used for fault location, and the influence of the transition resistance is partially eliminated, it is no longer applicable to the fault location method modeled by the distributed parameter line model, mainly because the line impedance Z mea It is a nonlinear function of line resistance, inductance, and capacitance per unit length, and it is difficult to decouple; other solutions such as assuming that the impedance of the opposite end system is known or assuming that the current at the fault point is in the same phase as the current at the observation point, the super / On UHV long lines, the error caused is unacceptable, so it is difficult to directly apply the traditional single-ended impedance fault location method to EHV / UHV long lines

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