Complex distribution network positioning method

Abstract

The invention discloses a complex distribution network positioning method. The method comprises: S1, an effective value of a zero-sequence voltage is calculated continuously; and when the effective value is larger than a voltage setting value, occurrence of a ground fault at the system is determined and positioning protection is started; S2, a corresponding zero-sequence current signal is extracted by line CTs installed at all nodes of a distribution network, low-pass filtering and interference signal removing are carried out on the signals to obtain a pure fault component; S3, analysis and fitting processing is carried out by using a Prony algorithm to calculate all sinusoidal functions of zero-sequence current pure fault components of all nodes at the same frequency, and then an amplitude value As and a phase feature theta s of the corresponding sinusoidal function under the dominant frequency component with the most obvious transient signal are obtained, so that the interference onpositioning by a non-deterministic factor is eliminated effectively; and S4, correlation coefficient array [rhosAB, rhosBC, rhosCD] between dominant frequency components of all nodes of a fault line is calculated and comparison of all correlation coefficients is carried out to realize fault positioning. The complex distribution network positioning method has advantages of high positioning accuracyand strong anti-interference ability and the like.

Description

technical field [0001] The invention mainly relates to the technical field of electric power system relay protection, in particular to a complex distribution network network positioning method. Background technique [0002] There are many outgoing lines in the distribution network, the structure is extremely complex, the operation mode is changeable, and there are a large number of overhead-cable hybrid lines on the line, which greatly increases the difficulty of accurate location in the event of a fault. With the comprehensive construction of smart distribution network, the requirements for the safety and reliability of power grid operation control are getting higher and higher. Therefore, it is urgent to study an accurate and reliable positioning method. [0003] The traditional positioning method based on steady-state components has weak fault characteristics due to the compensation effect of the arc suppression coil, and the fault boundary between the faulty section and ...

AI Technical Summary

Problems solved by technology

The transient component has obvious signal characteristics, high detection sensitivity, and is less affected by factors such as fault initial phase angle and transition resistance, and has a better positioning effect in the resonant grounding system of pure overhead lines, so it has become a research hotspot. However, the existing positioning methods based on zero-sequence current or zero-sequence power analysis are not effective in line selection and positioning in systems containing overhead-cable hybrid lines, and when the distribution network is resonantly grounded, due to the power frequency component and attenuation DC components, noise and other components, if not dealt with, will reduce the accuracy of positioning

Using the location method of wavelet packet and characteristic frequency band correlation analysis, if the wavelet basis function is not selected properly, it will be difficult to achieve accurate fault location

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