Self-adaptation ground distance protection method and system

Abstract

The invention provides a self-adaptation ground distance protection method. The method is implemented on a power grid to which a new energy power generation device is connected. The method includes the steps that the real-time measured impedance, at the time of occurrence of a ground fault, of a measured protection point is obtained, and according to the intrinsic parameters of the new energy power generation device and the actually measured operating data, at the time of occurrence of the ground fault, of the new energy power generation device, the current equivalent impedance of the new energy power generation device is calculated; according to the current equivalent impedance of the new energy power generation device, the real-time measured impedance of the measured protection point is corrected; the corrected real-time measured impedance is compared with a preset protection setting value, and whether the protection action is started or not is determined according to the comparison result. According to the embodiment, it is unnecessary to change the protection setting value, and the method can effectively meet the requirement of the new energy power generation device for relay protection in different operation modes, increase the correct action rate of relay protection and accords with management rules and operation and maintenance systems of relay protection.

Description

technical field [0001] The invention relates to the technical field of new energy relay protection, in particular to a method and system for adaptive grounding distance protection. Background technique [0002] Relay protection is the first line of defense among the three lines of defense for the safe operation of the power system, and it is of great significance to the reliable operation of the power system. In order to meet the characteristics of relay protection, the fixed value of each line distance protection must be set according to the protection regulations, and the distance protection of each line also needs to be coordinated. [0003] With the grid connection of new energy power generation devices, it brings great challenges to traditional line distance protection. If the line distance protection is still set without considering the new energy power generation device, it will cause the protection to malfunction or refuse to operate; if the distance protection is s...

AI Technical Summary

Problems solved by technology

If the line distance protection is still set without considering the new energy power generation device, it will cause the protection to malfunction or refuse to operate; if the distance protection is set according to a certain operation mode of the new energy power generation, that is, a certain output, then Because the equivalent impedance of the new energy power generation device varies with its output data and is uncontrollable, it may still cause malfunction or refusal of the protection

[0004] In the prior art, there are two methods of line distance protection suitable for the connection of new energy power generation devices, including: 1. The distance protection is set according to the rated output data of the power generation device, but when the output data of the power generation device changes, then The protection may malfunction or refuse to operate; 2. Adaptively modify the protection setting value according to the real-time operation situation. Although it can better meet the protection requirements, in the actual application process, the protection setting value cannot be changed arbitrarily. Otherwise, it does not conform to the current management regulations and operation and maintenance system of relay protection

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