Fault direction identification method for distribution network with distributed generation

Abstract

The invention discloses a distributed power source-containing power distribution network fault direction identification method. According to the method, an existing fault direction identification method is improved and optimized on the basis of the phase of fault current; on the basis of 0.02s of basic time delay, if the phase of the fault current ranges from 85 degrees and 95 degrees, 0.02s is delayed, so that the phase of the fault current can be in a normal algorithm identification range; and the vector delta of a fault direction is judged through calculation, so that the fault direction can be judged reliably. The fault identification method is not affected by factors such as power flow directions, ground resistance, fault types, the capacity ratios and positions of DGs and harmonics; and the algorithm can reliably identify fault directions in the full length range of a line. A situation that the phase of current is 90 degrees is finely analyzed, the possibility of wrong judgment under a condition that the phase of the current is about 90 degrees can be greatly reduced, and reliability can be improved.

Description

technical field [0001] The invention relates to the field of relay protection of distribution networks, in particular to a method for quickly identifying fault directions of distribution networks containing distributed power sources, which is suitable for use in distribution networks containing distributed power sources. Background technique [0002] Due to the access of more and more random Distributed Generations (DGs), the radial power distribution network has become a multi-terminal power supply network, which requires a large number of directional elements to be added on the basis of the original three-stage current protection, such as Directional components such as power directional relays constitute a three-stage directional current protection. For distribution network automation construction, if a large number of similar directional components such as power directional relays are used, the increased cost will become an inevitable problem. Therefore, it is imminent t...

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Problems solved by technology

[0031] In order to solve the problem that the method of judging the fault direction based on the fault current phase is prone to be unreliable when the fault current phase approaches 90°, the present invention improves the above fault current identification method and provides a new distributed power distribution Fast direction identification method for grid faults

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