Current differential protection method for smart distribution network

Abstract

The invention relates to a current differential protection method for a smart distribution network, which comprises: mounting current transformers and smart distribution terminals at the positions of all switches in the smart distribution network, wherein each smart terminal serves as an agent, the agents are connected with one another through an optical fiber Ethernet, and the positive directions of all currents is the direction from a system power supply to the end of a circuit; automatically detecting the working state of a communication network through the agents, and determining if to perform current differential protection; when the communication network fails to work normally, applying the conventional three-stage current protection; when the communication network works normally, applying current differential protection and using the current differential protection as main protection; and allowing a local agent to compute a differential current and a braking current according to the local switching current detected by the local agent and downstream switching current transmitted by a downstream agent and determine if the protection is actuated. The overcurrent protection is local backup protection, and the protection of an upstream agent is local remote backup protection.

Description

technical field [0001] The invention relates to a current differential protection method suitable for an intelligent distribution network, and belongs to the technical fields of distribution network protection and intelligent distribution network. Background technique [0002] Smart distribution grid (SDG) is an important part of smart grid (SG), and the difference between smart grid and traditional grid is more obvious in distribution network. The level of intelligence and automation of the existing distribution network is much lower than that of the transmission network, so the intelligence of the distribution network is an important part of building a smart grid. Since there are a large number of distributed power sources (DG) in the smart distribution network, after the DG is connected to the distribution network, the distribution network will no longer be a pure single power supply and radial power supply network. If the system fails, the magnitude of the short-circuit ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the shortcomings that the traditional current differential protection cannot be applied to the existing distribution network, and propose a current differential protection method suitable for the intelligent distribution network. The information exchange of information, using the current phasor flowing through the local switch and the current phasor flowing through all the downstream switches to construct the differential value and the braking value, and realize the relay protection of the smart distribution network by comparing the size

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