An overcurrent protection method, fixed value optimization method, and optimization system for a distribution network with distributed power

Abstract

The invention discloses a distribution network overcurrent protection method with a distributed power supply, and a fixed value optimization method and system, and belongs to the technical field of distribution network relay protection. When a fault occurs, a data acquisition system acquires a fault current flowing through each inverse time limit overcurrent relay in the distribution network witha distributed power supply; according to the inherent characteristics of the fault current and the inverse time limit overcurrent relay and the selectivity, the sensitivity and reliability requirements of the relay protection, a mathematical model is established, wherein the mathematical model comprises an objective function and a constraint condition; a particle swarm optimization based on crowdsearch is employed to perform particle optimizing of the time setting coefficient and starting current of the inverse time limit overcurrent relays; and according to the optimal particles, the time setting coefficient and starting current of each inverse time limit overcurrent relay are subjected to re-assigning, and faults are cut off in the shortest time. The problem is solved that the relay fixed value is improperly set after the distributed power supply is accessed into the distribution network.

Description

technical field [0001] The invention belongs to the technical field of distribution network relay protection, and in particular relates to an overcurrent protection method, a fixed value optimization method and an optimization system for a distribution network including a distributed power supply. Background technique [0002] In order to save resources and protect the environment, a large number of distributed generation (DG) is connected to the distribution network. While DG provides convenience for people, it also brings some problems. For example, the fluctuation of DG output will cause the original distribution network The fault level has changed such that the original setting of the relay is no longer applicable and a new setting is required. The inverse time overcurrent protection has the function of three-stage current protection to a certain extent, and its action time is shortened with the increase of the short-circuit current, which has a certain degree of adaptab...

AI Technical Summary

Problems solved by technology

When choosing an intelligent optimization algorithm, there is a wide range of choices, such as genetic algorithm, ant colony algorithm, simulated plant growth algorithm, differential evolution algorithm, etc. , but the programming of the above algorithm is relatively complicated and difficult to implement

The particle swarm optimization algorithm has few parameter settings, and the program is simple and easy to program, so it is the most widely used. However, because the particle swarm optimization algorithm is easy to fall into the local optimal solution, it is necessary to make corresponding improvements to jump out of the local optimal solution.

[0005] In the hardware system, the single-chip microcomputer currently does not have an exponential calculation function, and there is an exponential calculation formula in the operating characteristics of the inverse time overcurrent relay, so the hardware system only needs to be equipped with a single-chip computer and cannot meet the inverse time overcurrent of the distribution network with distributed power. Optimizing the Fixed Value of Relay

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