Intelligent protection circuit and method of unified power quality conditioner

Abstract

The invention provides an intelligent protection circuit of a UPQC (Unified Power Quality Conditioner). A series current converter of the UPQC is connected between a load i1 and an electric power system US through a coupling transformer UC; a parallel current converter is connected between the load and the electric power system directly and located in a circuit which is arranged behind the coupling transformer; two ends of the coupling transformer are in parallel connection with an antiparallel silicon controlled rectifier SCR and a fifth circuit breaker CB5; two ends of the antiparallel silicon controlled rectifier SCR are provided with disconnecting switches; a first circuit breaker CB1 is connected with the connected position of the coupling transformer and the electric power system; a second circuit breaker CB2 is connected with the connected position of the coupling transformer and the load; a third circuit breaker CB3 is connected with the connected position of the series current converter of the intelligent protection circuit and the electric power system; a fourth circuit breaker CB4 is connected with the connected position of the parallel current converter of the intelligent protection circuit and the electric power system. The invention also provides an intelligent protection method of the UPQC. The intelligent protection circuit and method of the UPQC can achieve rapid and efficient fault protection on the UPQC.

Description

technical field [0001] The invention relates to an intelligent protection circuit of a unified power quality controller for medium-voltage flexible AC power transmission and distribution in a power system. The invention also relates to a method for intelligently protecting the unified power quality controller by using the circuit. Background technique [0002] With the development of smart grid, various non-linear loads and large-scale power electronic devices are used more and more frequently, which brings convenience but also brings serious crisis to the power quality problem of the power system. Unified Power Quality Conditioner (Unified Power Quality Conditioner, UPQC) is a compound circuit that can solve voltage and current quality problems at the same time. Aiming at the characteristics of comprehensive compensation when there are voltage and current problems in the distribution line at the same time, it occupies an important position in the development of the future ...

AI Technical Summary

Problems solved by technology

The secondary winding of the current transformer cannot be opened, otherwise it will cause dangerous high voltage to burn the equipment, so when a short circuit fault occurs in the distribution power system, the series side converter in the UPQC cannot be disconnected from the secondary side of the current transformer open

If a circuit breaker is used to bypass the circuit on the primary side of the coupling transformer, due to the long operating time of the circuit breaker, it is still impossible to achieve fast and efficient fault protection for the circuit

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