Star-connection capacitor bank switching module

Abstract

A star-connection capacitor bank switching module is disclosed. The star-connection capacitor bank switching module comprises a star-connection capacitor bank, three controllable switches K1, K2 and K3, three small inductors L1, L2 and L3, three capacitor pre-charging circuits 10, 20 and 30, and a silicon controlled rectifier driving circuit, wherein the N input terminal of the star-connection capacitor is connected with the null line LN of a distribution network line; A, B and C input terminals are connected with the first ends of the three small inductors respectively; the second ends of the three small inductors are connected with LA, LB and LC phase lines of the distribution network line through the three controllable switches respectively; the three capacitor pre-charging circuits are connected with the three controllable switches in parallel; and the three output ends of the controllable switch driving circuit are connected with the control ends of the three controllable switches respectively. The star-connection capacitor bank switching module is connected with the distribution network line; three-phase reactive power time-sharing compensation can be realized; the generation of surge current in the capacitor switching process can be effectively avoided; impact current that may be caused when the capacitor is connected to the power grid can be reduced; and the service life of the module is prolonged.

Description

technical field [0001] The invention relates to a star-connected capacitor bank switching module used in a three-phase power optimization device. Background technique [0002] The asymmetrical operation of the distribution transformer will generate a large amount of negative sequence current and zero sequence current. These negative sequence current and zero sequence current will seriously pollute the power grid, greatly increase the power loss of the power grid, reduce the output of the transformer, and threaten the safety of the distribution transformer. operation, seriously affecting the quality of power supply. The national standard GB50052-2009 "Specifications for Power Supply and Distribution" and DL / T572-2010 "Transformer Operation Regulations" all have strict requirements on the size of the neutral line current and the unbalance of the three-phase current when the distribution transformer with Y / YN0 connection is running. . [0003] The three-phase power optimizati...

AI Technical Summary

Problems solved by technology

This kind of compensation device has high cost, large volume, large harmonic pollution, high maintenance cost, and is not suitable for frequent operation.

Using an AC contactor to switch will generate a large surge current in the line, which will affect the service life of the capacitor and even cause the capacitor to explode

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