Transformer-isolated static Var generator and control method thereof

Abstract

The invention discloses a transformer isolated static Var generator and a control method thereof. The transformer isolated static Var generator comprises current transformers, voltage transformers, a boosting transformer, a static Var generator (SVG) starting device, resistance-capacitance (RC) filtering branches, module current transformers, output reactors and converter units, wherein the output ends of at least two converter units are connected with the output reactors; after passing through the RC filtering branches for higher harmonic filtering and passing through the SVG starting deviceconsisting of output end resistors and contactors, the output of each converter unit is connected in parallel at a low voltage bus; after total current is synthesized, voltage is boosted to a power grid voltage by the boosting transformer; each module is connected with the module current transformer; the low voltage bus is connected with a low voltage side voltage transformer and a low voltage side current transformer; and a high voltage bus is connected with a power grid side voltage transformer and a power grid side current transformer. By the technical scheme provided by the invention, theoutput current and SVG capacity of the static Var generator are increased, the SVG is endowed with higher harmonic filtering capacity, and system redundancy is increased.

Description

technical field [0001] The invention relates to a power quality control device and a method thereof, in particular to a transformer isolation type step-up phase-shifting multiple static var generator and a control method thereof, which are widely used in various power systems. Background technique [0002] With the rapid development of my country's national economy, the inductive and nonlinear loads in the power grid continue to increase, such as: rectifiers, asynchronous motors and electric arc furnaces, etc. The continuous access of these loads makes the power quality of the power grid continue to deteriorate. In mining, metallurgy, port and petrochemical industries. [0003] The main way to solve the power quality problem of the current power grid is to install devices such as FC, TSC or TCR. FC is fixed reactive power compensation, which will overcompensate and undercompensate when the reactive power of the load changes, and FC is passive filtering, the filtering effect...

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to provide a parallel multiple converters, so that the total output current can be increased, and then through the isolation and boost of the transformer, the output voltage can increase the voltage of the user grid. The transformer isolated static var generator and its control method solve the problem of large Power SVG switching frequency is low, the output power is insufficient, the DC side between the converters is not independent, the reliability of the converter is reduced and the technical problems of damaged equipment are inconvenient to replace

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