The Method and Structure of Switching on and off, and Regulating the Voltage of a Transformer Substation

Three-phase thyristor keys are intended to form the in-rush starting currents of electrical equipment with their subsequent shunted electrical apparatus in steady state operation. With reference to transformer substations, they perform shockless connection of the power transformer without generating inrush currents and voltage slump. To extend the functionality of thyristor keys it is proposed, except for shockless connection of the power transformer, to perform its disconnection without arcing between contacts of electrical apparatus, and perform continuous voltage regulation when used by the consumers when changing line voltage. The proposed method and structure for its realization on the basis of three-phase thyristor keys, a twinned reactor and a capacitor bank allows in case of change of the line voltage, simultaneously with the stabilization of the output voltage of a substation, to stabilize the generated reactive power at the input of the substation without creating current distortion in the power transformer and the line.

I. Introduction

Existing transformer substations of industrial enterprises are equipped with electrical devices with mechanical contacts [1]–[10], which do not provide shockless connection of the power transformer, its disconnection without arcing at the switch and continuous voltage regulation on the input voltage of the power transformer of the substations and when used by the power consumers. The capacitor banks (CB) applied in the transformer substation generate reactive power [11]–[26], which varies depending on the deviations and voltage fluctuations on the line and create additional losses from fluctuations of the phase of the mains current. This work is addressed to eliminate these shortcomings, which proposes the method and structure of switching on, switching off, voltage regulation and generating reactive power of a transformer substation and structure for its implementation.