Design and Hardware Implementation of SVC using Thyristorised Control for improving power factor and voltage profile of inductive loads

In power system the voltage level at different buses changes with the change in load. The voltage level at the load side must be maintained within permissible range irrespective of the type & magnitude of the load. For maintaining voltage fixed within permissible limits, it is necessary to maintain the balance of reactive power in the system as reactive power is directly related with voltage. That means reactive power generation and absorption must be equal. Any mismatch occurs in the reactive power balance affects the bus voltage magnitude. SVS provides a fast, smooth and step less variation of compensation by injecting or absorbing reactive power into the line. In this paper, a compact control circuit for balancing the load and correction of power factor in a single phase system is presented. Thyristorised control circuit is developed by using different circuit models. This circuit parameter calculation is based on unity power factor approach. A laboratory prototype of a Thyristor Switched Capacitor (TSC) at 230 V, 50 Hz and by taking static load (chock coil and lamp load) and dynamic load (single phase induction motor) of different values is designed and implemented. Also, a new approach for balancing reactive power of the system by implementing Thyristorised control circuit and changing value of capacitor as per the requirement of the system and measured the value of power factor and voltage. This measuring technique is based on gate pulses generated for anti-parallel pair of thyristor for triggering capacitor connected in series with it. Finally, a brief description of the system block diagram is given together with results for both static and dynamic loading condition of the prototype built.