Prototype Hardware Model Development of HVDC Transmission System

Abstract

The project entails simulating a model of a complete HVDC transmission line and prototype hardware model of HVDC transmission system. This involves the design of converter circuitry, gate firing units, gamma detection circuits, rectifier and inverter control systems and passive harmonic filtering circuits. The complete model converts AC power into DC power by controlled rectifier and then again converts this DC power into AC power by line commutated inverter, after transmitting DC power through the cable. This action is controlled automatically by the system. For prevention of large fluctuation in direct current due to variation in AC system voltage, maintaining direct voltage near rated value and prevention of commutation failure in inverter, three basic controls for rapid control of converters are implemented. Constant current control for both rectifier and inverter, CEA (constant extinction angle) control for inverter and CIA (constant ignition angle) control for rectifier. Conversion of power, bi-directional power flow on HVDC link and behaviour of HVDC link during fault occurrence and fault clearance are main objective of this project. Simulation of complete HVDC transmission system for 2.2 kW, 415 V, 50 Hz System is done in simulation software package. The gate firing using the Individual Phase Control (IPC) scheme and the Equidistant Pulse Control (EPC) scheme have been simulated to observe their relative advantages and disadvantages. By using ARDUINO DUE micro-controller, complete HVDC control system and gate firing units are implemented in hardware model. Thus, complete working model of prototype HVDC transmission system is developed using the basic concepts and appropriate circuitry.