Analysis of VSC-HVDC system feeding a passive network

With the advent of Thyristor technologies, High Voltage Direct Current (HVDC) transmission system is used for transmitting large amount of power over long distance. It is a mature technology and has been playing a vital role in both long distance transmission and in the asynchronous interconnections. VSC-HVDC systems represent recent technology in the area of DC power transmission. One of the limitations in using conventional HVDC system is that it is difficult to connect to a weak network with no local generations nearby. VSCs are based on IGBTs that can be switched on and off by control signals and can be operated at high frequencies. Since VSC, has the capability to control both active and reactive power, it has become a widespread applications in power system. In this paper, the behavior of a VSC-HVDC system when connected to a passive network is studied under the steady state and transient conditions. The simulations are carried out using Real Time Digital Simulator (RTDS) available at CPRI, Bangalore. Simulation results proved that the modeled controller has good steady state and transient response during the faults. Performance of VSC-HVDC is also studied when feeding the loads like motors and found that the system response is satisfactory.