IMPORTANCE OF “HVDC” using “VSC” IN THE PRESENTDAY SITUATION:

Rapid developments in the field of power electronic devices with turn off capability like IGBT (insulated gate bipolar transistor)and GTO( GATE TURN OFF DEVICES)makes the VSC(VOLTAGE SOURCE CONVERTERS) getting more attractive for HVDC. This new innovative technology provides substantial technical and economical advantages for direct applications compared to conventional HVDC.VSC based HVDC systems  are applicable for  high power rating (up to 200MW) .The VSC based HVDCinstallations has several advantages compared to conventional HVDC.Depending on the design of the DC circuits     1) Current source converters     2) Voltage source converters In the CURRENT SOURCE CONVERTERS ,we have to keep voltage as constant where as in CURRENT SOURCE CONVERTERS,we have to keep voltage as constant The world of converters may be divided into two groups    1) One group needs an AC system to operate and called as line commutated converters     Vsc1 acts as rectifier Vsc2 acts as inverter In the VSC based HVDC , there are no losses since we are not using any capacitor and inductor. In the Ac supply, as we are using Inductor and Inductor and hence losses are very high. Hence HVDCs’ are being employed now a days. VSC HVDC HAS THE FOLLOWING ADVANTAGES No need for short circuit power for commutation. Can even operate against black Networks. Can operate without communication between stations. Can operate to control the power continuously in one direction. APPLICATION’S OF HVDC TRANSMISSION USING VSC: High capacity control system Solid dielectric DC cable HVDC Light offers advantages due to the possibility to independently control both active and reactive power HVDC Light employs Insulated Gate Bipolar transistors (IGBTs).                                                                                                                                     By                                                                                                R.Sateesh Kumar                                                                                                    10H71A0240( 3rd EEE )