Historical sketch, constitution of EHV AC and DC links, Limitations and Advantages of AC and DC Transmission.
Valve Characteristics, Properties of converter circuits, assumptions, single phase, three phase converters, choice of best circuits for HV DC circuits.
Analysis with grid control but no over lap, Analysis with grid control and with over lap less than 60 deg, Analysis with overlap greater than 60 deg, complete characteristics of rectifier, Inversion.
grid control, basic means of control, power reversal, limitations of manual control, constant current versus constant voltage, desired feature of control,actual control characteristics, constant -minimum -Ignition –angle control, constant –current control,constant –extinction –angle control, stability of control.
Introduction, DC reactor, voltage oscillations and valve dampers, current oscillations and anode dampers, DC line oscillations and line dampers, clear line faults and reenergizing the line.