Preventing DC over-voltage in multi-terminal HVDC transmission

A study was made of power reduction control which is used to avoid DC over-voltage for multi-terminal HVDC transmission of offshore wind power. Voltages and frequencies of offshore AC wind farm networks are used for transmitting control signals for the power reduction control. These methods do not require fast communication. Power reduction sharing among the offshore wind farms using the different control signals was analysed. The control systems were also compared against the DC chopper method to prevent a DC overvoltage. Simulation and experiments were carried out to evaluate the control systems.Data comprise experimental and simulation results (all as a functino of time):for increase of offshore, AC network frequency - AC grid voltage, power of converters, DC voltage and ratio of reduction of AC wind-farm voltage ;for reduction of offshore-network voltage – AC grid voltage, power of converters, DC voltage and ratio of frequency of increase of AC wind-farm voltage;using chopper resistor – AC grid voltage, Power of converters, DC voltage and Duty ratio of reduction of DC chopper;for reduction of offshore AC network voltage – Power of converters, DC voltages and Ratio of voltage reduction;for increasing offshore AC network frequency – Power of converters, DC voltages and Ratio of frequency increase;using chopper resistor – Power of converters, DC voltages and Duty ratio of reduction of DC chopper.Research results based upon these data are published at http://doi.org/10.17775/CSEEJPES.2015.00011