Experimental investigation of grid frequency coordination control system in 500 kV DC converter station of East China power grid

Abstract

Direct Current (DC) transmission system is an important part of the interregional grid. However, the frequency impact of power grid caused by DC blocking is more serious with the continuous increase of scale of single DC transmission. The frequency coordination control system is applied to the receiving-end power grid in High Voltage Direct Current (HVDC) transmission system. In the cases of single-infeed HVDC blocking, multi-infeed HVDC blocking or fast power drop, the frequency coordination control system can reduce the frequency fluctuation of power grid by instantly promoting the transmission power of the rest normal DC systems and reducing power loss. The frequency coordinated control substation is an executive device of the system at the converter station. It keeps communicating with the coordinated control master station for real-time monitoring the operation of converter station, reports the fault and executes the remote power boost instructions. Taking the frequency coordinated control substation of 500 kV conventional DC systems as a research background, the load of converter station in a regional power grid is analyzed. The working mechanism of frequency coordination control system in the cases of current converter station fault or other station faults is analyzed. The actual effect of a frequency coordination control system on a converter station in East China power grid is investigated by testing the actual power, voltage and current variation of a conventional DC transmission system.