Research On The Key Technology Of Power System Black Start With Large Hydro-power Stations Assisted

In recent years,with the rapid development of ultra-high voltage technology and new energy sources,the Regional Interconnection of the power grid has been significantly enhanced,and the system's capacity for large-scale optimal allocation has been further enhanced,the possibility of large-scale power failure due to improper handling of large-scale interconnected system fault measures has further increased.Therefore,the reasonable and effective recovery plan can effectively shorten the time of power outage and reduce the loss caused by the accident,which is of great significance to ensure the implementation of emergency plan.In this paper,the key technology of black-start scheme is studied by using large hydro-power plants as black-start power supply to improve the power grid's ability to deal with large-scale blackouts.First,the reasonable black-start power supply and start-up units are determined according to the actual power grid development and the selection principle of black-start power supply,through the capacity comparison method and the impedance comparison method,the self-excitation condition in the black-start process is identified,and the reasonable and feasible black-start path of the power grid is established,the static and transient over-voltage capability of the power system is checked from the point of no-load line over-voltage and impulse load in the early black start-up period,and the transient stability capability of the small and weak interconnected system is evaluated Finally,from the point of view of relay protection,safety automatic device,dispatching automation and Communication,the specific requirements of the secondary system are put forward to ensure the realization of the black-start scheme.The simulation results show that the black-start scheme developed in this paper will not occur self-excitation phenomenon in the course of air-filled line of large hydro-power plant,in the normal operation mode of black start,the system voltage and frequency fluctuation are within the allowable range,and the system has good anti-fault impact ability,which can quickly and effectively realize the large-areapower grid load recovery.