Research On Starting Path Selection Of Extended Black-start Scheme

In recent years,with the construction of Inner Mongolia power grid,especially wind farm,solar photovoltaic power station and UHV line,the scale of Inner Mongolia power grid is expanding and the complexity is increasing.Therefore,the risk of large-scale power outages in Inner Mongolia power grid is increasing.In order to reduce the power failure losses,it is urgent to restore power supply.The black-start scheme is the most important measure to restore power supply as soon as possible after the blackout accident.Therefore,it is of great and far-reaching significance to study the black-start process of Inner Mongolia power grid and to formulate an effective and reasonable black-start scheme.Based on the idea of extended black-start and taking the Inner Mongolia power grid as the background,this paper studies the extended black-start scheme with Wanjiazhai hydropower station as the black-start source and the surrounding 10 thermal power plants as the started power plants.Firstly,an extended black-start scheme optimization calculation model is established,and the optimal power plants combination scheme and the corresponding start-up paths are searched by using the Dijkstra and the Depth First Search algorithm.Secondly,based on the selected program,the simulation model is built on the RTDS simulation platform and to simulate the process of black-start detailedly.This paper focuses on the analysis of the frequency overvoltage and operation overvoltage in the recovery process of lines for the started power plants,and the problem of voltage and frequency stability when the power plants' load is put into,and the voltage problem when the units are connected to the grid.Finally,after the started units are started successfully and forming a stable small system with the hydropower station,recovering the important load in the network and analyzing the problem of frequency overvoltage and operation overvoltage generated on the transmission line and the voltage and frequency stability problem when the important load is put into.After the simulation and analysis each stage in the process of black-start,the feasibility of the expanded black-start scheme is verified.