Risk Analysis Of Cascading Failure Based On Power Flow Tracing Method

With the rapid growth of UHV grid, regional grids become more closely linked,long-distance transmission and large regional power grid interconnection is asignificant feature of modern power grid. Because of electricity market mechanisms,the grid often runs at a limit state. In recent years, worldwide large area blackoutmakes network security issues become increasingly prominent, exposing thevulnerability of large interconnected power fully. Because of the serious impact on thegrid caused by cascading failures and the complexity of modern grid, how to preventcascading failure of the power system has been a hot and difficult issue. This paperpresents a method to study risk assessment of cascading failures, the main work ofthis paper is as follows:Firstly, a cascading failure analysis method based on the power flow tracing isstudied in this paper. We can get utilization coefficient of the target line by powerflow tracing, determine the generator and load nodes which need to be adjustedquickly, effectively improve the load flow and prevent cascading failures’development.Secondly, in order to save computation time, we can use active power indicatorsto select initial failures, which will seriously affect the safe operation of the system, sothe number of the initial failures in contingency set is reduced. At the same time,considering magnitude of flow change and the extent of overlimit in the target line,this paper defines an indicator to screen the next fault line.Finally, this paper defines two Indicators: risk of failure chain and vulnerability ofline. We can quantify the influence of control measures on safe and stable operation ofthe system, and select system weaknesses by the calculation of the indicators,providing reference for the dispatchers.