The Security Assessment And Reliability Analysis Of The Langfang Power System

It took place hundreds of cascading outages at home and abroad in reccent 20 years, which have brought the serious influence to the ormal order of seciety and resulted in tremendous loss to national economy. Langfang grid is the important part of Jingjintang grid, whether safty and stability in operation have a heavy impact on Jingjintang grid. Therefore, it is quite important to carry on the security assessment to the grid of Langfang, find out the weak spots and improve them in time.First, detailed analysis to off-normal voltage and element overload in the grid of Langfang have been made. In addition, this report analyses N-1, N-2 of Langfang grid in normal method of operation detailedly. Then it finds out the weak spots or areas and calculates static transmission limit of each main transmission line with modal analysis in the base of the biggest load levels of summer and winter of 2007. Finally, it calculates transient transmission limit, critical clearing time of 220kV lines and short-circuit current of each bus with the analysis of transient state of Langfang grid.