Study On The Security Risk Assessment Of Regional Electric Power System

In recent years, with the development of economy and society, electric power system is gradually developed into a super-large complex nonlinear systems, as a result, it leads to higher demands and challenges for the security and stability control of modern electric power system. Experts have more confidence in guaranteeing electric power system to be secure and stable with the promising prospect of smart grid. With the complex structure of the grid constant evolution, factors which some existing methods can not be assessed continue to be the direct cause of blackouts, which made Chinese government realize the exiting methods could maintain statabillity of electric power system,however, they can’t control the risk involved in electric power system effectively. So except for continuing developing the present methods, more comprehensive risk assessment system should be established from the application point of view.This paper constructs a complete index system about electric power system security risk assessment. Through analyzing large-area-blackout occurred in recent years at home and abroad, it summarizes the cause of the blackout occurred. On this basis, with large area blackout for the target(zero level indicators), it establishes a hierarchical assessment index system with four levels through the advantages of fault tree analysis model, which laid the foundation for the subsequent risk assessment. Because the arge-area-blackout comes from extreme natural disasters and power construction frequently last few years, it extends original indicator system to both aspects, which enriches and improves the evaluation system and makes the assessment more adaptable and operable widely.This paper proposes calculation about electric power system security risk evaluation indices based on the AGA-AHP algorithm. In the risk assessment process, it involves a lot of qualitative and quantitative indicators, and dimensionless process to indicators shows its rigorous logic. Corresponding weights and risk scores are calculated by AHP for each of these indicators. In order to reduce the subjective effects of human factors and the amount of calculation about consistency of judgment matrix optimization, this paper combines accelerating genetic algorithm and analytic hierarchy process, whichachieves the synchronization between sort weight and consistency test about judgment matrix and reflects the coordinated and inclusive approach.This paper conducts a pilot assessment according to the actual operation of the province A’s electric power system. Through analyzing running situation and characteristics of province A’s electric power system, with statistics about the risk of regional power over the years, it conducts specific assessment calculations towards to the province’s power grid. The assessment related to a total of 184 four indicators and 38 three indicators and gives value at risk of power system operation in the region, which provides a theoretical guidance for reducing the risk level of the province’s system.