Vulnerability Risk Evaluation Of District Complex Power Grid

The analysis and assessment of the regional power grid vulnerability risk is a hot topic in the research of the safe and stable operation of the power system.In view of the existing research on the indicators of vulnerability risk analysis is not clear,and the assessment methods are chaotic.In this paper,a new risk evaluation index system for vulnerability is proposed,and a new evaluation method based on fuzzy comprehensive evaluation model is proposed.Some achievements have been made.The main contents and achievements of this paper are as follows:(1)Based on fuzzy comprehensive evaluation model,a method for power grid vulnerability risk assessment is proposed.This method establishes the index system of vulnerability risk assessment,and calculates the vulnerability risk score of the power grid based on the fuzzy comprehensive evaluation model.This method takes into account the safety,stability,reliability and other risk indicators of grid operation to obtain the score that reflects the real vulnerability of the power grid.Based on the analysis of the vulnerability risk of a provincial power grid,the vulnerability risk score of the power grid in the region is calculated.The calculation results show that the score can effectively reflect the vulnerability of the grid.(2)The risk assessment model of the regional power grid vulnerability is established by considering the automatic operation of power system,such as operations of the power automatic switchover device,the low-voltage and low-frequency load shedding device and the automatic power transfer program.This paper analyzes the cause of the change on vulnerability risk of the power system,under the influence of the automatic operation.And the corresponding vulnerability risk assessment model is established.An example is given to evaluate the effectiveness of the automatic operation on vulnerability risk assessment by considering the automatic operation or not.The evaluation results validate the effectiveness of the model and show the effect of the automatic operation on the vulnerability risk.(3)Based on the state enumeration method,a risk assessment method of regulatory operating system is proposed.The power flow safety risk,voltage safety risk and system weak link of the power system state after the dispatching operation are analyzed.The alarming process systems of the high risk state and the system weak link are established to provide the control personnel with alarming information for large risk system state.These messages can remind the operators to avoid the operations may trigger high risk system state.