Research On Fault Diagnosis And Risk Awareness Technology Of Inexact Power Grid

Fault diagnosis and risk assessment of power grid is of great significance to the security and stability of power system.However,there are randomness and volatility in the operation of primary equipment in power grid,and there are data errors,missing,refusing to move and misoperation in the operation of secondary measurement and protection equipment,which leads to the incompleteness and uncertainty of sample information of the whole power grid,and it is difficult to realize reliable fault diagnosis and risk assessment of power grid.Therefore,in this paper,probability interval is used to describe the results of inaccurate power grid diagnosis and assessment,and the method of power grid fault location and risk assessment is studied based on imprecise mathematical theory.(1)Propose a non-accurate fault location method of "flash fingerprint" on the transmission line.By optimizing the PMU configuration node as a power flow fingerprint,the probability interval corresponding to different fault types is calculated using inaccuracy theory combined with the power grid fault principle,and the fault is identified and the specific location of the line is located.(2)A risk assessment method based on D-S evidence theory and utility theory is proposed.Firstly,the life model of each component in the power grid is established,and the reliability interval of each element is obtained by using the reliability theory.Secondly,according to utility theory and system stability theory,the severity index of different fault combinations is calculated.Finally,combined with reliability and severity,the risk index range of the whole power grid is calculated to realize the risk assessment of power grid.This paper uses the IEEE11 model and a regional power grid model simulation in Sichuan to verify the feasibility and accuracy of the fault diagnosis method.The results show that the diagnosis method proposed in this paper has strong fault tolerance and accurate fault location.A simplified power grid model is used to simulate and evaluate the risk assessment method in the article.The results show that the method can predict the behavior and trend of the power system after failure,and the calculated risk index can reasonably judge and evaluate the current power grid.Operational safety level.In summary,the research results of this article will help to improve the security and analysis level of grid operation.