Seismic Vulnerability Analysis Of Outdoor Substation System

Electricity is one of the important energy to maintain social production and life.With the rapid development of national economy,the demand of power energy increased largely.As one of the main part of the power system,substation played a key role to ensure power system operating safety,including exchange and adjustment of power grid voltage,control the power flow,etc.Once the substation is damaged by earthquake,it will not only destroy regional power system,but also lead to serious secondary disasters and heavy economic losses.Therefore,it’s important to analyze the seismic performance of substation.This paper start from the seismic vulnerability of electrical equipment to carry out substation seismic reliability analysis.The main research contents and conclusions are as follows:(1)Based on the historical earthquake damage data,the main failure modes and causes of electrical equipment under the earthquake were summarized.The finite element model of substation electrical equipment with different support height,cross section and ceramic material was established,and the influence of different parameters on the dynamic characteristics of the support-equipment system and the seismic response was obtained through numerical analysis.Based on the above research results,the reasonable value of the dynamic amplification factor of the support during the seismic analysis of the equipment was determined.The research results show that the support has a certain dynamic amplification effect on the equipment.The amplification effect increases significantly with the increase of the height of the bracket,and decreases slightly with the increase of the cross-section size of the bracket.The acceleration amplification factor under the action is greater than the minimum value of1.2 given by the Standard.(2)Established a set of motion equations for independent equipment and coupling system connected by flexible bus,then solved by using the Runge-Kutta method.The influence of each key parameter was quantified by using backward elimination method and the response ratio formula connected by flexible bus was obtained.and the bus coupling effect and seismic response law was revealed and characterized.(3)22 seismic records were selected from the PEER database to perform the incremental dynamic time history analysis(IDA)of substation electrical equipment by using peak acceleration and maximum equivalent stress as seismic intensity index and engineering requirement paramenters.The probability seismic demand model of electrical equipment under different support height,cross section and ceramic material was established.and the seismic vulnerability model of electrical equipment under different support parameters was carried out.Then,Drawn the corresponding seismic vulnerability curves.The seismic vulnerability data of substation electrical equipment at home and abroad were summarized and compared with the analytical vulnerability data obtained in this paper.(4)The substation damage grade was defined from the system level,and the failure state of substation system was evaluated by the output power loss ratio.According to the characteristics of substation system,an efficient algorithm for network connectivity analysis of substation system was proposed,which was improved on the basis of traditional warshall algorithm.Then,based on the damage grade partition index and the improved connectivity algorithm,combined with the vulnerability data of electrical equipment,the algorithm was applied to the seismic vulnerability analysis of substation system,the seismic reliability of substation system was analyzed by Monte Carlo simulation method.On the basis of the study of relevant theories and analysis methods,a case study was made.The analysis method proposed in this paper can be used to evaluate the seismic performance of substations and provide theoretical basis for the prediction,reinforcement and recovery of substations before earthquakes.