Quantitative Risk Evaluation And Algorithm Studies On The Maintenance Of HVDC

With the continuous development of power grid, HVDC has become the main way forinter-regional power exchange with high-capacity. How to improve the operational reliabilityof HVDC by arranging a reasonable maintenance for DC channel is an important issue thatoperation department and equipment department in power industry are very concerned about.Since HVDC transmission systems have played core role in power grid in500kV andabove high-voltage level, the decisions for the maintenance of HVDC systems are hard tomake by operation department because of the considerations of the whole gird’s security,which also caused scheduling conflict with the maintenance department on work goals.Therefore, the maintenance department had to let HVDC running with small defects insteadof eliminating them as soon as possible in scheduled outage, which is not conducive tolong-term stable operation of power grid.At present, the reliability research of HVDC focus in its availability, but the currentreliability evaluation index cannot quantify the impact of outage of HVDC toward the entirepower grid, so it is difficult to provide substantive guidance or recommendations for thearrangement of overhaul. Therefore, it is necessary to put forward a new evaluation algorithmto analyze the reliability impact brought by the maintenance of HVDC to power grid system,so as to offer useful tools for evaluate the opportunity of HVDC systems’ maintenanceprovide the analysis of operational risk, which can achieve the goal of improving themanagement of HVDC between operation and maintenance.Combining the actual research, this paper presents a fuzzy assessment algorithm toquantize the risk of the overhaul of HVDC system. It can be built a fuzzy risk evaluationsystem by combining reliability assessment methods and fuzzy evaluation theory, in which therisk indicators and their algorithms are proposed. Then the difference of indicators will becalculated to reflect the impact on the reliability of power grid under the state that HVDC ison service and off, and provide the suggestions for maintenance plan from the outcome ofassessment.In order to test the validity of the algorithm, this paper designs the quantitative riskassessment program based on MATLAB. Taking the four HVDC systems in Southern Power Grid as research case, this paper calculates the assessment of shutdown risk of HVDCsystems under different operation states. The results of the simulation show that the proposedmethod can give a correct proposal on maintenance which conform to the theoretical analysis,and have a good guiding significance and engineering application value for the maintenancemanagement of HVDC systems.