Reliability Assessment And Application Of County Electric Power Network Planning

Scientific and rational power grid planning is the premise of power grid, which is under safe, reliable and economic operation. The power network planning’s task is to minimize the total power grid construction and operation costs, which is ensured the safe and reliable electric power is delivered to user. In doing county distribution network planning, first is to analyze the status of the local power grid, and do reliability assessment for various running indicators. In doing reliability analysis, N-1criterion is always used for assessing the reliability of substations and lines.It is described power grid planning and reliability theory, introduced the reliability evaluation index in this paper, which is focused on the calibration of line N-l,checksum main transformer N-1and the load rate, and analyzed the operating characteristics of the county power grid. It is described several flow calculation method and based on the operating characteristics of the county power, the improved forward and backward substitution algorithm is proposed, which is applied to pressure parts distribution network flow calculation. Based on the different operating characteristics of power network at all levels, different flow calculation methods are used to calculated the results. Combined with N-1criterion, assess the reliability of the power grid.Finally, based on the above theory, this article uses Microsoft’s Visual Studio2010development platform and SQL Server2008database, county-level N-1grid reliability evaluation system is developed. The system is capable of drawing element modeling, flow calculation and grid reliability analysis. And the system is applied to the status of De’an distribution power network reliability assessment. The results show that the system is simple, practical and accurate calculation. In addition, the improvement of forward and backward substitution method is used in medium voltage lOkV power network flow calculation, which proved that this method is feasible. Through the above work, a reference is provided to enhance the reliability of power system planning and decision-making level and management level.