A Transmission Network Short-term Planning Decision System Based On EMS & Credibility Theory

With the continuing expansion of power system, the manual planning can not find the optimal solution from lots of candidates. Therefore, people are considering the transmission expansion method which can automatically form solutions and calculate the best one as a result.Due to increasing uncertain factors with the deepening of the electric power system reform, the transmission expansion considering uncertainties is recently paid attention to at home and abroad. Power flow calculation is the basic tool of planning. This paper introduces the Credibility Theory which researches fuzzy phenomena to power flow and establishes fuzzy power flow arithmetic. It has strict math fundament so can be benchmark for others. Besides, it can give expectations and variances for analyzing and decision. The transmission expansion is always depending on off-line data.Recently, EMS has been widely used. Thus we can use online data to calculate expansion planning. This mode not only can lower the cost and the difficult of use, but also enhances the results'credibility. A transmission planning system based on EMS is proposed in the paper, which uses sensitivity analysis to form set of candidates, design four calculating types and use genetic algorithm and linear programming to get the optimal solutions.IEC 61970 standards is proposed for data exchange. This paper implements the dual convert between SVG and EMS graphic format. With the import of CIM/XML and SVG, the transmission planning system can base on different EMS data. Considering publicity of plan schemas, a graphic platform based on WEB is designed in this paper. Through browsers, users can see the future network and do simulative operations, then maybe give response to planners.