The Intelligent Analysis And Decision Support System For Power Grid

With the increase of power grid scale and the architecture tends to be increasingly complex, the management of power grid operation and the social responsibility of power supply enterprise increase. The power grid is growing as intelligent dispatching system; it demands the system realizing refined management through the perfect technologic support. The system can manage the operation of power network and also can do the intelligent calculation and analysis, provide assistant decision.There're a lot of calculation and analysis software for power grid. BPA,PSASP,PSS/E software are commonly used by now in china. They're important for operation analysis of power grid. But at the mean time, the software's diversity cases the difficulty of the maintenance of power grid's data models. The analysis of contingency and the calculation of the thermal stability limits are still not yet perfect. To solve these problems, the intelligent analysis and decision support system is developed to manage and analyze the operation of provincial grid. The system realizes the unified maintenance of the network's data model and the calculation of the thermal stability capability under different operation modes and different load levels; it also realizes the security correction of power network and provides the information of assistant decision. This article briefly introduces the whole instructor of the system, describes main functions including the generation of the operation modes, the calculation of power flow, the calculation of thermal stability capability, the security correction and so on.This paper mainly study on the calculation of transmission interface's control limit. The security operation requires that the power system can meet the load demand of the normal power supply and satisfy the thermal stability constraints, and also can withstand the impact of contingency. Based on the basic principle of engineering calculation method of the thermal stability capability, this article makes the calculation of transfer/residual coefficients after contingency into program. The paralleled lines or transformers are defined as a device group. Relations of the post-contingency and pre-contingency active power flow for device groups are studied. The post-contingency active power flows are formulated as linear functions of pre-contingency active power flows with the concept of transfer/residual coefficients. The constraints on device group's active power flow are formulated according to the short-term and long-term thermal stability limit. By the motive to maximize the minimum ratio of control limit to corresponding pre-contingency active power flow, a linear programming model is proposed to optimize the thermal stability control limit for device groups. The proposed linear programming model is solved by simplex method, and is divided into islands to improve calculation efficiency. The control limits of user defined transmission interfaces are deemed as the sum of that of related device groups. The calculation software has been developed based on C++ language. It can conveniently provide variety capabilities on condition of different maintenance schedules and different load levels to enhance the refined management.