Development Of A General-purpose System Of Relay Protection Setting Calculation

With the development of electric power industry, the scale of power grid and the capacity of single machine extend continually. The quantity and difficulty of technology for relay protection setting calculation and management increases greatly, and the corresponding request becomes more and more complex. Design of a general-purpose system of relay protection setting calculation and management for power plant plays an important role on reducing the work of the relay protection workers, decreasing the percentage of protection device's false action. It's helpful to enhance the efficiency and validity of relay protection setting calculation.In this article, a general system used for relay protection setting computation of power plants is proposed based on Visual C++ 6.0 and Access database. Various system networks of power plants can be easily built by using the Graphics model. And the setting calculation model contains conventional protections and computation protections. Therefore, different customer's requests could be satisfied, and the multi-functions of Graphics modeling, data management, fault analysis, protection setting computation and fixed value management are realized.Firstly, the system gross structure, software developing environment and function characteristics of models are introduced. Then the Network topology analysis and knowledge of faults of power system are also involved. Considering models when network is operated, calculation formulas and variant solving kinds of faults are also expatiated. Different setting computation principles of protective devices with individual protective theory are analyzed. And the computation system of relay protection with general character has been framed. Finally, a total assessment about the whole system's performance is evaluated.This friendly man-machine interface system can be operated and maintained easily. And it has been used on Tong Liao power plant and the local thermal power plant. It is proved performing well, as all targets were achieved.