Study on flexible power system protection relay coordination software based on user-defined principle

The regional characteristic of relay setting calculation principles brings a challenge to the flexibility of relay coordination software, which restricts the expansion and application of relay coordination software at a certain extent. This paper proposes a flexible power system relay coordination software based on user-defined principles to meet different requirements of different electrical power companies. The common functional composition of relay coordination software is introduced firstly. Then, the flexibility of relay coordination software is discussed in detail from the points of power system operating conditions combination, step relay setting calculation, protective device setting calculation and relay setting listing. It is a good approach to achieve the flexibility of relay coordination software that protection engineers define relay setting calculation principles which will be used in relay coordination software according to their requirements. Finally, the paper presents an realization scheme for the flexible relay coordination software based on user-defined principles. The relay coordination software accomplished based on the proposed scheme will reduce a lot of workload for the maintenance of the software, and will be more flexible and expandable.