Development And Testing Of Substation-area Backup Protection In Intelligent Substations

Along with the increasing complexity and flexibility of power grid, the traditional configuration of relay protection cannot satisfy the requirements, especially for the traditional backup protection which is defined by stepwise principle, it has massive disadvantages such as complexity in setting and coordination, slow speed in action and so on, which exerts certain danger for safe and stable running of power system. Intelligent substation adopts a series of new technologies, and accomplishes information sharing in the substation based on IEC61850, which provides benefits for research of new backup protection. This dissertation researches substation-area backup protection new principle, implementation technology and testing method based on substation-area backup protection in intelligent substations. The main tasks are described below:The intelligent substation relay protection configuration new method which has distributed main protections and centralised substation-area backup protection is proposed. In this new method, main protections configurated in dependently by intervals, and centralised substation-area backup protection is also configurated to accomplish backup protection function of the substation. Substation-area backup protection method based on current differential principle is researched, which divides the substation into different differential areas in order to justify and locate faults, and to accomplish backup protection function by coordinating with main protection. A typical220kV substation simulation model is built by utilising PSCAD, and the accuracy of this principle is verified.Substation-area backup protection equipment based on current differential principle is developed. This equipment adopts multiprocessor structure and multitask operation system, and can support IEC61850-9-2and GOOSE communication. It acquires voltage and current sampling data, switch status and main protection action information to accomplish backup protection functions of the substation. The testing of substation-area backup protection equipment based on digital relay protection device is accomplished, in which digital relay protection device and substation-area backup protection equipment are configurated, and tests of normal running, action failure of main protection, action failure of switches and so on are conducted. In this way, the accuracy of substation-area backup protection equipment logic actions is verified.The substation-area backup protection equipment testing method based on RTDS is proposed, and substation-area backup protection equipment testing by using RTDS is conducted. The substation primary system simulation model is built by using RTDS, in which fault-controlled and circuit breaker controlled subsystems are configurated, and GTNET-SV and GTNET-GSE (GOOSE) are also configurated. The closed-loop test towards substation-area protection equipment is conducted. By simulating different working condition of normal operation, internal fault and erternal fault and analysing simulation results, the dynamic performance of substation is verified.