Research And Application On Overload Control Strategy In Power System

The high requirement of reliability and continuity of power automation system makes it necessary to work all the time without any interruption. However, it is difficult to completely avoid the faults caused by human and non-human factors in the running system, including electronic equipment overloading, substation losing electricity and so on. Therefore, eliminating overload automatically is an important and indispensible function of power automation system.In order to eliminate equipment overload automatically, the loads or part of loads carried by device are required to be transferred. BATS (Busbar Automatic Transfer Switch) device is an economic and effective technical measure with uninterruptable power supply to users. This paper did some researches on wide-area BATS (Busbar Automatic Transfer Switch) protection of power grid, and could automatically eliminate overloads with soft BATS technique. Overload elimination not only improves the reliability and continuity of power dispatching automation system, but also reduces the installation and maintainability of BATS device in power system.This paper researches the actual operation modes and structures of power grid, and makes an analysis of BATS application. The basic BATS models are classified, built and automatically searched with power grid structure topological analysis by BFS (Breathe First Search). Compared with the conventional BATS, the soft BATS technique can save the cost of device and be easily maintained. Meanwhile, BATS models can be updated according to varieties of operation modes of power grid.Owing to exceeding the load-carrying capacity, electrical device overloads. The limitation value of current and power in the base property of device is threshold value. Heavy device is the one, of which the current or power exceeds the threshold value. When there is heavy device in power system, the BATS model that includes heavy device is automatically searched, and BATS strategy is correspondingly generated. The generated BATS strategy is verified by EMS (Energy Management System) to check if there is new device overloads by BATS switch operation and the flow calculation is constricted. With the EMS system verification of the generated strategy, it is proved that using soft BATS technique to eliminate overloads is practical and feasible.This paper use FAHP (Fuzzy Analytic Hierarchy Process) to find out the best strategy. In consideration of the rapidity, economy and stability aspects of power system, the comprehensive weight of each BATS strategy is calculated. The BATS strategy with largest comprehensive weight is the best strategy.