The Design Of Low Frequency Load Shedding Distributed Device For Protecting Power System

The paper is mainly about researching the control problem of safety and stability of electrical network. when electric power system meets active vacancy , it is able to remove Secondary load with the change of frequency automatically, restrain voltage and the drop of frequency effectively and avoid the occurrence of accidents and the splitting of power grid. It aims at monitoring system frequency of some local electrical network, including some Large-scale power units like industry and mining enterprise and hospital with autonomous generating set and transformer station, and removing partial load by plan automatically in order to guarantee the whole system to operate well.The paper introduces the principle of low-cycle deloading and computational method of tuningset and introduces hardware design principle and software control method of deloading device. It uses single chip computer to do sample at the instantaneous value of alternating electric quantity, and then uses the way of calculating root mean square to acquire measured effective value and uses software to substitute partial hardware function, which is the one of innovation point in the paper.The device avoids the defect of point out deficiencies of fixed configuration relay which exists in many similar products. According to actual demand, we can use value set menu and separately allocate every relay export, which makes the export affiliate to other rounds and the whole device used more widespread and more conveniently.