Research And Development On Microcomputer-based Protection For Small Capacity Power Units

It's time to develop small hydropower in many countries. Many medium and small thermal power plants are pressing on with technological improvement. From both market and promoting technology progress point of view, it's quite necessary to research and develop a set of microcomputer-based protection aimed at small capacity power units to replace the former transistor and electromagnetic protections. In the paper, the protection scheme of small capacity power units is put forward, and the grounding resistance formula of "ping-pang" generator exciting winding of variable bridge is educed. Furthermore, the whole set of protection hardware circuit is designed and the program is written. All the devices are debugged. Percentage restraint characteristics of differential protection and impedance characteristics of loss-of-excitation protection are tested automatically using advanced device. The difficulties encountered and solutions are summarized. In the end, the next step of the theme is viewed.Zhao Bing(automation of electric power systems)Directed by prof. Huang Shaofeng...