Study On Asymmetry Three Governors Of Electric Control System For Wujiang Hydroelectric Plant, Guizhou Province, China

Loading uninterrupted transformation of electric power system results in frequent fluctuates of the electric net. Based on the departure degree about direction and numerical value at 50Hz, delivered horse power of hydraulic turbine generator unit should be adjusted constantly to maintain the rotate speed (frequency) of machine sets in a certain range, and keep it around the rated speed to meet demand of the first frequency modulation. For the attemper command, it needs to control the active power of hydraulic turbine generator unit to satisfy the second demand of the frequency modulation(AGC), and to achieve control tasks, such as starting up, shut down, emergency shutoff, etc. which are the fundamental tasks to implement the adjust command or control command in modern times.The thesis will discuss governor changing for large hydraulic turbine (250MW), based on the modification works of capability increased at Wujiang hydroelectric plant, Guizhou province, China. With the investigation and study of functionality, capability characteristics of large hydroelectric governors and its development at home and abroad, this paper sets forward a asymmetry structure of three governors applied to the electric adjustors of the water turbine regulation system. Thus, two same control units A and B will form the automatic control core by parallel connection means.A small set of PLC, as a control unit of velometer(C), not only have the monitoring and judging functions for automatic control system of governor in real time, but also can accomplish the auto-control and hand operate function for speedgoverning system, which will fulfill those self-regulation tasks which include starting up, shut down, fluctuating loading, emergency shutoff, etc.Furthermore, frequency modulation of electric net is also discussed in detail for speedgoverning system of the hydroelectric plant; which include the first frequency modulation and the second frequency modulation, and the paper shows a analytic study on asymmetry frequency measurement of hydroelectricity unit, PID arithmetic ant its operating conditions, too.