When the inverter is running power to the standard frequency power network, the speed can be changed without changing the windings at all. This type of generator can guarantee the standard frequency of the generator output when changing the speed. The Yevsk hydroelectric power station in Karelia is equipped with this type of generator and has a capacity of 40 MW. The two pumped-storage power stations in Japan are equipped with motor-generators, of which the capacity of the large-scale pumped-storage power plant is 320 MW. The variation range is ±5%. When the water head changes, the above-mentioned generator can ideally ensure that the turbine operates in an optimal state. The disadvantage is that the capacity of the excitation system is large. The excitation capacity is proportional to the change in speed, which creates the problem of introducing these capacities into the rotor windings by brushes on the unit shaft. The capacity of the excitation system of the Dahei Pumped Storage Power Station is 72 MVA. The total cost of the generator is 115% higher than that of the expected ordinary generator. Two-speed synchronous hydroelectric generator. The generator has a double stator winding with a pole on the rotor and is a patented product of ABB (Germany). The number of poles of the rotor is adapted to low speeds, and when converted to high speeds, some poles are connected. When the rotational speed changes, the external transfer switch connected to the pole of the rotor through the brush on the generator shaft connects the poles of the rotor. This type of hydroelectric generator has already started production and has been put into operation in many pumped storage power stations in Europe and China's Panjiakou pumped storage power station. According to the information provided by ABB, the cost of such generators is 7% higher than that of conventional generators, but in the case of preferred dual speeds, the efficiency loss of the turbine can be completely avoided. Apple Headset Wireless Charger Qi Certified Charger,Apple Wireless Charger,Apple Watch And Phone Charger,Apple Headset Wireless Charger wzc , https://www.dg-wzc.com