| 摘要 |
PURPOSE:To switch the operation mode of water turbin in a prompt and smooth manner, by opening a flow control valve rapidly to a no-load opening or to a greater opening so that an S-shaped part of the characteristic curves of flow rate and torque is etingished substantially. CONSTITUTION:In switching the mode of operation f a reversible pump-turbine from its condenser operation to power generating operation, air is removed from a runner chamber, and then guide vanes are opened at a certain high speed. Here, providing that the operating point of the pump-turbine has entered into an S-shaped part at a point P1 of a characteristic curve 6A and if the guide vane opening speed is kept high, the operating point gets out of the characteristic curve 6A but gets into another characteritic curve 7A corresponding to a greater opening angle, along a transient path shown by the dotted line in the drawing. Therefore, rapid transition to pumping flow is not caused since the S- shaped part does not exist substantially in the operational range of the pump- turbine at the time of switching the mode of its operation. |
