摘要 |
<p>Steam flow to a turbine is reduced by partially closing intercept control valves to reduce turbine speed to a reference speed after sudden increases above this speed caused by sudden decreases in turbine load. Circuitry for developing a command signal for closing the valves in response to a difference between the reference speed and the actual speed of the turbine is provided. The command signal magnitude is varied to cause rapid closing motion of the valves during that portion of valve movement having little effect on steam flow and less rapid closing motion during that portion of valve movement having substantial effect on steam flow, thereby compensating for a nonlinear relationship between valve movement and change in steam flow.</p> |