| 摘要 |
<p>PURPOSE:To avoid unnecessary stoppage of a steam producing plant even when the turbine speed fluctuates by sending an open signal to a breaker in accordance with the load quantities before and after the load is disconnected and a selection controlling rod actuating signal. CONSTITUTION:When load disconnection occurs and a power load unbalance relay is actuated, a system stabilizing device 55 limits the load by opening a prescribed number of breakers (some of 58-62) connected with a load line so that the system load can become a certain value (for example, 20%) a prescribed time (for example, 1.0sec) under a condition where selection controlling rod insertion (SRI) actuating signals 71 and 72 are available and the then load quantity of a BWR plant is a certain value (for example, 20%) or higher and the load at the moment when the power load unbalance relay is actuated is a certain value (for example, 70%) or higher. Therefore, even when the turbine speed fluctuates due to a disturbance in a power system and the turbine speed is to be reduced to a moderate speed, the operation of a steam producing plant can be continued by avoiding unnecessary stoppage of the plant.</p> |
