| 摘要 |
PURPOSE:To improve the reliability of a device, by providing discriminating levels with dead zones so that a difference between selected generators cannot be generated, and by discriminating the device with an error generated by active power. CONSTITUTION:When a breaker CBL is interrupted, then power is excessively fed and frequency is heightened. The heightening of the frequency is computed by a voltage-momentary value obtained via voltage transformers PT1-PT3, and at the same time, through current informations, active power is computed and is fed to a central unit Co from signal wires C1-C3. By the central unit Co, based on the active power(P1-P3) and the frequency(fl-f3), it is discriminated that generators G1-G3 are connected to systems and are normal when the deviation between the frequencies f1-f3 is within a set range sides, when the deviation exceeds the set value, then the generators G1-G3 are selectively interrupted, and the frequency is prevented from being heightened. Besides, when the average value of the frequencies fl-f3 exceeds a discriminating level, then an error included in the sum of the active power of the generators G1-G3 and a comparison value are compared with each other, and according to the result of the discrimination, the generators G1-G3 are selectively interrupted. |
