| 摘要 |
PURPOSE:To realize a more economical and stable reactive power compensating device by subtracting and correcting automatically a long period reactive power fluctuation portion of a system, detecting only a reactive power fluctuation portion which changes suddenly and controlling the reactive power thereby. CONSTITUTION:A reactive power compensating (SVC) circuit 10 goes to 0% or 100%. When this current is allowed to pass through a Q detecting circuit 20' and a low-pass filter 41, an average Q signal 42 is obtained. By subtracting a bias signal (1/2QSVC) 44 corresponding to the capacity of the circuit 10 from the signal 42, a correcting signal 45 is obtained. The signal 45 is a negative signal and a positive signal when it is smaller than the signal 44, and when it is larger than the latter, respectively, and as the signal 45 is shifted from the signal 44, it becomes a large signal and detected. The signal 45 is added to a signal 24-31+33 of a Q detecting part of a conventional load side, and goes to a control signal 35. The signal 45 is corrected so as to go to zero when a conventional control signal 34 is negative, and also, so as to be lowered when positive is large, and becomes a control signal operated within a range of about '0'-DELTAQ. |
