| 摘要 |
PURPOSE:To control reactive power over wide ranges, by adjusting a location of a tap of a transformer for a converter by obtaining the maximum allowable value of phase control angles in the case when operating the converter by detecting voltage and currents at the direct current side of an alternating-current and direct-current exchanging device. CONSTITUTION:The output of a constant-current control circuit 8, a constant-voltage control circuit 10 and a constant-allowance angle control circuit 13 is fed to a minimum voltage select circuit 14 to select voltage that gives the minimum phase control angle, and the larger side between the voltage and the output voltage of a function generator 15 is input to an automatic pulse phase shifter 18 by means of diodes 17A, 17B. This device is operated using a phase control angle beta as the maximum allowable value. Consequently, reactive power can be changed while the reactive power remains as it is apporoximately kept constant by altering a location of a tap of a transformer 2A for a converter by means of a tap drive circuit 11 when varying reactive power, thus controlling reactive power over wide ranges without enlarging the capacity of valves, etc. |
