| 摘要 |
PURPOSE:To improve a power factor by controlling a lag quantity so that the lag quantity coincides with the phase advance quantity of a reactive power compensation device in a period of the reactive power of a load does not occur. CONSTITUTION:Current signals from a lag current detection CT 20 and a phase advance current detection CT 21 are inputted to a lag Q detector 22 and a phase advance Q detector 23 with a voltage signal from PT 5 connected to a high voltage bus 3 and an reactive power signal is detected. The negative value Qref of a phase advance reactive power signal Q3 and the averaging 24 value of a lag reactive power signal +Q2 are operated in an adder 25 and an output from the adder 25 is inputted to a controller 26. Then, the output signal is inputted to a negative signal cut circuit 27 and the output signal is inputted to an adder 17 with the output signal Qsvc of a Q detector 6. At that time, the signal from the circuit 27 is outputted only when lag reactive power is large. When the reactive power detection value of the load 4 is '0', only the signal from the circuit 27 is inputted to the adder 17 and thyristors 13 and 14 make the operating current small. Then, the lag quantity is reduced and it approaches a phase advance current. |
