| 摘要 |
PURPOSE:To execute automatic voltage control even in case when a load side of a transformer is varied, by controlling selectively input voltage of an automatic voltage control control relay by a flow direction of electric power from the primary and the seconary sides of the transformer. CONSTITUTION:In case when the electric current direction is A, an electric power flow detecting relay 91 detects voltage and current by PT3 and CT4, respectively, and its B contact 91Xb1 is closed, therefore, voltage is supplied to an automatic voltage control relay 90 from the PT3. The relay 90 compares voltage of this PT3 with reference voltage, and in case when it is higher and lower, voltage-down and voltage-up are instructed to a tap changer. In case when the electric current direction is B, the relay 91 detects voltage and a current by the PT3 and the CT4, respectively, and its A contact 91Xa1 is closed, therefore, voltage is supplied to the relay 90 from the PT2. The relay 90 compares voltage of this PT2 with the reference voltage, and in case when it is higher and lower, voltage-down and voltage-up are instructed to the tap changer respectively. |
