| 摘要 |
PURPOSE:To attain tap change with similar control system to any load by flowing a current to a load through a nonlinear resistor at tap change, detecting a voltage applied to thyristors and giving an ON/OFF operation command of a solid-state switch properly. CONSTITUTION:Suppose that a tap increase detecting contact selecting a tap C of a transformer is operated by a tap increase command detection circuit 24 of a control circuit 23, an output 123 of an OR circuit 106a is at an H level and an output 124 of an OR circuit 106b is at an L level. When a tap decrease command is given externally and a tap decrease command detection circuit 25 is turned on, an output 118 of the circuit 105a goes to an L level to stop the trigger command of thyristors 8, 9. A load current flows to the nonlinear resistor 27 in parallel with the thyristors 8, 9, and after a voltage applied to the thyristors 8, 9 for a prescribed time by a voltage detector 22 connected in parallel with the thyristors 8, 9 is confirmed, thyristors 6, 7 connected to a tap 3 to be selected are turned on. |
