| 摘要 |
PURPOSE:To reduce fluctuation of the load current of a controller for the electric power source of a thyristor by a method wherein output of the controller is made to rise up to the equal value with the load current flowed just before starting of by-pass pair operation, an outside control signal is made as small, and output of the controller and the outside control signal are changed over automatically. CONSTITUTION:Before execution of by-pass, output cosalpha of a high value selecting circuit 9 is 25% of the same value with output cosalphaO of the controller 2, the load voltage Ed is 50% of Ed1+Ed2, and the load current is controlled also to be 50%. At this time, because a relay contact 8a is in OFF, mismatching cosalphaB between output cosalphaB2 of a function generator 7 is 0%, and the high value selecting circuit 9 selects the output of a controller 2. When a by-pass pair command BP is generated next, relay contacts 8a, 8b are made to ON and 8c to OFF to make as cosalpha=50%, a thyristor bank 4b form by-pass pair, and Ed1 becomes 50% when Ed2=0, and the load voltage Ed and the load current Id are not changed. Accordingly fluctuation of the load current at the time of performance of by-pass pair can be held at the minimum. |
