| 摘要 |
PURPOSE:To uniformly divide the whole voltage of a thyristor valve by using as an insulting post between thyristor modules opposed to upper shielding electrodes the post having a large electrostatic capacity. CONSTITUTION:Thyristor modules are sequentially connected in series from a lower part to an upper part via a bus bar, and an upper shielding electrode 10 is mounted on the thyristor module of uppermost stage to prevent a corona discharge due to the concentration of an electric field at the highest potential section. A lower shielding electrode 12 is provided at the lower stage of the module. In this case, an insulating post 15 between the uppermost stage module 6 and the electrode 10 is composed to that having a large electrostatic capacity. Thus, when a voltage surge having a sharp peak invades to a thyristor valve, a current at that time does not flow to a reactor and a thyristor nearest at an applying end, but flows to a snubber circuit of a reactor and a thyristor of lower stage, thereby alleviating a dv/dt.
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