METHOD FOR LIMITING VOLTAGE ACROSS SERIES-CONNECTED THYRISTORS OF HIGH-VOLTAGE RECTIFIER

摘要

METHOD FOR LIMITING VOLTAGE ACROSS SERIES -CONNECTED THYRISTORS OF HIGH-VOLTAGE REC TIFIER The method according to the invention for limiting voltage across series-connected thyristors of a high-voltage rectifier as a voltage surge is applied thereto consists in limiting voltage across groups of series-connected thyristors with a specified number of thyristors in a group, which is selected to suit the voltage surge parameters. For this purpose, voltage is measured across the thyristor next to the point to which the voltage surge is applied, and then across the following thyristors. When voltage across the first thyristor raises to a preset level, total voltage across the thyristors is successively measured, starting from the first thyristor, until it reaches a level equal to the ratio between the voltage surge amplitude and the total number of series-connected thyristors of the rectifier, multiplied by the number of thyristors giving the preset total voltage level which corresponds to the number of thyristors in the group. Voltage across the group is limited to this level.