| 摘要 |
1,245,685. Electric transformers. BROWN, BOVERI & CO. Ltd. 3 June, 1969 [5 June, 1968], No. 27925/69. Heading H1T. [Also in Division H2] A monitoring arrangement for an HVDC converter comprising a series string of semiconductor rectifier stages (see Division H2) includes a transformer having a plurality of primary windings 2 (Figs. 1 and 2) each toroidally wound on a respective annular core 3 and coupled to a common secondary winding 4 and common tertiary winding 7 contained within a U-shaped insulating sleeve 9 which is threaded through the core. The cores are pre-magnetized by a direct current through the tertiary 7 and to a level close to or at saturation level. The transformed primary voltages are aggregated in the secondary winding. An indicator 6 responds to the arithmetic mean of the secondary voltage and produces a warning signal at a certain limit value indicating that an excessive number of rectifier stages have failed. |
