| 摘要 |
The method enables the switching capacity of a high-voltage circuit breaker (5) intended for 60 Hz to be tested in a test system with a 50 Hz high-current source (1) in that the time of the last current half-wave is shortened at the ratio 50 to 60 before the switch arc is extinguished. This shortening can be achieved either by opening the contacts of an auxiliary switch (6), connected in series with the switch (5) to be tested and having a relatively high arc voltage with respect to the switch (5) to be tested, before the last zero crossing of the current or by using the small half-wave of an asymmetric current. The latter solution, however, is only suitable for switches having arc times of around 11 ms at a maximum. With longer arc times, the switch is wrongly loaded by the large half-wave of the asymmetric current in this solution. The slope of the current at the last zero crossing of the current, which is correct at 60 Hz, can be set in accordance with the principle of the controlled current superimposition with the aid of the known synthetic test circuit. <IMAGE>
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