| 摘要 |
<p>PURPOSE:To provide a potential transformer in which ferro-resonance does not occur, by selecting a magnetic flux density at rating of the potential transformer below a specific ratio of the saturated magnetic flux density. CONSTITUTION:An oscillating frequency after opening the circuit breaker, can be made lower than a 1/3 frequency value of that of the power source 1, by selecting a magnetic flux density at rating of the potential transformer below 28% of the saturated magnetic flux density. For general various gas insulated switch gears in an effective grounded system, a condition causing ferro-resonance can be eliminated, so the ferro-resonance does not occur. Where silicon steel plates are used as core material, since the saturated magnetic flux density of the silicon steel plates is 20,000 gauss, the magnetic flux density at rating may be selected below 5,600 gauss.</p> |
