| 摘要 |
<p>PURPOSE:To enable the use of normal differential relay by adding separated windings to high voltage winding and low voltage winding around cores, using one low voltage winding as parent winding and the other low voltage winding as child winding, and then obtaining residual voltage no less than that in normal state. CONSTITUTION:When voltage is applied on high voltage winding 1, cores 14, 24 are excited and magnetic flux phi is produced. If cross sectional areas of two cores and loads of parent and child windings 2, 3 are equal to each other respectively, magnetic flux phi/2 flows through each core and the same level voltage is caused at each terminal of windings 2, 3. Then, when the short is ocurred on the second lead of the parent winding 2, overcurrent flows through the parent winding circuit and the magnetic flux of the core 14 is offset to 0. Thus offset magnetic flux is transmitted to the core 24 for the winding 3 and the magnetic flux of the core 24 becomes to phi, so that terminal voltage of the winding 3 becomes 2 times more than that in normal state. Accordingly, when shorted between terminals of the parent winding, residual voltage of the child winding increases over that in normal state, thereby enabling to operate a differential relay with low sensitibity sufficiently.</p> |
