| 摘要 |
<p>PURPOSE:To contrive compactness and light weight for expanding the capacity of the limit to transformer transportation and to obtain the constant voltage of low-voltage tertiary windings and the freedom of delta and star connections by a method wherein the built-in winding in each phase is composed of delta connection in isolating a LVR section with tertiary winding from a main transformer section. CONSTITUTION:The main transformer 11 section in each phase is composed by winding a built-in winding 10 with a series winding 14 and shunt winding 15 on at least one iron core leg. Meanwhile, each voltage regulator 12 at on-load is composed by winding a tap winding 6, exciting winding 7, and low-voltage tertiary winding 8 on at least one iron core leg. In this way, as the built-in winding 10 in each phase is composed of delta connection, a problem on the third harmonic wave is solved and no zero-phase current flows to the outside even if operation is made by the main transformer 11 in each phase only. Accordingly, no induction fault to communication lines occurs. As zero-phase impedance is also decreased, fault current becomes high. Therefore, detection sensitivity will not decrease.</p> |
