APPLICATION OF DC VOLTAGE TO HIGH VOLTAGE TRANSMISSION LINE

摘要

PURPOSE:To enable the securing of a DC voltage for measurement of an insulation resistance under a hot-wire condition of a high voltage transmission line, by drawing a power source of a DC voltage from the secondary side of a grounding transformer. CONSTITUTION:A line voltage of a high voltage transmission line 1 is applied to the primary side 21 of a grounding transformer 2 and to the secondary side 22 in a lower level. The sum of voltage on the secondary side of the transformer 2 becomes zero. This is because phases of voltage maintain a balance: when viewed from one phase on the secondary side of the transformer 2, a fixed AC voltage is held. This AC voltage is turned with a power source transformer Tr to a desired level and an AC voltage output of the transformer Tr is turned to a desired level with the rectification by a rectifier Rec and a DC voltage is applied to a primary side neutral point 20 of the transformer 2. Thus, when the line 1 is in a hot-wire condition, an AC voltage is always generated at a fixed level, thereby always securing a DC power source for measuring insulation resistance of the line 1.