Distribution transformer EJGF series

drysubstationhigh-voltage

Type EJGF combined transformers are used in high-voltage substations within the 245-550 kV range. They transfer high voltage and high current into standardised, equivalent values for meters, measuring and protection devices. The voltage transformer component is located in the top of the pressure-resistant head housing and the current transformer cores at the bottom. In the current transformer unit, the iron core is set to high-voltage potential and the secondary windings to earth potential. The current transformer cores are fitted in a protective core shell made of massive cast aluminium, which is connected short-circuit proof to the bushing. The secondary outlets are passed through the SF6 /air bushing in the connection terminal box on the base support of the insulator. The current distribution along the insulator is optimised by a special layout of the control electrode inside the silicone composite insulator. The housing components consist of helium-tight, corrosion-resistant cast aluminium. All housing components under pressure are individually typetested according to applicable pressure vessel standards. The SF6 gas density is monitored by a temperature-compensated gas density monitor with alarm contacts. The special design means the function of the gas density monitor can be checked without dismounting it. A corrosion-resistant metal rupture disc, protected by a metal cover, located at the top of the head housing ensures safe pressure relief in case of error. The generously designed terminal box is equipped with a cover that opens sidewards.