Work

Following works are to be carried out at 220 KV substation sector 129 Noida under ETD-I Noida to attend SF6 gas leakage of Y-phase pole of 220 KV SF6 CB (Siemens make) of 220 KV bus coupler bay. (a) Detect pole leakage by SF6 gas leakage detector. (b) Extract SF6 gas from pole unit by help of SF6 gas extraction unit and store it in empty SF6 gas cylinder. (c) Dismantling of top cover from Y-phase pole unit and opening of fixed contact chamber from pole unit. (d) Cleaning of all fixed and moving contacts, polishing the contacts and apply micro carbon grease on contact surface. (e) Replace pole top cover O-ring, absorbant and refitting the same. (f) Adjust closing and tripping coil plunger gap after cleaning. (g) Apply vaccum in pole by help of vaccum pump upto specified value and keep it for 4/5 hours and check no loss of vaccum. (h) Complete overhauling of pole-shaft mechanism assembly of all three poles. (i) CB open time test. (j) CB close time test. (k) CB close-open time.

Replacement of main NRV and gas pipe line including O-rings of Y-phase pole. Work consists of dismantling of main NRV with pipeline and replace it with new NRV and pipeline at its place. Afterwards, fill SF6 in all poles at desired level for satisfactory completion of work. NRV and gas pipeline as per standard technical specification of CB are to be provided by contractor.