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Understand HDPE Sheath in a EHV Cable is purely for mechanical protection.Then why so much importance is given to check electrical integrity of HDPE sheath in EHV Cable?Why do we need graphite coating to test the electrical integrity of HDPE sheath .

Why do we need online oil drying system in transformers? With aircell in use,ingress of moisture is anyway likely to be low.So why do we still need additional online oil drying system?

In my organization...Upto 4MW Motor ratings is fed from 6.6kV,3150A (Vacuum Circuit Breaker feeder). Motor ratings above 4MW.... is fed from 33kV Bus through a 33/11kV auto transformer. The circuit breaker operations does not demand frequent operations and hence Vacuumm contactor is not a must...

Both ALF(Accuracy Limit Factor) and ISF(Instrument Safaty Factor) for Current Tranformer mean the same. Why do we have separet terminologies for these two?

How does lower flux density and lower current density help to improve life of Power Tranformers.

Dear All, Request your inputs on which is better for 33kV cable termination in GIS --Outer cone or Inner cone ? Is there any limitation with either of the design Outer Cone vs Inner Cone?

Which is the most preferred type of PD sensor used for PD measurement in EHV cable? We have copper foil type PD sensor in our EHV cable network which are placed every 500 metre. What is the sensitivity of copper foil type sensor in terms of distance from occurrence of PD location? Understand...

Which is the most preferred PD sensor used for PD measurement in EHV cable? We have copper foil type PD sensor in our EHV cable network which are placed every 500 mtr. What is the sensitivity of copper foil type sensor? I understand HFCT sensor can sense PD upto 1km on its either side and hence...

How is Motor parameters such as efficiency dependent on type of load i,e whether is is for pump application or Fan application.

How is DC output voltage of a full wave rectifier higher that AC input voltage?

What exactly is meant by "2xLine frequency"in motor vibration readings? Why is it more prevalent in 2 pole motors?

In conventional method of PD measurement , why is partial discharge measured in pC?

Why do we need corona shield in a EHV transformer dry type termination?The same is not applicable in a GIS dry type termination.

Is it a common practice to lay conductor strand(Aluminium or copper) in helical formation in EHV cable?Pl advise.

Copper wire is wound helically on the extruded insulation layer of (semicon+XLPE+semicon) in a typical MV/HV Cable.And again copper tape is wound helically on the copper wires in the opposite direction.Is there a purpose of winding these in opposite directions? Different manufacturers follow...

Why do we need disconnector + earth switch after every component in 220kV GIS ? This is not the case in 33kV GIS. For e.g In a typical Bay we have "disconnector+earth switch" after busbar assembly,after Circuit breaker,and again after current transformer. Pl advise.

How is rotating load coupled with rotating motor shaft?

Why is a deflector used inside EHV termination/jointing kit?

What is the use of High speed grounding switch in EHV GIS and in which location of the bay is it exactly used? Why only in line feeder bay? Some specs mention that both earthing and high speed earth switch should be able to make a fault..some specs say only high speed earth switch needs to have...

In a typical conventional LV busduct, Matt black paint is painted on busbar as well as inside of busduct enclosure. While black paint on busbar shall help in radiation of heat from the busbar towards outward direction. I feel black paint on inside of busduct enclosure too shall radiate heat in...