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Thanks Kiribanda...what you have mentioned is understood. However am not clear why do we need to check electrical integrity of HDPE sheath.What damage will it do the cable if there is a micro hole in the sheath ? HDPE sheath is purely for mechanical protection ,then why do we need to check...

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...

In our specification its mentined that Flux density should not exceed 1.6Tesla and Current density should not exceed 2.5Amps/mm2.None of the vendors came back to us stating that this is not ok or they should be allowed to choose flux/current density.What could be the reason?

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, Waiting for your inputs! Thanks in advance. Regards

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?

Electricpete and Edison--thanks a ton for the inputs.You two seem to be encyclopedia on motors.Interesting reads indeed --highly technical though.

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

Cuky2000--Do you mean that it is because of Very Fast transient wave(VFT)and resultant voltage that may develop, earth switch is provided for every component?

Need more inputs on this topics.Please share your inputs.

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

Hello Cuky2000, Many thanks for the input and the links.They are absolutely helpful. I was referring to cable being terminated to GIS(220kV) inside a indoor substation.Why those don't have corona shield.

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