why we are testing cables with DC supply not with AC supply?
Answer Posted / malik
Power cables testing is 2 types IR and Hipot.
1. megger normally D.C, we required the resistance value of
the insulation. AC megger till not to use.
2. Hi pot test, we apply the AC voltage low Frequency(VLF),
we measure the leakage current value. this kit we cannot
measure for the resistance value if the insulation.
so we use AC supply and DC supply for the different
application.
| Is This Answer Correct ? | 3 Yes | 8 No |
Post New Answer View All Answers
Why let through energy not considered for ACB breaker while cable sizing?
what is relation between ct and pt ratio with multiplication factor of a energy meter? is there any other factor on which multification factor depend?
My load is 1635 KW. & current pf is 0.884, I have to improve it for 0.99.Please suggest what KVAR value is needed?
What is excitation in case of dc motor?
HI SIR, AM PREPARING FOR RRB FOR SECTION ENGINEER POST. PLZ SEND ME THE PREVIOUS QUESTION PAPERS AND HELP ME. I HAVE NO ENOUGH TIME MY EXAM DATE IS 22ND JUNE.... MY EMAIL ID IS nalla.amarnath@gmail.com
Q.1:What protection will be used on HT and LT side of 33/0.4 KV, MVA transformer. Indicate capacities of protective device to be used. Q.2:Which types of back-up protections are used in the power transformers? What do you understand by the term over travel in the relay? Q.3:How star and delta connected winding transformer are provided from earth fault
Is it possible to download the Siemens Selection Chart(TYPE 2 coordination) for 1) fuseless selection 2)Fuse selection
why is a power transformer used only occasionally?it is used to step up at generating stations?and that needs to be done all day long !!!!!!!
I have c license but I don't know eligibility of Max Kilo Volts under the electrical licensing board.
How to Calculate Current Rating of SDFU (Switch Disconnector Fuse unit) for Protectionof Capacitor Bank connected to Busbar of 800Amp,in LV side of 11/0.433KV, 250KVA Transformer?
What is genrally the % Impedance of a Dg set? How can we calculate Earthing conductor size for a DG set?
Draw the single line diagram of the power station?
234 MVA Generator 3 phase Short circuit current Values required? Gen set Rating-234 MVA, Gen Voltage-18kv, PF;0.8, Xdv:23.5 %, Transformer Rating-18/380KV, 680MVA,Yndd1 two winding, Step up TR, ZT:35.50 %,X/R 4.33 Gen CB Position, CB open ,Disconnected open, Generator Running Voltage 18 Kv, Bi mistakes generator side earth switch Closed during that time short circuit current level in 3 Phase required, and how to test on site 234MVA Generator Short circuit current,
Define piezo-electric effect?
Please tell me the earthing procedures adopted for the STAR-STAR 3 Phase transformer in india and give a better sugession for earthing