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Hi, If a metallic bar is continuously heated by a heater, how the final temperature of the metallic bar can be calculated? I'm looking for some formula's to do manual calculations without resorting to sophisticated softwares. Metallic bar is not enclosed and on one side is in touch with a...

Hi, Imagine an MV switchgear is going to bypass an isolated gap in a busbar/conductor, etc. I want to know if anyone has seen an MV cubicle design where both incoming and outgoing cables to both sides of the gap terminate in the same MV cubicle. Is that at all possible? is there any standard...

Hi, my question is what happens if a power transformer is loaded most of the time close to half its full capacity and only for a very short period close to its full capacity. this happens in a design where a solar farm is going to be connected to grid (230 kV). should any special design be...

Hi, all the transformers in a subtransmission network are Dyn11, in another part of the network a transformer with the vector group of YNd1 is going to be used for an industrial complex .there is no chance of paralleling of transformers but the primary of them are all connected in a ring of 132...

hi,does anybody know what is the purpose of earth pit in the earthing system of a susbstation? where it should be located?if it is for testing what is the purpose of test and what happens if it is not included in the design? is it for connecting of the shield wire to the substation earth system...

Hi,imagine a double star ungrounded medium voltage capacitor bank connected together by unbalanced CT in their neutral.the star arrangements are not of equal size.one having 2 *180 KVAR and the other 3*180 KVAR units at each phase.while the contractor could use 150 KVAr unit capacitors to make...

Hi,a vendor has offered me 2 similar distance relays for 230 kv transmission line protection.usually we reqiure 2 different hardwares or 2 different algorithms in relays for distance protection.but this vendor has no such thing.I want to know your experience and ideas about using similar...

Hi, I need to know if there is any standard for usage of CAT 5 cable for transmission of data in the switchyard of the high voltage substations .let's say is it ok to use these kind of media instead of fiber optic cable in the HV and EHV environment for substation automation projects? thanx a lot.

why in the power frequency tests of HV power cables the two ends of cable on the reel are immersed in water ?and what conditions this water should have? thanx

what would be the best protection device to be used between battery and charger?MCB or Fuse ? thanx

if you are buying a single core power cable and manufacturer provides you the type test of a three core power cable with another cross section and same voltage level would it be acceptable? thanx

an auxiliary transformer were to be designed with the following specification: U1/U2=3.3/0.4 KV(+2*2.5%, -2*2.5%). V full load =3 KV Uk=4% after FAT it became clear that transformers have the ratio 3/0.4 KV. manufacturer says that the problem could be solved by changing tap steps to be (+2*2.3%...

all the cables used in a substation are armoured .which end of the cable armour should be earthed.inside control and protection panels or in the marshalling kiosks at the switchyard? thanx.

when I was inspecting a medium voltage switchgear I noticed that in some parts the silver plated buses are in direct contact with copper busbars.when I commented, they said that they have sold many of this equipment without having heard of a problem.any idea on how this bimetalic junction works?

The formulas that are derived in ANSI/IEEE c37.012 "IEEE application guide for capacitance current switching for AC high-voltage circuit breakers rated on a symmetrical current basis" are for what situation?I mean could they be used for both earthed and non-earthed neutral conditions...

can anybody give me some information about the type of rectifiers that are used in zinc electrowinning plants? thanx.

I need to have some information about type of semiconductors used in the rectifiers for different metal electrowinning specially zinc. I appreciate your help.

usually specs require using stranded copper cables for substation applications .what is the problem with solid copper? thanx.

suppose you want to design a failsafe system.what position of contact should be used for signalling and interlocking purposes?N.O or N.C position? what is the advantages and disadvantages of each one? thanx.

If a vacuum type breaker with a breaking capacity of 31.5 KA and voltage level of 12KV is used in a system with a voltage level of 3KV would the breaking capacity change?