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It is a conventional bushing CT. A battery was connected momentarily between H1 and H0. A miliammeter was connected to the secondary to read the deflection.

Hi, While testing polarity check on transformer ct and the battery applied to the primary, a dangerous voltage and arcing may be generated while disconnecting the battery from the transformer winding. This happened to a very experienced technician last week. I just want to be sure that i...

Hello We have several outside control cables and ct cables that were damaged by small animals. They are too long to simply replace them all. What are your procedures and criteria to fix these cables? I would like to fix them with heat shrink or 3M tape and perform a megger if the outer sheath...

The model is a GE KSO 69 kV 1965 serial number 58135. The mecanism is SD-19. My question is for this specific breaker, but also for others of the same type because this question is often raised in battery calculation

Hi, The Tripping and closing coil are feeded by the battery at 125 Vdc. Do you know how many amperes and how much times is needed to open and close the breaker? I check the manual but didn't see the answer. Thanks

Hi, we have an outside 125 V DC pannelboard with CSA certification with a lot of rust. We would apply a coat of paint mainly to improve its aesthetics, but some questions arose. Are we losing the CSA certification and is that there is a standard that can direct us in the method to use? Thanks

After some research, it might be quartz sand. Do you are aware of any other kind of sand use in ct design?

We dismantle high voltage old oil current transformers. When we remove the oil, there is often sand or something similar in the oil. Is this really sand? To send to the decontamination, we must indicate the type of material and we are not sure. Thanks and happy holidays

It was about the damage to the strands. It's a small nick, but it happen often and i don't know any standard that help to determine if it's ok or not, specially with the outer strands open. In this case, the outer strand aren't open enough to cause problem, but many time it happen and we don't...

Hi, Would you accept this cable (see attach file)? Is there a standard on which we can rely to determine whether a damaged cable is acceptable or not, like one with the stranding a little bit open...

Typically, the grounding resistor should be rated for a short time, like 10 second. So you have to clear the fault before 10 second. The fuse probably won't see the fault, since the fault current is small. So if you use low resistance grounding, you must have a relay and something to clear...

Thanks for the answer. That's a good solution to move the lug, but the cable will be too short. The term "neutral" was confusing me also, but Bussman call them this way. A FAQ on the square d website was confusing me also: "Square D does not offer a dummy fuse, nor do we support the use of a...

Hi, We have a Westinghouse 200 amperes 600 volts safety switch with 200 amperes class R fuse. We do some modification on our distribution system, so a other safety switch will be installed upstream with the same fuse, but we want to keep the first safety switch for a disconnection point and to...

When the distance relay are directed foward, there's a little part they see backward. DOC will just see foward. If you don't want the distance protection to operate on a fault backward of the protection, you combine it with a DOC with a logical function "AND".

The 2 drive will not be connected. So it's not really a 12 pulse drive. But the load on the 2 drive will always be equal. We do that to reduce harmonic on a very weak system, with no utility, only generator. Sibeen, if we don't ground the wye, by regulation, we have to had a ground fault...

correction, the primary is also a delta winding

Hi, To achieve a 12 pulses drive on a 600 volts systems, we have an isolation transformer with two secondary, one wye and one delta. There's one drive (ASC800 from ABB) on each secondary We plan to ground solidly the neutral of the wye winding (the primary is also a wye with the neutral...

Hello, We have a 69 kV system. the critical impulse flashover for our suspension insulator is 385 kV minimum. Normally, the supension insulator are installed phase-earth, with a cold and hot end. We have to install some phase-phase, what will be the impulse flashover for these? From what i...

Thanks scottf I found the CSA standard that talk about that.

Hi, I try to understand what's the difference between a C800 and a 10L800 CT. From what i understand, it's pretty much the same thing, considering 10% error on the C class. I think the L class is from an old standard, ASA (american standard association), and the C class from a new standard...