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Is there any difference between RFCT and HFCT used in measuring partial discharge.

Single line diagram of the system The datasheet of the equipment to be protected.

We have 132kV GIS switchgear with outgoing cables connnected. The cable needs to be tested at HV AC at 75kV. The voltage transformer is a fixed type above the cable box. Disconnecting mean are provided inside the cable box, but degassing would be required to remove that link. Should the GIS be...

NiCd battery electrolyte should be changed when the specific gravity drops to 1.17 or when carbonate content reaches 75 g/l. Lifetime of valve-regulated lead acid batteries depends on initial specification and operating conditions, i.e. temperature and float voltage. Typical replacement...

The only reason I can think of is to have a balance supply on the bus that they are feeding.

Hello Everyone Im conducting a research on major cause of failure of power transformers nowadays. In this regard we are looking for failed power transformer equal or above 100MVA,132kV preferably in Europe or Asia, Did anyone come across such a case. I would be very greatful for the leads in...

If its really 15kV then a single conductor should be very heavy for a transmission line to carry.Perhaps that is the reason 2 conductors per phase could have been used. At a height of 50' with an approximate pole spacing of 60m, you cannot judge the source of sound. It is, coming from the...

Never heard of 15kV transmission lines.Must be at least 33kV.By a rule of thumb you can determine the voltage level of a transmission line by counting the insulator discs supporting the line.Each disc is about 10kV. The buzzing sound as explained by David is corona due to dirty insulators.

We have a circuit breaker with 110DC spring charging motor. It is to be used in a switchboard where the the supply is 220VAC. Can we use an industrial type converter (220Vac-110Vdc) of suitable rating to supply power to the charging motor,instead of replacing the motor itself. thanks in advance...

Thanks Scotty and Marmite for your valuable feedback. I have reviewed the websites of the companies mentioned and they seems to be suitable. Lets see how it turns out.

Hi Scotty Im in the Middle East. The production of this type was shifted to New Zealand long time back so i dont think they still have the competency in Siemens UK.But if you can refer me to any third party in the UK it would solve the problem.

Does anyone know of any company(apart from Reyrolle Pacific Switchgear.Newzeland) involved in providing maintenance services on Reyrolle's LMT2 type switchgear. The maintenance work involves 11kV bus bar including replacement of all shrouds, Monoblocks & thorough fare Bushings for all panels...

What are the advantage and disadvantage of having a Generator Circuit Breaker between the Generator and Transformer. In some installations I noticed a GCB is not used and the generator is directly connected to the transformer. Thanks in advance for your valuable feedback

In my opinion all three CTs must be shorted.

What are the standards or criteria for selection of CT primary rating for a motor feeder? If motor full load current is 40A, can I use a 40/1 CT OR the CT has to be rated higher say 50/1 or 60/1?? Let me know the guidelines please. If 40/1 CT cannot or should not be used, what are the...

Hi Everyone. Is it advisable to use a portable PD measurement system that can analyse PD in live conditions on 13.8kV Switchgear which is hardly 3 years into service.The Switchgear is installed in an airconditioned room.OR is it advisable to install a viewing window on busbar, cable and breaker...

thanks to everyone for the valuable information.

Hi Guys Could anybody list standard tests for Life assesment of 11kV Air Insulated switchgear which is about 10 yrs old considering no maintenance has been carried out so far.What kind of test equipment would be required to carry out those tests.Would it be necessary to do mechanical endurance...

In a substation 132/33/11kV, the SC rating of 33kV CB (MOCBs) is 31.5kA. The client is being proposed replacement with vacuum CBs rated 25kA considering the fact that the neutral point on the 33kV side is isolated and grounded by 17 Ohm reactor. Is it advisable to use the 25kA CB instead of the...

I needed some expert comments that is why im sharing this information. There is a product in the market called intelligent light information system. It is installed in the switchgear in busbar compartments and individually in each CB compartment to protect from internal arc.The smallest of arcs...