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For that rating of TX, I would want Buchholz (gas and surge) protection, so environment issues (wet marine) aside, I would usually go for conservator design. Sealed tank designs can have overpressure trip device, but it won't give you early warning of a developing problem.

If your switchgear is conventional spring close / open mechanism, then a solution might be to fit a DC No-Volt release coil on the breaker. This is becoming more common on embedded generator schemes (where the generator manufacturer doesn't want their machine destroying because it can't be...

The answer to your question is given in BS EN (IEC) 60909-0:2016 Sect 7.1.1 Table 2.

The interpretation of the results is no different to what we have all been saying, in that a Stator ground fault will be in the region of 426A for the 3 gens, as per your latest calc. I think the bit that you are not getting is that the software is calculating the fault at BUS-5, not a fault...

So presumably you have chosen a 15.88ohm NER to get your 400A? The Easypower calc will have also taken into account the impedance of the ZigZag, hence 384A, not 400A. Add in the 10A from the Gen = 394A at the Bus..........not quite the theoretical 410A, but the 10A contribution from the...

What's wrong with conventional air insulated / solid insulated switchgear in conjuction with VCBs? Most Euro manufacturers offer this design up to about 24kV. The dry air gear you are referring to is a "compact" alternative to GIS gear, but I'm not sure if it goes higher than 24kV, but I'll...

The 'e' on the end of the MW rating normally means electrical power, therefore the set should be able deliver 2MW electrical output. The engine shaft power output will be slightly higher to allow for losses. If you want 2MW export in addition to 90kW of Aux. load, then your set is undersized...

Some thoughts / further questions.... Any modification to the existing certified JB (filling or purging or whatever else) invalidates the certification. Proprietary purging systems monitor air flow, and in a Zone 1 area, you normally have to cut the power on loss of air flow and not...

Hydrogen is a gas group IIC gas. You have a IIB enclosure......quite different. Hydrogen requires very low energy to ignite. The terminations should be Ex'e' certified, so if you have busbars in the enclosure with no "Ex" marking, then they probably shouldn't be there.

The IP rating of an enclosure only relates to its ability to keep out solids (dust) and fluids, not air. An Ex 'e' enclosure to EN 60079 is not required to contain an internal explosion, the enclosure is there only for ingress protection. Ex 'e' is the "increased safety" concept, where even if...

The +/-2% tolerance is applied to the Time/Current curve. The 30...50ms is the time taken for the trip output relay to energise in all cases when the the trip threshold has been reached.

The Main-Tie-Main configuration only really has its advantages if you follow that philosophy all the way down the system (i.e. you have 2 supplies to each downstream board, fed from each side of the main board). Where you have a single supply to a plant or piece of equipment with the...

On anything above 1kV system voltage, you would only ever use a ring CT such as that over an insulated bushing, and then, more often than not, also with an earthed metallic (non-ferrous) sleeve between the bushing and the CT, such that there is almost no chance of a flash-over to the CT.

@ Krisys A daft question.......have you checked the markings on the sheaths of the existing cables (or get someone to send a photo)? I can't think of an occasion where I have come across a HV cable with no voltage grade imprinted in the sheath. In a "normal" 11kV system (in the UK anyway) the...

A word of caution when switching DC on relay contacts - use hermetically sealed relays, or relays with perfect dust seals, not just "any old plug-in relay"! The positive pole of the contact attracts dust over time and seems to occur at DC voltages above around 40V. The higher the voltage, the...

In motor circuits there is often an Emergency Stop button, or other safety interlocks (system over-pressure etc) which may wired in "fail safe" configuration, such that the opening of a normally energised (held closed) safety contact, or an open circuit in the wiring removes the DC control...

You need to consult the switchgear manufacturer, or look in their installation manual. Just because it has been tested in accordance with IEC 62271-200 does not make it inherently safe. The manufacturer should be able to provide you with the minimum room dimensions and room volume that have to...

@ Rajendrarohra1978........you don't state what type of plant you are referring to, but circuit breaker DC No-Volt trip coils are often used on embedded generation (usually up to a few tens of MW), and as a matter of fact, some genset manufacturer's will not warranty the set unless these are...

For switchboards in IEC land, an RMS and Peak value is assigned to a fault rated switchboard e.g. a switchboard built to EN 61439 and having a short time withstand rating of 50kA would have a peak (Ip) withstand rating of 105kA.

@Parchie, You have an 11.25MW DG to start a 40MW GTG, the OP states that he has 5 x 800MW??? gas sets and a 500kVA DG, no mention of any other sets!