I heard in a recent conference that the next edition of IEEE 1584 will not come with any equations? Can anyone confirm if this is the case?
The reasoning is that private industry funding was sought by IEEE & NFPA joint committee to repeat arc testing and make new arc hazard equations. This is...
Modula2,
Agreed. This is my thinking also. The question is, how is this determined by calculation. The affect on incident energy outcomes can be huge is the reduced motor contribution is overlooked, especially in LV motor control centers.
Hi,
I have also been thinking about the effect that motor contribution makes to incident energy calculation. The various methods of motor contribution calculation are, as I understand them, based on the premise of a bolted-fault. This represents worst case as the system voltage in 0V at the...
Waross,
Excellant question. I was alluding to this also and I think the answer is no, the are not in phase. My computer-based analysis reveals quite different phase angles and I supposed this makes sense when you consider the screen current has components that are induced from the current...
jchrist,
In this instance there are 3 per phase 3 x 1C cables without transposition or cross-bonding of screens along the run and with both screen and armour earthed at each end.
In a recent discussion with a colleague, we were looking at ways to measure the magnitude of armour current in a numner of parallel single-core HV cables with having to break-in between the armour and the earthed gland.
With the use of flex-CT's (i.e. rogowski coils) below (CT2) and above (CT1)...
Waross, Thanks for this quick reply. In this instance, this is a standard surface installation with 3 x 1C per phase from a gas turbine to an incomer circuit breaker panel.
On the issue of the path for circulating currents, I suppose that for an armour to be effective as mech protection, the...
I have an industrial client who has suffered a cable failure whereby the screen bond on a single core cable (6.6kV Cu/XLPE) at the end of a short run had a ‘thermal excursion’ burning through the termination kit and cable insulation. Eventually, the protection activated with a phase-earth fault...
fullofwind,
I am part of the DIgSILENT organisation, but when I was a customer, I taught myself how to use the software. Having said that, I would recommend training; it is far more effecient and DIgSILENT run courses regularly. Tell me which country you are located in and I will put your in...
I have an MCCB with extensive internal arcing that doesn't make sense.
The breaker supplies a module in a 600V active harmonic filter (module 2 of 4). The prospective fault level is (say) 25kA @ 600V but there has been no fault that we can see. The breaker is a modern european design, 400A MCCB...
This is always the problem with private parallel generation. When you have loss of supply from the network you would be expecting that your generators will look after critical loads at your facility. Whilst doing so your HV feeder to the supply transformer would remain disconnected until your...
To SphincterBoy,
Gosh - your username takes so getting used to.
I assume from your reply that you have used the PowerFactory demo; of course this the integrated power system analysis package rather than the protection settings management database (PowerWare) that I was talking about.
With the...
HiSet,
Firstly, I work for DIgSILENT in Australia so have a bias. I was working for another company up until 6-months ago and our evaluation showed that PowerWare (DIgSILENT's protection setting management platform) was by far the leader in this area. It has very comprehensive relays models...
On the other side, I have used DIgSILENT PowerFactory for 4 years and it is great. Like anything it takes a some work up front, but DIgSILENT has excellent technical support and has regular updates (several per year). As far as bugs go, my experience has been different, I can't recall too many...
