Search results for query: *

Oh man, I just read it as soon as I posed this... Thank you, 7anoter4. 310.60 Conductors Rated 2001 to 35,000 Volts. (A) Ampacities of Conductors Rated 2001 to 35,000 Volts. Ampacities for solid dielectric-insulated conductors shall be permitted to be determined by tables or under engineering...

I see that in the 0-2000V section, but I do not see a similar paragraph in the 2001-35kV section.

I know this topic has been discussed a lot here, but I have a situation with a twist that I haven't seen discussed elsewhere. For the overwhelming majority of the run I'm concerned with, it's a textbook three-conduit system directly out of the examples in NFPA 70. For about ten feet before it...

Looking to get consensus here. I have an application where we can either open a 13.2kV vac breaker (feeding a 2000kVA transformer) or a 3000A 480V unit substation breaker (fed by said transformer). There are about 1200A worth of load on the 480V side. Both breakers can be opened remotely...

The sources are fed from different circuits in the same upstream sub, and they always float between the same two taps when the load is split. Additionally, there are other feeder breakers on the upstream bus (the one with T1). The feeder breakers we're discussing represent about half the total...

I probably do have enough information to perform those calcs. I do struggle with the idea of circulating current - what is physically happening. Are you aware of any good explanations of this?

The transformers have tapchanger controllers (beckwith m-2001d) which use the circulating current method. They're always within one tap position of each other, and we do have an off-tap alarms being monitored. The feeder length on one side is about 1000' and it's 750' on the other side. The...

This is an NESC application. The load on either feeder is fine for the cable size and 51/50 relay settings. The system is redundant so that either feeder can handle the entire present day load of the plant should one side have an outage.

Right - so we will see the majority of the current flow through the (2) sets of 750s, but we won't see any objectionable circulating current or reverse power flow or anything strange like that..... Right?

We have a situation where we are planning to parallel conductors of different length and characteristics. We have a 15kV M-T-M switchgear with paralleled transformers (automatic tap changer controls fully commissioned for paralleling), but the gear is run with the tie normally open. This gear...

That's correct, Kiribanda. The gens are standby - they will only operate when there is a utility outage. The transfer switch that the owner would like to buy is closed transition type. I'm thinking the correct configuration is to ground the gen neutral, run 3-wire to delta 480 side of...

One line is attached. I know it lists the transformer on there at grounded wye to grounded wye, but that will be updated. I'm thinking it's wye configured gens with the neutrals grounded, and that feeds a step up transformer which is delta on the gen side and wye on the utility side. I'm just...

I'm hoping to get some advice for integrating some parallel generators and a step-up transformer at an industrial plant. We have (4) 1MW generators which will be paralleled and backfeed a single 480-13.2 step-up transformer. This will feed a service rated MV ATS and pick up the entire plant...