Hello:
I work for a US government agency.
We recently replaced our 30 year old substations in our administrative building.
Quite recently a grounded\shared neutral situation caused a feeder ground fault relay to trip the feeder breaker.
To remedy the situation we will have to revise the...
Hello:
A small pump house building was recently connected to our 4.16kV overhead distribuition system. Basicall the system consists of a 150kVa pad mounted transformer (4.16kV Delta Pri - 208Y/120V Sec.
At the pole cutouts the surge arresters are tied to a ground rod at the pole base. The...
Hello:
In the US the two main fire codes (IFC and UFC)impose a limitation of 50 gal of electrolyte for UPS VRLA battery systems.
Apparently the official interpretation is that the 50 gal of electrolyte is the aggregate sum of the battery systems in a specific space (data center, battery room...
Hello:
A decision was made by my management to install surge arresters at every other pole of a 69kV line thats 3200 feet long between the utility metering point and the main substation 69kV incoming switch. The distance between poles is 200 ft. The line has a guard wire.
Also the surge...
Hello:
We recently specified Doble testing (tip-up) on a 750/1000kVA dry-type transformer (20+ years old) as part of a comprehensive test regimen. Our NETA certified test company said that they would do it, but would not be able to get any useful information because the transformer is a...
Who can legally perform power systems and arcflash studies?
Can they be performed by technicians who will then use the study results to set protective relays and select fuses.
Sundale,
Just a reminder that there are people of all races in Mexico, Panama, Cuba, Puerto Rico and the majority of Central and South American countries.
Hidalgoe
Hello:
A 12.470kV/4.16kV, 3750kVa trafo is being used at our campus facility to supply sundry loads at 4.16kV through a secondary VCB with 50/51 relay protection. It was decided by some of our technicians to use it as a step up transformer to supply a 12.47kV load while a new feeder is being...
Hello:
We have Westinghouse Power Centers in one of our buildings. These centers have ASLR dry type transformers (12.47kV,500/666kVA, 150 degree C rise, Sharon Plant, 1978)). Recently one of these transformer caught fire and released a lot of smoke over a period of 1/2 hour. Our fire dept...
Hi:
Our local utility does not transpose its HV lines (as far as I can see by looking at its transmission and subtransmission lines).
Is there a need to be worried about this as far as overcurrent relaying is concerned?
Thank you kindly,
hidalgoe
HellO:
What have been the results of recent engineering debacles, like Boston's Big Dig concrete section that fell and killed some folks in a car or Katrina meant for PE's as far as liability and ethics are concerned?
davidbeach,dpc,jghrist,stevenal:
I called a colleague who was familiar with the SEL 351S and discussed this relay's multi-functionality. We came to the conclusion that what I need is separate OV/UV protection; a relay that will provide the time-voltage characteristics that I want for OV/UV...
rbulsara:
I appreciate your concern.
I have over 35 years of experience as a PE and power systems engineer. I have done projects for small and large industrial plants and for colleges, universities, hospitals and a few medium sized utilities.
My motivation was obtaining advice on a relay I...
