Dear Folks,
Is there a way to wire a Form 6S meter to accommodate Form 5S Meter requirements. The Switchgear instrumention available are 2 PT's and 3 CT's, the PT's are connected A-B & B-C while the three CT's are connected in star configuration. We only have Form 6S meter which if I understand...
Dear Folks,
I'm trying to figure out how the analysis dist. software we use calculate the impedance values for our system. My calculations match the software except for one area.
System/Source Information:
R1 (Utility-Per Unit)=0.0096 @100 MVA Base, @115 kV Base
X1 (Utility-Per Unit)=0.0761...
Thank you all for your insight, your input and willingness to help. I will continue my struggle with the SEL 351S -;o)). Please keep me posted and in your thoughts if you find any helpful thoughts on the 351S.
Thanks again and best regards to all
In the directional overcurrent relay settings, they ask you for values for Z1F (relay forward impedance) and Z2F (relay reverse impedance)!! What is really strange is that the 67 elements (67P,N,G,Q) are listed under non-directional overcurrent element and only 50Q/G elements are listed under...
Folks,
SEL 351S Relay Settings started to confuse me, they use the 67 Directional Overcurrent element and the 32 Reverse Power element backward, in my opinion.
Have any of you worked or dealt with setting this kind of relay. My application is for dual-feed industrial substation and I want to...
dpc, sslobodan, stevenal, and jghrist,
Thank you all for your valuable input. I applied the guidelines you provided me and it seems very proper to use. I confirmed that as I plotted (using the software i use) the TCC for the relays versus the TX thermal damage curve, TX inrush current curve...
Folks,
I'm hoping you share your opinion with me on this.
Do you consider the Minimum Utility Fault Current on the transformer primary side when setting the instantaneous element for the protective relay (115 KV side) or you need to be concerned only with the Maximum Fault Current??
Should...
Dear Folks,
May someone please explain to me the difference between MV circuit breaker auxiliary contacts versus spare ones.
I got a little bit confused after looking at the GE-Power VAC PVDB breakers schematics, they list all auxiliary contacts that are equipped with the breaker (for example...
Thanks folks,
Your input has been extremely helpful and I appreciate the time you took to answer and help me with my question.
I'm going to contact ALCAD since they are the battery manufacturer, also, I'm going to check IEEE 1115 as 0210972 suggested.
Since dpc and Rajt stressed that I need...
Dear Folks,
We are about to replace an old oil MV Circuit Breaker with new MV Vacuum one.
The old breaker trip circuit coil is rated 12.7 amps @ 48VDC, close coil and charge motor was 240 VAC.
The new breaker trip circuit coil is rated 17 amps @ 48VDC, The close coil (17 amps) and charge...
Dear folks,
Thank you all for your help and feedback, I really appreciate the time and efforts you took to share your jknowledge and experience with myself.
ScottyUK, actually, the TX is a substation TX at one of our dist. subs. We're replacing the sub. breakers and want to make sure that all...
Dear folks,
What is the most effective method to confirm and check the phase angle relationship for the load and source side CT's for a transformer differential relay?
The transformer is 30 MVA, 115/12.47 kV, Delta/Wye with 30 degree phase shift. The CT's are connected Wye (on TX delta side)...
Dear Folks,
what are the recommended commissioning tests on replacement of medium voltage circuit breakers?!
I made a list that included CT ratio and polarity tests, hipot test for the bottles, resistance tests for the contacts, megger test for the insulation, finally, functionality test for...
Dear folks,
Scenario:
We have 3 peak-only generation units, 1000 kw, 1250 kVA, 4160-2400 volts each. All generate to a common bus then to a 3750 kVA step-up transformer to 12.47 kV dist. level. They tie to utility through NO breaker on the 12.47 kv TX side. The TX is Star on gen. side and Delta...
DiscoP,
Thanks for clearing the function of the two 'a' contacts, it didn't seem to make any sense to me before you explained it.
in the old breakers, the two 'a' contacts were in series and we did have access to the node between them, we took the first 'a' contact to a remote trip ckt and...
jghrist,
Thanks so much, you got it right, I thought they would label the circuits (T=Trip, C=Close), instead they labeled them G=Green, R=Red, as you wisely guessed.
DiscoP,
That is very much what we have on the VAC-Breaker, my guess would be the two 'a' series contacts serve as back-up to...
jghrist, I'm sorry for the confusion, I meant taking one of the aux. contacts to SCADA, the two 'a' contacts I mentioned are internally wired and I won't change that.
Does anyone know what does the R and G means in the 89 Control Switch Circuit (Selector Switch)??
Dear Folks, Thank you all for your help. You were right, I looked at the control/wiring dwgs, there is no alarm function or pressure status contacts associated with the VAC-CB.
The trip coil ckt. has two 'a' contacts in series with it, these we're taking to SCADA, another paraller trip ckt. has...
We're about to replace old oil CB with new GE-VAC CB. Control dwgs for new CB shows two outputs to each of Remote Trip Ckt. and Remote Close ckt. Any advice on how best to utilize each of these 4 ckts (to the two remote trip and two remote close ckts)?
In the old breaker we had a Low Pressure...
