What is the Normal Current Through NGR of 25 MW, 11 KV TG Set

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satendrakumart Commentator Join Date: May 2011 Posts: 61 Good Answers: 1	What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/21/2012 5:39 AM
	Dear all I observed too much heating in NGR cubical of our TG set. The resistance of our NGR is 62 ohm with 100 A rating. I measured the current through NGR with clamp meter, it is showing 7 amps. As per my calculation, about 3 KW heat energy is being dissipated in NGR box. I think it is sufficient to heat the box. Casing temperature of the box is 94 degree C. Whether this current is normal in this type of NGR or there is some fault in the system? I have not measured the current through NGR in past, neither I have experienced such heat in our NGR. I asked the supplier of NGR, they told to measure the 3rd harmonic, it is found 4A. Finally they are saying that it is within the limit. But I am not satisfied with the answer and using cooling fan to cool the NGR from outside.
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#1 "Re: What is the normal current through NGR of 25 MW, 11 KV TG set" by PWSlack on 11/21/2012 6:32 AM (score 2)

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#3 "Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set" by Wal on 11/21/2012 11:05 PM (score 1)

PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32209 Good Answers: 839	#1 Re: What is the normal current through NGR of 25 MW, 11 KV TG set 11/21/2012 6:32 AM
	It indicates two things: The protection equipment arrangments around the generator are inadequate, and There is a phase-to-earth or neutral-to-earth fault in the downstream network, which needs to be eliminated before someone gets hurt/killed by electric shock. Eliminate the cause. If there is no qualified electrician to hand, hire someone in. Do it now/today/this morning/immediately. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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TonyS Guru Join Date: Aug 2010 Location: Resting under the Major Oak Posts: 4347 Good Answers: 181	#2 In reply to #1 Re: What is the normal current through NGR of 25 MW, 11 KV TG set 11/21/2012 9:34 PM
	If not sooner __________________ The reports of my death are greatly exaggerated.
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Wal Guru Join Date: Jun 2011 Location: Phnom Penh Posts: 4019 Good Answers: 102	#3 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/21/2012 11:05 PM
	Sounds a bit excessive. Turn off the load branch circuits one by one until you find the one that causes the largest change. Start looking for a fault in this branch. If there are no changes noted then get back to us. __________________ Difficulty is not an obstacle it is merely an attribute.
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32209 Good Answers: 839	#4 In reply to #3 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/22/2012 3:19 AM
	It would be rather interesting if the heating effect were unchanged with the generator running completely off load, wouldn't it? __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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Wal Guru Join Date: Jun 2011 Location: Phnom Penh Posts: 4019 Good Answers: 102	#5 In reply to #4 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/22/2012 5:26 AM
	Certainly would be. 3kW/24MW= 3,000/25,000,000=0.012%, hmm....I wonder what load the measurements were made at? Just looking at that resistor "rated" at 100A now. 62ohm makes its rating 62kW, so its working well within its survival range too.... Maybe 3kW is really OK or at least tolerable after all. The uber hot cabinet could probably do with some better ventilation. Let's see what OP comes up with. __________________ Difficulty is not an obstacle it is merely an attribute.
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satendrakumart Commentator Join Date: May 2011 Posts: 61 Good Answers: 1	#6 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/22/2012 5:34 AM
	Calling external agency to analyze the problem. Diagnosis will be communicated to forum.
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satendrakumart

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Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set

11/22/2012 5:38 AM

Date	Time	Frequency	U1 RMS	U2 RMS	U3 RMS	U1 THD	U2 THD	U3 THD	U1 CF	U2 CF	U3 CF	V1 RMS	V2 RMS	V3 RMS	V1 THD	V2 THD	V3 THD	V1 CF	V2 CF	V3 CF	A1 RMS	A2 RMS	A3 RMS	A N-E RMS	A1 THD	A2 THD	A3 THD	A1 CF	A2 CF	A3 CF	KF1	KF2	KF3	W1	W2	W3	W Total	Wh1	Wh2	Wh3	Wh Total	var1	var2	var3	var Total	varh1	varh2	varh3	varh Total	VA1	VA2	VA3	VA Total	VAh1	VAh2	VAh3	VAh Total	PF1	PF2	PF3	PF Mean	DPF1	DPF2	DPF3	DPF Mean	Tan1	Tan2	Tan3	Tan Mean
		Hz	V	V	V	%	%	%				V	V	V	%	%	%				A	A	A	A	%	%	%							W	W	W	W	Wh	Wh	Wh	Wh	var	var	var	var	varh	varh	varh	varh	VA	VA	VA	VA	VAh	VAh	VAh	VAh

11/20/2012	12:14:00 PM	49.82	11100	11090	11100	0.7	0.7	0.7	1.43	1.42	1.42	6420	6410	6410	2.6	2.5	2.4	1.46	1.46	1.45	995.3	984.2	994.5	13.1	1.4	1.4	1.3	1.41	1.41	1.42	1	1	1	5812911	5726079	5752884	17291873	8073	7953	7990	24016	2646820	2644768	2747331	8038920	3676	3673	3816	11165	6387174	6307392	6375257	19069823	8871	8760	8855	26486	0.91	0.91	0.9	0.906	0.91	0.91	0.9	0.907	0.45	0.46	0.48	0.463
11/20/2012	12:14:05 PM	49.81	11100	11100	11100	0.7	0.7	0.7	1.43	1.43	1.42	6420	6410	6410	2.6	2.5	2.5	1.45	1.46	1.45	989.3	978.3	988.4	13.1	1.5	1.5	1.3	1.42	1.41	1.42	1	1	1	5776464	5690913	5716405	17183782	16096	15857	15930	47883	2635070	2632859	2734805	8002735	7336	7330	7614	22280	6349120	6270456	6336926	18956502	17689	17469	17656	52814	0.91	0.91	0.9	0.906	0.91	0.91	0.9	0.907	0.45	0.46	0.48	0.463
11/20/2012	12:14:10 PM	49.8	11100	11090	11100	0.7	0.7	0.7	1.43	1.42	1.42	6410	6410	6410	2.7	2.6	2.5	1.46	1.46	1.45	991.4	980.3	990.5	13.1	1.4	1.5	1.4	1.41	1.42	1.42	1	1	1	5781471	5695091	5720556	17197119	24126	23767	23875	71768	2654219	2651594	2754072	8059886	11022	11013	11439	33474	6361629	6282121	6348993	18992743	26525	26194	26474	79193	0.91	0.91	0.9	0.905	0.91	0.91	0.9	0.906	0.46	0.46	0.48	0.467
11/20/2012	12:14:15 PM	49.8	11100	11090	11100	0.7	0.7	0.7	1.43	1.42	1.42	6410	6410	6410	2.6	2.6	2.6	1.47	1.46	1.46	991.7	980.7	990.9	13.1	1.5	1.5	1.4	1.42	1.41	1.42	1	1	1	5788542	5702971	5728549	17220062	32166	31688	31831	95684	2644290	2642054	2744170	8030513	14695	14682	15251	44628	6363929	6285255	6351916	19001100	35364	34924	35296	105584	0.91	0.91	0.9	0.906	0.91	0.91	0.9	0.907	0.46	0.46	0.48	0.464
11/20/2012	12:14:20 PM	49.8	11100	11100	11100	0.7	0.7	0.7	1.43	1.42	1.42	6420	6410	6410	2.6	2.6	2.4	1.46	1.46	1.45	990.5	979.5	989.7	13.1	1.4	1.5	1.3	1.42	1.41	1.42	1	1	1	5783245	5697247	5723014	17203506	40198	39600	39780	119578	2640754	2638680	2740705	8020140	18363	18347	19057	55767	6357639	6278639	6345425	18981703	44194	43644	44109	131947	0.91	0.91	0.9	0.906	0.91	0.91	0.9	0.907	0.46	0.46	0.48	0.464
11/20/2012	12:14:25 PM	49.81	11100	11090	11100	0.8	0.7	0.8	1.43	1.42	1.42	6410	6410	6410	2.6	2.6	2.5	1.46	1.46	1.45	990.2	979.2	989.3	13.1	1.4	1.5	1.3	1.42	1.42	1.42	1	1	1	5785305	5699786	5725111	17210202	48233	47517	47731	143481	2628208	2625963	2727981	7982153	22013	21994	22846	66853	6354316	6275615	6341834	18971765	53019	52360	52917	158297	0.91	0.91	0.9	0.907	0.91	0.91	0.9	0.908	0.45	0.46	0.48	0.462
11/20/2012	12:14:30 PM	49.8	11100	11090	11100	0.8	0.7	0.7	1.43	1.42	1.42	6410	6410	6410	2.5	2.6	2.6	1.47	1.46	1.46	993.5	982.5	992.7	13.1	1.4	1.5	1.3	1.42	1.41	1.42	1	1	1	5804564	5719126	5744714	17268405	56295	55460	55710	167465	2636541	2634059	2736253	8006853	25675	25653	26646	77974	6375295	6296565	6363088	19034947	61874	61106	61755	184734	0.91	0.91	0.9	0.907	0.91	0.91	0.9	0.908	0.45	0.46	0.47	0.462

Wal Guru Join Date: Jun 2011 Location: Phnom Penh Posts: 4019 Good Answers: 102	#8 In reply to #7 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 11/22/2012 6:42 AM
	What were the readings 1 month, 6 months and 1 year ago? __________________ Difficulty is not an obstacle it is merely an attribute.
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Anonymous Poster #1	#9 Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set 04/24/2017 7:38 AM
	Hello Dear I am also facing Same Problem , Please tell the Reason and remedy. Mobile/Whatsup: +919639006677 Thanks
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#1 "Re: What is the normal current through NGR of 25 MW, 11 KV TG set" by PWSlack on 11/21/2012 6:32 AM (score 2)

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#3 "Re: What is the Normal Current Through NGR of 25 MW, 11 KV TG Set" by Wal on 11/21/2012 11:05 PM (score 1)

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Anonymous Poster (1); PWSlack (2); satendrakumart (2); TonyS (1); Wal (3)

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What is the Normal Current Through NGR of 25 MW, 11 KV TG Set

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