Load reading - INCONSISTENCY

[melvinkoshy]

I have two nos. of 2 MVA 11kV /433V transformers feeding a facility which the loads are predominantly computer loads under UPS.

When I feed the loads on Transformer-1, the reading shows 430MW and when I switch over to Transformer -2, the reading shows 650MW and even 750MW.

What is the reason for this inconsistency? What should I do in order to rectify this problem?

 

[junkhound]

I have two nos. of 2 MVA 11kV /433V transformers feeding a facility which the loads are predominantly computer loads under UPS.

When I feed the loads on Transformer-1, the reading shows 430MW and when I switch over to Transformer -2, the reading shows 650MW and even 750MW.

What is the reason for this inconsistency? What should I do in order to rectify this problem?

Fix your instrumentation ??

 

[zbang]

When I feed the loads on Transformer-1, the reading shows 430MW and when I switch over to Transformer -2, the reading shows 650MW and even 750MW.

What is the reason for this inconsistency??

(I assume you mean kilowatt, not megawatt there.)

You must have down-stream metering, many data centers meter down to the branch circuit. Even just looking at feeders, how do those add up? You need to know what the loads are really drawing; only then will you even know which transformer's readings are correct.

If you do start at the top, is everything identical? I mean everything? (Obviously something isn't.) Were the readings OK then changed or did they always read different?

You need to look at everything a lot more closely, and if an obvious problem doesn't appear, let us know what you did find. Otherwise there isn't much to go on.

 

[ptonsparky]

Fix your instrumentation ??

Sounds like something along this line is screwed up.

 

[melvinkoshy]

Yes I meant kW there. sorry for the typo. I will check from the downstream and post it.

 

[melvinkoshy]

Fix your instrumentation ??

yes, I will check it up.

 

[Jraef]

You are feeding computers through UPS systems you say? That implies they are non-linear loads that will be rich in harmonics. The effects the harmonics have on the transformers will be different if the transformers are not absolutely identical, and even then, there are very slight differences in winding patterns, connections, cable lengths etc. that will result in apparent load differences. The load is not likely all that different, but the effect of the harmonics on your meters may be different.