Power Flow Analysis for Industrial Facility

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designer82

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A large textile mill facility has a problem where the kW's coming in from the utility are double what is being distributed at the loads.
About 1,300 kW's coming in from the utility and about 650 kW's being measured as distributed (via individual branch meters to each utilization branch).
Also their power factor is terrible, about .68
They would like a power flow analysis to see where all the kW's are going.

My thought is gather all cable size/length info from utility transformer all the way to all branches and loads. Have an electrician measure kW's at all utilization branches, downstream & upstream of utility xfmr. Also gather as much specific load info as possible.

Enter all that info in ETAP and run the power flow calculation to try and identify any electrical system inefficiencies.

How would you do it?
 
Or do you mean the kVA coming in from the utility is double the kW being distributed?

With a pf 0.68 it could well be so. Still not good though.

If the pf really is 0.68 that facility is going to be paying a small fortune in penalty charges. Time for some double checking of the numbers.
 
designer82 said:
A large textile mill facility has a problem where the kW's coming in from the utility are double what is being distributed at the loads.
About 1,300 kW's coming in from the utility and about 650 kW's being measured as distributed (via individual branch meters to each utilization branch).
Also their power factor is terrible, about .68
They would like a power flow analysis to see where all the kW's are going.

My thought is gather all cable size/length info from utility transformer all the way to all branches and loads. Have an electrician measure kW's at all utilization branches, downstream & upstream of utility xfmr. Also gather as much specific load info as possible.

Enter all that info in ETAP and run the power flow calculation to try and identify any electrical system inefficiencies.

How would you do it?
Click to expand...
There is no way this can be. Whatever power comes into the building has to get used.

With a crazy PF like that it is possible that what is being measured coming in is kVA and what is being used is kW.

Seems to me they need to deal with the crazy PF.
 
I would review the sources of this data. It's probably not the case that system losses inside the facility are 50%. Are they sure they are really metering ALL loads. Or as mentioned, the input data is in kVA, not kW. I can believe a pf of .68 in a mill.
 
Thank you for your replies.

The suggestions are great. I need to first obtain actual data. It could be the incoming power is being measured in KVA, the owner may not be explaining it properly.

Would power factor correction capacitors be recommended for this project to get their pf closer to 1?
 
designer82 said:
Thank you for your replies.

The suggestions are great. I need to first obtain actual data. It could be the incoming power is being measured in KVA, the owner may not be explaining it properly.

Would power factor correction capacitors be recommended for this project to get their pf closer to 1?
Click to expand...
Absolutely, but you should have some EE help in doing it. VFDs and PFC do not always play well together. Definitely a NOT on the same motor.
 
Improving the power factor will not drastically improve the overall efficiency. Efficiency is a function of actual power (kW) losses. Improving power factor would reduce the total current, and this would reduce the resistive losses in the system, but that is not one of the major issues related to power factor.
 
As had been suggested by others, there is some bad data being used in this early stage of discussion.
ETAP load flow analysis is not going to help you. You need to just think of accurate info placed on the oneline and kirchhoff's laws (KCL & KVL).
If they are getting penalized on their utility bill for low power factor, then power factor correction capacitors with required filtering is a good idea. If they get no penalty, then the backback is very small and not worth it.
 
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