Hello Bigpapa, and thank you for the interesting post!
We should look at this scenario from the KWHs consumption first, to determine if there is an issue.
The POCO has submitted Billing Statements to the Client, which show the Consumption for a typical Billing Period of 1,400 KWH.
I am _Assuming_ this Billing Period is 30 Days (30 Days between reading of KWH Meter).
I am also _Assuming_ the KWH Meter is a Standard Analog type, with a Rotating Register and 4 or 5 Physical "0-9" Dials, driven by the Rotating Register.
If the Client is billed at a Single Flat Rate, of let's say 12˘ / KWH, this would be $168.00 for a consumption of 1,400 KWH. Not too bad at all!
If the Client is billed per "Basic & Rate Exceeding", then the results may be as follows:
1. Basic Lifeline = 1st 500 KWH @ 12˘ / KWH = $60.00
2. Remaining 900 KWH @ 18˘ / KWH = $162.00
Total for 1,400 KWH Consumption / 30 Day Billing Cycle = $222.00
Still not too bad; close to what I pay.
The values and Breakdowns listed above would be typical for a Standard Analog type KWH Meter.
If the Client has a Digital (TOU) Meter, the Billing Rates will be reflected per the Time Of Use, so anything above Basic Lifeline Consumption may become inflated - possibly as high as 45˘ / KWH for peak Hours.
With that in mind, let's look at the Breakdown of 1,400 KWH per 30 Days:
1,400 KWH for 30 Days = 46.67 KWH per Day.
46.67 KWH per Day = 1.94 KWH per Hour.
Also, 46.67 KWH per Day would equal 5.834 KWH running for Eight Hours.
Could the Client be using this level of Power under normal circumstances? It is very likely.
Reference the Cooling / Heating Equipment.
If the Cooling is Three Tons / Heating is 36,000 BTU, the Peak Power Drawn from the POCO would be somewhere between 6.0 KW and 10.5 KW - depending on efficiency.
Figure an average of 8.25 KW running for a total of Six Hours each Day, and the 46.67 KWH per Day Consumption is easily done!
This does not include Lighting and other Loads.
The best way to address this scenario is to decide if there is a reason for your Client to Consume much less than an average of 46.67 KWH per Day.
This can be a simple Revelation:
Are the Lights always on?
What Appliances are running?
Are the Heating and Air Conditioning "Fighting" for Dominance?
True Power Consumption is what the KWH Meter tallies. Low Power Factor will not show a Readable KWH Consumption, unless there is <.50 PF constantly on the 15 KVA Maximum Apparent Power Rating of the First Transformer.
This would be evident at the First Transformer's Input as Overheated Conductors.
15 KVA @ 240V would equal 62.5A, so if the Primary Feeders are #2 AL. Protected by a 70/2, there would be noticeable Heat with a constant 15 KVA Load (+ 3 Hours at 15 KVA).
Measuring PF at the Transformers with no Load will show the results of the Core Losses and the Transformer's Primary to Secondary "Stabilizing Load" (mostly in VARs, however whatever Heat is produced will be equivalent Wattage).
About the same will be found under Full Load or 50% Load, just with higher Heat - which would improve the Power Factor.
Lastly, if 50% of the Transformers' Maximum Apparent Power Rating was drawn for Eight Hours each Day, with a Power Factor of 80%, this would result in 48 KWH per Day.
15 KVA x 0.5 = 7.5 KVA.
7.5 KVA x 0.8 PF = 6.0 KW.
6.0 KW x 8 Hours = 48.0 KWH.
I have a few Questions to pose:
1. Is the Client's Meter a TOU Digital Type?
2. Did the Client request investigation regarding excessive Billing Amounts or excessive Consumption?
3. What are the Client's typical Loads?
4. Could the 46.67 KWH per Day be normal?
Any additional information you could add would assist greatly in a much more accurate Guess...