Reasonable priced power monitoring equipment

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electricguy61

electricguy61

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Remotely running business in Bay Area, CA from Med
I installed a generator (Cummins 20KW) for a customer earlier this spring.

He reports that in addition to the normal exercise period (Wed 8am), the generator is coming on at midnight every night, running for 15 minutes, and shutting down.

My guess is something in the neighborhood or with PG&E is being tested every night, causing a momentary voltage drop.

Can the forum recommend a reasonably priced power monitor that would record momentary spikes and drops?

Thanks
 
Best bet is to rent a unit or sub this work out, Short term investment, unless you really see a need to own a PQ analyzer.
 
Fluke 189. It's not an average data logger. It can be set to record intervals, but also setup to instantly capture deviations that exceeds n %(minimum 1). The percentage is configured by you.

If you set it for 10min, it will record and retain minimum, maximum and average value for ten minutes
If during ten minutes it detects a deviation that exceeds say 4% as you configured it will make an additional point as an incident event.
 
You can borrow one from the San Francisco PG&E office. It a bit tricky to use but it is a nice unit. FREE to rent.
 
Since its happening exactly at midnight every night, I would stake out the location with an ordinary meter, if it is a power fluctuation, it would have to be one with a long duration to cause the transfer switch to start the generator. The fifteen minutes is probably the cool down cycle timer. If you want proof to show the POCO if its on their end, there is a company called Electrorents that I believe is based in California, that will ship the recorder to you. Rental is not all that expensive.
 
Ask the customer if street lights go out. If there's a wide spread disturbance low enough to start the generator, HPS and MH will drop out and they take a few minutes to come back on.
 
electricguy61 said:
I installed a generator (Cummins 20KW) for a customer earlier this spring.

He reports that in addition to the normal exercise period (Wed 8am), the generator is coming on at midnight every night, running for 15 minutes, and shutting down.

My guess is something in the neighborhood or with PG&E is being tested every night, causing a momentary voltage drop.

Can the forum recommend a reasonably priced power monitor that would record momentary spikes and drops?

Thanks
Click to expand...

what we in the poco recommend that you take a look at the settings of the generator. first we recommend that the under/overvoltage protection relay is calibrated and is properly set. that usually means that the settings must be beyond the plus/minus 10% of the voltage contracted with the utility.

since the power lines have reclosers we also recommend that a time delay of around 2 seconds be introduced. this would eliminate nuisance starts due to recloser action.
 
Check Clock Exerciser

Check Clock Exerciser

electricguy61 said:
I installed a generator (Cummins 20KW) for a customer earlier this spring.

He reports that in addition to the normal exercise period (Wed 8am), the generator is coming on at midnight every night, running for 15 minutes, and shutting down.

My guess is something in the neighborhood or with PG&E is being tested every night, causing a momentary voltage drop.

Can the forum recommend a reasonably priced power monitor that would record momentary spikes and drops?

Thanks
Click to expand...

ElectricGuy61,
Most genset manufacturers have exercise clocks that can accept multiple exercise programs. I suspect that the unit is programmed for 2 separate run periods. Cummins bought Onan transfer switches, I would look in the Onan/Cummins
owners/operators manual to disable the midnight exercise period. If you give me the model # or manual # of the ATS I can help you with the reprogramming. I keep a pretty good library on transfer switches:)

If the clock exerciser is externally hard wired and not internal to the controller then I will need the make and model of the clock.
Tks
 
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I would also suspect something in the programming. Nothing the utility, or anybody else does is that exact!

Also, Robbitan has some good ideas with the programming to make sure your generator only runs in the event of an extended outage. You don't want the generator to come on for a momentary outage (2-5 seconds). More often than not, a fault on the utility system is temporary and results in only a momentary outage.
 
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