Intermitant Powerloss

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chris1bcoo

Member
Looking for some input.
I have a customer that is complaining of her power shutting off intermittently. Her main complaint is at approx. 3.45 PM twice a month the electronic clocks in the kitchen, 2 bedrooms adjacent to the kitchen & the front door electronic locks are shutting off briefly.
Just long enough to have to reset the clocks/lock.
A little history we wired the house 4 1/2 years ago. 6mos after the house was completed it was hit by lighting. Several of the electronic devices were replaced we found no damage to the electrical system and added roof spikes that are bonded correctly.
I have checked the outlets in question and the breakers. (FOUND NOTHING) So I changed the breakers for the affected areas. Still no resolution. Had the utilities check the transformer and found no problems.
The house has an underground 2oo amp main panel outside just feeding the sub panel in the garage witch is feeding the whole house. The house Voltage is 122/244.
Any Ideas
 
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petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
Re: Intermitant Powerloss

sounds like you have a fair number of clues as to where to look. something happens at a specific time twice a month and only affects a couple of circuits.

I'd be looking for what happens at those times and what those circuits have in common.
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: Intermitant Powerloss

I am betting that the circuit feeding the area is being hit a couple of times a month. Ask her to check with the neighbors for the same problem. If it is only her, then the problem is internal. If the neighbors are having the same problem (I'll bet they are), the electric utility is relaying the circuit at the substation for some reason at this time. Trust me on this, the trouble man would not have a clue, this will have to be pursued through the engineering supervision. :D
 
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pqtest

Member
Re: Intermitant Powerloss

Ask the local utility to install a graphical power quality monitor if they have one. I suspect that you will find that many voltage sags are present on this system.

Just a heads up, most utilities don't have a PQ monitor available for public use but rather a recording voltage / current meter that they send out. Recording voltmeters cannot document most PQ events because they are too fast- ask them to send out a monitoring device that meets IEEE standard 1159, which is a power quality monitoring equipment and installation standard.

Your other option is to go to Ebay and buy an old Dranetz 606 monitor for about $100.00 and check it out yourself. These old Dranetz units work great and you can get the thermal recording paper at most office supply stores. Watch out for the internal nicad batteries- they may need to be replaced (10 AA), otherwise the device wont be able to capture deep sags or outages. These 606 units don't have a graphical output but rather simple text printouts.

With the data collected, you can figure out what is causing the problem.

Mark
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: Intermitant Powerloss

Just a heads up, most utilities don't have a PQ monitor available for public use but rather a recording voltage / current meter that they send out.
Click to expand...
I am not so sure about that statement. I know for a fact that we have that type of equipment and we can do power quality work that most electrical contractors can not do and we help them out with our equipment. I suspect that most electric utilities have the equipment but will not use it unless they feel there is a need for that type. :D
 
physis

physis

Senior Member
Re: Intermitant Powerloss

Charlie, I love knowing a guy on the inside!

PQtest, do you know the sample rate of those 606's?
 
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pqtest

Member
Re: Intermitant Powerloss

Charlie-

May I ask what brand and model of equipment you are using? Our experience has been that most utilities use a Rustrak Ranger or AMEC DM-II / DM-III, and we do work nationwide. These units cannot capture PQ events, but are excellent tools otherwise. The only utility (so far) that I have run into that has the proper PQ equipment is Pacific Gas and Electric in SoCal. We keep a list of PQ service providers and other consultants for referrals and would like to add your organization to the list- could you pm me with the information about your program? Thanks!

physis-

I've heard different numbers over the years but the bottom line is that these units are 20+ years out of date and not much technical information is out there. Dranetz no longer supports them, but they might be able to answer your question. An ideal replacement for the 606 units is the ACR Powerwatch or the Fluke VR101. (These units are the exact same thing- Fluke is just putting a private label on the Powerwatch) Costing about $600.00, they only provide a text output and some simple graphics- they cannot display the actual waveform of the captured disturbance. One drawback- you need to bring along a laptop to the job site to program and download the unit.

Mark
 
physis

physis

Senior Member
Re: Intermitant Powerloss

PQtest,

A small point, being in California, isn't PG&E north and Edison south? I don't know where the line is though.
 
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charlie tuna

Senior Member
Location
Florida
Re: Intermitant Powerloss

i am not bragging---but i don't know how electrical contractors get along in business without some half decent power recorder. it stops alot of complains and un-necessary questions concerning power problems! i have two metrosonics power recorders---my power company has one! it records or monitors all aspects of the power 30 times per cycle. i invested in this unit ten years ago -- other contractors heard i had it and began hiring me to monitor their problems--i ended up buying a second unit. they have payed for themselves over and over. i charged to set them up and $35.00 a day and the time to download and formulate the report! engineering groups began calling me to provide them power quantity recordings.....
 
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pqtest

Member
Re: Intermitant Powerloss

physis

You are absolutely correct- it is San Diego Gas and Electric that I was thinking of.

SDG&E has an excellent PQ section on their web site as well as other useful resources.


Mark
 
physis

physis

Senior Member
Re: Intermitant Powerloss

Sounds like a cool way to do business Charlie. I can't afford anything too elaborate but I was thinking at $100 one of those 606's might be nice to have.

[ January 23, 2005, 05:20 PM: Message edited by: physis ]
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: Intermitant Powerloss

I don't have the type of equipment that our power quality division has at their disposal, I just know they have done this type of work and they have a shop full of electronics. :D
 
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charlie tuna

Senior Member
Location
Florida
Re: Intermitant Powerloss

i large office building called us because another contractor recommended us because we had the equipment. we went on an engineering office floor that was full of draftsmen. each station had it's own stand alone computer with a small ups unit. they were beeping continuously here and there throughout the floor. we knew we had a low voltage problem when we took readings on the 480 volt bus duct riser. it was down to 230 volts between phases. the secondary voltage off the tenant transformer was 90 volts or less! we went to the main switchgear and took readings from the incoming vault ---it was the same----low!

they had already called the power company who denied any problems. we set up a data recorder for twenty four hours and downloaded the information. the management company called for a meeting with the power company officials. they(power company) (three salesmen and a guy from the meter shop) showed up for the meeting and again denied any problems on their end of the system. when i gave each of them a copy of the data recorder's results --- they studied them for a couple of minutes and then asked to leave the room for a few minutes----five minutes later they came back in and explained(admitted) they had some major problems with their primary feeders ---and that it would not be corrected for another month!! we then found the building had two primary feeders and we could remove some major loads off the damaged primary by selecting certain chillers and associated equipment. the thing that forced them to the truth was the data recorder's report. the meter tech told the salesmen "you can't argue with these facts"! it has always been the way the power company operates---"admit nothing"! if they had explained the problem to the building --- the building could have helped reduce the effects by selecting loads!!!
 
physis

physis

Senior Member
Re: Intermitant Powerloss

Charlie E.'s gotta have something to say about that. I would thing that would be atypical power co. behaviour.

I'm starting to get kinda interested in this PQ stuff. It would be more in the middle of what I used to do and what I do now.
 
charlie

charlie

Senior Member
Location
Indianapolis
Re: Intermitant Powerloss

It depends a lot on the management of the electric utility and the personnel they have working for them. If that happened at my company, I wouldn't bet much on their ability to reach retirement. :mad:
 
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pqtest

Member
Re: Intermitant Powerloss

physis, and anyone else interested in PQ-

You might actually do better holding off on buying that Dranetz 606 for now and investing in a training class.

PowerCET (www.PowerCET.com) is the nations leading power quality training firm, and they are located in CA. Many of their classes are on CD for about $200.00 each but they hit the road on a regular basis for those who learn better in a classroom setting.

You can always rent a PQ monitor in the future and pass the cost on to the customer.

In case anyone is wondering- PowerCET is not my company.

Mark
 
rick hart

rick hart

Senior Member
Location
Dallas Texas
Re: Intermitant Powerloss

A few years back we were having some power problems- voltage sags just enough to start generators, transfer back and forth, really annoying the surgeons. The utility said their equipment checked out and the problem was on our end. We had just put Powerlogic monitoring stuff in about six months prior, and it showed that we were low on one phase- C phase to be exact- by a thousand volts (13.2kV service).
I was able to take a waveform capture and fax it to the utility. Needless to say, they were impressed and went and looked again.
What they found was a capacitor bank had only closed on two phases while the indicator showed all three connected.
Since then, when we tell them we are seeing something, they believe us. There has been a few times they have called to inquire if we were seeing something on power monitor because they didn't have anything already in the field a sensitive.
What it sounds like to me on this problem is something similar- same problem at the same time. Maybe not cap switch but something on the delivery service is causing the sags. Why it only presents itself on a few circuits is bothersome though.
 
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ken987

Senior Member
Re: Intermitant Powerloss

This reminds me of the timing electrical meter that was installed long ago for a water heater. I was going to take it and install it somewhere but figured the power company would trace it and it come back to me eventually.
 
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