Unstable Electrical Supply from Local Source (13kv)

I used a full disclosure monitor made by Realiable (now part of Fluke). I rented it from an outfit by the name of Telogy. Check out the Fluke 1750 at http://www.telogyllc.com/application_details.aspx?applid=1

I would hire an electrical contractor. In that way you will have it in writing from an independent source. Will not be your word against the utility company.

I agree Ozzb. I'll bet that the problem is caused by the substation switching that is done to match demand, and the substation may not have suppressors installed on its switchgear. Also to consider-any close upstream or downstream users who move large switchgear. A professional power quality contractor is who is needed here, as he will seek the extremes of the span of the voltage and current levels, as well as seek out spikes and transients that can be very difficult to find without sophisticated recording equipment.

Best Regards,

Ing. Robert Forbus

Hello Jeff in Mexico

If you use a local Electrical Contractor for the monitoring, it may be possible he is a friend or relative of a person in your Electricity Suppliers.

The best solution is to use an entirely independent Electrical Consultant or Engineer, with no 'ties' to the Electricity Supplier, or yourself.

That way, proper professional independence is maintained, and the report would thus be acceptable, hopefully to both parties.

Kind Regards....

Hi, i knew a company in india which manufactors Feeder monitoring system which logs allthe instantanious electrical parameters every 5 to 15 min intravals, stores the data for more then 10 years.

You may use Fluke 43-B for monitoring independent phases on low voltage side on 24 hours basis and thereafter take print-outs for further investigation by your internal distribution management team / by the utility company. Monitoring on low voltage side though has the uncertainty of internal Transformer malfunction attached to the analysis. This will however be applicable if you are using one transformer which feeds three factory areas and will not apply if you are using three transformers for three factory areas.

Regards

I use an Amprobe DM-II Pro (I think they are now up to the DM-IV). This is a three-phase monitor/recorder. I think they run on the order of $3000 or so...Variable recording periods, catches spikes and sags, rated up to 1000 V RMS.

I use the Socomex Diris A40 meter with the RS485 Jbus/Modbus module attached to the unit. This is then connected to a PC running software developed in Thailand. It has everything you need to monitor and log voltage, current, KVAr etc. Can also export to excel etc. Socomec has software but it's too expensive. Send me an email if you're interested and I will get you some prices.

When I worked in industry, the standard for these measurements was Dranetz. Try Googling them.

You may be approaching the problem from the wrong direction. If you prove the instability with charts and reports you have now embarrased the local utility managers who probably don't have the authority or budget to fix the problem anyway. Utilities in Mexico have a way of being unstable and unreliable, but when confronted give shrugs and denials.

You would be ahead of the game researching how to resolve the problem for your factory. If you can clearly define the symptoms for this forum there are a lot of sharp cookies out there who can suggest solutions.

Been there, wiser for the experience.

Electro Industries has a variety of high-quality digital meters for very reasonable cost. I've used their meters for nearly 20 years, and have never had a bad experience.

The Shark series meters have many options, including RS485, ethernet (wired or wireless), onboard data logging and power quality including THD. The best part is that you can order just the functions you need, without a lot of extra bells & whistles. If you later decide you need more options, you can upgrade in the field via simple software changes, without disconnecting the meter or even removing it from service.

I would say that during the summer months demand is great and the LOAD TAP Changers are Maxed out on the Power Grid that you are fed from good luck trying to get those guys to address this.