Recommendations on power logger for medium voltage distribution circuits 6

[ccourville]

Hello,

I work for a small electric distribution utility in Massachusetts. I need to perform an energy studies on our 7970/13800grd Y system at various points both three phase and single phase. We are experiencing voltage rise issues we believe that are caused by the solar generation customers on our circuits that are back feeding the system. As this is medium voltage, My thoughts are to build a primary metering setup with PT's and CT's and connect a power logger to the secondary outputs to capture data.

Does anyone have a product, setup, or experience in this that you feel is best for this situation?

best regards,

CCourville

 

[Overvoltage]

Had good experience with CP Linescope. Would avoid needing the separate CTs/PTs and is fairly relocatable in the future.

Also PMI makes good stuff, but you'll need to mount a transformer and CTs as they only work at secondary voltages.

 

[Palletjack]

What kind of relays you have on your system now?
These can be used to do what you want. We have several Tavrida’s on the system with 651R relays we monitor power flow, voltage fluctuations, etc..

 

[mls1]

We purchased a PowerSight data logger a few years ago to take measurements on a medium voltage rectifier. We have a number of AEMC and Dranitz loggers but the PowerSight had an option for medium voltage probes that can be placed directly on the line without PT. They are rated 15kV and come with hot stick extensions to apply them. The software and HMI are a bit clunky but the logger also had bluetooth which allowed us to monitor and control with the logger sitting inside the cabinet. You might check them out.

 

[bacon4life]

Depending whether exactly what data you need there are several other approaches to consider:

Voltage measurements -To avoid messing with medium voltage stuff, I sometimes have data loggers set at nearby customer meters. By measuring load as well as voltage, it is easy to tell which voltage fluctuations are coming from the system and which are caused by the local load changes. If I have lots of nearby service transformers, I'll pick a customer that I suspect has minimum load or minimal voltage drop on the transformer and secondary cable.

Loading measurements-There are several brands of hotstick compatible clamp-on meters available for 15 kV. They can accurately measure current, but they only provide a very approximate voltage reading. If you have bi-direction flows of both real and reactive power, it can be tricky to determine the direction of power flow.

Smart meters-I have just started to incorporate voltage data from customer AMI meters into system studies.

 

[ccourville]

I thanks all of you for sharing your information.

Overvoltage,
I am familiar with PMI's stuff and have their meter socket recorder, which is excellent. Ill check out the CP Linescope - that looks interesting

PalletJack,
Our town is feed from an investor owned (National Grid) 13.8kv feeder. No sub in our town. We have a NOJA recloser at the town line, and two others in the system to provide system protection. I can get plenty of info at each one of them, but I am looking for a mobile set up to check various places in town.

mls1,
Thanks for the info on the powersight setup. Those 15kv rated clamp on PT's look interesting. How did you connect the CT's to measure the load?

baconforlife,
Thanks for the "thinking outside the box" ideas. You have some good points there as well. The clamp on load loggers i've seen are not bi-directional. Smart meters our in our 5-10 year plan. We just installed driveby Itron meters a few years back.

Friday I will dig into some of the suggestions here and see what I can find.

Thanks for the help.

CC

 

[PQ Guy]

CCourville,
we have created a PQ belwether station using a primary metering rack with a PQ meter ION 8650 and MV instrument class pt/ct rack for accuracy.

Generally solar panel proliferation causes over voltage for a couple of reasons. The most prevalent however in our area is harmonics caused by inverters.

With a good meter you can determine the harmonic contribution and determine best remediation.

A cap bank with an inductor tuned for the offending frequencies becomes a sink hole for the frequencies. i have also seen on a large scale solar farm where a voltage regulator was used to drive the incoming voltage down so the solar farm could produce at a lower level allowing them to push on to the distribution system without elevating its output.

PQ Guy in Texas

 

[bwen08]

You might investigate the sensor from Aclara. I'm fuzzy on the specifications as its been awhile since they tried peddling them here, they have a website to use for data analysis and I believe they were cellular so you didn't have to worry about the communications.

https://www.aclara.com/products-and...ntrols/grid-monitoring-platform/power-sensor/