×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

MV kwh meter
2

MV kwh meter

MV kwh meter

(OP)
I need to specify - design a 4160V kwh meter onto some U.G feeders. The only accessable location is at a bank of oil switches for which all feeders enter. I am looking at installing the pt's and ct's in the hv compartment below these switches. I am looking at discrete CT's and PT's, but it is starting to become a kludged up mess.
Q. Are there small 5KV CT-VT combinations for meters that can be neatly installed?

RE: MV kwh meter

2

If the 4160V system is ungrounded or high-resistance-grounded, a PT assembly like http://www.geindustrial.com/products/specs/3pt360.pdf may work.  If the CTs are in a common location, one PT set could serve several low-burden 2-element watthour meters/transducers.  It may be desirable to serve meter/transducer auxiliary power from a separate source.
  

RE: MV kwh meter

Suggestion: Visit
http://www.thomasregister.com
and type Transformers: Instrument under Product or Service, which will return 113 companies to approach to

RE: MV kwh meter

(OP)
One PT. YES!, that helps alot.

RE: MV kwh meter


Understand that the link was to an open-delta PT, 4200V 3ø 3-wire to 120V 3ø 3-wire.
  

RE: MV kwh meter

Suggestion: The three-phase three-wire power supply system only requires two PTs and two CTs for the Aaron kWHr connection (or Blondels Theorem).
See Reference:
Donald G. Fink, H. Wayne Beaty "Standard Handbook for Electrical Engineers," 13th Edition, McGraw-Hill, Inc., 1993.
Page 3-29 Section 73.
When the total load is balanced, energy may be measured with one CT, and one kWHr meter (or power with one Wattmeter) using Y box, as shown in Fig. 3-28. This arrangement, which creates an artificial neutral, has two branches which have the same impedance and power factor as the kWhr meter (or wattmeter's) voltage circuit, which is third branch of the Y. Total energy (or power) is three times the reading of the kWhr meter (or Wattmeter).

RE: MV kwh meter

Considering the price of 5 kV CTs and VTs run about $300/each, I would not think it would make sense to risk assume perfectly balanced loads in an effort to save 1 VT and 1 CT. If wrong, you could waste $600 pretty quick in lost revenue!

RE: MV kwh meter

(OP)
By one PT, I meant a 3-phase PT simular to the busbar PDF file link. This system is delta-wye grounded so it is low impedance grounded. I have not thought about the consequences of using a common PT in this case, however, the system supply is derived from a common main bus so I do not see a problem.

 As for the CT's, are all 5KV class CT's Bar type, or do they make solid core donut types also? I have not done the thomas site because the last time I tried My computer was inadated with pop-ups, I had to reboot.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources