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A combined CT-PT metering unit (CTPT unit, also called metering equipment or M.E.) is a single three-phase, oil-cooled outdoor unit that replaces the three CTs and three PTs used for metering. Laxmi Engineering, Bhopal, manufactures these units up to 33 kV and specialises in very low ratio units with high accuracy, such as class 0.2S.
Where CTs and PTs are required only for metering, a combined CT-PT unit is an economical, reliable and very compact solution.
Key specifications
| Parameter | Value |
|---|---|
| Construction | Three-phase, oil-cooled, outdoor |
| Voltage ratings | 11 kV, 22 kV, 33 kV |
| Accuracy class | 0.1, 0.2, 0.2S, 0.5, 1, 3P, 5P |
| Primary current ratings | Up to 2500 A |
| Burden | Up to 200 VA and above |
| Voltage factor | Up to 1.9, continuous |
| Short-time current (STC) | Up to 50 kA for 3 seconds |
| Secondary terminal box | IP55 |
| Replaces | 3 CTs + 3 PTs used for metering |
| Standards | IS 16227 and IEC 61869 |
| Testing | Designs type-tested at NABL accredited labs; in-house 400 kV impulse testing laboratory; all routine tests done in-house |
Types and ratings
• 33 kV CT-PT combined unit
• 22 kV CT-PT combined unit
• 11 kV CT-PT combined unit
Low ratio, high accuracy units - We specialise in very low ratio (low current rating) CT-PT units with high accuracy class, for use in 0.2S class three-phase metering systems.
Customised designs - Parameters are customised as per the customer's requirements, up to 33 kV rated voltage.
Applications
• Three-phase metering where CTs and PTs are required only for metering purpose.
• Outdoor installations of power utilities.
• High accuracy (0.2S class) metering at very low current ratings.
Frequently asked questions
What is a CTPT metering unit?
A CTPT metering unit, or combined CT-PT unit, is a single three-phase unit that contains the current transformers and potential transformers needed for metering. One unit can replace a combination of three CTs and three PTs. Laxmi Engineering makes these units oil-cooled, for outdoor use, up to 33 kV.
Why use a combined CT-PT unit instead of separate CTs and PTs?
Where CTs and PTs are required only for metering, a combined CT-PT unit is an economical, reliable and compact solution: a single unit does the work of three CTs and three PTs.
Which voltage ratings and accuracy classes are available?
Laxmi Engineering manufactures combined CT-PT units for 11 kV, 22 kV and 33 kV, in accuracy classes 0.1, 0.2, 0.2S, 0.5, 1, 3P and 5P.
Does Laxmi Engineering make low-ratio CTPT units?
Yes. Laxmi Engineering specialises in very low ratio CT-PT units with high accuracy, for use in 0.2S class three-phase metering. Primary current ratings go up to 2500 A.
Which standards and tests apply, and where are the units made?
The units are made as per IS 16227 and IEC 61869. Designs are type-tested at NABL accredited labs, all routine tests are done in-house, and Laxmi Engineering has an in-house 400 kV impulse testing laboratory. The units are manufactured at its factory in Govindpura Industrial Area, Bhopal, Madhya Pradesh.
Request a quote
Send us your requirement — voltage rating, CT ratio, accuracy class and burden — and our sales team will get back to you.
Phone: +91-755-2586141 · Mobile: +91-6261549929 · Email: sales@laxmile.com