Wound Type Medium Voltage Current Transformer · 3.3kV–33kV

Wound Type Medium Voltage Current Transformer (33kV)

Straton Electricals' wound-type CT range transforms high currents up to 2000A into standardised 1A or 5A outputs for revenue-based meters, protective relays, and current monitoring instruments. Available as indoor Resin Cast, outdoor Cycloaliphatic Resin Cast, and OIP instrument transformer designs across 11kV, 25kV, and 33kV, these medium voltage current transformers suit outdoor pedestal-mounted and air-insulated switchgear installations. A trusted current measurement transformer with precision instrument transformer design compliant with IEC 61869-1&2 and IS 16227.

  • Transforms high currents up to 2000A into standardised 1A or 5A outputs
  • Available as indoor Resin Cast, outdoor Cycloaliphatic Resin Cast, and OIP designs across 11kV, 25kV, and 33kV
  • Suited to outdoor pedestal-mounted and air-insulated switchgear installations
  • Compliant with IEC 61869-1 & 2 and IS 16227
Wound Type Medium Voltage Current Transformer (33kV)

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Certifications

Certified and Approved For

IEC 61869-1 & 2 / IS 16227 Type-Tested IEC 61869-1 & 2 /
IS 16227 Type-Tested
APTRANSCO & TGTRANSCO Approved APTRANSCO &
TGTRANSCO Approved
Technical Specifications

Wound Type Medium Voltage Current Transformers: Technical Specifications

System Voltage3.3 | 6.6 | 11 kV up to 33 kV
Rated Primary Current5A to 2500A
Rated Secondary CurrentUp to 5A
Extended Current Rating120%
Operating Frequency50Hz / 60Hz
Class of InsulationB / F
Standard Ambient Conditions-5°C to +40°C
AltitudeUp to 1000m above mean sea level
Accuracy Class0.2s | 0.2 | 0.5 | 0.5s | 1.0 | 3.0 / 3P / 5P
Output (Burden)5 VA to 60 VA
Short Time Current (STC)Up to 40 kA
ApplicationOutdoor Pedestal Mounted / Air Insulated Switchgear
Product Types

Types of Wound Type Medium Voltage Current Transformer (33kV)

Indoor Resin Cast Wound CT

Indoor Resin Cast Wound CT

Vacuum-impregnated and moulded with epoxy resin, providing uniform dielectric strength through dry-type insulation — maintenance-free, no oil, no periodic servicing.

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Outdoor Cycloaliphatic Resin Cast Wound CT

Outdoor Cycloaliphatic Resin Cast Wound CT

Cycloaliphatic epoxy resin construction engineered for outdoor pedestal-mounted and air-insulated switchgear installations.

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OIP Wound CT

OIP Wound CT

Oil-impregnated paper insulation with fine-graded bushing construction for uniform dielectric strength throughout the active part and core.

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Key Features

Key Features of Wound Type Medium Voltage Current Transformers

Oil-impregnated paper insulation with fine-graded bushing construction provides uniform dielectric strength throughout the active part and transformer core
Partial discharge-free performance up to power-frequency withstand voltage validated under IEC 61869-1&2 type test conditions
Nitrogen-free stainless steel bellows compensates oil volume variation, maintaining pressure equilibrium across all ambient service conditions
Stud-type DIN terminal design ensures installation-friendly, torque-rated secondary terminal connections for metering and protection circuits
Tan delta tap available on request for in-service power factor and dissipation factor diagnostic testing of OIP CT insulation
Epoxy resin moulded CT vacuum-impregnated and moulded with epoxy resin, providing uniform dielectric strength throughout the active part via dry-type insulation
Partial discharge-free CT performance up to power-frequency withstand voltage — validated under IEC 61869-1&2 type test conditions
Maintenance-free CT construction — no oil, no periodic servicing, no filtration required across the entire service life of the RC-type CT
Compact dry-type transformer design — installation-friendly for space-constrained indoor and outdoor medium voltage transformer applications
Tan delta tap available on request for in-service dissipation factor and power factor diagnostic testing
Applications

Applications of Wound Type Medium Voltage Current Transformer

Straton's Wound Type Current Transformer range delivers reliable Medium Voltage Current Transformer performance for Electrical Protection System and Metering System integration across MV installations.

Wound primary CT applications for accurate current measurement
Protection Relay integration within MV substations and panels
Switchgear-integrated current sensing for metering and protection
Instrument Transformer applications requiring stable wound-primary accuracy

Wound Type Medium Voltage Current Transformers: Our Product Range

Explore wound type CT technical data across 11kV CT specifications to 33kV CT specifications, covering primary and secondary rating, accuracy class, burden, and insulation details.

  • 11kV range: 11RC01, 11RC02, 11RC03, 11RC04, 11RC05, 11RC06, 11RC09, 11RC10
  • 33kV range: 33RC01, 33RC02, 33RC03, 33RC04, 33RC05, 33RC06, 33RC07, 33RC08
  • Outdoor OIP range: 11OC-W, 25OC-W, 33OC-W

Contact our engineering team for the full datasheet on any model in this range.

FAQ

Frequently Asked Questions

A wound-type CT is an instrument transformer where the primary winding is wound around the core, transforming high currents up to 2000A into standardised 1A or 5A outputs across medium voltage CT applications.
Wound type CTs are deployed across air insulated switchgear, outdoor substations, electrical panels, and industrial automation systems — serving 11kV and 33kV systems for revenue metering, protection relaying, and switchgear and industrial CT applications across India's power infrastructure.
Straton Electricals' wound type CTs deliver high accuracy performance across 0.2S to PS accuracy class ratings, featuring compact design, enhanced insulation for partial discharge-free operation, reliable performance up to the rated thermal limit, and superior electrical safety across all medium voltage installations.
Critical wound-type current transformer maintenance includes periodic insulation testing using an insulation tester, terminal connection check on secondary wiring, cleaning, oil leakage inspection for OIP units, secondary circuit verification across protection relay outputs, and regular thermographic monitoring by a qualified maintenance engineer.
CT accuracy class directly determines metering and protection accuracy — Class 0.2S minimises ratio error and phase angle error for precision metering devices, while Class 5P10 ensures reliable protection system response under fault conditions, with every wound type current transformer rated across varying load conditions.
Wound-type current transformer manufacturing at Straton Electricals' testing laboratory follows IEC 61869-2, IS 2705, and ANSI C57.13 — covering routine and type tests, including dielectric and accuracy tests, ensuring every unit meets global CT testing standards.
The core-wound vs bar type CT difference lies in primary winding construction. A wound-type transformer has multiple primary turns wound around the core design for lower currents, while a bar-type transformer uses a single solid bar primary for high current CT construction types.
Talk To Us

Looking for Reliable Medium Voltage Current Transformers?

Straton Electricals manufactures 11kV and 33kV wound-type current transformers in Resin Cast, Cycloaliphatic Resin Cast, and OIP constructions. Contact our engineering team for technical support, product selection, and customised specifications.

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Downloads

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Technical Datasheet

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GA Drawing

General arrangement & dimensional drawing Download

Type-Test Summary

CPRI / ERDA type-test certificate summary Download
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