Current Transformers up to 33kV for metering and protection
Amrest Electricals Limited is a manufacturer, exporter and supplier of high-performance Current Transformers (CTs) up to 33kV. We focus on quality, innovation and customer-centric solutions, offering CT technology for accurate metering and reliable protection in electrical systems.
Our products are engineered to perform efficiently in diverse industrial and utility environments.
Three types of Current Transformers
Indoor resin cast
Designed for indoor installations and manufactured using high-grade epoxy resin, giving excellent insulation and safety.
Key features
- Compact and maintenance-free design
- High mechanical and thermal strength
- Superior insulation with epoxy resin casting
- Flame-retardant and moisture-resistant
- High accuracy for metering and protection
Applications
- Switchgear panels
- Control rooms
- Industrial power distribution
Outdoor oil-cooled
Built for outdoor environments, using high-quality insulating oil for cooling and insulation for long-lasting, stable performance.
Key features
- Excellent heat dissipation
- Suitable for harsh weather conditions
- Robust and corrosion-resistant construction
- Long service life
- High reliability in continuous operation
Applications
- Substations
- Transmission and distribution networks
- Utility power systems
Outdoor resin cast
Maintenance-free and environmentally friendly, ideal for outdoor installations without the need for oil.
Key features
- Oil-free, eco-friendly design
- UV-resistant and weatherproof
- High dielectric strength
- Compact and lightweight
- Minimal maintenance requirements
Applications
- Outdoor switchyards
- Renewable energy installations
- Industrial outdoor setups
Compare the types
| Type | Installation | Insulation | Typical use |
|---|---|---|---|
| Indoor resin cast | Indoor | Epoxy resin | Switchgear panels, control rooms, industrial power distribution |
| Outdoor oil-cooled | Outdoor | Insulating oil | Substations, transmission and distribution networks, utility systems |
| Outdoor resin cast | Outdoor | Epoxy resin (oil-free) | Outdoor switchyards, renewable energy, industrial outdoor setups |
Ratio, cores, accuracy class and burden are defined as per customer/project requirement.
IEC standards for Current Transformers
The standard for instrument transformers moved from the IEC 60044 series to the IEC 61869 series. The key parts for Current Transformers are:
- IEC 61869-1: general requirements for all instrument transformers
- IEC 61869-2: additional requirements for Current Transformers (replaces IEC 60044-1)
This section is a general reference. Applicable standards and test documentation are confirmed in the technical offer for each project.
Parameters defined for every CT
Accuracy classes
- Metering: classes such as 0.2, 0.2S, 0.5 or 0.5S. The “S” classes give higher accuracy at very low currents, which matters for billing.
- Protection: classes such as 5P10 or 10P20. “5P” means 5% error and “10” is the accuracy limit factor, so the CT can carry 10 times rated current without saturating.
Insulation level (33kV class)
- Rated power frequency withstand voltage: typically 70kV
- Rated lightning impulse withstand voltage: typically 170kVp
Routine tests under IEC 61869-2
Routine tests specified for Current Transformers include:
Terminal markings
Verification of terminal markings (P1, P2, S1, S2).
Power-frequency withstand
Voltage withstand test on primary and secondary windings.
Partial discharge
Partial discharge measurement, especially important for resin cast units to confirm there are no voids in the epoxy.
Inter-turn overvoltage
Inter-turn overvoltage test on the secondary winding.
Accuracy test
Ratio error and phase displacement checked against the applicable class.
What to send us
Share as many of these details as you have, or send your datasheet or BOQ directly.
Manufacturer, exporter and supplier
We supply Current Transformers for India and for projects in the following countries and regions:
- India
- United Arab Emirates
- Dubai
- Sharjah
- Saudi Arabia
- Bahrain
- Iraq
- Kuwait
- Oman
- Qatar
- Afghanistan
- South Africa
- Zambia
- Tanzania
- Ghana
- Nepal
- Bhutan
- Bangladesh
- Indonesia
- Kenya
- Malaysia
- Turkey
- Zimbabwe
- and other countries