Every reliable electrical system depends on precision measurement. From grid substations to industrial control panels, current transformers (CTs) play a vital role in measuring current and enabling safe protection and automation. Among the various CT designs, resin cast current transformers stand out for their durability, insulation strength, and accuracy.
Built to withstand environmental stress and electrical transients, resin cast CTs have become indispensable in power plants, utilities, and industrial facilities.
Know About Measurement and Control: Resin Cast
Current Transformers in Modern Power Systems
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What Are Resin Cast Current Transformers?
A resin cast current transformer is a type of instrument transformer where the windings and core are encapsulated in epoxy resin. This provides mechanical strength, electrical insulation, and moisture resistance — ideal for both indoor and outdoor applications.
Primary Functions:
- Current measurement for metering and monitoring
- Signal input for protection relays
- Isolation between high-voltage circuits and control systems
Engineering Advantages of Resin Cast CTs
1. Excellent Insulation and Environmental Resistance
Epoxy resin casting ensures high dielectric strength, preventing moisture ingress and surface tracking.
2. Mechanical Durability
The solid resin enclosure protects against vibration and impact — critical for industrial and transport applications.
3. High Accuracy for Protection and Metering
Resin cast CTs deliver stable ratio accuracy and phase response, ensuring precise readings even under dynamic loads.
4. Maintenance-Free Operation
With no oil or gas filling, these CTs require zero maintenance, reducing lifecycle cost.
Zetwerk’s Resin Cast CT Manufacturing Capabilities
Zetwerk as one of the leading cast resin transformers manufacturers meets global accuracy and safety standards.
Design and Materials
- Core: High-permeability silicon steel
- Casting: Vacuum-sealed epoxy resin for complete insulation
- Accuracy classes: 0.2S, 0.5S, 1.0 as per IEC 61869 and IS 16227
Testing and Certification
Each CT undergoes:
- Ratio error and phase angle tests
- Insulation resistance and dielectric tests
- Partial discharge and temperature rise verification
Zetwerk ensures every transformer meets its specified burden, ratio, and class accuracy under full load.
Applications in Modern Power Systems
Resin cast CTs are used in:
- Switchgear panels for current measurement and protection
- Substations for energy monitoring
- Renewable projects (solar/wind) for export metering
- Industrial plants for motor and feeder protection
Their compact, enclosed design makes them ideal for urban or dusty environments where oil-filled units are impractical.
Why EPCs and Utilities Trust Zetwerk
- End-to-end production control: Core cutting, coil winding, resin casting, and testing.
- Precision engineering: Low ratio error and minimal phase deviation.
- Proven quality assurance: Type-tested to IEC and IS standards.
- Custom configurations: Indoor/outdoor mounting, bar type or ring type designs.
Zetwerk’s CTs are engineered for long-term reliability and metering precision, ensuring accurate data for power control and billing systems.
Conclusion
Accurate current measurement defines safety and control in every electrical network. Resin cast current transformers combine robust insulation, precision accuracy, and zero maintenance to deliver unmatched reliability for modern power systems.
Zetwerk manufactures high-quality, type-tested resin cast CTs engineered to meet the needs of EPCs, utilities, and industrial customers. Each unit reflects precision design, certified testing, and dependable performance.
For projects where accuracy and reliability matter most, partner with Zetwerk — where engineering precision powers every measurement.
FAQs
a. They are robust, maintenance-free, and provide excellent insulation for harsh environments.
a. Yes, they can operate outdoors with IP-rated enclosures.
a. 0.2S, 0.5S, 1.0 depending on application (metering or protection).
a. No. Their solid construction eliminates routine maintenance.
a. Zetwerk delivers precision-engineered, type-tested CTs built for reliability and accurate current measurement.
