In modern power transmission and distribution systems, precise measurement and safety assurance are fundamental to maintaining grid stability.
As a globally leading manufacturer of power quality solutions and electrical sensors, ZHIMING Group deeply understands the extreme requirements for reliability, accuracy, and insulation performance in high-voltage power systems. Our High Voltage Current Transformer product series is specifically engineered to meet these challenges, widely applied in high voltage transmission and distribution systems, new energy generation, and large-scale industrial sectors.
We are committed to being your most trusted sensing partner in high voltage power systems through standardized high-quality products and personalized custom solutions.
What is a High Voltage Current Transformer?
A High Voltage Current Transformer, abbreviated as HV CT, is a sensor device that operates on the principle of electromagnetic induction. It accurately converts a large primary current (ranging from hundreds to tens of thousands of Amperes) in a high-voltage power system into a standardized small secondary current (typically 5A or 1A) according to a strict ratio. It is primarily used in AC power systems with rated voltages above 1kV.
Benefits of High Voltage Current Transformer
The core value delivered by using ZHIMING High Voltage Current Transformers:
1. Ensures High Voltage System Safety and Reliability
High Voltage Electrical Isolation: A robust insulation structure (utilizing high-quality epoxy resin casting or SF6 gas insulation) effectively isolates the high voltage primary circuit from the low voltage secondary circuit, providing a solid safety barrier for downstream equipment, systems, and operating personnel.
Critical Equipment Protection: Provides accurate current signals to relay protection devices, ensuring rapid and reliable operation to clear system faults like overcurrents and short circuits, thereby protecting expensive primary equipment like generators and transformers.
2. Enables Accurate Metering and Efficient Management
High-Precision Measurement: Offers high accuracy classes like 0.2S and 0.5, meeting the stringent requirements for billing, energy metering, and system monitoring, providing trustworthy data for energy management and cost accounting.
Supports Smart Grid Construction: Outputs standard signals for seamless integration with smart meters, data acquisition systems, and energy management platforms, serving as the fundamental sensing unit for building digital and intelligent grids.
3. Optimizes System Operation and Lifecycle Cost
Reduces Long-Term Maintenance Costs: Exceptional weather resistance and long-term stability minimize maintenance needs and power outage losses caused by equipment failure.
Improves System Operational Efficiency: Accurate measurement data facilitates load analysis and predictive maintenance, optimizing grid operation strategies and enhancing overall operational efficiency.
Application Scenarios
ZHIMING High Voltage Current Transformers, known for their exceptional electrical performance and environmental adaptability, serve the following critical fields:
1. High Voltage Transmission and Distribution Networks
High voltage current transformers are indispensable components in power plants, substations, converter stations, and distribution networks for current measurement, energy metering, and relay protection, ensuring safe and stable grid operation.
2. New Energy Generation Sector
High voltage current transformers are widely used in booster stations and grid connection points of photovoltaic power plants and wind farms for precise current measurement, meeting grid connection and system monitoring requirements.
3. Large Industrial Facilities
High voltage current transformers are used in captive substations and distribution systems of industries like metallurgy, chemicals, and rail transit for measuring and protecting major loads such as large motors and electric furnaces.
4. Critical Infrastructure
High voltage current transformers are used in locations with extremely high demands for power supply reliability and continuity, such as data centers, airports, and ports, ensuring current monitoring and protection for critical loads.
5. Special Environment Applications
Some high voltage current transformers models are specifically designed for harsh environments like damp tropical regions, high altitudes, and salt fog, suitable for applications such as offshore wind power platforms.
Advantages & Technical Highlights of High Voltage Current Transformers
ZHIMING Group ensures our High Voltage Current Transformers maintain industry-leading performance and reliability through continuous R&D and stringent quality control:
1. Excellent Electrical Insulation Performance
High voltage current transformers utilizes high-quality epoxy resin for vacuum casting or SF6 gas insulation, offering high insulation strength and low partial discharge, capable of withstanding lightning impulses and switching over voltages in high voltage systems.
As outdoor products, high voltage current transformers use UV-resistant epoxy resin, providing good weather resistance for long-term endurance against sunlight, rain, and pollution.
2. High Accuracy and Wide Dynamic Range
Cores made of high-permeability silicon steel or amorphous materials, combined with optimized winding design, ensure measurement accuracy and linearity over a wide current range (e.g., from 5% to 120% of rated current).
High-voltage current transformers offer various winding configurations for both metering and protection applications, meeting different needs for measurement and protection.
3. Robust Mechanical Structure and Diverse Designs
Sturdy housing structure with good mechanical strength and sealing performance; some products feature explosion-proof design for operational safety.
High voltage current transformers provides various structures including through-type (window type) and bushing type, adapting to different installation methods and space constraints.
4. Stringent Quality Assurance and Standards Compliance
High voltage current transformers design and manufacturing comply with international, national, and industry standards such as IEC 60044-1, IEEE C57.13, and GB 1208.
Undergoes comprehensive type tests and routine factory tests in certified laboratories, ensuring the performance and reliability of every unit.
FAQs
Q1: Why must the secondary side of a High Voltage Current Transformer never be open-circuited during operation?
A1: Under normal operation, the magnetomotive force from the primary current is largely counteracted by that from the secondary current. If the secondary opens, this demagnetizing effect vanishes. The core becomes highly saturated, producing a large magnetic flux that induces a dangerous high voltage in the multi-turn secondary winding, severely threatening equipment insulation and personnel safety. The core can also overheat and damage the transformer. Therefore, the secondary circuit must always remain closed during installation, testing, or maintenance. If disconnection is necessary, the secondary side must be reliably short-circuited first.
Q2: What is the difference between a metering and a protection High Voltage Current Transformer?
A2: They have different design goals and performance requirements:
Metering CT: Focuses on measurement accuracy within the normal current range. It is designed to saturate early during system fault conditions to protect connected instruments from high current surges.
Protection CT: Focuses on transformation characteristics under fault conditions (currents much higher than normal). It requires the composite error not to exceed a specified limit at a specified multiple of the primary current (Accuracy Limit Factor – ALF), ensuring correct operation of protection devices. Therefore, they are not interchangeable.
Q3: Can ZHIMING High Voltage Current Transformers operate reliably in harsh environmental conditions?
A3: Yes. Specific models within our High Voltage Current Transformer range are engineered for harsh environments. These products feature enhanced insulation materials, superior sealing performance, and corrosion-resistant coatings, making them suitable for applications in areas with high humidity, significant temperature variations, salt spray (coastal/offshore), or high altitudes. Please consult our technical team for the most suitable product for your specific environmental challenges.
Q4: Can ZHIMING provide specially customized High Voltage Current Transformers?
A4: Yes. ZHIMING possesses a strong R&D and engineering team capable of providing flexible personalized customization services based on specific customer requirements (such as non-standard ratios, special accuracy requirements, extreme environmental adaptability, specific interfaces, or mounting dimensions). We also offer products compliant with various international standards (e.g., IEC, IEEE, ANSI) to serve global markets.
