I. 110kV Combined CT/VT Unit Selection Scheme
For utility companies and large industrial power consumers, the Combined CT/VT Unit represents the most efficient solution for Revenue Metering. By integrating both current and voltage sensing elements into a single physical housing, this "two-in-one" design addresses the dual challenges of measurement precision and substation footprint optimization.
1. Core Product Features & Advantages
Revenue Metering Excellence: Specifically designed as the primary interface for high-voltage billing, our units offer high-precision windings (up to 0.2S class) to ensure fair and accurate energy accounting.
Significant Space-saving: By combining two functional devices into one, the unit reduces the number of support structures and insulators required. This is a critical advantage for compact urban substations or when upgrading existing facilities with limited space.
Easy Installation: Fewer individual components mean reduced civil work, simplified cabling, and faster mechanical assembly, leading to a significant reduction in overall project commissioning time.
Integrated Insulation System: Utilizing a shared insulation medium (oil or gas), the unit ensures a uniform dielectric stress distribution, enhancing the overall Insulation Reliability of the metering point.
Reduced Maintenance Points: With fewer primary connections and seals compared to separate CT and VT sets, the risk of leakage is halved, and routine inspection cycles are simplified.
2. Technical Standards & Reliability
HENGFENGYOU ELECTRIC GROUP produces Combined Units that fully comply with IEC 61869-4, ANSI/IEEE, and GB standards. As a designated supplier for the world's top 500 enterprises, we utilize high-grade materials to ensure our metering units operate reliably even in harsh environments with C5M anti-corrosion requirements.
II. Design and Installation Scheme
1. Substation Integration
The Combined CT/VT Unit is typically installed at the "point of common coupling" (PCC) or the entry of a dedicated consumer substation. Its integrated nature allows for a much cleaner busbar layout and reduces the complexity of the secondary protective and metering wiring.
2. Installation Key Points
Structural Support: Due to the combined weight of both sensing elements, ensure that the mounting structure is designed for the specific center of gravity of the unit.
Secondary Circuit Management: The unit features a unified secondary terminal box. Precise labeling is essential to separate the high-precision metering signals from protection signals.
Sealing Verification: For oil-immersed types, verify the Hermes-sealed integrity after installation to maintain the precision of the internal components.
III. Commissioning and Intelligent O&M
1. Handover Testing
To ensure billing accuracy, the following rigorous tests are performed:
Combined Error Test: Verifying that both the CT and VT elements meet their respective accuracy classes under simultaneous operation.
Insulation Resistance & Tan Delta: Confirms the health of the shared insulation system.
Polarity & Ratio Check: Essential to ensure that the energy meter rotates in the correct direction and records accurate consumption.
2. Smart Metering and Digitalization
As a "Smart Electric Global Service Provider," we offer units compatible with the latest digital grid technology:
IoT Metering: Can be paired with smart gateways to provide real-time remote monitoring of power quality and consumption via the Internet of Things.
IEC 61850 Ready: Supports digital output for seamless integration into modern Digital Substations.
IV. Technical Overview Table
| Dimension |
Core Content |
Recommended Solution/Standard |
| Selection |
Purpose & Efficiency |
Revenue Metering / Space-saving |
| Technical Specs |
Installation Ease |
Easy Installation / Integrated Design |
| Installation |
Site Layout |
Substation Entry / PCC Point |
| Compliance |
International Quality |
IEC 61869, CE, SABS, UL |
V. About HENGFENGYOU ELECTRIC GROUP
Since 1990, HENGFENGYOU ELECTRIC GROUP has been a leader in the transmission and distribution industry. Our Combined CT/VT Units are the result of decades of R&D, aimed at providing utilities with the most reliable and cost-effective metering solutions. With 6 production sites and a commitment to investing 6% of revenue in R&D, we continue to innovate for the global energy transition.
VI. FAQ
1. Why is the Combined Unit preferred for high-voltage metering?
It provides a dedicated, high-precision metering point in a single, Space-saving package, reducing overall project costs.
2. Can the CT and VT elements have different accuracy classes?
Yes, we can customize the unit so the metering windings have 0.2S class accuracy while protection windings have standard 5P20 ratings.
3. Does a fault in one element affect the other?
Our units are designed with internal shielding and separation to minimize the risk of a fault in the CT element affecting the VT element, and vice-versa.
4. Is it easier to maintain than separate units?
Yes, because there are fewer support insulators to clean and fewer oil-seals to monitor.
5. What is the maximum voltage for these combined units?
While common at 33kV-110kV, we offer solutions up to 220kV depending on specific grid requirements.
6. What certificates are available for international trade?
We provide CB, CE, UL, and SABS certifications to meet the legal requirements of over 50 countries.
