I. 110kV Electromagnetic VT/PT Selection Scheme
In high-voltage substation instrumentation, the Electromagnetic Voltage Transformer (VT/PT) remains the gold standard for applications requiring ultimate signal fidelity. This solution is specifically engineered to provide High Precision and a Stable linear output, ensuring that protective relays and metering instruments receive an exact replica of the primary voltage.
1. Core Product Features & Advantages
High Measurement Precision: Utilizing high-permeability magnetic cores, our VTs minimize phase displacement and ratio errors. They are ideal for high-accuracy class requirements, such as 0.2 or 0.2S for trade settlement.
Specialized Anti-resonance Design: Electromagnetic VTs in unearthed or resonant-earthed 110kV systems can be susceptible to ferroresonance. Our units feature dedicated Anti-resonance designs, including optimized magnetic flux density and integrated damping measures to prevent core saturation and equipment damage.
Stable Linear Performance: The transformer maintains a highly linear output voltage even during system transients or voltage fluctuations, providing reliable data for complex power quality analysis.
Robust Insulation Reliability: Designed with premium oil-paper or gas insulation systems, these units are built to withstand lightning impulses and switching surges common in 110kV networks.
Climate Adaptability: The outer porcelain or composite insulators are designed for high-pollution environments, ensuring long-term durability in diverse global climates.
2. Technical Standards & Compliance
HENGFENGYOU ELECTRIC GROUP manufactures VT/PT units that strictly adhere to IEC 61869, ANSI/IEEE C57.13, and GOST standards. Our status as a designated supplier for Fortune Global 500 enterprises reflects our commitment to delivering world-class accuracy and safety.
II. Design and Installation Scheme
1. Configuration in 110kV Substations
Electromagnetic VTs are typically installed at the busbar or line entry points of the substation. For 110kV applications, they are often configured as single-phase units connected in a Y-configuration to provide both phase-to-ground and phase-to-phase voltage information.
2. Installation Key Points
Sealing Integrity: For oil-immersed VTs, maintaining the "Hermes-sealed" environment is critical. During installation, all valves and gaskets must be verified to prevent moisture ingress that could lead to resonance-related failures.
Damping Resistor Integration: To further enhance Anti-resonance capabilities, primary or secondary damping resistors may be installed according to the specific system grounding scheme.
Secondary Circuit Safety: Ensure that the secondary winding is never short-circuited. High-quality terminal blocks and fused protection are standard for every installation.
III. Commissioning and Intelligent Maintenance
1. Essential Handover Tests
To guarantee performance, the following tests are conducted before the unit is energized:
Ratio and Phase Error Test: Performed at various voltage levels (80% to 120% of rated voltage) to confirm High Precision.
Excitation Curve Mapping: To identify the saturation point and ensure the VT operates within the linear region during normal and emergency conditions.
Insulation Oil Analysis: For oil-filled units, testing for dielectric strength and moisture content is mandatory.
2. Smart Monitoring and Digitalization
By integrating with the HENGFENGYOU smart monitoring platform, the VT/PT becomes an active data node in the Digital Substation:
Ferroresonance Detection: Real-time monitoring of secondary harmonic voltages to identify and alert operators of resonance risks.
Accuracy Self-Check: Comparison logic within the smart gateway to detect aging-related drift in measurement accuracy.
IV. Technical Overview Table
| Dimension |
Core Content |
Recommended Solution/Standard |
| Selection |
Precision & Stability |
High Precision (0.2S) / Stable Linear |
| Technical Specs |
Safety Design |
Specialized Anti-resonance Protection |
| Installation |
Layout & Sealing |
Busbar/Line entry; Hermes-sealed |
| Compliance |
Global Standards |
IEC 61869, ANSI, CE, SABS |
V. About HENGFENGYOU ELECTRIC GROUP
With over 30 years of experience in the transmission and distribution industry, HENGFENGYOU ELECTRIC GROUP is a global leader in providing "Smart Electric" solutions. We invest 6% of our annual revenue into R&D, focusing on the digitalization and intellectualization of substation equipment. Our products are currently serving more than 50 countries, helping utility providers achieve optimal network efficiency and security.
VI. FAQ
1. What is the main advantage of an Electromagnetic VT over a CVT at 110kV?
Electromagnetic VTs offer superior accuracy and a more Stable linear response, which is critical for precision revenue metering.
2. How does the "Anti-resonance" design work?
It typically involves using a core with lower flux density and adding a damping resistor to the open-delta secondary winding to dissipate energy from ferroresonance.
3. Can these VTs handle high-pollution coastal areas?
Yes, we offer insulators with C5M class anti-corrosion and high creepage distances to ensure reliability in salt-spray environments.
4. Is it necessary to perform a partial discharge test?
Yes, to ensure the long-term Insulation Reliability of the internal dielectric under high-voltage stress.
5. Does HENGFENGYOU provide secondary terminal boxes?
Every VT comes with a weatherproof, sealable secondary terminal box to protect the high-precision output signals.
6. What is the lead time for a 110kV PT?
Our standard delivery time is approximately 30 days, supported by our 6 production sites in China.
