Grounding Transformer: Complete Guide for Industrial Facilities, Utilities, EPC Contractors and Power Engineers
A grounding transformer is a critical component in medium-voltage power systems. Whether you are designing a solar plant, wind farm, industrial substation, or distribution network, you need a reliable grounding method to ensure system stability, fault protection, and personnel safety.
This article explains what a grounding transformer is, how it works, the types available, how to size one, and why many engineers and EPC companies prefer working with Transformateur Evernew, one of China’s leading grounding transformer manufacturers.
What Is a Grounding Transformer?
A grounding transformer is a special transformer that provides a neutral grounding point for power systems that otherwise have no neutral. These include:
Delta-connected distribution systems
Wind farm collector systems
Solar PV plants
Industrial MV networks
Temporary or isolated power systems
By creating a neutral point, grounding transformers enable:
Safe dissipation of fault current
Protection operation during single-line-to-ground faults
Stable system voltage
Compliance with utility and IEEE/IEC grounding requirements
Why Do Power Systems Need a Grounding Transformer?
Many MV systems (e.g., 6.6kV, 11kV, 13.8kV, 22kV, 33kV) are delta-connected and do not naturally have a neutral. Without grounding:
Fault currents rise dangerously
Protective relays may malfunction
Overvoltage can damage equipment
Arc flash risk increases
Power system becomes unstable
A grounding transformer solves all these issues by providing:
✔ Neutral reference point
✔ Controlled ground-fault current
✔ System voltage stabilization
✔ Improved reliability and safety
This is why grounding transformers are essential in utility, industrial, mining, renewable energy, and oil & gas projects.
Types of Grounding Transformers
1. Zig-Zag Grounding Transformer (Most Common)
A zig-zag transformer is designed with special winding interconnections to create a neutral point.
Avantages :
Compact
Cost-effective
Low zero-sequence impedance
Industry’s most widely used option
Used heavily in:
Parcs éoliens
Industrial substations
2. Wye-Delta Grounding Transformer
A standard transformer with a wye-connected winding to form a neutral.
Avantages :
Can supply auxiliary loads simultaneously
Suitable for certain industrial applications
Where Grounding Transformers Are Used
1. Solar Power Plants (Utility-Scale PV)
A grounding transformer is required on MV collector systems (6.6–33kV) to stabilize the network and ensure inverter protection.
2. Wind Farms
Used on collector feeders and substations to ensure neutral grounding and prevent equipment overvoltage.
3. Industrial Facilities
Factories, chemical plants, steel mills, mining sites, and refineries use grounding transformers for system protection and fault control.
4. Utility Distribution Networks
Used in isolated or delta-connected feeders where no natural neutral exists.
5. Temporary Power Stations & Large Generators
When generators operate in parallel or isolated mode, grounding transformers provide fault current path and stabilize system voltage.
Grounding Transformer Sizing Guide (Engineering Overview)
Sizing depends on:
1. System Voltage (e.g., 11kV, 13.8kV, 33kV)
Determines insulation level and BIL requirements.
2. Desired Ground Fault Current
Engineers must define:
Minimum and maximum zero-sequence current
Typical values: 200A – 1200A
3. Duration of Ground Fault (10s, 30s or 60s)
Determines thermal rating.
4. Continuous kVA Rating
Often ranges from 500 kVA to 5000 kVA, depending on system design.
Evernew Transformer can help customers verify calculations based on IEEE/IEC standards.
Advantages of Using a Grounding Transformer
Prevents transient overvoltage
Ensures proper relay coordination
Protects expensive MV equipment
Improves stability of renewable power plants
Enhances safety during single-line-to-ground faults
For EPC contractors, correct grounding design reduces risk, simplifies approval, and ensures long-term reliability.
Read More：How to Choose the Right 25 kVA–500 kVA Distribution Transformer
How Evernew Transformer Supports Global Clients
Evernew Transformer is one of China’s leading manufacturers of medium- and high-voltage transformers. With a factory in Nantong, Jiangsu covering 500 acres and over 300 engineers, the company provides:
✔ High-quality grounding transformers (500 kVA – 5 MVA)
✔ Zig-zag & Wye-Delta options
✔ Voltage levels: 6.6kV / 11kV / 13.8kV / 22kV / 33kV
✔ Oil-immersed, dry-type, and customized designs
✔ ANSI / IEEE / IEC compliant products
✔ Fast delivery for EPC & utility projects
✔ Export capability to USA, Canada, Latin America, Africa, Middle East
Evernew Transformer has delivered grounding transformers for:
Solar PV plants (20–200 MW)
Parcs éoliens
Réseaux de distribution des services publics
Mining and industrial facilities
Why Engineering Firms and EPC Contractors Choose Evernew Transformer
1. Strong Manufacturing Capacity
500kV workshop, advanced production lines, strict QA testing.
2. Technical Expertise
Over 300 engineering professionals + full design customization.
3. Global Export Experience
Transformers exported to North America, South America, Southeast Asia, Africa, Middle East.
4. Competitive Cost Without Compromising Quality
Ideal for EPC tenders and cost-sensitive industrial projects.
5. Fast Delivery & Strong Support
Critical for renewable energy and utility project deadlines.
Conclusion: Grounding Transformers Are Essential for Modern Power Systems
Whether you are an engineer, EPC contractor, project manager, or industrial facility operator, a grounding transformer is vital for system stability and safety. With the rise of renewable energy projects and delta-connected MV networks, the demand for reliable grounding solutions continues to grow globally.
Transformateur Evernew provides high-performance grounding transformers tailored to your project’s voltage level, fault current, and system requirements.
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