Overview

Rockwill Zigzag (Z-Type) Grounding Transformers provide a reliable artificial neutral grounding solution for power systems where the neutral point is unavailable, such as delta-connected or ungrounded star systems. These specialized transformers create a stable neutral point for connecting arc suppression coils (Petersen coils) or neutral grounding resistors, ensuring safe and effective system grounding.

Additionally, Rockwill grounding transformers can be equipped with a secondary winding to supply auxiliary power, offering a cost-effective alternative to separate station transformers.

Key attributes

Key Applications

• Substations and distribution networks (35kV and below)

• Industrial power systems requiring a neutral grounding point

• Renewable energy plants (wind/solar farms) with ungrounded sources

Main Technical Specifications

• Rated Capacity: 100kVA to 5500kVA

• Rated Voltage: Up to 35kV

• Insulation Class: Class F (compliant with IEC 60076)

• Connection Type: Zigzag (Z-Type) for optimal zero-sequence performance

• Zero-Sequence Impedance: Low impedance (~10Ω) for efficient fault current handling

Key Features & Benefits

• Advanced Zigzag Winding Design – Unlike conventional transformers, Rockwill’s Z-Type configuration ensures zero-sequence flux circulates within the core, minimizing impedance and enhancing grounding performance.

•  Full-Capacity Arc Suppression Support – Compatible with 90-100% rated capacity arc suppression coils, far exceeding the 20% limit of standard transformers.

• Dual-Purpose Functionality – Optional secondary winding allows the transformer to supply station power, reducing the need for additional equipment.

•  Dry-Type, Cast Resin Construction – Maintenance-free, flame-resistant, and suitable for harsh environments.

• High Efficiency & Reliability – Engineered for stable operation under fault conditions, preventing magnetic saturation.

•  IEC 60076 Compliant – Manufactured to international standards for global reliability.

Why Choose Rockwill?

Rockwill grounding transformers deliver superior performance, safety, and cost savings by combining neutral grounding and auxiliary power supply in a single unit. Their optimized design ensures enhanced system protection, reduced downtime, and lower installation costs—making them the ideal choice for modern power systems.