| Brand | ROCKWILL |
| Model NO. | 35kV Dry Type Grounding Transformer Cast Resin 3 Phase |
| Rated capacity | 400kVA |
| Phases | Three phase |
| Series | DKSC |
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.
-
Ensuring Reliability: A Deep Dive into Transformer MaintenanceIntroductionElectric transformers are the backbone of modern power distribution systems, silently enabling the reliable delivery of electricity to homes, businesses, and industries. As these critical assets age and the demand for uninterrupted power grows, the importance of diligent transformer maintenance has never been greater. This essay explores the essential role of transformer maintenance, highlighting the value of proactive care, the impact of advanced diagnostic technologies, and the traVziman09/03/2025 -
How does a transformer work?Transformer Operation PrincipleA transformer is an electrical device that operates on the principle of electromagnetic induction to transfer electrical energy from one circuit to another. It enables the adjustment of voltage levels within an alternating current (AC) system, either stepping up (increasing) or stepping down (decreasing) voltage while maintaining the same frequency.Working Principle:Basic ComponentsA transformer consists of two coils, known as windings—the "primary winding" connectRockwell09/03/2025 -
Constant testing of high-voltage cable lines1. Definition of High-Voltage Cable Line Constant TestingHigh-voltage cable line constant testing refers to the systematic measurement, using specialized instruments, of electrical parameters such as resistance, inductance, capacitance, and conductance before a cable line is commissioned or after major maintenance. The aim is to obtain fundamental data characterizing the electromagnetic properties of the cable, serving as a critical testing phase that provides accurate parameter support for poweOliver Watts09/03/2025 -
Technical Analysis of 220 kV High-Voltage Cable Construction in Winter1.Work Environment Requirements and Safeguard MeasuresBased on technical requirements for cable equipment storage, laying, transportation, laying, transposition, testing, and cable terminations, the project owner and construction units have conducted extensive trials and implemented protective measures regarding ambient temperature, humidity, bending radius, traction control, and route optimization. These measures ensure high-voltage cable quality and on-site safety under harsh winter conditionsJames09/03/2025 -
Withstand voltage test of high-voltage cablesWithstand voltage test is an insulation test, but it is a destructive test that can reveal insulation defects difficult to detect in non-destructive testing.The test cycle for high-voltage cables is three years, and it must be conducted after non-destructive tests. In other words, the withstand voltage test is performed only after all non-destructive tests have been passed.Most high-voltage cables used today are cross-linked polyethylene (XLPE) cables, which can have large cross-sections and covOliver Watts09/03/2025 -
Analysis of Abnormal Causes of High-Voltage Cable Grounding Circulation and Typical CasesI. Introduction to Cable Grounding Loop CurrentCables rated 110 kV and above use a single-core structure. The alternating magnetic field generated by the operating current induces a voltage on the metallic sheath. If the sheath forms a closed circuit through the earth, a grounding loop current will flow on the metallic sheath. Excessive grounding loop current (loop current exceeding 50 A, more than 20% of the load current, or a ratio of maximum-to-minimum phase current greater than 3) not only aFelix Spark09/03/2025
-
Intelligent Operation Solution for 12kV Vacuum Circuit Breakers: Integrating Real-time Monitoring & Lifetime OptimizationⅠ. Equipment Operation & MaintenanceIntelligent Monitoring System IntegrationMulti-parameter Real-time Monitoring: Embedded sensors (temperature, displacement, Hall effect current sensors) track contact temperature rise, mechanical characteristics (opening/closing speed, overtravel), coil current, and partial discharge signals. Data undergoes preprocessing via edge computing prior to cloud upload.Lifetime Prediction Model: Dynamically evaluates remaining lifespan using electrical wear dataRockwill06/10/2025 -
SF6 Circuit Breaker Solutions for Outdoor Installation (Anti-Pollution & Seismic Resistance)I.Core Challenges in Outdoor InstallationIn high-voltage transmission and distribution systems, SF6 circuit breakers are exposed to complex outdoor environments for extended periods, facing the following critical issues:Pollution & Insulation DegradationDust, salt fog, and industrial pollutants in outdoor environments easily adhere to equipment surfaces. In coastal or industrial areas, pollution levels may reach Class IV, resulting in insufficient creepage distance and triggering flashoRockwill05/12/2025
