Three Phase Pad Mounted Transformer-Mounted on the Pad -City or Rural Electrical Distribution Use
11kV / 22kV / 33kV
Pad-Mounted
IEEE / IEC Compliant
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Precision Zig-Zag (ZNyn11) & Wye-Delta Grounding Solutions Engineered for Israel’s MV Distribution, Solar PV Generation & Heavy Industrial Grids to IEC 60076 Standards.
Explore our certified range of oil-immersed and cast resin dry-type transformers, custom-built for robust zero-sequence earthing, voltage step-down, and neutral point establishment.
Understanding the engineering imperative of custom OEM grounding transformers across ungrounded delta MV networks, solar photovoltaic step-up substations, and critical industrial microgrids in Israel.
In electrical power distribution networks operating across Israel—including 11kV, 22kV, and 33kV utility lines managed under Israel Electric Corporation (IEC / חברת החשמל) frameworks—many medium-voltage transformer windings are connected in an ungrounded Delta (Δ) configuration. While delta systems prevent immediate trippings during a single-phase-to-ground fault, they introduce extreme operational hazards: destructive transient overvoltages, ferroresonance, and unlocalized arcing grounds.
A Custom OEM Grounding Transformer (Earthing Transformer) solves this fundamental vulnerability by providing a stable, low-impedance neutral point. Connected in a continuous Zig-Zag (ZN, ZNyn11) or Wye-Delta (Ynd11) topology, the grounding transformer permits zero-sequence fault currents to flow harmlessly to earth, triggering protective relays instantly while clamping line-to-ground transient voltages within safe insulation thresholds.
The primary performance metric of a Zig-Zag grounding transformer is its minimal zero-sequence impedance combined with extremely high positive-sequence impedance. The zero-sequence impedance per phase is expressed as:
In a Zig-Zag configuration, magnetic flux produced by zero-sequence currents in the two halves of the winding on the same core leg act in direct opposition. This flux cancellation yields an exceptionally low reactance $X_0$, allowing controlled neutral current ($I_N = 3 I_0$) to bypass the core without causing magnetic saturation during short-time earth fault conditions (typically rated for 10s, 30s, or 60s duty cycles).
Interconnected star (Zig-Zag) windings equalize phase voltages under unbalanced load conditions while eliminating third-harmonic voltage distortion across the neutral bus without needing a secondary delta winding.
Optional secondary star winding ($yn$) rated from 50kVA up to 630kVA allows the earthing transformer to simultaneously function as a station service transformer supplying local 400V/230V SCADA and lighting loads.
Engineered to operate seamlessly with Neutral Grounding Resistor (NGR) cabinets, limiting ground fault currents to predetermined levels (e.g., 100A, 200A, or 400A) to prevent equipment damage in sensitive sites.
Tailored transformer manufacturing tailored to Israel's extreme desert ambient conditions, dense urban underground networks, and aggressive coastal marine environments.
Israel's aggressive targets for renewable energy generation (30% solar power by 2030) have driven massive utility-scale PV plants in high-temperature regions like the Negev Desert. Solar inverter step-up transformers frequently employ ungrounded Delta medium-voltage outputs. Our custom oil-immersed grounding transformers withstand ambient thermal spikes exceeding +50°C and intense solar radiation, providing reliable zero-sequence earthing for solar substations and Battery Energy Storage Systems (BESS).
Industrial installations along the Mediterranean coastline (Haifa Bay, Ashdod Port, desalination complexes) face harsh C5-M Atmospheric Corrosivity (ISO 12944). We supply custom OEM grounding transformers equipped with hot-dip galvanized cooling radiators, marine-grade stainless steel hardware (SS316L), polyurethane multi-coat paint systems, and hermetically sealed tanks to eliminate saltwater and chemical mist intrusion.
In high-density commercial developments, underground parking structures, and transit infrastructure across the Gush Dan region, fire safety mandates dictate zero liquid dielectric risks. Our Cast Resin Dry-Type Grounding Transformers comply with IEC 60076-11 F1 (Fire Behavior), E2 (Environmental Condensation), and C2 (Climatic Shock) classifications, delivering safe indoor earthing without oil leak hazards.
As private energy generation expands across industrial parks in Israel, isolated microgrids require dedicated earthing transformers to preserve system stability during islanding transitions from the Israel Electric Corporation grid.
Modern Israeli engineering specifications increasingly call for grounding transformers fitted with current transformers (CTs) and temperature sensors directly wired into SCADA RTUs for predictive maintenance and real-time neutral current tracking.
Comprehensive engineering parameter guide for electrical design consultants, procurement directors, and EPC contractors specifying equipment for Israeli projects.
| Specification Parameter | Oil-Immersed Grounding Transformer | Cast Resin Dry-Type Grounding Transformer |
|---|---|---|
| Voltage Classes (kV) | 11kV, 22kV, 33kV, up to 66kV Class | 6.6kV, 11kV, 22kV, 33kV Class |
| Vector Connection Group | ZNyn11, ZNad11, Ynd11 (Custom available) | ZNyn11, ZN0, Ynd11 |
| Fault Duration Duty Rating | 10 Seconds, 30 Seconds, 60 Seconds, Continuous | 10 Seconds, 30 Seconds, 60 Seconds |
| Neutral Current Range ($I_N$) | 50A to 2000A (Custom engineered to NGR) | 50A to 1000A |
| Auxiliary Power Winding | Optional 50kVA - 630kVA (400V/230V, 3-Phase 4-Wire) | Optional 50kVA - 400kVA (400V/230V) |
| Cooling Method | ONAN / ONAF (Synthetic Ester / Mineral Oil) | AN / AF (Natural / Forced Air) |
| Standard Compliance | IEC 60076-6, IEC 60076-1, IS 2026, IEEE C57.121 | IEC 60076-11, F1 / E2 / C2 Fire & Climate Class |
| Environmental Protection | IP54 / IP55 / IP65 Hermetically Sealed Tank | IP20 to IP44 Sheet Steel / Stainless Enclosure |
| Corrosion Resistance Class | ISO 12944 C4 to C5-M Heavy Industrial/Marine | Powder Coated Enclosure (Indoor/Outdoor) |
Combining over two decades of transformer engineering heritage in Rajkot, Gujarat with rigorous international quality standards to deliver custom OEM solutions.
Established in 2004 in Rajkot, Gujarat, India, our state-of-the-art facility incorporates complete in-house core cutting, automated foil and wire winding, vacuum drying chambers, tank fabrication, and automated surface painting labs under a single unified quality control plan.
By utilizing continuous copper and aluminum sheet foil winding for low voltage and zero-sequence coils, our designs eliminate axial short-circuit mechanical forces, reduce localized hot-spot temperature rise, and significantly extend operational life under severe through-fault conditions.
Every grounding transformer undergoes mandatory routine testing (winding resistance, voltage ratio, vector group, insulation resistance, zero-sequence impedance, separate-source withstand voltage, and induced overvoltage). We welcome client witness testing and third-party inspection (SGS, TÜV, Bureau Veritas).
We provide fully customized, heavy-duty wooden crate packaging, nitrogen blanket pressurization during transit for large oil units, and complete export documentation dossiers (GA Drawings, Type Test Reports, Guaranteed Technical Particulars, Certificate of Origin) to streamline import clearance across Israeli customs.
Expert answers addressing compliance, vector group sizing, custom OEM capabilities, and procurement workflows for Israeli projects.
Our grounding transformers are engineered and tested in accordance with international standards IEC 60076-6 (Reactors and Grounding Transformers), IEC 60076-1, IS 2026, and IS 1180. We easily customize electrical parameters, dielectric clearances, and accessories to align with Israel Electric Corporation (IEC) technical specifications and local SI standards.
A Zig-Zag (ZN) connection is physically more compact and cost-effective because it requires only a single core-coil assembly to achieve zero-sequence flux cancellation. Unlike Wye-Delta transformers, which require a secondary closed delta winding to handle zero-sequence current circulating, a Zig-Zag winding inherently blocks zero-sequence current from transferring to the secondary side while reducing overall continuous no-load losses.
Yes. We supply fully integrated grounding packages consisting of the grounding transformer, matching Neutral Grounding Resistor (NGR) cabinet (stainless steel grid element rated for 10s, 30s, or continuous duty), current transformers (CTs), neutral disconnect switches, and protection relays pre-wired inside an outdoor IP55/IP65 enclosure.
To provide an accurate technical bid, please provide: (1) System Nominal Voltage (e.g., 11kV, 22kV, 33kV), (2) Required Neutral Ground Fault Current (e.g., 100A, 200A, 400A), (3) Fault Duration Duty (e.g., 10 seconds or 30 seconds), (4) Auxiliary Power Rating if needed (e.g., 100kVA 400V/230V), and (5) Installation environment details (Indoor Dry-Type or Outdoor Oil-Immersed/C5-M Coastal).
Standard custom oil-immersed grounding transformers are completed within 4 to 6 weeks following final technical drawing approval. Custom high-capacity units or dry-type transformers with integrated NGR cubicles typically require 6 to 8 weeks. Fast-track production lines are available for urgent utility or industrial breakdown replacements.
Absolutely. We welcome customer representatives and third-party inspection agencies (such as SGS, TÜV Rheinland, Bureau Veritas, or Intertek) to witness full factory routine testing, temperature rise tests, impulse voltage tests, and zero-sequence impedance measurements at our Rajkot manufacturing facility prior to dispatch.
Consult with our senior electrical application engineers to review your single-line diagrams (SLD), calculate zero-sequence impedance requirements, and receive a competitive technical proposal for your project in Israel.