Zigzag Neutral Grounding Transformer to IEC Standards – Factory Direct Sales
Zigzag Neutral Grounding Transformer manufactured to IEC standards is a reliable solution for establishing an artificial neutral point in medium-voltage power systems. Designed with a precision zigzag winding configuration, it provides low zero-sequence impedance during ground faults while maintaining balanced operation under normal conditions. This enables effective limitation of earth fault currents, improved system protection coordination, and enhanced grid safety.
Produced under strict IEC compliance, the transformer features a robust core design, high-quality conductors, and reinforced insulation systems to ensure long-term stability and fault withstand capability. Factory direct sales allow for flexible engineering support, competitive pricing, and shorter delivery cycles.
- Primary Voltage Ratings 34.5/33/24/12kV or others
- Secondary Voltage Ratings 480/277V, 400/230V, 380/220V, no LV winding or customized
- H.V. Tap Range ± 2×2.5% HV taps or others
- Type Earth transformer
- BIL 30/200kV 30/170kV or others
- Standards IEEE, ANSI, NEMA, IEC, GB
- Application utility substations, industrial networks, and renewable energy facilities
- Power Rating Customized
- Certificate UL ,CESI
- Cooling Method ONAN, KNAN
- Oil Mineral Oil or FR3
- Opeartion Grounding
Technical Specifications
Customization Optional
Packing and Shipping
Manufacturer Test
Routine Testing
Application
Technical Specifications
Zigzag Neutral Grounding Transformer to IEC Standards – Factory Direct Sales
Technical Specifications
Accessories
| Rated Power | Customized | |
| Rating Primary Voltage | 2.4-34.5kV | |
| Secondary Voltage | 480/277V 400/230V 380/220V Customized |
|
| Frequency | 50/60Hz | |
| Vector Group | ZNd, ZN | |
| Winding Material | Aluminum/Copper | |
| Zero-Sequence Impedance | Customized | |
| Altitude | ≤1,000m or Customized | |
| Color | ANSI 70 Light gray/Munsell 7GY3.29/1.5 or customized etc | |
| Tank material | Mild Steel, 304 Stainless Steel | |
| Insulating Oil Weight | 1000 kg | |
| Total Weight | 4200 kg | |
| Outline Dimensions（L×W×H）in. | 2500×1100×2500（mm) | |
| HV Bushing |
| LV Bushing |
| Tap changer |
| Oil level gauge |
| Oil temperature indicator |
| Pressure relief device |
| CT |
| Lifting hook for complete transformer |
| Name plate |
| Radiators |
| Oil upper filtering valve |
| Oil drain valve with 3/8" sampler |
| Terminal box |
Customization Optional
Zigzag Neutral Grounding Transformer to IEC Standards – Factory Direct Sales
The IEC-standard zigzag neutral grounding transformer is available with extensive electrical customization to meet diverse network grounding philosophies. Rated voltage, capacity, and zero-sequence impedance can be engineered according to specific system requirements. Fault current limitation levels may be precisely defined, allowing the transformer to operate with or without an external neutral grounding resistor. When required, an integrated or separately mounted NGR can be designed with customized resistance values, thermal ratings, and short-time withstand capabilities. Customers may select copper or aluminum conductors based on efficiency targets, thermal performance, and lifecycle cost considerations. Continuous and intermittent fault duty ratings can also be configured to align with protection relay coordination and fault-clearing times.
Mechanical and environmental customization ensures suitability for various installation conditions. The transformer can be designed for indoor substations, containerized power units, or sheltered outdoor environments. Insulation class, temperature rise limits, and cooling design are adjustable to match ambient temperature and ventilation conditions. Noise-optimized core designs are available for installations near sensitive areas. Optional features include temperature monitoring devices, grounding current indicators, space heaters, and enclosures with different IP protection levels. This flexible customization approach ensures seamless integration, operational reliability, and compliance with project-specific technical standards.
Packing and Shipping
Zigzag Neutral Grounding Transformer to IEC Standards – Factory Direct Sales
Packing and shipping of the zigzag neutral grounding transformer are executed according to strict factory quality and logistics procedures to ensure safe delivery. Before packing, the transformer undergoes a final inspection covering assembly integrity, terminal alignment, insulation condition, and surface finish. All exposed electrical terminals, grounding points, and sensitive components are protected with insulating covers and shock-resistant materials.
The transformer is wrapped with moisture-proof and dust-resistant packaging materials suitable for long-distance transportation. For export shipments, additional protective layers are applied to prevent vibration damage and environmental exposure. Accessories such as grounding resistors, monitoring devices, and mounting hardware are packed separately in clearly labeled crates to facilitate identification and on-site installation.
The main transformer unit is secured on reinforced wooden or steel pallets designed to support its weight and maintain stability during lifting and transit. Shock-absorbing pads and internal bracing are used to reduce mechanical stress during road, rail, or sea transportation. All wooden packaging materials comply with ISPM 15 international phytosanitary regulations.
Clear handling instructions, lifting points, center-of-gravity markings, and safety warnings are displayed on each package. Complete shipping documentation—including packing lists, factory test reports, operation manuals, and certificates of conformity—is provided to ensure smooth customs clearance and site acceptance. This comprehensive packing and shipping process ensures the transformer arrives ready for installation and commissioning.
The transformer is wrapped with moisture-proof and dust-resistant packaging materials suitable for long-distance transportation. For export shipments, additional protective layers are applied to prevent vibration damage and environmental exposure. Accessories such as grounding resistors, monitoring devices, and mounting hardware are packed separately in clearly labeled crates to facilitate identification and on-site installation.
The main transformer unit is secured on reinforced wooden or steel pallets designed to support its weight and maintain stability during lifting and transit. Shock-absorbing pads and internal bracing are used to reduce mechanical stress during road, rail, or sea transportation. All wooden packaging materials comply with ISPM 15 international phytosanitary regulations.
Clear handling instructions, lifting points, center-of-gravity markings, and safety warnings are displayed on each package. Complete shipping documentation—including packing lists, factory test reports, operation manuals, and certificates of conformity—is provided to ensure smooth customs clearance and site acceptance. This comprehensive packing and shipping process ensures the transformer arrives ready for installation and commissioning.
32
32 years of industry experience
Manufacturer Test
Zigzag Neutral Grounding Transformer to IEC Standards – Factory Direct Sales
Progress Test
Progress testing is conducted throughout the manufacturing process to ensure compliance with IEC standards and internal quality requirements. Incoming raw materials such as magnetic core steel, conductors, insulation materials, and structural components are inspected upon receipt. Core assembly inspections verify lamination stacking accuracy, dimensional tolerances, and magnetic performance.
During winding and insulation stages, inspections confirm conductor placement, insulation thickness, and mechanical rigidity. The windings undergo controlled drying and thermal conditioning to eliminate moisture and stabilize insulation properties. Intermediate electrical tests, including winding resistance and insulation resistance measurements, are performed prior to final assembly.
Mechanical inspections verify enclosure construction, grounding connections, and terminal integrity. All inspection results are recorded in progress test reports, ensuring traceability and readiness for final acceptance testing.
Design Tests
All transformers will be tested after finishing the production, test items as follows:
♦ Insulation Power Factor
♦ Winding Resistance
♦ Impulse Tests
♦ On load Loss Test
♦ No Load Loss Test
♦ Leak Test
♦ DC Insulation Resistance Test
♦ Transformer Turns Ratio/TTR (All Tap Voltages)
♦ Impedance Voltage & Load Loss (Rated Voltage)
♦ Excitation & No-Load Loss (Rated Voltage)
♦ Applied Voltage
♦ Induced Voltage
♦ Lightning Impulse
♦ Insulation Resistance (Rated Voltage)
♦ Temperature Rise
Transformer Factory Acceptance Test
The Factory Acceptance Test verifies that the zigzag grounding transformer meets contractual and IEC requirements. Tests include winding resistance measurement, insulation resistance testing, and impedance verification. Functional tests confirm correct zigzag grounding behavior and neutral performance.
Temperature rise tests validate thermal design, while noise measurements confirm compliance with environmental limits. Visual and dimensional inspections ensure assembly quality. All results are documented in a detailed FAT report for customer approval.
Tests verify grounding impedance characteristics, short-time current withstand capability, and insulation strength. Auxiliary equipment such as temperature sensors and grounding indicators is functionally tested. Mechanical inspections ensure enclosure integrity and terminal strength. Upon completion, a comprehensive FAT report is issued prior to shipment.
Routine Test - On load Loss Test
Purpose of Testing
The purpose of On-load Loss Test is to measure the active power loss of the transformer under rated voltage and rated load, evaluate its energy efficiency level and design compliance, and provide a basis for energy consumption calculation and performance optimization during operation.
Testing Equipment
Power transformer test system (e.g. OMICRON, ISA, Tettex, Vanguard, etc.)
Voltage source and current source (usually rated voltage, or adjusted according to the test standard, such as 10 KV, 20 KV, 35 KV, etc.)
Temperature and humidity meter (used to record ambient temperature and humidity for correction of test data)
Voltage source and current source (usually rated voltage, or adjusted according to the test standard, such as 10 KV, 20 KV, 35 KV, etc.)
Temperature and humidity meter (used to record ambient temperature and humidity for correction of test data)
Pre-Test Preparation
Disconnect the transformer high voltage, low voltage and neutral power supply to ensure that the equipment is properly grounded and safely discharged.
The test environment should be dry and rainless, with a relative humidity of less than 75% and a recommended temperature range of 20–30°C.
The test environment should be dry and rainless, with a relative humidity of less than 75% and a recommended temperature range of 20–30°C.
Test Progress
Connect the Test Instrument:
Connect the test equipment to the appropriate terminals of the device under test and ensure that all wiring is correct and the device is well grounded.
Apply Test Voltage:
Apply the specified test voltage at the rated frequency and adjust the low voltage side to maintain the rated current (or specified current).
Connect the test equipment to the appropriate terminals of the device under test and ensure that all wiring is correct and the device is well grounded.
Apply Test Voltage:
Apply the specified test voltage at the rated frequency and adjust the low voltage side to maintain the rated current (or specified current).
Measure and Record
Start the test and record the following parameters:
On-Load Loss Power
Input Power and Output Power
Current
Voltage
Temperature (temperature rise or winding temperature)
Ambient temperature and humidity during the test
On-Load Loss Power
Input Power and Output Power
Current
Voltage
Temperature (temperature rise or winding temperature)
Ambient temperature and humidity during the test
Temperature Correction
The measured loss data is corrected based on a reference temperature (usually 20°C) to ensure the accuracy of the results.
Repeat Testing (if necessary)
Test different tap positions (Tap Changer) and record and compare the load loss data of each tap point.
Evaluation Criteria (Reference)
Evaluate the test results based on the equipment type and manufacturer requirements. If the load losses are low and the efficiency is high, it is considered "normal".
*These comprehensive tests ensure that each transformer meets performance standards and operates
reliably under various conditions.
Application
Applied in utility substations and industrial power systems to establish a stable neutral point, limit earth fault current, and enhance protection coordination in medium-voltage networks.
Technical Advantages
● 30+ years of manufacturing experience
● ISO and UL certified production
● Customized cable and transformer solutions
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What is a Transformer?A transformer is an electrical device used to change the voltage of alternating current (AC). It works on the principle of electromagnetic induction, converting high-voltage current into low-voltage current or low-voltage current into high-voltage current. Transformers are widely used in power transmission, distribution systems, and various electronic devices.
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Do you have UL listed?Yes, our transformer has UL listed. We have exported to America many pad mounted transformer,substation transformer and HV.
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