Oil-Immersed Neutral Grounding Transformer for Ground Fault Protection 17.5kV-40.5kV

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Key attributes

Brand	ROCKWILL
Model NO.	Oil-Immersed Neutral Grounding Transformer for Ground Fault Protection 17.5kV-40.5kV
Rated voltage	33kV
Rated frequency	50/60Hz
Rated capacity	800kVA
Series	JDS

Description

Rockwill three-phase oil-immersed Z-type earthing transformers are designed for medium-voltage power systems requiring a reliable artificial neutral point. Featuring a fully sealed oil-immersed structure with optimized zigzag (ZN) winding, these transformers provide stable neutral grounding for ungrounded or resistance-grounded systems from 17.5 kV to 40.5 kV.

They effectively limit ground fault currents, suppress arc grounding overvoltage, and enhance grid stability. Manufactured in compliance with IEC standards, these units are suitable for distribution networks, industrial facilities, and commercial power systems.

Key Features

Medium-Voltage Neutral Grounding ：Provides an artificial neutral point for ungrounded or resistance-grounded systems, enabling connection of neutral grounding resistors or arc suppression coils.
Optimized Z-Type Winding ：Zigzag (ZN) winding configuration delivers low zero-sequence impedance, ensuring efficient fault current path and sensitive relay protection.
Oil-Immersed Fully Sealed Construction ：Durable sealed tank design with mineral oil insulation ensures long service life, strong overload capacity, and maintenance-free outdoor operation.
Customizable Capacity Range ：Rated capacity from 30 kVA to 3000 kVA, configurable per system requirements.
Integrated LV Auxiliary Winding :Optional secondary winding at 200–440 V for station service power supply.

Technical Parameters

Parameter	Value
Highest voltage for equipment (Um)	17.5 / 24 / 36 / 40.5 kV
Rated frequency	50 / 60 Hz
Number of phases	Three
Connection group	ZN (zigzag)
Rated capacity	30 – 3000 kVA (customizable)
Winding material	Copper or aluminum (customizable)
Cooling method	ONAN (oil natural air natural)
Insulation medium	Mineral oil
Auxiliary winding	Optional (200 V – 440 V)
Installation	Indoor or outdoor
Standards compliance	IEC 60076-6, IEC 60076-1, ISO 9001

Insulation Levels by Voltage Class

System Voltage	Um (kV)	PF (kV)	LI (kV)
15 kV	17.5	38	95
20 kV	24	50	125
22 kV	24	50	125
30 kV	36	70	170
33 kV	36	70	170
35 kV	40.5	95	200

Environmental Conditions

Max ambient air temperature	+40°C
Max 24h average ambient air temperature	+35°C
Min ambient air temperature	-25°C
Altitude	≤ 1000 m
Max relative humidity (24h average)	≤ 95%
Max relative humidity (1 month average)	≤ 90%
Max water vapor pressure (24h average)	2.2 kPa
Max water vapor pressure (1 month average)	1.8 kPa
Solar radiation	≤ 1000 W/m²
Pollution level	II

Applications

Medium-voltage distribution network neutral grounding
Industrial plant power distribution with resistance-grounded systems
Utility substations and switching stations
Commercial and institutional building power systems
Renewable energy power collection and grid connection

Solutions for earthing transfoemer

Intelligent Maintenance Services and Sustainable Solutions for Z-Type Grounding Transformers

Intelligent Maintenance Services and Sustainable Solutions for Z-Type Grounding TransformersZ-type grounding transformers are critical for stabilizing ungrounded or delta-connected power systems by providing a low-impedance path for zero-sequence currents during faults. Integrating intelligent maintenance and sustainability practices enhances their reliability while minimizing environmental impact. Below is a structured analysis of advanced solutions:I. Intelligent Maintenance Services Real-Time

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Documentation Resource Library earthing transfoemer

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FAQ for earthing transfoemer

Q: What are the special design requirements for earthing/grounding transformers used on ships or offshore platforms?

Marine/offshore transformers demand salt-spray-resistant insulation, compact oil-free construction, reinforced vibration-proof design (meeting IEC 60076-5 Class 3), customized shipboard voltages/frequencies (e.g., 6.6kV/60Hz) with auxiliary windings for onboard loads, and natural air cooling (KNAN) for reliable enclosed-cabin operation.

$3600.00

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Model

JDS-800/33

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