Neutral Earthing Transformer-NET

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Product Overview

Neutral Earthing Transformer-NET

High-voltage rated voltage	6 kV, 10 kV, 20 kV, 35 kV (typical); custom voltages available
Rated capacity	Ground Mounted Transformer: Sized According To System Capacitive Current; Earthing-cum-station-service Transformer: 50 kVA - 2500 kVA
Power Supply Mode	Grounding And Station-service Power Supply; Suitable For Distribution Network And Substation Applications
Frequency	50 Hz; 60 Hz Custom For Overseas Projects
Cooling Type	Oil-immersed: ONAN / ONAF; Dry-type: AN / AF; User-selectable
Fluid Type	Mineral Oil; Biodegradable Ester Fluids Optional

Basic Electrical Parameters
High-voltage rated voltage	6 kV, 10 kV, 20 kV, 35 kV (typical); custom voltages available	Rated capacity	Ground Mounted Transformer: Sized According To System Capacitive Current; Earthing-cum-station-service Transformer: 50 kVA – 2500 kVA
Power Supply Mode	Grounding And Station-service Power Supply; Suitable For Distribution Network And Substation Applications	Frequency	50 Hz; 60 Hz Custom For Overseas Projects
Cooling Type	Oil-immersed: ONAN / ONAF; Dry-type: AN / AF; User-selectable	Fluid Type	Mineral Oil; Biodegradable Ester Fluids Optional
Winding Connection Vector Group	Znyn0 (Earthing-cum-station-service); Zn0 (Ground Mounted Transformer)	Zero-Sequence Impedance	Custom-designed According To System Capacitive Current And Arc-suppression Coil Parameters
Short-Time Earth-Fault Current	Custom Per Project System Parameters; Duration Options: 10 s / 60 s	No-Load Current	< 0.3% – 0.6% (Measured At Rated Voltage)
Tap-Changer	Off-circuit Tap-changer; On-load Tap-changer Generally Not Applied	Insulation Level	Matched To GB 1094 And IEC 60076-3 Per Voltage Class
Functional Type	Ground Mounted Transformer / Earthing-cum-station-service Transformer	Construction Type	Oil-immersed Type / Dry-type
Primary Voltage	10 kV (Reference Application)	Secondary Station-Service Voltage	0.4 kV (Reference Application)
Typical Model	10 kV Znyn0 800 kVA Oil-immersed Earthing-cum-station-service Transformer	Reference Cooling Arrangement	ONAN Oil Natural-air Natural Cooling

Winding And Earthing Performance
Winding Connection Vector Group	Znyn0 (earthing-cum-station-service); Zn0 (Ground Mounted Transformer)	Zero-Sequence Impedance	Custom-designed according to system capacitive current and arc-suppression coil parameters
Short-Time Earth-Fault Current	Custom per project system parameters; duration options: 10 s / 60 s	Short-Time Earth-Fault Withstand	Complies with standard requirements for short-time single-phase earth-fault energization; winding temperature rise and mechanical strength satisfy GB 1094-5
Winding Configuration	Z-type zig-zag winding; each phase consists of two half-windings connected in reverse series	Secondary Winding	Optional auxiliary secondary winding for station-service power supply
Zero-Sequence PT Interface	Available as a special option	Excitation Characteristics	Low excitation current; excitation curve keeps away from saturation zone to prevent ferro-resonance
No-Load Current	< 0.3% – 0.6% (measured at rated voltage)	Tap-Changer	Off-circuit tap-changer; on-load tap-changer generally not applied

Insulation And Dielectric Performance
Insulation Level	Matched to GB 1094 and IEC 60076-3 per voltage class	Partial Discharge Level	Oil-immersed: < 100 pC at 1.5 x rated voltage; dry-type meets GB 1094.11 partial discharge requirements
Dry-Type Insulation	F/H-class epoxy casting available	Dielectric Fluid	Mineral oil / biodegradable ester fluids optional
Thermal Performance	Long-term no-load temperature rise within standard limits; short-time fault heating under single-phase earth conditions calculated with safety margin	Service Life	>= 30 years under normal distribution network conditions
Core Material	High-permeability, low-loss grain-oriented silicon steel; M-4 / M-5 grade or equivalent	Noise Level	Typical <= 65 dB(A) at 1 m; low-noise version available upon request

Mechanical Construction And Protection
Functional Type	Ground Mounted Transformer / Earthing-cum-station-service transformer	Construction Type	Oil-immersed type / dry-type
Tank Sealing	Oil-immersed tank passes full vacuum and positive-pressure integrity tests	Dry-Type Enclosure	IP-rated protective enclosure optional
Corrosion Protection	C5-M high-corrosion-protection coating optional for coastal and chemically aggressive environments	Temperature Monitoring	PT100 winding-temperature sensors available for dry-type units
Special Configurations	Zero-sequence PT interface, temperature controller, oil-level monitoring available	Reference Cooling Arrangement	ONAN oil natural-air natural cooling

Reference Configuration And Compliance
Typical Model	10 kV Znyn0 800 kVA oil-immersed earthing-cum-station-service transformer	Primary Voltage	10 kV (reference application)
Secondary Station-Service Voltage	0.4 kV (reference application)	Reference Cooling Arrangement	ONAN oil natural-air natural cooling
Standards	IEC 60076-1/2/3/5; IEC 61869; GB 1094.1-2-3-5; GB 1094.11; GB/T 10229-2019; DL/T 620; DL/T 1057; JB/T 10431	Export Compliance	RoHS & REACH; EPA 40 CFR Part 761 PCB-free dielectric-fluid policy
Carbon Footprint	LCA life-cycle assessment documentation available upon request	Application	Ground-mounted grounding and station-service applications

Protection & Accessories

Reliable Protection System and Flexible Accessories

Our Pad Mounted Transformers are equipped with reliable protection devices and accessories to ensure safe operation in underground distribution systems and utility applications.

Standard Accessories

HV/LV Bushings

Reliable medium voltage connection with excellent insulation performance.

Oil Level Gauge

Easy monitoring of insulating oil level for maintenance.

Pressure Relief Device

Improves transformer safety under abnormal conditions.

Drain Valve

Convenient oil draining and maintenance operation.

Tap Changer

Off-circuit Tap Changer (OCTC), ±2 × 2.5%

Nameplate

Provides complete transformer rating and technical information.

Optional Accessories

Temperature Indicator

Monitors transformer operating temperature for reliability.

Remote Monitoring System

Supports smart grid and remote transformer condition monitoring.

Surge Arrester

Protects pad mounted transformers against lightning and voltage surges.

Key Features of Transformers

Key Benefits:

Enhanced operator and public safety
No exposed high-voltage components
Suitable for underground distribution systems
Reliable operation in outdoor environments

Key Benefits:

Weather-resistant construction
Corrosion-resistant surface treatment
Secure locking compartment
Suitable for public and utility applications

Key Benefits:

Space-saving installation
Low-profile outdoor design
Easy inspection and maintenance
Ideal alternative to overhead distribution systems

Available Configurations:

Loop feed distribution system
Radial feed distribution system
Dead-front cable connection
Customized MV and LV connection arrangements

Available protection and accessories include:

High voltage fuses
Current limiting fuses
Load break switches
Surge arresters
Pressure relief devices
Temperature monitoring systems

These protection solutions help ensure safe operation under different load and fault conditions.

Key Benefits:

Low no-load losses
High energy efficiency
Excellent thermal performance
Long operational lifetime

Manufacturing & Testing

Strict Quality Control and Transformer Testing

Every Pad Mounted Transformer undergoes comprehensive testing to ensure high reliability, safety and long service life according to international standards.

Routine Tests

Transformer Ratio Test

Ensures accurate voltage transformation performance.

Winding Resistance Test

Verifies winding quality and electrical performance.

No-Load Loss Test

Checks transformer core efficiency and energy performance.

No-Load Loss Test

Confirms transformer rated efficiency under operating conditions.

Impedance Test

Ensures correct electrical characteristics and system compatibility.

Dielectric Test

Verifies insulation strength and operational safety.

Special Tests

Temperature Rise Test

Validates thermal performance and cooling capability.

Lightning Impulse Test

Tests insulation capability against surge conditions.

Partial Discharge Test

Ensures insulation quality and long-term reliability.

Everything We Do Is At A High Standard

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WHAT WE DO

CTSS Transformer Applications and Solutions

We design and manufacture liquid-filled power transformers and distribution transformers for a wide range of applications, including solar power, data centers, industrial facilities, and utility systems. With experienced engineers and advanced manufacturing capabilities, we provide customized transformer solutions and complex winding designs to meet the specific electrical and performance requirements of each project.