Compact Pad Mounted Transformer

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Product Overview

Compact Pad Mounted Transformer

High-voltage rated voltage	6 kV–24 kV; up to 34.5 kV for North-American export
Low-voltage rated voltage	0.4 kV; export versions can be customized to 480 V / 208 V etc.
Rated capacity	50 kVA–2500 kVA
Power Supply Mode	Loop-feed type / Radial-feed type
Frequency	50 Hz; 60 Hz customizable for overseas projects
Cooling Type	ONAN – Oil Natural Air Natural cooling

Technical Specifications

High-Voltage Rated Voltage	6 kV–24 kV; up to 34.5 kV for North-American export	Low-Voltage Rated Voltage	0.4 kV; export versions can be customized to 480 V / 208 V etc.
Rated Capacity	50 kVA–2500 kVA	Frequency	50 Hz; 60 Hz customizable for overseas projects
Power Supply Mode	Loop-feed type / Radial-feed type	Vector Group	Dyn11 / Yyn0 optional
Tap-Changer	Off-circuit tap changer ±2 × 2.5%	Cooling Type	ONAN – Oil Natural Air Natural cooling
Insulation Level	Matched with GB 1094 and ANSI C57 standards according to voltage class	Enclosure Protection	IP54
Ambient Operating Temperature	-25 °C to +40 °C	High-Temperature Version	Up to +55 °C available
Transformer Structure	Fully-sealed, conservator-free oil-filled design	Installation	Outdoor pad-mounted installation
Overall Volume	Approx. 1/3 of a European-style box-type substation of equal rating	Low-Voltage Compartment	Independent air-insulated compartment
Core Material	High-permeability, low-loss grain-oriented silicon steel, M-4 / M-5 or equivalent	Core Construction	Five-step stepped-lap fully-mitered-joint construction
Tank Design	Fully-sealed tank without conservator	Tank Testing	Positive-pressure and negative-pressure tightness testing
Radiator Arrangement	External radiators with natural heat dissipation	Standard Anti-Corrosion	C3, C4, C5, CX-H
Heavy-Duty Anti-Corrosion	C5-M coating optional for coastal salt-spray environments	Dielectric Fluid	Mineral oil; high-fire-point eco-friendly dielectric fluid optional
High-Voltage Load Switch	2-position / 4-position oil-immersed load switch	Fuse Protection	Bayonet-type fuse + backup current-limiting fuse
Surge Arrester	Oil-immersed surge arrester	High-Voltage Configuration	Fully integrated within the sealed transformer oil tank
Power Supply Configuration	Loop-feed / radial-feed	Cable Connection	Fully-insulated elbow-type cable connectors
Underground Cable Connection	Suitable for underground cable distribution systems	High-Voltage Component Testing	Oil-immersed voltage withstand and operation-cycle tests
Low-Voltage Compartment	Independent air-insulated compartment, fully separated from the oil-filled HV tank	Low-Voltage Equipment	Low-voltage circuit breakers, metering and outgoing circuits
Reactive Power Compensation	Optional	Intelligent Measurement & Control	Optional
Temperature Monitoring	PT100 temperature sensor optional	Oil-Level Monitoring	Oil-level indicator optional
Pressure Protection	Pressure-relief device optional	Remote Communication	Optional intelligent data acquisition and remote communication module
Communication Protocol	Modbus-RTU / Modbus-TCP	Monitoring Integration	Backend monitoring-platform connection supported
Noise Level	Typical ≤65 dB(A) at 1 m	Partial Discharge	<100 pC at 1.5 × rated voltage for transformer main body
Temperature Rise	Complies with GB 1094 and ANSI standards	Thermal Margin	≥20% thermal margin reserved for short-time overload
Protection Performance	Two-stage dual-fuse protection for overload and short-circuit protection	Service Life	≥30 years under normal outdoor operating conditions
Carbon Footprint Documentation	LCA life-cycle-assessment documentation available upon request	ESG Support	LCA documentation available to support customer ESG reporting
Typical Model	ZGS11-12/0.4-800 kVA loop-feed pad-mounted transformer	Primary Voltage	10 kV
Secondary Voltage	0.4 kV	Reference Cooling	ONAN – Oil Natural Air Natural cooling
Reference HV Configuration	4-position oil-immersed load switch	Reference Protection	Bayonet-type fuse + backup fuse protection
LV Configuration	Low-voltage incoming + multiple outgoing circuits, metering and intelligent measurement-control unit	Reference Enclosure	IP54, C3, C4, C5, CX-H anti-corrosion coating
Reference Installation	Outdoor pad-mounted installation	Special Options	Elbow-type cable-connector interface and remote-communication module
North-American Standard	ANSI/IEEE C57.12.00 / C57.12.34	Power Transformer Standard	IEC 60076 Series
Prefabricated Substation Standard	IEC 62271-202	Chinese Prefabricated Substation Standard	GB/T 17467-2020
Combined Transformer Standard	JB/T 10217	Oil-Immersed Transformer Standard	GB 1094 Series
Low-Voltage Switchgear Standard	GB 7251 Series	Seismic Standard	IEEE 693 optional for high-seismic-zone projects
Export Substance Control	RoHS & REACH	PCB-Free Dielectric Fluid	EPA 40 CFR Part 761; mineral oil / high-fire-point ester fluid optional

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.