VV and VI transformer

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Product Overview

VV and VI transformer

High-voltage rated voltage	Up to 35 kV
Low-voltage rated voltage	Customized according to project requirements
Rated capacity	10 kVA - 5000 kVA per single-phase unit; combined three-phase capacity available
Power Supply Mode	V-V connection; two independent single-phase transformers forming a V-V connection
Frequency	Not specified in the source document
Cooling Type	ONAN / ONAF for oil-immersed type; AN / AF for dry-type

V-Connected Transformer Technical Specifications

Parameter	Value	Parameter	Value
High-voltage rated voltage	Up to 35 kV	Low-voltage rated voltage	Customized according to project requirements
Rated capacity	10 kVA – 5000 kVA per single-phase unit; combined three-phase capacity available	Power Supply Mode	V-V connection; two independent single-phase transformers forming a V-V connection
Frequency	Not specified in the source document	Cooling Type	ONAN / ONAF for oil-immersed type; AN / AF for dry-type
Vector Group	V-V0	Transformer Type	V-connected transformer; V-V connection transformer
Connection Configuration	Two separate single-phase transformers combined to provide three-phase power conversion	Voltage Conversion	Three-phase voltage conversion using V-V connection
Transformer Structure	Modular single-phase transformer units	Installation Method	Ground-mounted installation
Transformer Medium	Oil-immersed or dry-type	Insulation Level	Designed according to IEC and GB standards; compatible with South American power grid insulation requirements
Ambient Temperature	-20°C to +50°C	High-temperature Version	Available for tropical areas
Altitude	≤1000 m	High-altitude Design	Insulation reinforcement available for high-altitude applications
Core Material	High-grade oriented silicon steel sheet	Core Manufacturing Process	Step-lap stacking technology
Winding Material	High-quality electromagnetic wire	Winding Configuration	Flat or round electromagnetic wire winding
Dry-type Insulation Process	Vacuum impregnation	Oil-immersed Insulation Process	Vacuum oil filling
Enclosure Protection	Anti-corrosion coating	Outdoor Suitability	Suitable for outdoor service; resistant to rain and salt fog
Environmental Adaptability	Suitable for high-temperature, high-altitude and humid conditions	Application Environment	Indoor and outdoor applications
Factory Acceptance Test	Winding resistance; voltage ratio; vector group check; no-load test; load loss measurement; insulation test; optional partial discharge test	Short-circuit Test	Not included in factory FAT; performed by an authorized third-party test institute
Winding Resistance Test	Included in FAT	Voltage Ratio Test	Included in FAT
No-load Test	Included in FAT	Load Loss Test	Included in FAT
Insulation Test	Power frequency withstand voltage and induced voltage test	Partial Discharge Test	Optional
Power Continuity	If one single-phase transformer fails, two-phase power supply can be maintained for a short time	Maintenance	Simple structure, few fault points and low daily maintenance requirements
Transportation	Single units can be transported separately; suitable for sites with limited transportation conditions	Replacement	Individual single-phase units can be replaced separately
Economic Advantage	Two single-phase transformers provide three-phase power supply with lower equipment cost than a three-unit single-phase solution	Footprint	Smaller footprint compared with three separate single-phase transformers
Applicable Standards	IEC 60076; GB 1094	Dry-type Standard	IEC 60076-11
Oil-immersed Standard	IEC 60076-2	Export Compliance	Designed to meet IEC and Chinese GB requirements and support South American export projects
Railway Application	Small traction power supply for electrified railway	Mining Application	Mining power distribution
Renewable Energy Application	Small PV and wind farms; off-grid PV systems	Remote Area Application	Three-phase power renovation in remote areas
Industrial Application	Small industrial power distribution and temporary three-phase power supply for factories	Overseas Application	South American overseas engineering projects and small-to-medium three-phase power renovation
Core Performance	Low no-load loss and low vibration noise	Insulation Reliability	Ample insulation margin with vacuum processing options
Outdoor Protection	Anti-corrosion enclosure coating for rain and salt-fog environments	Structural Advantage	Modular design with convenient installation and removal
Documentation	Factory test reports, drawings and operation manuals	Installation Support	On-site technical guidance for installation and commissioning
Warranty Support	Technical support provided during the warranty period	Export Documentation	Inspection documents available for South American import customs clearance

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.