Project Report: Single Phase Pole-Mounted Transformer Deployment

Project Reference

Rural Distribution Network Expansion Program – East Africa Region

Project Type

Medium-scale rural electrification / low-voltage distribution upgrade

1. Project Background

This project is part of a rural electrification expansion program initiated by the local utility company, with the primary objective of addressing insufficient low-voltage network coverage and unstable end-user voltage levels.

The project area is characterized by the following conditions:

* Dispersed village distribution with long feeder distances

* Insufficient existing supply capacity, resulting in noticeable voltage drops at the network end

* Load profile mainly consists of residential consumption and small agricultural equipment

* High cost and low economic feasibility of deploying three-phase distribution infrastructure

Following preliminary technical evaluation, the client determined to adopt a single-phase pole-mounted distribution transformer solution for segmented network optimization.

2. Technical Specification Requirement

Based on the technical specification provided by the client and on-site survey data, the required parameters were defined as follows:

 Rated capacity: 10kVA / 25kVA / 50kVA

 Primary voltage: 11kV (with tolerance variation depending on grid conditions)

 Secondary voltage: 230V / 110V (site-specific configuration)

 Frequency: 50Hz

 Cooling method: Oil-immersed, natural cooling (ONAN)

 Installation type: Outdoor pole-mounted installation

 Loss level: Compliant with IEC distribution transformer efficiency standards

 Ambient conditions: High humidity and elevated temperature environment

Additional requirement:

Stable operation under non-ideal grid conditions, including voltage fluctuations and unbalanced loads.

3. Engineering Design Adaptation

To adapt to the actual operating environment, the standard design was modified as follows:

3.1 Core Material Selection

Grain-oriented silicon steel was adopted to optimize magnetic flux path, reduce no-load losses, and improve long-term operational efficiency.

3.2 Winding Reinforcement

The winding structure was reinforced to improve resistance against impulse voltage, lightning-induced surges, and grid voltage fluctuations.

3.3 Tank & Protection System

The tank structure was designed with reinforced steel thickness and anti-corrosion coating to ensure long-term outdoor operation in high humidity environments.

3.4 Bushing & Connection Standardization

High-voltage and low-voltage bushings were standardized according to local distribution network requirements to minimize on-site modification work.

4. Manufacturing & FAT Process

All units underwent standard factory acceptance testing (FAT) prior to shipment, including:

No-load loss and load loss measurement

 Insulation resistance test

 Power frequency withstand voltage test

Temperature rise test (sampling-based)

Oil leakage and sealing inspection

All test results met the required technical specifications before batch shipment.

5. Delivery & Site Implementation

The equipment was delivered in multiple batches to align with the on-site construction schedule.

Installation was carried out by the local power construction contractor, with remote technical support provided, including:

Pre-installation wiring verification

 Installation positioning and lifting guidance

 Pre-energization inspection checklist confirmation

Load monitoring recommendations during commissioning

No structural modifications were required during installation, and the overall construction timeline remained in line with the original schedule.

6. Commissioning Results

Following commissioning, the equipment was monitored during the initial operational phase, with the following observations:

Significant improvement in end-user voltage stability

More balanced load distribution across feeder lines

No abnormal temperature rise detected during early operation

Protection devices operated correctly without misoperation

Noticeable improvement in residential power supply reliability

The equipment is currently in continuous operation, and routine maintenance is being carried out according to standard inspection cycles.

7. Project Outcome Summary

Based on operational performance, the single-phase distribution solution demonstrated strong suitability for this region, particularly in the following aspects:

Expanded power coverage under low investment conditions

Reduced distribution losses at the network end

Improved stability in weak grid environments

Simplified infrastructure construction requirements

This batch of equipment has been referenced as a baseline configuration for subsequent rural grid modernization projects of a similar nature.

8. Engineering Note

The key value of this project lies in:

Replacing traditional three-phase expansion with a properly engineered single-phase distribution structure under non-ideal grid conditions, achieving a balanced trade-off between cost efficiency and power supply stability.

9. Contact for Similar Projects

For project-based technical consultation or transformer supply requirements:

OEM / ODM customization available

Grid-specific voltage design support

Technical drawings and specification matching available upon request