TSTY transformer for Mauritania's National Electricity Authority

Project Location: Nouakchott, Mauritania

Purchaser: Mauritania's National Electricity Authority (SOMELEC)

Core Equipment: 200 630kVA 15/0.4kV all-copper winding oil-immersed distribution transformers

Contract Amount: RMB 15 million

Project Status: Fully delivered and operational, integrated into the national distribution network in batches

Project Background

Mauritania, located in northwestern Africa, covers an area of ​​over one million square kilometers, but most of its electricity load is concentrated in the capital, Nouakchott, and its surrounding areas. In recent years, with the growth of the urban population and the rapid increase in industrial and commercial electricity demand, SOMELEC's existing distribution network equipment has become increasingly problematic due to its aging, inefficient, and frequent failures.

The National Electricity Authority launched a new round of urban and rural distribution network upgrade and renovation plan, a core component of which is the large-scale replacement and addition of distribution transformers to reduce line losses, improve power supply reliability, and adapt to future renewable energy grid integration needs.

The 200 630kVA 15/0.4kV oil-immersed transformers tendered this time will be deployed in several residential areas, commercial centers, and light industrial parks in Nouakchott, replacing aging equipment that has been in operation for over 20 years, while also providing power access for new developments.

Dual Challenges of Localization and Cost Control

During the initial project research, SOMELEC discovered that while many international brand transformers on the market offer excellent performance, they suffer from two prominent issues:

Standard Incompatibility

The Mauritanian power grid uses a 15kV medium-voltage level (33kV in some areas, but 15kV is the primary voltage in the capital), with a 400V/230V three-phase four-wire system on the low-voltage side at a frequency of 50Hz. Furthermore, the local grid voltage fluctuates significantly, requiring transformers with a wide on-load and off-load voltage regulation range. Some imported equipment is designed according to European or North American standards and cannot directly meet local needs.

Limited Procurement Budget

As a public utility, the National Electricity Authority is highly sensitive to project costs. International top-tier brands often quoted prices exceeding the budget, while low-priced non-standard products presented potential quality risks. Clients needed to find the optimal balance between technical compliance, operational reliability, and reasonable pricing.

Furthermore, Mauritania's desert-edge climate, characterized by high temperatures, frequent dust storms, and significant diurnal temperature variations, placed special demands on transformer casing protection, heat dissipation, and sealing. The lifespan of ordinary outdoor equipment in this region was often shortened by more than 30% compared to expectations.

TSTY Solution

Upon learning of the tender information, TSTY's International Business Division quickly assembled a dedicated team comprised of technical, commercial, and logistics personnel to develop a comprehensive bidding plan addressing the client's pain points.

1. Precise Matching to Local Power Grid Standards

Voltage Combination: For Mauritania's 15kV main grid, a 15±2×2.5% / 0.4kV no-load tap changer structure was provided, covering the daily fluctuation range of the power grid.

Connection Group: Utilizing Dyn11, a stable 220V single-phase lighting power supply was provided, while effectively suppressing third harmonics and reducing neutral point current.

Frequency: 50Hz, fully compliant with Mauritania's national power grid standards.

2. Enhanced Tropical Desert Design

Protection Rating: IP54 outdoor enclosure, enhanced with dust filter and sand cover; all fasteners are made of stainless steel.

Optimized Heat Dissipation: Corrugated oil tank fin spacing increased to 18mm, improving self-cleaning capability; top oil temperature limit increased to 55K (45℃ ambient temperature).

Breathing System: Equipped with large-capacity dual breathers and built-in molecular sieve desiccant, extending replacement intervals.

3. All-Copper Windings and Energy Efficiency Commitment

Winding Material: 100% electrolytic copper, purity not less than 99.97%, ensuring overload capacity and short-circuit withstand strength.

Loss Control: No-load loss ≤850W, load loss ≤6500W (120℃), exceeding Mauritania's local energy efficiency standards, with an estimated annual energy saving of approximately 3000kWh per unit.

4. Winning the Open Bidding: After two rounds of evaluation—technical and commercial—TSTY stood out among numerous bidders, becoming the only Chinese supplier to win the bid for this project. Following the signing of the contract, 200 transformers were produced and shipped in three batches, each batch accompanied by an independent factory test report and a third-party inspection certificate (SGS).

This order demonstrates TSTY's ability to meet the stringent bidding requirements and rapid delivery capabilities of a national power company-level client, and also lays a solid foundation for its reputation in subsequent similar projects in Senegal, Mali, and Côte d'Ivoire.