63 MVA Power Electronic Transformer-242/10.5 kV | South Africa 2024

A powerful core, stable output-our transformers keep your business running strong!

01 General

1.1 Project Description

Two units of 63MVA Power transformers were exported to South Africa in July 2024.  The voltage is 242 to 10.5 kV, 242 kV primary, 10.5 kV secondary. The two transformers are used in photovoltaic power stations in South Africa.

This 63MVA, 242/10.5 kV power transformer is engineered as a highly reliable and efficient cornerstone for electrical transmission and distribution networks. It expertly steps down high-voltage electricity from 242 kV to 10.5 kV, providing a stable and continuous power supply for industrial complexes and municipal grids. With its robust capacity, the unit is built to handle significant loads while incorporating advanced design to minimize losses, ensuring superior energy efficiency, reduced operational costs, and enhanced durability. In essence, it represents a perfect blend of robust performance and intelligent design, guaranteeing grid stability and serving as a trusted investment for a sustainable energy future.

1.2 Technical Specification

63MVA power transformer specification and data sheet

1.3 Drawings

63 MVA step down power transformer diagram drawing and size.

02 Manufacturing

2.1 Core

Each limb of the core supports the step down power transformer windings, with the size and shape of the limbs designed based on the rated power (80MVA) and voltage level. Horizontal sections of the core, called the yoke, connect the three limbs at the top and bottom, forming a closed magnetic circuit. The core is made of high-permeability, low-loss cold-rolled grain-oriented silicon steel sheets to minimize core losses (including hysteresis and eddy current losses). The core limbs and yoke form a closed magnetic circuit. Magnetic flux is distributed across the three limbs, with each phase’s flux passing through the yoke and linking with the other two phases, ensuring balanced three-phase flux.

2.2 Winding

The number of turns, cross-sectional area of the conductor, and spacing of each section are optimized based on the transformer’s voltage level, power capacity, and current requirements. Since the winding is continuous, the magnetic field is uniformly distributed across the winding, reducing the effects of leakage flux. The evenly spaced turns ensure a smooth voltage distribution, reducing inter-turn voltage stress and insulation strain. The tight arrangement of the winding parts makes the magnetic circuit more closed, minimizing leakage reactance and improving transformer efficiency.

2.3 Tank

When the thickness of the steel plate along the box is less than 12mm, the flat steel material of Q235 material is used, and the punching machine is used to cut off the mold. When the thickness of the steel plate along the box is > 12mm, the steel plate of Q235 material is used, and the material is cut by the CNC fire/plasma cutting machine. The bottom of the transformer tank is made of Q235 steel plate. When the thickness of the steel plate is less than 14mm, the cutting machine is used. When the thickness of the steel plate is > 16mm, use the CNC cutting machine to cut the material. After the box wall is assembled, chemical treatment is carried out according to OFL.140.5060 pickling phosphating process. The cover of the transformer tank is made of Q235 steel plate. When the thickness of the steel plate is less than 14mm, the cutting machine is used. When the thickness of the steel plate is > 16mm, use the CNC cutting machine to cut the material.

2.4 Final Assembly

03 Testing

04 Packing and Shipping

05 Site And Summary

Advantages of hot dip galvanizing

For chip radiators for 63 MVA step down power transformer, the hot dip galvanizing process offers several important advantages:

• Corrosion resistance: The hot dip galvanizing layer can effectively prevent the erosion of air and water on the metal and improve the service life of the radiator, especially in wet or corrosive environments.

• Wear resistance: The galvanized layer can also increase the wear resistance of the heat sink, making it less likely to be damaged in physical friction or collision.

• Simple maintenance: Hot dip galvanized radiators require almost no additional maintenance, reducing the need and cost of later maintenance.

• Improve heat dissipation efficiency: Although hot dip galvanizing is mainly for corrosion prevention, it can indirectly improve heat dissipation efficiency by keeping the surface of the radiator smooth and rust-free.