Phase Shifting Transformers

Overview

The Phase Shifting Transformer is designed for installations where rectifier and drive loads inject harmonic currents back into the supply network. By providing multiple secondary windings with controlled angular displacement, the transformer enables multi-pulse rectifier topologies that cancel low-order harmonics at the source rather than filtering them after the fact.

DATSAN manufactures phase shifting transformers in 12, 18, 24, 36 and 48 pulse configurations, selected according to the harmonic limits the installation must meet.

How Pulse Number Affects Harmonic Performance

Each configuration produces a different set of phase-displaced secondary voltages:

• 12-pulse — two three-phase outputs displaced by 30°, cancelling the 5th and 7th harmonics
• 18-pulse — three outputs displaced by 20°
• 24-pulse — four outputs displaced by 15°, additionally cancelling the 11th and 13th harmonics
• 36 and 48-pulse — six and eight outputs respectively, for the most demanding power quality requirements

In a 24-pulse arrangement only harmonics of the order 24k±1 remain on the supply side, with the 23rd being the first to appear. Higher pulse numbers push the first significant harmonic further up the spectrum, reducing voltage distortion across the distribution system and supporting compliance with IEEE 519 limits.

Typical Applications

• Variable frequency drive (VFD) systems
• Rectifier and DC power supply installations
• Solar power plants and inverter stations
• Battery energy storage systems (BESS)
• Oil & gas processing facilities
• Water pumping stations and irrigation infrastructure

Key Design Features

• 12 to 48 pulse configurations — winding arrangement selected to the required harmonic spectrum
• Multiple phase-displaced secondary windings with controlled impedance matching between windings
• Harmonic-tolerant construction — designed for continuous operation under the thermal load that harmonic currents impose
• IP65 / NEMA 4X cable boxes for dust-tight and water-jet-resistant terminations
• Corrosion-resistant tank options — painted, fully hot-dip galvanized, or stainless steel (304 or 316L)
• Cooling flexibility — radiator or corrugated wall construction

Impedance Matching Matters

Harmonic cancellation in a multi-pulse system depends on the secondary windings presenting closely matched impedances. Unequal impedance between windings degrades cancellation and allows harmonics that the topology should have eliminated to reach the supply. DATSAN addresses this during design and verifies it through routine testing, so the installed performance matches the calculated spectrum.

Built for Harsh Environments

Industrial and energy sites expose equipment to conditions that shorten the life of conventionally specified transformers:

• Tank material selected according to the corrosivity of the installation site
• 316L stainless steel available for coastal, saline and chemically aggressive atmospheres
• Full hot-dip galvanizing as a cost-effective alternative for moderately corrosive sites
• Sealing and termination systems rated for dust ingress and high-pressure washdown

Why Choose DATSAN?

• Over 30 years of transformer engineering experience
• Project-specific winding design rather than catalogue adaptation
• Proven supply to international energy and industrial projects
• In-house manufacturing and accredited testing capability

Standards & Compliance

• IEC 60076
• ANSI C57
• IEEE 519 harmonic limits (system-level compliance supported)
• ISO 9001 Quality Management System
• ISO 14001 Environmental Management System
• ISO/IEC 17025 Accredited Testing Laboratory
• CE Marking
• Routine, type and special tests available upon request

Customization & Technical Support

Every unit is configured around the rectifier or drive system it will feed:

• Pulse number and secondary winding arrangement
• Voltage ratio, impedance and vector group
• Tank material and surface protection system
• Cooling configuration and accessory package
• Cable box rating and termination type