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ABB Drive Isolation Transformer
Model: DTM-500-11-VFD
4-hour response · Pricing in SAR · Delivery across all KSA regions
DTM-500-11-VFD — ABB Drive Isolation Transformer
ABB drive isolation transformers are purpose-designed distribution transformers providing galvanic isolation between the utility supply and variable frequency drive (VFD) systems. Unlike standard distribution transformers, drive isolation transformers are wound to withstand the harmonic content injected by six-pulse rectifier front-end drives — which can include current harmonics at the 5th, 7th, 11th, and 13th order with THDi levels exceeding 35% — without overheating or suffering insulation degradation. The reinforced winding insulation, copper-foil electrostatic screen between primary and secondary, and derating for harmonic loading make ABB drive isolation transformers the technically correct solution for powering VFD front-ends in facilities where supply impedance is low and harmonic propagation must be controlled.
Drive isolation transformers provide an additional function: they create an impedance boundary that limits the rate-of-rise of fault current (di/dt) seen by drive IGBTs during supply disturbances, protecting the drive's input rectifier and DC bus capacitors from voltage spikes caused by switching events on the MV supply network. For high-power drives above 200 kW where the cost of IGBT replacement significantly exceeds the transformer cost, an ABB drive isolation transformer is standard engineering practice and is specified by ARAMCO and SABIC drive engineering standards for critical rotating equipment.
In Saudi Arabia's petrochemical and process industries, drive isolation transformers are specified for every VFD installation above 132 kW at ARAMCO and SABIC facilities where SAES-P-100 electrical engineering standards explicitly require isolation between the MV bus and VFD front-ends. MARAFIQ and SWCC desalination plants specify drive isolation transformers for all seawater pump and high-pressure pump VFD installations to prevent harmonic propagation into the desalination facility's utility supply network, which feeds sensitive instrumentation and control systems. The NEMA K-factor rating (typically K-13 for six-pulse VFD loads) ensures the transformer can handle the expected harmonic current spectrum without thermal damage.
Razz Middle East supplies ABB drive isolation transformers sized to match specific drive ratings from project specifications. We provide factory test certificates (routine and special tests per IEC 60076-1), SASO conformity documents, and coordinate delivery to site with installation supervision and transformer commissioning including turns ratio, insulation resistance, and no-load loss verification tests.
Technical Specifications
Full specifications for the DTM-500-11-VFD
- Power Range
- 50 kVA–2000 kVA (project-specific)
- Primary Voltage
- 11 kV / 6.6 kV / 3.3 kV / 400 V
- Secondary Voltage
- 400 V / 690 V (to match drive input)
- Cooling
- ONAN (oil) or AN/AF (dry-type cast resin)
- Harmonic Rating
- K-13 or K-20 NEMA factor
- Electrostatic Screen
- Copper foil between primary and secondary
- Vector Group
- Dyn11 / Dd0 / Yyn0 (12-pulse available)
- Loss Grade
- AA0 (IEC 60076-20)
- Insulation Class
- F (155°C) for harmonic loading
- Tap Changer
- OCTC ±2×2.5%
- Standard
- IEC 60076-1 / SASO / NEMA TR-1
Key Features & Benefits
- K-13 or K-20 NEMA harmonic rating confirms the transformer can safely carry the harmonic current spectrum from six-pulse VFD front-ends — including 5th, 7th, 11th, and 13th harmonics — without exceeding winding temperature limits, meeting ARAMCO SAES-P-100 and SABIC drive installation requirements.
- Copper-foil electrostatic screen between primary and secondary windings attenuates common-mode noise conducted from VFD switching transients back to the supply bus, protecting upstream metering, protection relays, and sensitive control system power supplies from high-frequency interference.
- Limits supply fault current rate-of-rise (di/dt) seen by drive IGBT input rectifiers during upstream supply switching and fault events, protecting expensive IGBT assemblies in high-power drives above 200 kW where a single IGBT replacement costs more than the transformer.
- Available in 12-pulse configuration with dual secondary windings (Dd0 + Dy11) providing phase-shifted output to a 12-pulse drive rectifier, reducing input current THDi from 35% to under 8% for facilities where harmonic distortion must comply with IEEE 519-2014 limits at the point of common coupling.
- Dry-type cast resin option (AN/AF cooling) eliminates oil fire risk for indoor substations and basement electrical rooms in commercial towers and hospitals, meeting NFPA 70 and IBC fire safety requirements without the fireproof bund wall required for oil-filled transformers.
- Factory routine tests per IEC 60076-1 including transformer ratio, winding resistance, no-load loss, load loss, and insulation level (AC withstand and lightning impulse) with test certificate provided for ARAMCO and SABIC project inspection authority approval.
- SASO conformity documentation and ECRA type approval available for Saudi Electricity Company (SEC) connection approval submissions, ensuring the drive isolation transformer meets Saudi Arabia's national electrical equipment import and installation requirements.
Industrial Applications in Saudi Arabia
- Variable frequency drive installations at ARAMCO gas compression stations and pipeline pump stations, where SAES-P-100 mandates drive isolation transformers for all VFDs above 132 kW connected to the facility's 13.8 kV or 6.6 kV distribution bus.
- Seawater intake pump VFD systems at SWCC and MARAFIQ desalination plants, where drive isolation transformers prevent the 35% THDi harmonic current from six-pulse VFDs propagating into the facility's supply network and interfering with DCS and safety instrumentation power quality.
- Large chiller VFD installations at mega-project district cooling plants (NEOM, Qiddiya, King Abdullah Financial District), where the drive isolation transformer provides the impedance boundary required to meet IEEE 519-2014 harmonic limits at the SEC metering point.
- 12-pulse drive front-end configuration at SABIC petrochemical plants for large extruder, compressor, and pump VFDs above 500 kW, where the phase-shifted dual secondary reduces supply THDi below the 5% limit specified in SABIC's electrical design standard ESD-P-003.
- Indoor substation cast-resin drive isolation transformers for commercial tower basement electrical rooms in Riyadh and Jeddah, where fire safety regulations prohibit oil-filled transformers within 3 metres of occupied space and require Type AN/AF dry-type equipment.
- Water injection pump VFD installations at ARAMCO offshore platforms, where the drive isolation transformer's electrostatic screen prevents switching transients from VFDs coupling into the platform's safety-critical 690 V essential services bus feeding fire and gas detection systems.
- Renewable energy plant auxiliary power VFDs at REPDO utility-scale solar farms, where grid-connected inverter transformers are required to isolate the inverter DC bus from the AC collection grid and meet SEC's harmonic distortion limits at the point of grid connection.
Industrial Supplier in Saudi Arabia
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Frequently Asked Questions — DTM-500-11-VFD
Common questions from buyers in Saudi Arabia and the GCC