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3 Phase Power transformers - LV/MV transformers for Utility/PV/Wind/Mining/Defence/Transport Industries.
Three phase or single phase dry-type low voltage (LV) transformers are used as isolation transformers or to adjust the voltage level in the LV/MV distribution grid. These transformers are used in the utility industry to step the voltage down from transmission voltages to distribution voltage levels in substations. Tortech manufactures and tests distribution step down transformers rated up to 33kV (HV) to 240V (LV).
These transformers are made and tested to AS/NZS 60076.11. 3 phase units can be supplied either as Open or Enclosed units. Enclosed units are tailor made to suite harsh Australian conditions. Indoor units (IP23) are made of Mild steel powder coated to RAL 7035 Transformer grey colour. Outdoor units are made with an Ingress protection rating of IP56 with powder coated mild steel or Marine grade stainless steel enclosures. Tortech has over 29 years of experience in transformer design and manufacture and is involved extensively R&D in house and is also involved with PhD graduates from Australian universities.
Please feel free to view the presentation from Michael Larkin CPEng at Engineers Australia, Chatswood regarding the temperature rise of dry type transformers. Tortech has also been involved in researching partial discharge in Cast resin units and short circuit strength of power transformers.
Tortech has the capability to manufacture split winding transformers for centralised PV power plants with specific inter-winding impedance requirements. Split winding transformers have to be carefully designed and manufactured to account for harmonic and DC content supplied by centralised PV inverters. Tortech has recently manufactured cast resin units rated 1.6MVA and 1.5MVA for an installation in Murchison Western Australia. This project is for a research site and is part of the largest radio telescope in the world.
Special transformers such as 6 and 9 transposed Zigzag and earthing YNd transformers have also been manufactured previously for the Defence industry. These special transformers are used for deriving a neutral in un-earthed systems. Tortech also has the capability to manufacture current transformers at its facility in Sydney. Our capability ranges from large generator current transformers with thousands of turns to split core current transformers that are getting more popular for metering electricity.
Tortech can provide test reports by a NATA certified laboratory if required. The windings are made of copper or aluminium and insulation class materials H(180ºC), F(150ºC) and C(220ºC) are used. Cast resin transformers are pre-dominantly made with aluminium windings. The reason for this approach is because of the similarity of co-efficients of expansion between epoxy resin and aluminium. It is our experience that copper winding based cast resin transformers have the potential of cracking with constant hot-cold cycles.
Special cast resin units can be made with fire retardant or self extinguishing resin material. These transformers can also be made in special circumstances (tunnels - railway and mining industry) with a special cast resin that decomposes in to water if it is subject to fire conditions.
Partial Discharge in Resin Cast transformers:
Short Circuit Strength of transformers:
Features:High efficiency (GOSS or Amorphous cores used)
Enhanced heat dissipation design (Enclosure designed to naturally cool the transformer).
Class H (180°C) or Class F (150°C) insulation used. (Ensures reliable operation under high ambient temperatures).
In-rush current can be minimised by using certain winding techniques in conjunction with appropriate core materials.
Stainless steel enclosures for applications with close proximity to salt water are available as an addition. Low regulation.
Transformer can be double varnished to have a high resistance to corrosion.
Excellent noise rejection due to the presence of the Earth screen between the primary and secondary windings.
Indoor IP23 or outdoor IP56 / IP65 weather proof enclosures available.
Very low magnetic stray field due to the arrangement of primary and secondary windings.
Hard-wired terminals to terminal block at rated current. Mounting of the transformer inside the enclosure to ensure sufficient space for cables at the rated current.
Optional taps at +2.5% and +5% for excellent regulation. (Excellent for regulating voltage in grid-connected Inverter systems /PV systems).
C-Channels and lifting eyes on the transformer for ease of installation.
High voltage test (Up a maximum of 70kVrms and 28kVDC depending on the rating).
OPTIONAL TYPE TESTS:Temperature rise test to AS/NZS 60076.11:2004. Partial discharge test *applicable to Resin Cast units and HV oil filled units. Impulse lightning test and switching test *applicable to HV units.
Contact our sales team on : +61 2 9642 6003
Test Report TO AS/NZS 61558/600076
LV/MV ISOLATION TRANSFORMER BROCHURE