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Transformer Oil Management System (TOMS)


Install our TOMS oil filtration systems and reap the benefits!*
Reduce tapchanger maintenance costs and inspection intervals (up to seven years)

* Extend oil life
* Reduce contact erosion (less re-strikes during tapchanging)
* Produce consistent high dielectric strength and low ppm
* Reduce wear and coking


Versitility - just one of our TOMS units can filter up to six tap changers, or a combination of main tanks and tap changers.


Automate filtration processes - each TOMS unit has an integrated Programable Logic Controller (PLC) and an easy-to-use control/display unit which allows you to automate the entire system.

Proven - our TOMS units have been installed and tested in Transpower New Zealand for over 15 months. Transpower New Zealand owns and operates New Zealand's national electricity grid.


The Transformer Oil Management System (TOMS) removes contaminants from insulating oil at a flow rate of 580 litres per hour. It is designed to prolong the life of expensive transformers and tap changers. It can be permanently mounted, and can be set for automatic and unattended operation.


The system can automatically filter up to six vessels of varying volume removing particles, moisture or both. Filter cycle frequency can be controlled manually or automatically as desired - all on line.

Each TOMS system is fully self contained. Where needs differ there are options and models available to suit any application.

System Features
The main features of each TOMS system are:
* It can filter oil in the main tanks and tap changers - up to six tanks
* Flow rate of 580 l/hr
* Can be permanently positioned
* Can be set for manual and automatic (unattended) operation
* Filter cycle can be set according to need
* Has built in alarm monitoring system including over pressure and abnormal main tank flows
* Built using high quality components
* Features a weather proof 316 SS enclosure
* Comes with 12 inch BSP pipe connections
* 3 way valve allows make up oil to be added
* Pump can be used to fill or drain tanks
* Runs on a 230 VAC 5 A supply
* For single phase transformers, level switches are provided for the conservator


Control System
A PLC (controller) is used to control and monitor the whole operation. It sets up the timing sequences and notes the number of litres filtered in tap changers. It also records the number of filter cycles and filter changes. The controller responds to overpressure and tap changer low or high flows by safely shutting down and displaying the cause of the problem.



The system can be manually controlled to enable oil draining, top up or transfer between compartments via a set of illuminated push buttons on the control panel. The number of compartments to be filtered and compartment volumes can be input into the PLC via a user interface. The interface also allows filter cycle frequencies to be adjusted on site. System status and fault conditions are displayed on the interface unit.


Filter Housing
The Tap Changer filter housing contains a Velcon Filters Inc. SD 718P3 filter cartridge. This cartridge has a nominal rating of 12 micron and is designed to remove particle solid contaminants and dissolved water.
The main tank filter housing contains a Velcon Filters Inc. model SD 718 filter cartridge. This cartridge removes dissolved moisture in the oil to less than 10 ppm. Each SD 718 cartridge will hold approx 500 ml of water before saturation.

Pressure Switch
The adjustable pressure switch senses pump outlet pressure and shuts the unit down if the pressure exceeds the preset level. The switch is factory set at 40 psi. It can be adjusted in the field up to a maximum of 75 psi to protect the cartridge from over-pressurisation.


3 Way Inlet Valve
A 3-way valve is positioned at the oil pump inlet to the TOMS. This valve allows make-up oil to be introduced into the tap changing equipment.

External Solenoid Valves
Direct acting solenoid valves are fitted to the transformer end of each supply and return hose. A valve pair will automatically open when a compartment is to be filtered and close at filtration completion. The valves will only open when energised and will automatically close in the event of a filter unit trip or power failure.

Pipe Work
Pipe work and fittings used are 316 stainless steel to ensure maintenance free operation over many years. Connection to the transformer is completed via a stainless steel universal coupling, which allows for transformer unit changes to be carried out with the minimum of hassle.



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