Long term improvements of all power transformers insulating system characteristics

VIMAP RCID - continual online transformers dry-out system

Working principle

VIMAP RCID is on line dry-out system designed for safe continual unattended operation on energized power transformers.

Dehydration is performed by circulation of transformer oil through columns with granulated synthetic adsorbents (molecular sieves) which attract water molecules and permanently hold them in  the pores of their active surface. By this process insulating oil is dried out in a matter of hours or days. However, cellulose insulation drying is far slower process which cannot be significantly influenced at.

Disturbing moisture equilibrium by continuous oil drying, water diffusion from the wet cellulose insulation to already dried oil is possible, thus slowly removing moisture from solid insulation.

About 99% of water in power transformer is stored in cellulose insulation while only about 1% is in the oil.

Water in power transformers occurs from three sources:

» water left from production

» atmosphere water absorbed through unmaintained breathers and gaskets

» water created by cellulose depolymerization, i.e. thermal degradation

Field of application

» Preventive maintenance

New or previously dried power transformers- continual maintenance of low moisture level in both oil and cellulose insulation

» Corrective maintenance

Transformers with increased content of moisture- reduction of moisture in complete insulation, improvement of insulation characteristics, increase of power transformers safety and its lifetime

Main features

» No oil heating - no undesired effects from oil heating on overall oil quality

» No oil vacuuming - no other parts to maintain or protect - longer equipment lifetime

» No oil inhibitor removed

» No dissolved gasses removing for continuous trending of important fault diagnostic gasses

VIMAP RCID technical characteristics

» Oil dehydration by water adsorption

» Hanging frame, bolt down stand, cabinet or wheels mounted

» Transferring data to substation automation system confirming to IEC 61850 available as an option

» Moisture management system SCADA compatible

Continual on-line direct reading sensors mounted on both inlet and outlet lines of the system display moisture contents (ppm) and oil temperature (°C) and indicate adsorbents saturation level

» Remote monitoring package

Ethernet board– working parameters are available via web browser or via email

» Safety package with remote alarming

Oil leakage, air ingress and high/low pressure sensors shut the system off, isolating it from the transformer, in the event of any malfunction; CMGSM module sends SMS notification in case of unit malfunction

» Control box with front view window containing 7” touch display, PLC, relays, wiring terminations and other ancillary components

» On-site sound and visual alarm

» Various numbers of columns

» Water holding capacity – appx.. 5 kg each column

» Electric motor - from 0.2 kW to 1.5 kW

» Pump with bypass valve up to 600 l/h

» Frequency converter

» Particle filter 10 µm

» Flow indicator or flow meter

» Available in several sizes and configuration to suit all power transformer sizes and conditions

» Custom made designs are available according to specific customer’s requirements

Read more about water in power transformer and its devastating influence on insulation system

Our scientific papers

Case studies

VIMAP RCID can be accommodated to any power transformer size. Varying the number of columns, quantity of adsorbents and pump flow we can meet any customer requirement. Please contact us and we will suggest you the best solution for your application.

If pipes cannot be used to connect VIMAP RCID to power transformers than our unique leakage detection and information system is the best solution for you.

It consists of dual containment hoses with incorporated capacitive sensors and solenoid valve. Sensor will detect any oil leakage on the inner hose, trigger sound and visual alarm, send SMS and/or email to predetermined numbers and addresses, shut off  the electric motor and consequently close solenoid valve mounted on transformer bottom valve, thus disconnecting VIMAP RCID from the transformer.

Adsorbents saturation

Level of adsorbents saturation is monitored by moisture sensors. Comparing inlet and outlet moisture content readings it is easy to determinate efficiency of adsorbents. When the columns are saturated, i.e. when the input ppm is very close to being the same as the output ppm, then the columns can be exchanged.

Products \ VIMAP RCID