System Overview and Application
The PTss Online Transformer Dryout System is an online dehydration and filtration system designed to remove dissolved moisture from transformer oil and gradually reduce moisture from the solid cellulose insulation while the transformer remains in service. Its purpose is to improve insulation dryness, IR values and overall transformer reliability without requiring traditional offline dry-out methods.
Yes. The system is designed for online processing. It can be connected to a transformer in service and used for unattended operation, subject to proper installation, site safety practices and PTss operating instructions.
The system can be used on transformers above approximately 5 MVA and up to 500 MVA, up to 765kV. Earlier project references include use on 400 kV reactors and high-MVA transformers. Final applicability should be confirmed against the transformer rating, oil volume, operating condition, valve arrangement and selected PTss model.
Yes. The system is intended to be portable or semi-portable. It can be mounted or connected on one transformer, dismantled after the dry-out/filtration campaign, transported and then refitted on another suitable transformer. After years of experience utilities now prefer a fixed type of Online Dry Out System for each Transformer or Reactor.
Yes. The system is described as outdoor-suitable and may be mounted on the transformer body or installed as a ground-mounted/trolley-mounted unit, depending on site arrangement and model configuration.
Yes, the system is safe for unattended online use when properly installed. Practical clearance, earthing, hose routing, oil leakage prevention and access requirements should still be checked during site installation.
The system generally includes oil circulation, moisture-removal media cartridges, filtration elements, sensors, control logic and optional communication/SCADA interface. A detailed bill of components should be taken from the current PTss catalogue or project-specific offer. PTss Operating Manual contains all details for ease of usage and operation.
Drying Process and Performance
The system removes dissolved moisture from the transformer oil. As the oil becomes drier, moisture migrates from the cellulose insulation into the oil to re-establish equilibrium. Continuous or repeated circulation gradually lowers moisture in both oil and insulation
Free water can be removed by many conventional methods, but dissolved moisture is harder to remove and is the key concern for long-term insulation health. Removing dissolved moisture from oil helps pull moisture out of the cellulose insulation, improving insulation condition and IR values.
The duration depends on transformer size, oil volume, wetness, operating temperature, load cycle, ambient conditions and target dryness. As a guideline from the source material, a 10 MVA transformer with approximately 8,000 litres of oil, operating around 55 Ā°C oil temperature and starting at about 3-4% moisture by dry weight of insulation, may require about four weeks to reduce moisture below about 1.5%. Larger, colder or wetter transformers may take longer and some cases may take months.
Only an estimate can be made before connection. A more reliable assessment is possible after the equipment is connected and the online monitoring system begins estimating moisture by dry weight of insulation and tracking the drying trend.
The endpoint is reached when moisture by dry weight of insulation (%M/DWI) remains within the safe target range for the transformer voltage class on a sustained basis. The TIMES (Transformer Insulation Moisture Estimation System) module helps determine relative moisture saturation in oil, oil temperature, ppm moisture in oil and estimated %M/DWi.
The documents refer to bringing moisture by dry weight of insulation below approximately 1.5% as a recommended healthy condition in the example provided. The final target should be selected based on transformer voltage class, operating criticality, applicable standards and customer maintenance policy.
Yes. The stated objective of removing dissolved moisture from oil and gradually drying the cellulose insulation is to improve insulation dryness and IR values, thereby supporting better dielectric performance and reliability.
No. The process is designed to treat and dry the existing oil. Oil replacement is not the normal purpose of the system unless a separate project requirement specifies it.
Operation, Monitoring and Safety
The system is designed for unattended operation. Remote monitoring through SCADA is available through an Ethernet interface, and IEC 61850 interface is described as optional on customer request.
The online sensor and control system monitors water activity/relative saturation in oil, oil temperature, ppm moisture in oil and estimated percentage moisture by dry weight of insulation (%M/DWI). These parameters help validate the dehydration process.
TIMES stands for Transformer Insulation Moisture Estimation System. It is the module/software integrated for estimating moisture in the solid insulation using monitored oil moisture and temperature data.
Yes. the equipment can connect through an Ethernet port to a PC. TIMES SCADA software is available as an optional item to validate and monitor the process.
The preventive measures are incorporated to avoid static charge during use. Site-specific safety procedures, earthing and manufacturer operating instructions should always be followed.
Yes, the system can be mounted/connected and the transformer can be taken into service or remain online for processing, subject to proper installation and operational clearance.
Consumables, Filtration and Maintenance
Yes. The system uses media cartridges for moisture removal. Consumable life depends on transformer wetness, oil quantity, moisture content and operating conditions.
The moisture holding capacity is 10.2 litres of dissolved moisture capacity per cartridge set. Treat this as model- and cartridge-set-specific. The correct capacity should be confirmed from the current PTss offer or technical datasheet for the supplied model. The replacement cost is roughly INR 70,000 per set of 6 cartridges.
Consumables should be sourced from PTss or its authorized representatives to ensure compatibility, performance and warranty compliance.
Consumable life is estimated from transformer data such as MVA/KVA rating, oil volume, initial moisture level and operating condition. PTss offers the use of software/estimation tool results once transformer details are available.
The online Transformer Dryout System offers moisture removal and oil conditioning. For exact filtration micron rating, element type and contaminant-removal performance, refer to the current PTss model datasheet or commercial offer, generally 0.5 and 1.0 micron removal capabilities are there.
PTss provides field support and can send engineers on short notice. General response time is within about one week or 7-10 days depending on location. Current service commitments should be confirmed in the contract or offer.
The long field experience and repeat use by utilities, with machines moved from substation to substation and limited service calls reflects trouble free performance. Actual performance depends on operating discipline, site conditions, preventive maintenance and consumable replacement.
Power, Dimensions, Manufacturing and Commercial Information
The fixed machine installed capacity of 0.5-2 kW and approximate energy consumption of 0.75 kWh. Power consumption is described as very low compared with conventional offline dry-out methods. Exact consumption depends on model and operating configuration. More options are available on specific requests.
A sleek/OEM version of approximately 545 mm x 775 mm x 1525 mm and about 250 kg is available. Use the current PTss model datasheet for final dimensions which varies from Model to Model.
The equipment is 100% manufactured in India under technical knowhow from Velcon Systems/Parker, USA.
The prominent users are as Power Grid Corporation of India, NTPC, NHPC, NPCIL, DVC, State Transmission Utilities, Daman Electricity Board, Bhakra Beas Management Board, JSW, Upper India Steel, Vardhman Group and Malana Power Company. Specific details are available on request along with case studies from various utilities.
Yes. PTss sales or representatives can assist with user reference contacts and visits to nearby installations, such as PGCIL locations, subject to customer permission and availability.
It ranges from about INR 2.5 lakh to INR 8 lakh, while prospective customers can email requirements for a suitable model and offer. Treat pricing as indicative only. Final pricing depends on transformer rating, model, accessories, monitoring options, taxes, logistics and service scope.
The built-in online sensor and control system provides water activity, oil temperature, ppm moisture in oil and estimated %M/DWI. However, customers may still use independent oil testing such as BDV, DGA, moisture ppm or other diagnostic tests as part of their maintenance program.
Customer-Facing Clarifications
Useful information includes transformer MVA rating, voltage class, oil quantity, oil temperature profile, load profile, current moisture/ppm data, insulation condition, valve availability, site layout, desired drying target and whether remote monitoring/SCADA integration is required.
PTss can position online dry-out as a practical reliability improvement method that removes dissolved moisture while the transformer remains in service, reduces outage dependency, uses low power, allows continuous monitoring and avoids many operational disruptions associated with offline dry-out methods.
No. Drying time, consumable life, mounting method, power consumption, cartridge capacity, dimensions and commercial offer vary by transformer condition and PTss model. The FAQ should be used as a general guide, and final commitments should be based on the applicable technical datasheet and offer.