Moisture Protection Technology for Transformers in Tropical Regions

Moisture, humidity, and corrosion are factors that can dull the performance of an electrical transformer with time. With specific regard to the tropical areas, in this white paper, we will analyse how the company Delixi Electric solves such issues with smart and advanced technologies, smart designs, and future-oriented developments.

1) Executive Summary

The transformers in tropical regions encounter extreme environmental factors, which may adversely influence their performance and lifespan. Yes, the transformers face extreme humidity, frequent rains, and a saline atmosphere, which makes conditions very difficult for electrical insulation, core components, and structural integrity.

The ingress of moisture is among the leading causes of transformer failure in the region, and leads to insulation failure, oil pollution, and unexpected outages.

Delixi Electric is a renowned brand in the power distribution industry and has in-depth expertise in designing transformers for regions which are moisture and high-humidity-prone. The company incorporates advanced materials, active seals, and smart monitoring systems to ensure that its transformers perform reliably, even in the harshest tropical conditions.

By considering all the above issues, Delixi's engineering incorporates advanced insulation systems into hermetically sealed tanks and active breathing filter systems. Well, this document addresses the specific issues related to operating transformers in tropical environments and describes the innovative solutions which Delixi Electric has devised to address these issues.

It discusses two case studies from Southeast Asia and Brazil and captures extensive field work results in the reduced maintenance and failure rates of transformers. Moreover, it discusses some principles of optimal transformer configuration selection and gives preliminary estimations of cost-effective moisture protection investment.

2) Tropical Climate Challenges

We all know that tropical-specific transformers suffer from extensive, harsh, humid weather. High year-round moisture, heavy rainfall, and high ambient temperature accelerate the breakdown of materials and therefore require moisture management.

Additionally, the majority of these tropical areas are near salt coastlines, which creates a corrosive salt-laden air. This greatly enhances the risk of corrosion to the transformer.

High humidity effects on transformer components

The humid tropical climates where the average relative humidity exceeds 80% present a challenging barrier to the preservation of electrical insulation. Humidity serves as a persistent threat. In the case of transformers, their parts would be exposed to moisture in the atmosphere continuously, because moisture can enter through small apertures, deteriorated seals, and even due to pressure differentials.

Intrusion of moisture reduces the dielectric strength of insulation for materials, paper and cellulosic compounds, especially. Even the encapsulating resin of the dry-type transformers can absorb moisture, and therefore, over a period of time, begin to deteriorate the dry-type insulation resistance.

Eventually, this moisture intrusion increases the chances of partial discharge and electrical breakdown of the insulation over time. In addition, the moisture-rich environment may lead to condensation during the cooler periods of the day.

This condensation can develop on the internal metallic parts, for example, windings and core clamps, creating conductive pathways for tracking, corrosion, and electrical discharge.

Common moisture-related failures (windings, insulation, oil degradation)

Moisture intrusion can cause a lot of problems for different components of a transformer. Certain tropical regions have documented the following failures as the most common:

• Insulation Breakdown: This failure stems from the introduction of moisture, in combination with humidity. What happens is that the dielectric strength of solid insulations decreases. Consequently, this leads to localised heating of the windings, then insulation creepage, and a crash of the winding structure.

• Deteriorated transformer oil: In oil-immersed transformers, even traces of moisture can diminish the oil's insulating properties. It also accelerates the formation of acids and sludge, the ageing of the insulating paper, as well as corrodes metal components.

• Short circuits and flashovers: The internal components and electrical parts have a higher tendency of surface tracking due to the bushings and terminals having reduced insulation resistance. This can also cause the formation of arcs and high-voltage flashovers, which may lead to disastrous failures.

• Swelling and delamination: Apart from all, some insulation materials also soak up water and can physically expand, or even peel. This strain can detach soldered insulation layers, making them more prone to electrical harm.

In the absence of proactive design and real-time tracking, these failures can lead to a wide range of issues such as infrastructure failures, increased asset damage, and extensive repairs, resulting in higher overall costs.

Corrosion risks in coastal tropical areas

Tropical coastal areas are more complicated due to exposure to salt. The combination of airborne salt and high moisture levels creates a metal surface exposure like rusting and pitting at a faster rate.

Transformers placed in such locations usually demonstrate the first signs of corrosion on the radiators, clamping components, bolt threads, and grounding terminals. In worst cases, salt may intrude under the coating layer, leading to corrosion on the coating layer and even peeling.

This kind of damage is not only mechanical but also electrical, compromising the reliability of electrical contacts. This can lead to numerous safety and operational risks.

Additionally, the corrosion can lead to rust that may penetrate the bushings or insulation, leading to potential shorts or insulation faults. Without a good protective approach, these tropical coastal regions substantially decrease the service life of the transformer and require frequent transformer servicing.

3) Delixi's Moisture Protection Technologies

Given the moisture-related tropical issues, Delixi Electric has a range of moisture-control technologies that protect them from condensation and salt corrosion. These technologies also include innovations related to materials, designs, and monitoring and maintenance protocols of transformers.

Material Solutions

Nano-Coated Insulation Materials

These nano-coatings and Delixi's epoxy resin SC(B)10 F-class transformers have windings with cast epoxy. These resin materials and nano-coatings provide moisture-proof and rust-proof properties. Thus, it reduces the absorption of moisture and enables better dielectric performance during high-humidity conditions. Moreover, the treated silicon-steel cores also have moisture-proof properties.

Hermetic Sealing Techniques

Hermetically sealed oil-immersed transformers from Delixi separate the insulating oil from oxygen and external moisture effectively. This oil hermetic design ensures no moisture can permeate, and oil is protected from oxidative degradation, further extending oil life while internal corrosion is minimised.

Design Innovations

Breathing Systems with Silica Gel & Activated Carbon Filters

Activated carbon filters are designed to eliminate unwanted breather contaminants and acidic gases. It ensures the work of these filters is effective.

Condensation prevention designs

To combat the risk of condensation from changing temperatures, Delixi suggests installers pay close attention to the location of the oil-immersed transformers, ensuring adequate ventilation and temperature regulation. Thus, this greatly reduces the likelihood of condensation on the oil-immersed transformers.

Alright! Weather-resistant epoxy coatings on the transformer body and the internal moisture-repelling epoxy encapsulation all work together to greatly reduce moisture adhering and condensation tracking.

Monitoring & Maintenance

Online moisture monitoring sensors

Delixi endorses the integration of moisture monitoring systems on the transformer windings for sensor-based monitoring. In dry-type transformers, the mounting of moisture sensors and temperature detectors allows for the early detection of excessive moisture delays and hotspots, meaning proactive measures can be set to prevent harm and severe damage to the parts.

While specific models are not listed in Delixi Electric's documents, the descriptions of the products make mention of integrated monitoring systems that track vital parameters and sensors.

Predictive Maintenance Protocols

Delixi Electric places special focus on caring for the transformer through preventive maintenance measures as core practices to elongate the life of the transformer. Core practices include:

• Taking oil samples that analyse the moisture, dissolved gases, and checking for the acidity and dielectric strength.

• Replacing and checking the silica gel breathers to ensure internal dryness.

• Carried out thermographic scanning to both detect and diagnose the prevalence of cooling issues and early hot spot detection.

• Lessening and enhanced maintenance on the electrical connection, tightening to aid in the lessening of corrosion or increased resistance.

• Inspection and monitoring checks on the grounding integrity and visual checks for rust or damage to protective coatings are also needed.

These extensions and augmentations to the protocols can be employed directly to create a first-class system that will allow operations that can practically forecast failures and dial back on maintenance in the core components to speed up the workflows.

4) Case Studies

Delixi Electric's moisture protection technologies have been applied in regions having high humidity and chance of corrosion. Two case studies are provided to focus on one project in Southeast Asia and one project in Brazil to show the innovative value of Delixi's technologies in these environments.

Southeast Asia Grid Project (2023)

In 2023, Delixi teamed up with the national power utility in Southeast Asia to provide a set of dry and oil-immersed distribution transformers for a regional grid reinforcement program. The project includes the transformer installation in a coastal region with relative humidity levels averaging above 85%, and an annual rainfall exceeding 2500 millimetres on average.

An existing customer had issues with other suppliers' transformers failing due to insulation issues and oil degradation, primarily from water ingress and condensation. To overcome these challenges, Delixi provided SCB10 F-class dry-type transformers with epoxy resin encapsulation and oil-immersed transformers with hermetic seals and silica gel breathers.

This project confirmed the effectiveness of Delixi's moisture protection design and assisted in enhancing transformer reliability in harsh environmental conditions.

Brazilian utility partnership (2024)

Okay, in the first months of 2024, Delixi signed a strategic supply contract with one of the major utilities from North-East Brazil, a region with high temperature and humidity, as well as salt-laden winds from the Atlantic.

The client needed a transformer for the new substation infrastructure intended to service the industrial zones being developed along the coastline. Previous installations had a high probability of risk from external component corrosion and internal condensation. For this project, Delixi provided oil-immersed transformers with hermetically sealed tanks, nano-coated internal insulation, and outer corrosion-resistant coatings.

Delixi provided customised maintenance schedules and trained local personnel on maintenance procedures, including the inspection of breathers and oil testing, to support optimal maintenance for oil-immersed transformers.

After six months of operation, analysis confirmed zero water ingress, and all units continued to maintain oil dielectric strength well above the operational thresholds.

5) Implementation Guidelines

The selection of a transformer for a tropical environment is not that simple. It combines the evaluation of geographic and environmental risks and the use of the system, especially for the long term.

Selection criteria for different tropical environments

High-Humidity Inland Areas

Delixi SC(B)10 series dry-type epoxy resin transformers are best for deep inland locations with consistently high humidity but low salt exposure. These units have good insulation properties with low condensation risk internally.

In damp conditions found in industrial plants and residential substations, built-in temperature sensors and epoxy-encapsulated moisture proofing help mitigate damp-related damage.

Coastal Environments

Coastal areas with salt-laden air are better served with hermetically sealed, oil-immersed transformers with anti-corrosion coatings. With lacquers preventing moisture and oxygen, and optional silica gel breathers filtering air, Delixi sealed oil tanks are protected from oil degradation. Anti-rust coatings and grounding systems that lack corrosion must be applied to external surfaces.

Harsh Terrain Installations

Push button maintenance is ideal for limited access areas. Smart sensors and self-drying breathers are low-maintenance features.

Cost-Benefit Analysis of Moisture Protection Options

Although moisture protection features may boost initial costs, the long-term savings vastly outweigh. For instance:

+ Dry-type transformers with nano coatings are inspected less often and are easier to install in confined, enclosed, or ventilated indoor areas.

+ Sensors, along with predictive and preventive maintenance systems, support by lessening costly unplanned downtime.

All in all, the moisture-resistant designs are projected to reduce the expenses of maintenance and boost efficiency to almost 40% over a decade to a decade and a half of continuous operation.

6) Conclusion & Future Trends

Tropical climates require transformers to be protected more rigorously against humidity, corrosion, and moisture-related failures. Delixi Electric meets these needs with nano-coated insulation, hermetically sealed designs, and silica gel breathers.

Moreover, AI-powered maintenance tools are anticipated to boost transformer reliability. Delixi continues to lead these innovations, offering, providing sturdiness, intelligence, and efficiency, while equipping demanding tropical regions with reliable solutions. For such intelligent solutions, get in touch with Delixi right now!