Grids today carry higher loads, integrate more renewables and tolerate fewer outages than ever before. In this environment, a transformer failure is not just a technical incident – it is a direct hit on revenue, reputation and ESG performance. Behind many “sudden” breakdowns sits a slow, invisible problem: the condition of the insulation system. Oil quality, moisture in the paper, dissolved gases and particles quietly determine how much stress a unit can handle.

This is the space where HERING VPT has specialised for more than a century, using transformer oil treatment and vacuum technology to keep critical assets in service for longer. Instead of treating insulating fluid as a disposable commodity, the company treats it as an asset that can be protected and upgraded with the right processes.

What Really Ages a Transformer

Inside the tank, mineral oil and cellulose insulation operate under high thermal and electrical stress. Over time, heat and oxygen oxidise the oil, creating acids and sludge. moisture enters through breathers and seals; particles from switching events and wear accumulate; and dissolved gases rise during normal operation and faults. In older units, residual PCBs may still be present in the fluid.

The combined effect is a gradual erosion of dielectric strength and thermal performance: breakdown voltage drops, total acid number rises and moisture in the paper shortens expected insulation life. IEC and IEEE guidelines for transformer oils all point to the same conclusion – if moisture, gases and contamination are not actively managed, the transformer will age faster than its nameplate suggests and fail earlier than planned. For utility asset managers and industrial plant engineers, this is also where money quietly leaks away.

HERING VPT’s Integrated Oil and Vacuum Toolkit

Many suppliers offer a single machine; HERING VPT’s strength is integration. Its portfolio spans Transformer Oil Regeneration, Transformer Oil Purification, Vacuum Transformer Drying, Transformer Vacuum Plants, Transformer Oil Filtration, Degassing Systems, Mobile Transformer Oil Treatment, Transformer Oil Recovery, a dedicated PCB Removal System and Complete Transformer Service Solutions. Each technology targets a specific risk, but they share one purpose: keeping the insulation system clean, dry and stable.

During manufacturing, vacuum drying ovens and transformer vacuum plants provide deep, uniform drying and controlled oil impregnation. In daily operation, purification, filtration and degassing units keep routine contamination in check. For units that cannot easily be moved, mobile treatment plants bring these capabilities directly to the substation or plant gate, while regeneration and recovery strategies later in life reclaim “tired” fluid instead of sending it to disposal and PCB removal closes the loop for legacy assets.

Regeneration, Purification and Drying in Practice

After years in service, oil analysis often shows the same pattern: rising acidity, darkening colour, growing sludge potential and declining breakdown voltage. Traditionally, the answer has been simple but expensive – drain the fluid, buy fresh oil and pay for disposal. A modern transformer oil regeneration plant breaks that pattern by using adsorption, filtration and vacuum processes to remove acids, ageing by-products, sludge-forming compounds, moisture and polar contaminants.

In many projects, regenerated fluid again meets key parameters for new oil in typical industry guidelines, with lower total acid number and higher breakdown voltage. When this is combined with regular purification, effective filtration and proper vacuum drying of solid insulation, operators see three concrete benefits:

• Reliability: higher dielectric margins and fewer insulation failures.
• Cost control: reclaimed oil instead of constant replacement.
• Sustainability: less fresh oil produced and less waste oil burned.

PCB Removal, Mobile Treatment and Oil Recovery

Many networks still operate transformers installed when PCBs were common in insulating fluids. Today these substances are tightly regulated and represent both an environmental and reporting burden. HERING VPT’s PCB removal system uses chemical dechlorination to neutralise PCBs and related compounds, converting them into non-PCB residues while keeping most of the oil available for further treatment and reuse.

Once the PCB risk is under control, transformer oil recovery and regeneration strategies turn what used to be a linear “use and dispose” model into a closed loop. Mobile transformer oil treatment units then bring purification, filtration and degassing capability directly to remote or constrained sites – wind farms, solar parks, industrial campuses and remote substations. Together, these technologies cut waste-oil volumes, reduce logistics costs and help operators align asset management with their ESG targets.

Power systems are changing fast, and “fix it when it breaks” is no longer a viable plan for high-value transformers. Real advantage comes when regeneration, purification, vacuum drying, PCB removal, mobile treatment and oil recovery are combined into a single roadmap that matches your fleet’s age, loading and risk profile. For some organisations, the priority will be extending life on a handful of critical units; for others, it will be cleaning up PCB legacies or cutting waste-oil volumes.

If you are responsible for key transformers in a utility, industrial plant or OEM environment, the most effective first step is a structured review of oil analyses, moisture levels and loading patterns. From there, a tailored mix of technologies can be defined with HERING VPT’s engineering team – turning transformer care from a reactive cost into a strategic tool for reliability, compliance and sustainability.

How is regeneration different from purification?

Purification removes moisture, gases and particles from fluid that is still relatively healthy. Regeneration goes further by removing acids and ageing by-products, restoring many properties closer to those of new oil.

Where do mobile plants add the most value?

Mobile treatment units are most valuable where logistics are complex or outages are costly: remote substations, wind and solar parks, industrial campuses and high-voltage hubs with limited redundancy.