Frequency depends on transformer load and environmental conditions but is often recommended every 2–3 years. GlobeCore’s equipment allows quick on-site filtration or regeneration – reducing the need for oil replacement or external service.

One thing that often gets overlooked in discussions about filtration frequency is the trend toward continuous monitoring rather than relying solely on a fixed schedule. Transformer oil condition can change unpredictably due to thermal cycling, load spikes, or even minor breaches in sealing that cause the ingress of moisture or particulates more rapidly than expected. In many cases, periodic filtration combined with condition-based checks (such as dissolved gas analysis, water content, and particle counts) provides much clearer insight into when operational intervention is truly needed. This approach helps you avoid unnecessary procedures when the oil is still within acceptable limits and allows for a timely response before degradation accelerates.
Furthermore, the choice of filtration equipment really matters: modern vacuum oil filter machines are designed to remove particulate contaminants as well as dissolved gases and moisture, which can significantly extend the useful life of insulating oil. For more information on how vacuum oil filter systems are engineered to improve efficiency and support on-site maintenance, I recommend reading this article:
https://globecore.com/oil-processing/vacuum-oil-filter-machine/.

In addition to the points already raised, it’s worth emphasizing that operational priorities and risk tolerance should also influence the transformer oil filtration schedule. For assets in critical service or in environments with high humidity, frequent filtration combined with real-time condition monitoring can help in addressing the emerging issues before they begin to affect the equipment reliability. On the other hand, for older, lightly loaded transformers operating in stable environments, a condition-based approach informed by periodic testing (e.g., water content, dielectric strength, particle count) may allow for longer intervals between filtration cycles without increasing risks.
Another practical consideration is that filtration systems vary in capacity. Some purifiers can handle moisture, gases, and fine particles in a single pass, while others are optimized for specific contaminants. Selecting the right equipment and applying it at appropriate intervals can significantly improve oil longevity and overall transformer performance.
For a detailed overview of how transformer oil purifiers are engineered and how they fit into effective maintenance schedules, please check out this article:
https://globecore.com/oil-processing/transformer-oil-purifier/.

You’re absolutely right — move from calendar-based servicing to condition-based filtration. Continuous or near‑real‑time monitoring of moisture, particle count, dielectric strength and dissolved gas trends gives the earliest, most reliable indication that oil purification is needed. In practice this means equipping critical assets with online monitors and using their trend data to trigger on‑site vacuum dehydration/degassing and filtration; for example, systems like TOR‑5 are intended to monitor oil condition continuously and drive timely use of CMM purification units rather than a fixed timetable. There are concrete parameter triggers in some cases (for traction transformers GlobeCore recommends oil regeneration when acid number reaches 0.2 mg KOH/g), and Midel oil maintenance is scheduled to keep oils within target ISO 4406 cleanliness ranges based on monitoring dynamics rather than a preset interval.

For fleet management, apply a risk‑based hybrid approach: treat high‑risk or heavily loaded transformers as continuously monitored and perform filtration/regeneration as trends dictate, while lower‑risk, lightly loaded units can be sampled periodically (commonly every 6–12 months) and serviced only if water content, particle counts, DGA or dielectric strength deteriorate. Match the purifier type and capacity to the contaminant profile and oil volume — modern vacuum oil filter/dehydration units remove moisture, dissolved gases and fine particles much more effectively than simple particulate filters, which lengthens oil life and reduces oil replacement. If you want, I can tailor a condition‑based schedule for a specific setup (TOR‑5 plus CMM‑R or CMM‑600CF) and suggest monitoring thresholds and sampling cadence tied to your operational risk tolerance.