WearCheck boosts transformer efficiency, longevity

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oil, each with its advantages and limitations. Some of the common methods include:

• Furanic test: paper deterioration is the single biggest cause of transformer failure in RSA. WearCheck’s specialised furanic test enables the predicted DP value to be tested from the oil, rather than taking an actual paper sample, which is highly intrusive and often inaccurate.

• Furanic derivatives in transformer oil are correlated with the UV–visible spectral property. 2-FAL is the major furanic derivative and the most stable compound of deterioration of insulation paper. High concentration of furanic derivatives may indicate presence of thermal fault and also indicates the tensile strength of paper insulation life.

• Indicate potential issues with the transformer insulation or other components.

• Dielectric Breakdown Voltage (DBV) Testing: DBV testing is a technique used to measure the breakdown voltage of transformer oil under an applied voltage. DBV testing can detect changes in the oil dielectric strength, which can indicate potential issues with the transformer insulation or other components.

Transformers are critical components of mining projects, providing a reliable and stable power supply to operate equipment and machinery. However, transformers are prone to wear and aging, which can lead to malfunctions, failures, and unplanned downtime.

Condition monitoring specialist company, WearCheck, provides a range of world-class monitoring programmes – valuable tools to keep components operating at peak efficiency across many sectors, including for transformers.

WearCheck’s transformer division manager, Gert Nel, provides insight into getting the most out of a transformer, ‘The timely detection and diagnosis of potential issues in transformers are essential for ensuring the efficient and reliable operation of mining projects.’

In this article, Nel discusses how transformer oil condition monitoring can be used as a tool for predictive maintenance of transformers in mining projects, and provides a brief case study.

‘Transformer oil is an essential component of transformer insulation and cooling systems, playing a critical role in maintaining the transformer’s electrical and mechanical properties. The condition of transformer oil can indicate the health of the transformer, as changes in the oil properties can result from various forms of wear and aging. Therefore, monitoring the condition of transformer oil is a useful tool for predicting potential issues in transformers.

‘Transformer oil condition monitoring involves analysing the physical and chemical properties of the oil, such as furanic components, dielectric strength, IFT (interfacial tension), acidity, moisture content, and dissolved gas content. These properties can provide insight into the condition of the transformer insulation and other components, as well as potential issues that may be developing.

‘By analysing the oil properties over time, maintenance teams can detect changes in the oil condition and take appropriate actions, such as performing maintenance or replacing components, before a failure occurs.

‘There are several methods for analysing the physical and chemical properties of transformer

• Water Content Analysis: Water content analysis is a technique used to measure the moisture content of transformer oil. Excess moisture in transformer oil can lead to reduced insulation properties, corrosion, and other issues.

• Dissolved Gas Analysis (DGA) Test of Transformer Oil: DGA is the study of dissolved gases in transformer oil. It is also referred to as a DGA test. Whenever a transformer undergoes abnormal thermal and electrical stresses, certain gases are produced due to the decomposition of the transformer oil.

‘By using a combination of these methods, maintenance teams can gain a comprehensive understanding of the transformer oil condition and potential issues that may be developing. This information can be used to plan and execute maintenance activities and replacements proactively, thereby reducing unplanned downtime and maintenance costs.

‘A mining company in South Africa had several transformers operating in harsh environments, providing power to critical mining equipment. The transformers were subject to high temperatures, dust, and vibration, which could cause wear and tear over time. The company needed a reliable and cost-effective way to monitor the transformers’ condition and detect potential issues before they caused failures.

‘The company implemented a transformer oil condition monitoring programme, using a combination of DGA and other condition monitoring techniques. The programme involved taking regular samples of transformer oil and analysing them in a laboratory, using specialised equipment and software.

‘The DGA analysis provided valuable insights into the transformers’ health, detecting potential faults such as overheating, arcing, and insulation breakdown. Other analysis provided insights into the oil’s condition, detecting changes in acidity, moisture content, and viscosity. The combination of monitoring techniques allowed maintenance teams to detect potential issues early on, taking corrective actions before they caused significant downtime or safety hazards.

‘One of the transformers showed a significant increase in hydrogen and methane gases, indicating potential overheating or arcing. The maintenance team reduced the load on the transformer, allowing it to cool down, and replaced damaged components. Another transformer showed an increase in acidity and viscosity, indicating potential contamination or degradation. The maintenance team filtered and replaced the oil, restoring the transformer’s health.

‘The transformer oil condition monitoring programme proved to be a cost-effective way to maintain the health of the transformers, reducing the risk of unexpected failures and downtime. The programme allowed the mining operation to extend the life of the transformers, avoiding the need for costly component replacements.

‘The programme also provided valuable insights into the health of the mining equipment, allowing the company to take proactive measures to maintain their condition. The mine implemented a comprehensive maintenance programme based on the data collected from the transformer oil condition monitoring programme, reducing the risk of unexpected failures and improving the overall efficiency of the mining operation.’

Says Nel, ‘In conclusion, transformer oil condition monitoring is a valuable tool in predictive maintenance of transformers used in mining projects. The technique allows maintenance teams to detect potential issues early on, taking corrective actions before they escalate into significant problems. The combination of different monitoring techniques provides a comprehensive view of the transformer’s health, allowing maintenance teams to make informed decisions about maintenance and replacement.’

WearCheck, Africa's leading condi�on monitoring company, is commi�ed to serving the mining industry with its range of sophis�cated analy�cal techniques.

Our specialist oil, coolant and fuel tes�ng programmes allow customers to reduce maintenance costs, avoid unexpected mechanical failures and ul�mately reduce unscheduled down�me.

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