In the utilities industry, many types of maintenance can be performed. In this article, we will be discussing traditional corrective maintenance, where action is taken after failure, and condition-based maintenance (CBM), where intervention is guided by diagnostic data.
Having options for utility maintenance and testing is crucial. Oil and insulating-fluid analysis sits at the center of CBM for transformers, load tap changers (LTCs), and oil-filled circuit breakers. While the laboratory cost of routine testing is visible and predictable, the cost of corrective maintenance (unplanned outages, collateral equipment damage, safety risk, and emergency labor) is often underestimated.
Below, we’ll examine the cost-benefit of regular oil analysis using established maintenance economics and real diagnostic program data, rather than assumed ROI figures.
The Difference Between Corrective Maintenance vs. Condition-Based Maintenance
Corrective maintenance is defined as action taken after a functional failure has occurred. In contrast, condition-based maintenance (CBM) uses measured indicators such as oil composition, dissolved gases, and particulate contamination to identify developing faults before failure occurs.
Benchmark studies show that heavy reliance on corrective maintenance increases overall lifecycle cost due to:
- Unplanned outages
- Emergency labor and logistics
- Secondary damage to adjacent components
- Increased safety exposure
On the other hand, predictive and condition-based maintenance strategies shift work toward planned, targeted interventions that reduce both failure probability and failure consequence.
The True Cost Equation: Why Testing Cost Alone Is Misleading
Evaluating oil analysis solely on laboratory cost overlooks how diagnostics influence expected annual cost. A simplified but defensible cost framework is:
Total expected cost =
- Cost of testing and sampling
- Cost of planned maintenance actions
- + (Probability of failure × Consequence of failure)
Oil analysis primarily affects the last term by:
- Reducing failure probability through early fault detection
- Reducing failure consequence through controlled, scheduled interventions instead of emergency response
This approach aligns with maintenance economics used in federal facilities and utility asset management planning, where predictive maintenance programs are associated with 8–12% cost savings compared to time-based preventive maintenance alone.
Why Corrective Maintenance Remains the Most Expensive Option
Corrective maintenance concentrates cost into unpredictable, high-impact events. While routine oil analysis introduces a small, recurring expense, corrective failures often trigger:
- Emergency crew mobilization
- Replacement power costs
- Environmental and safety incident response
- Regulatory and reputational consequences
Maintenance benchmarking reveals that organizations relying heavily on corrective strategies incur a higher total cost than those utilizing predictive diagnostics as part of their CBM programs.
Why Oil Analysis Is a High-Value Diagnostic Input
Oil-filled electrical equipment provides a unique advantage: the insulating fluid acts as both a dielectric medium and a continuous diagnostic sample. Changes in fluid condition reflect thermal, electrical, and mechanical stress occurring inside sealed equipment.
TJ|H2b’s diagnostic programs estimate that insulating fluids contain approximately 70% of the available diagnostic information for oil-filled assets, making routine fluid analysis one of the most information-dense condition inputs available to utilities. Dissolved gas analysis (DGA) is recognized as a primary method for detecting developing faults such as partial discharge, overheating, and arcing before catastrophic failure.
So, let’s discuss different types of equipment analysis.
Transformer Oil Analysis: Avoiding High-Consequence Failures
Transformer failures are low-frequency but high-impact events. Industry reliability surveys consistently show that internal transformer failures often result in extended outages, environmental remediation, and (in severe cases) fire or explosion.
Routine transformer oil analysis—DGA, moisture, dielectric strength, and aging byproducts—supports:
- Early identification of abnormal fault gassing
- Moisture ingress detection before dielectric strength collapse
- Prioritization of units for further inspection or load management
By identifying deteriorating conditions months or years before failure, oil analysis enables utilities to plan outages and interventions when cost and system impact are lowest.
Learn more about TJ|H2b’s proprietary Transformer Condition Assessment.
Load Tap Changers: Targeted Maintenance Instead of Blanket Overhauls
Load tap changers represent one of the highest mechanical and electrical stress points in power transformers. Historically, many utilities relied on fixed-interval overhauls, regardless of condition.
TJ|H2b’s TASA® (Tap Changer Activity Signature Analysis) changes that by providing insights for the maintenance of insulating fluid. The TASA® program also uses particle analysis to learn more about the deterioration of materials that result in particle production. This includes information about in-service processes such as fluid degradation, contact deterioration, and mechanical wear of moving parts and rust formation.
Learn more about TJ|H2b’s proprietary Tap Changer Activity Signature Analysis.
Circuit Breakers: Reducing Labor-Intensive Interventions
For circuit breakers, corrective maintenance often involves extensive labor. TJ|H2b’s BOA® (Breaker Oil Analysis) diagnostic data demonstrates the economic advantage of condition-based approaches. BOA® program results indicate that only 3–5% of units typically require maintenance in a given year, allowing utilities to avoid unnecessary invasive work on healthy equipment.
Clients using our BOA® diagnostics saw interrupter failures decline after implementing condition-based diagnostics, further proving how targeted maintenance reduces both failure rates and long-term cost exposure.
Learn more about TJ|H2b’s proprietary Breaker Oil Analysis.
Oil Analysis as a Strategic Investment, Not a Line Item
The cost-benefit of regular oil analysis cannot be measured by laboratory invoices alone. Its value lies in how it reshapes maintenance behavior—from reactive response to informed, risk-based decision-making.
TJ|H2b’s diagnostic programs for transformers, load tap changers, and oil-filled circuit breakers are designed to support healthy asset management.
By applying standardized diagnostics across asset populations, utilities can:
- Identify developing faults earlier
- Target maintenance where risk is highest
- Avoid unnecessary invasive work on healthy equipment
- Reduce the probability and consequence of high-impact failures
Don’t wait for catastrophic failures to happen. Contact us today to learn which of our diagnostic tests are best for your needs!
