Advanced Transformer Bushing Monitoring: Preventing Failures Through Real-Time Insights

Advanced Transformer Bushing Monitoring: Preventing Failures Through Real-Time Insights

This is a Qualitrol Case Study. See the original article here

Introduction

Transformer bushings are critical components that enable the safe passage of high-voltage electricity. However, they are also one of the most common points of failure in transformers, with studies indicating that bushing-related issues account for up to 20% of major transformer failures. Alarmingly, nearly 70% of transformer fires are linked to bushing failures, highlighting the need for effective monitoring solutions.

The Risks of Bushing Failure

Bushing failures can lead to catastrophic events, including transformer explosions, fires, and environmental hazards. Even if a failure does not result in total destruction, the risk to personnel and surrounding equipment is significant. Issues such as insulation degradation, moisture ingress, thermal stress, and aging components all contribute to bushing deterioration.

The Role of Online Bushing Monitoring

Traditional periodic testing of bushings often fails to detect subtle degradation until it is too late. Modern online monitoring systems address this gap by continuously tracking key parameters, such as:

• Dissipation Factor (Power Factor): Provides insights into insulation integrity and moisture levels.
• Capacitance Changes: Detects insulation breakdowns and contact deterioration.
• Partial Discharge Activity: Identifies early-stage faults before they escalate.

High-accuracy monitoring systems use stable reference signals to detect even minor changes in insulation performance, enabling predictive maintenance rather than reactive repairs.

Case Study: Real-World Application of Bushing Monitoring

A utility operating an aging transmission network identified increasing fault activity on a 132kV overhead circuit. With the installation of an online bushing monitoring system, engineers were able to pinpoint the source of irregularities. The monitoring data revealed early signs of insulation degradation, allowing for targeted intervention before a failure occurred. This proactive approach prevented costly damage and ensured system reliability.

Conclusion

As power grids face aging infrastructure challenges, real-time transformer bushing monitoring is becoming an essential tool for utilities. By detecting early signs of deterioration, advanced monitoring solutions help extend asset life, reduce unexpected failures, and enhance overall operational safety. Investing in continuous monitoring technology is a strategic step toward improving transformer reliability and preventing costly downtime.