Realizing the Benefit of Substation Automation – Extending the Frequency of Substation Inspections through Real-Time Monitoring

Introduction

Our communities rely on a dependable, secure and robust electrical grid to power our homes, businesses and essential services. Central to this network are substations—critical hubs responsible for transforming and distributing electricity from generation sites to end-users. As electric utilities continue to modernize their infrastructure, high-voltage substations have seen significant upgrades, including the integration of advanced control and monitoring technology. However, a pressing question remains: are these utilities optimizing their operations to fully leverage these enhancements?

Decades ago, large high-voltage substations operated with round-the-clock staffing. However, the advent of Supervisory Control and Data Acquisition (SCADA) systems and advanced equipment monitoring technology prompted utilities to transition to unstaffed substations with scheduled field inspections. Substation operators or electricians now conduct inspections and respond to offline equipment or triggered alarms.

With advancements in equipment reliability, high-speed system protection, and enhanced remote monitoring capabilities, the frequency of substation inspections decreased from weekly to bi-weekly and eventually to monthly, all while maintaining high reliability.

Despite these significant equipment improvements and monitoring developments over the past thirty years, many utilities still adhere to the monthly inspection schedules to inspect highly instrumented and remotely monitored substations, accruing significant costs.

For substations equipped with comprehensive monitoring systems, there's an opportunity to rethink inspection frequency. Utilities should consider adjusting their approach by switching to quarterly, semi-annual, or less frequent inspections, saving labor costs and allowing highly trained staff to complete more critical work.

The Power of Real-Time Monitoring

The implementation of real-time monitoring for critical substation equipment has transformed substation operations from periodic field inspections to continuous 24/7 asset surveillance. This shift enables immediate detection of operational anomalies, facilitating swift response.

Real-time monitoring technologies, including battery monitors, transformer dissolved gas analysis monitoring, and high-resolution infrared security cameras, offer capabilities far exceeding routine or occasional field inspections.

The evolution of data analytics and asset monitoring has provided engineers and operators with transparency into the operation of critical substation elements, as outlined below:

1. Continuous Data Collection

• Sensors Everywhere: Real-time sensors embedded within substation equipment continuously monitor critical parameters such as voltage, temperature, humidity, and load. These sensors provide a constant stream of data.
• Centralized Control: Data is transmitted to a central control system. Engineers can track equipment performance without interruption, gaining insights into the health of critical assets.

2. Early Fault Detection

• Anomaly Detection Algorithms: Algorithms process real-time data, identifying deviations from normal operating conditions. Whether it's a sudden temperature spike or an unusual voltage fluctuation, these algorithms raise red flags.
• Automated Alerts: When anomalies occur, automated alerts notify substation personnel. Early detection prevents minor issues from developing into significant reliability issues.

3. Predictive Maintenance

• Data-Driven Insights: Predictive models forecast equipment degradation by analyzing historical data and real-time trends. These models consider actual asset conditions rather than fixed inspection intervals.
• Optimized Schedules: Maintenance schedules are adjusted based on predictive insights. Downtime is minimized, reducing costs and enhancing reliability.

4. Remote Monitoring

• 24/7: Engineers can remotely access real-time data, eliminating the need for physical presence at the substation.

5. Thermal Imaging and AI

• Seeing the Unseen: Thermal cameras capture heat signatures, revealing hidden faults or abnormal temperature patterns. These anomalies could go unnoticed during manual inspections.
• AI-Powered Analysis: AI algorithms process thermal images, identifying hotspots, loose connections, and insulation issues. Substation engineers receive actionable insights for targeted maintenance.

Additional benefits of utilizing real-time equipment monitoring include the opportunity to perform time-based preventive maintenance (PM) less frequently, offering valuable data supporting root cause analysis (RCA) for equipment failure investigations and offering data that can inform more reliable equipment selections on future projects, enhancing efficiency and effectiveness in substation design and implementation.

 

Other Considerations

While substation equipment can be effectively inspected onsite or remotely, when determining the frequency of the onsite inspection cycle, additional factors require consideration:

1. Environmental (oil leaks, containment condition)
2. Vegetation (inside and outside the substation)
3. Security (lighting operational, fencing intact, signage in place)

Over the past decade, the widespread deployment of high-resolution substation cameras, driven partly by the 2013 Metcalf event, has revolutionized remote inspection capabilities. These cameras have proven ideal for remote equipment, environmental, vegetation, and security inspections. Compared to dispatching field staff to remote substations regularly, remote inspections using cameras offer a much more cost-effective solution.

One utility, in particular, recognized the potential benefits of real-time monitoring in adjusting field inspection schedules. They conducted a thorough review of monthly inspection data to make sure that reducing the frequency of field inspections would not compromise the security or reliability of operations. Over six months of monthly field inspections, engineering staff meticulously examined substation inspection records across several hundred substations spanning a large geographic area.

Remarkably, no significant issues were identified during the monthly field inspections. Therefore, the utility concluded that the continued use of monitoring technology effectively supported less frequent, costly monthly field inspections.

 

Conclusion

The reliability of our electrical grid hinges on the critical role of substations. While inspection intervals can vary based on local regulations, utility policies, and the criticality of the substation, one constant remains the same: regular inspections—whether conducted in the field or remotely—are essential for safe and reliable power delivery.

However, real-time instrumentation monitoring requires a paradigm shift. By leveraging data-driven insights, we can significantly extend inspection frequency, enhance reliability and safety, and strengthen our electrical infrastructure against previously unseen failures. Real-time monitoring is the foundation of substation reliability and resilience and provides opportunities to monitor substation facilities more efficiently while assigning field staff to the most critical reliability activities.