A Coordinated Electric System Interconnection Review—the utility’s deep-dive on technical and cost impacts of your project.

Challenge: Frequent false tripping using conventional electromechanical relays
Solution: SEL-487E integration with multi-terminal differential protection and dynamic inrush restraint
Result: 90% reduction in false trips, saving over $250,000 in downtime

Transmission and Distribution (T&D) switchgear assets across North America and globally are aging while being subjected to increasing operational stress, higher fault duties, renewable interconnections, and evolving grid operating conditions. Historically, utilities relied on time-based maintenance and periodic inspections. While simple to administer, this approach often results in either unnecessary maintenance or, worse, unexpected in-service failures.

Modern utilities are rapidly transitioning toward condition-based maintenance (CBM) and risk-informed asset management, driven by online condition monitoring, advanced analytics, and standardized digital substation architectures.

Keentel Engineering applies these industry-proven methodologies to help utilities, developers, and asset owners improve reliability, extend asset life, and optimize capital planning.

Condition monitoring is the continuous or periodic acquisition of physical measurements that reflect the health of switchgear components and functions. These measurements are converted into Condition Indicators (CIs), which are then evaluated against known degradation mechanisms to determine asset condition and risk.

Key Definitions

Condition Measurement: Measurement of a physical parameter related to asset health (e.g., current, pressure, temperature).
Condition Indicator (CI): A quantitative or qualitative indicator derived from one or more measurements.
Symptom: A CI exceeding defined thresholds, indicating degradation.
Asset Health Index (AHI): An aggregated representation of asset condition and likelihood of failure.

Unlike traditional diagnostics that focus on individual tests, condition monitoring integrates multiple data streams to provide a holistic, technology-independent view of switchgear health.

Mechanical wear and friction in operating mechanisms
Contact erosion and increased resistance
Dielectric degradation of insulating media
Gas leakage and contamination
Control and auxiliary circuit failures

Each degradation mechanism is correlated with condition indicators using ranked relationships (high, medium, low correlation). This enables:

Selection of the most effective indicators
Reduction of unnecessary sensors
Improved diagnostic confidence
Support for Failure Mode and Effects Analysis (FMEA)

Keentel Engineering uses this correlation framework to design optimized monitoring and assessment programs tailored to asset criticality and utility objectives.

Basic Monitoring

Basic monitoring relies on data typically already available in breaker control cabinets:

Coil current and voltage
Auxiliary contact timing (52a/52b)
Cabinet temperature
Operation counters

This level provides strong insight into mechanical performance with minimal installation effort.

Intermediate Monitoring

Intermediate monitoring enhances diagnostics by adding:

Gas pressure and density trending
Main current monitoring
Static contact resistance

This level significantly improves detection of electrical wear, gas leakage, and insulation degradation.

Advanced Monitoring

Advanced monitoring provides the highest diagnostic accuracy and includes:

Contact travel and dynamic resistance measurement (DRM)
Partial discharge monitoring
Vibro-acoustic analysis
Infrared thermography and X-ray imaging

These methods are typically applied to critical assets or aging populations where life-extension decisions are required.

A critical insight reinforced is that asset age alone is not a reliable indicator of health. New assets may perform poorly, while older assets may remain in excellent condition.

The Asset Health Index (AHI) framework:

Aggregates condition indicators by failure mode
Preserves time-to-action urgency
Aligns with ISO 55000 asset management principles
Supports condition-based maintenance and replacement planning

Keentel Engineering develops switchgear-specific AHI models aligned with utility risk tolerance and regulatory expectations.

1. What is condition-based maintenance for switchgear?
Condition-based maintenance uses real-time and periodic condition indicators to determine when maintenance is required, rather than relying on fixed time intervals.
2. Why is coil current analysis so important?
Coil current profiles provide early insight into mechanical friction, plunger issues, and control circuit problems with minimal instrumentation.
3. How does gas density trending improve reliability?
Trending detects leaks well before alarm thresholds are reached, allowing planned maintenance instead of emergency outages.
4. What causes unexpected switchgear failures?
Incomplete diagnostics, unmonitored degradation mechanisms, extreme environmental stress, or incorrect data interpretation can all contribute.
5. How is an Asset Health Index calculated?
AHI aggregates multiple condition indicators by failure mode and assigns urgency-based scores rather than a single age-based value.
6. Is age a reliable indicator of switchgear condition?
discourages using age as a primary health metric.
7. Which indicators best detect contact erosion?
Cumulative interrupted current, dynamic resistance measurement, and arcing time are the most effective indicators.
8. How does IEC 61850 support condition monitoring?
IEC 61850 provides standardized logical nodes and data models for seamless integration with protection and control systems.
9. Can monitoring reduce forced outages?
Yes. Early detection of degradation allows corrective action before failure occurs.
10. How many sensors are needed for effective monitoring?
Using correlation analysis, utilities can minimize sensors while still capturing the most informative condition indicators.
11. What is the difference between monitoring and diagnostics?
Monitoring collects data; diagnostics interpret that data to identify degradation and failure modes.
12. Are non-intrusive methods reliable?
Yes. Most modern condition monitoring methods are non-intrusive and proven in service.
13. When is advanced monitoring justified?
Advanced monitoring is justified for critical assets, aging fleets, or when life-extension decisions are required.
14. Can monitoring be retrofitted to existing substations?
Yes. Most monitoring systems can be retrofitted with minimal outage impact.
15. How does condition monitoring support regulatory compliance?
It provides auditable, data-driven justification for maintenance, replacement, and capital planning decisions.
16. What role does FMEA play in switchgear assessment?
FMEA links condition indicators to failure modes, improving diagnostic accuracy and prioritization.
17. Are alternative gases supported in monitoring programs?
Yes. addresses SF₆ and alternative gas mixtures.
18. How often should condition indicators be reviewed?
Review frequency depends on asset criticality, operating duty, and observed degradation trends.
19. Does condition monitoring replace inspections?
No. It complements inspections by focusing them where risk is highest.
20. How can Keentel Engineering help my utility?
Keentel Engineering delivers standards-based, vendor-neutral lifecycle management solutions tailored to your assets and objectives.

In 1995, Sandip (Sonny) R. Patel earned his Electrical Engineering degree from the University of Illinois, specializing in Electrical Engineering . But degrees don’t build legacies—action does. For three decades, he’s been shaping the future of engineering, not just as a licensed Professional Engineer across multiple states (Florida, California, New York, West Virginia, and Minnesota), but as a doer. A builder. A leader. Not just an engineer. A Licensed Electrical Contractor in Florida with an Unlimited EC license. Not just an executive. The founder and CEO of KEENTEL LLC—where expertise meets execution. Three decades. Multiple states. Endless impact.