Breaker Performance Monitoring Extends the Life of Your Assets

High voltage circuit breakers are critical to the safety and effective operation of the electrical system. A circuit breaker must react quickly when a fault occurs to isolate fault currents from the rest of the system.

While much attention is given to the monitoring of transformer conditions, circuit breakers are by far the largest contributor to the occurrence of substation events, and they work in tandem with other enterprise asset management software to deliver the results users are looking for in the field.

A circuit breaker that fails to open on command or is slow to react exposes the rest of the system to excessive fault currents, resulting in premature aging and potentially dangerous and costly failures of transformers and related equipment.

Breaker Performance Monitors Provide Reliable Data

The Breaker Performance Monitor from Dynamic Ratings provides data concerning the condition of the stored energy system, allowing the BPM to detect failures before the apparatus is called to operate – which explains why asset management stakeholders are coming to rely more and more on this vital product.

Through the application of breaker monitoring, many of the conditions which can lead to breaker failure can be identified in their incipient stages, allowing for prognostic evaluation of breaker conditions to trigger corrective maintenance before the occurrence of a system event. To achieve optimal breaker reliability, condition-based monitoring is necessary for observing each of the breaker’s subsystems.

Challenges facing equipment include:

  • Inactivity
  • Stagnant lubricants
  • Sticking mechanisms
  • Seal degradation
  • Degradation in Mechanical Systems
  • Wear and tear
  • Fatigue
  • Misalignment
  • Corrosion of Contact Surfaces
Breaker Performance Monitor on a circuit breaker

Detailed Diagnosis

BPMs monitor every aspect of a circuit breaker through the Breaker Performance Monitor’s smart capture and advanced analytics to know the asset’s health in real time.

Dynamic Ratings’ Breaker Performance Monitor is the most comprehensive breaker monitoring solution available. With the inclusion of high-speed waveform capture, the BPM combines the most effective off-line and online testing methods into a highly customized online monitoring package, resulting in a monitor capable of performing the advanced analytics required to detect operating deficiencies well in advance of circuit breaker problems.

The waveform overlay feature will graphically show performance variances of each circuit breaker operation compared to first trip baseline, making diagnosis of circuit breakers problems easy to rectify before system failures occur.

Breaker Performance Monitor Waveform Capture Example

A complete diagnosis occurs with every operation of the breaker’s mechanical and electrical systems. Smart Capture uses a waveform analysis for graphical comparisons of breaker operations, providing a detailed analysis of first trip open and close times, identification of latch and bearing performance, lubrication issues, auxiliary contact condition and fault current values.

BPMs allow users to track performance degradation of each operation compared to first commissioned operations, and they also allow users to compare the wave forms themselves, clearly and visually (rather than being outlined as numerical data).

Complete diagnosis of the breakers’ mechanical and electrical systems provides a waveform analysis for automated graphical comparison of breaker operations, providing a detailed analysis of first trip open and close times, identification of latch and bearing performance, lubrication issues, auxiliary contact condition and fault current values.

Mechanical Monitoring

While there are multiple parameters to be considered when assessing the condition of a breaker’s mechanical systems, the introduction of high-speed waveform capture of the operating coils and main contacts offers a high level of insight concerning a breaker’s real-time operating condition and the development of operational defects in several ways.

Interrupter Condition

Precise cumulative I2T calculations allow internal inspections to be scheduled on an as-needed basis, reducing both the cost and manpower associated with time-based cyclic maintenance schedules.

Cabinet Heater Monitoring and Environmental Conditions Monitoring

Current and voltage monitoring of heaters to detect failures which can often occur between maintenance cycles leads to condensation in control cabinets which causes corrosion of control wiring, short circuits, and premature aging of electrical components.

Trip Circuit Monitoring

Monitoring of trip coil integrity provides the ability to detect changes in the trip circuit resistance, indicative to the condition of the trip coil and related components.

Trip circuit or red-light monitoring is another critical function of online monitoring. Trip circuit monitoring verifies the integrity of the control wiring, fuses, 52 A switch, trip coil, and all components in the trip circuit through the detection of low current flowing through the circuit when the breaker is in the closed position.

As the integrity of the trip circuit can be compromised by conditions such as faulty fuses, worn fuse holders, shorted or open operating coils and faulty wiring, many of these conditions can often occur between inspection intervals, resulting in a failure of the breaker to operate under fault conditions.

Trip Circuit
Pressure gauge for SF6 gas

Gas Monitoring for SF6

BPMs also employ multi-parameter sensors that monitor density, temperature, and humidity in insulating gasses. Alarms alert asset owners of leakage rates, trending of time until lock out and mass gas loss.

Most modern high voltage circuit breakers and switchgear primarily utilize SF6 as an insulating medium due to its high density and dielectric strength. These properties allow for a reduction in breaker size at higher voltage applications, and the reformation of by-products produced when extinguishing an arc back into SF6 makes it highly efficient and relatively low maintenance for use in circuit breaker applications. However, the ability of SF6 breakers to effectively extinguish arcing is directly related to the pressure and temperature of the SF6 gas.

Online monitoring allows gas pressure, temperature, and dewpoint to be constantly observed, which allows the asset owner to observe leakage rates and determine the amount of time until the pressure falls below operational levels, resulting in actuation of the 63 pressure relay, which serves to activate a tripping or blocking scheme. With this knowledge, the asset owner is provided a window of time in which to schedule planned maintenance and to avoid emergency outages.

The BPM Combines Offline and Online Testing Methods

Circuit breaker mis-operation is often identified as the root cause of transformer and other equipment failure. Without an electronic monitoring system in place, utilities are forced to rely on cyclic maintenance and off-line testing to determine breaker condition.

Due to aging infrastructure, decreasing operating budgets, and a decline in craft specialists, the ability to properly maintain breaker performance through the sole use of time-based inspections is becoming increasingly less effective, reducing both the reliability and safety of the bulk electric system.

And monitoring information cannot be obtained from reactive logging devices such as microprocessor-based protective relays.

Case Study

Consider one of our top case studies, where a large renewable energy provider was seeking a way to avoid unplanned outages related to their daily circuit breaker operation, and they needed to rethink how they operate.

At one of their locations, their circuit breakers were switching daily between generator and solar power, but in the previous year, one breaker had slowed to the point that the breaker fail scheme was forced to operate, which of course caused them to experience an outage at the plant.

Breaker Monitoring for Renewable Energy Generation Plants

After performing lubrication maintenance to the breaker and bringing interrupting times back within acceptable limits, a Dynamic Ratings’ Breaker Performance Monitor was installed in May 2021 to monitor the health of the asset.

Dynamic Ratings used non-intrusive sensors to simplify the ease of installation as well as preventing introduction of new errors, with our BPM providing the end user with continuous online monitoring of breaker interrupting times for each operation.

Condition based monitoring provided full visibility to the performance of the breaker, mitigating risk until a scheduled outage in January 2022 could be reached. During this planned outage, a more thorough examination of the breaker’s mechanism could be performed beyond the simple short-term corrective action taken the previous May.

FInal Operation Before the breaker trip occured

The Challenge

As indicated in the waveform capture comparisons of the initial operations after the initial installation in May, the breaker was operating in a consistent manner and was within nameplate-rated interrupting time parameters.

Due to the responsibility of this breaker to switch between steam generation and solar power, and because the Breaker Performance Monitor provides trip coil signatures for each operation, there was a minimum of two breaker operations per day, allowing a large amount of data concerning the breaker’s mechanical condition to be gathered over a relatively short time period

The breaker continued to operate within specifications, producing perfectly matched trip coil waveform signatures until October of that year — when a deviation of around 4ms was observed in the trip coil waveform. This slowing of the breaker continued to progress with subsequent operations, until the interrupting time had doubled the rated interrupting time as illustrated in the waveforms captured in late November.

Because phase currents were dropping below thresholds during the initial part of the trip operation, causing relaying to detect a full open operation when one had not actually occurred, the monitor detected this as a restrike and provided an alarm to the asset management team.

The breaker was then removed from service for maintenance, at which time offline timing tests were performed to verify that the monitor provided accurate notification of the breaker slowing two months prior.

The monitor did not just provide information that the breaker was exceeding interrupt time, but also provided an accurate diagnosis of the lubrication issues that were causing slow operations through comparison and assessment of the waveform signatures.

Contact Mechanism overview over time for the circuit breaker


The Breaker Performance Monitor was able to detect changes in the performance of the breaker far in advance of protective relaying that was being used, which then allowed a considerable time frame for repairs to be scheduled before the breaker mis-operation reached a critical stage.

Breaker Performance Monitor on a circuit breaker. It's a sunny day.

Any unplanned outage would have resulted in a loss of revenue due to lost generation distribution. As the results of the case study prove, Dynamic Ratings’ Breaker Performance Monitor is the most comprehensive breaker monitor currently available. Our BPM allows for monitoring of:

  • Interrupting times
  • Trip Coil and System Waveform signatures
  • Non-intrusive sensors
  • SF6 maintenance & monitoring
  • Motor monitoring
  • Heater monitoring
  • Cumulative I2T values
  • Operation counts

The Breaker Performance Monitor provides the user with critical information concerning breaker conditions, making the cost of monitoring not only worthwhile, but necessary.

If you’d like to know more, our experts can help you choose the perfect asset management products for your needs, so contact us today.