Circuit Breaker Monitoring | Detect Breaker Problems Before They Happen

The Role of High Voltage Circuit Breakers

What is a circuit breaker and how does it fit into the power system?

Circuit breakers are highly critical to the power protection system. They physically interrupt the power flow in order to protect critical assets such as a power transformer. Breakers protect critical assets from abnormal electrical conditions in applications ranging from residential homes to high-voltage transmission systems. In a home, a breaker is responsible for the protection of the home’s electrical system from excessive current flow. In a high voltage substation, breakers protect against fault current and also transfer loads and control cap banks and other VAR compensating equipment. They ensure steady power factor and system reliability. A household breaker requires little maintenance. However, a high voltage circuit breaker is quite complex and is made up of three systems: mechanical, electrical and insulating.

HV Circuit Breaker

Failure Modes of High Voltage Circuit Breakers

Can high voltage circuit breakers fail in a substation?

Yes! Misoperation of breakers is one of the most common root causes of failure in the substation. These failures can often be attributed to the circuit breaker’s mechanical systems remaining in a static state for long periods of time.

What can go wrong on a circuit breaker?

Long periods of inactivity plus exposure to temperature changes and contaminants can lead to degradation of the mechanism’s lubrication and control systems. While testing and maintenance of a circuit breaker’s operating system by maintenance personnel is the most common means of keeping breakers in optimal operating condition, this approach can at times lead to misdiagnosis of potential failure modes. Download this white paper to read more about failure modes…


Mechanical System

The majority of breaker failures can be attributed to a malfunction of one or more components in the mechanical system.

Electrical System

The electrical systems in circuit breakers require relays, control wiring, switches, fuses and CTs to ensure proper operation.

Insulating System

The insulating system consists of the bushings and the insulating medium of the main tank which could be SF6, mineral oil, vacuum or air.

Online Circuit Breaker Monitoring

What is online circuit breaker monitoring?

Online circuit breaker monitoring continuously evaluates the conditions of a breaker. Conditions which can lead to breaker failure are identified in their incipient stages which allows time to evaluate the breaker and take corrective action before a catastrophic event occurs.


72% of circuit breaker failures involves the mechanism


56% of failures are due to aging


75% of circuit breaker failures are due to mis-operations

What should I look for in a circuit breaker monitor?

  • High speed waveform capture analysis
  • Open arcing and interrupting time
  • SF6 values
  • Static and thermostatic state heater monitoring
  • Mechanism and ambient temperature
  • Contact wear
  • Motor monitoring (starts, current and run time)
  • Fault and operations count
  • Trip oil integrity

Introducing the Breaker Performance Monitor

Breaker Performance Monitor

Dynamic Ratings Breaker Performance Monitor is the most comprehensive circuit breaker monitoring solution available. With the inclusion of waveform capture, the BPM combines the most effective offline and online testing methods. The modular design is a highly customizable online monitoring package, resulting in a monitor capable of performing the advanced analytics required to detect operating deficiencies well in advance of breaker failure.


Additional Resources


Detecting breaker failure through waveform capture technology.


Circuit Breaker Monitoring 101 webcast about why breakers fail and what we can do to prevent it.


How circuit breaker monitoring helps detect problems before failure.