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.
Failure Modes of High Voltage Circuit Breakers
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
72% of circuit breaker failures involves the mechanism
56
56% of failures are due to aging
75
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
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.