Medium voltage circuit breakers & protection
Specialist knowledge of medium-voltage circuit breakers, protection relays and the functional relationship between switching, protection and tripping.
Switching and protection belong together
A protection relay may respond correctly, but ultimately the functional trip chain must operate successfully. Conversely, a mechanically well-functioning circuit breaker does not automatically mean the protection and control are operating correctly.
A technical assessment can therefore not always stop at a single component. Depending on the installation and configuration, a deviation may lie in the:
Medium-voltage circuit breakers
Assessment tailored to your situation
Depending on your situation, this may involve vacuum (VCB), SF₆, oil or another design. Relevant assessment areas may include:
- Visual and mechanical condition
- Mechanical operation
- Opening and closing times
- Pole synchronism where relevant
- Contact resistance
- Condition of the interruption system where relevant
- Coils, controls and operating mechanism
- Functional operation
Protection and trip chain
We explicitly treat the protection relay as part of the functional chain. Focus areas include, where applicable:
- Protection relay testing
- Secondary current injection
- Checking relevant settings
- Assessing relay response
- Output contacts
- Functional trip chain
Technical history in the Asset Passport
Request medium-voltage assessment?
Provide us with as many details as possible for a targeted response.
- Manufacturer and circuit breaker type
- Protection relay type (if present)
- Nameplate data
- Photos and available schematics
- Relevant settings
- Description of fault, maintenance, or test requirement