Is Your Old MV Power Breaker Technology Still Cost Effective and Functionally Sound?
Eaton provides the widest range of solutions for Medium Voltage Circuit Breaker problems of any MV Circuit Breaker manufacturer in the world. These solutions range from being a supplier of new factory parts and accessories for breaker maintenance all the way to being a supplier of MV replacement switchgear, and all points in between. There are so many solutions, and some that seem to compete with each other, that choosing the right solution for MV Breaker problems is sometimes a problem in itself. Finding the right solution is easy provided the right questions are asked.
All of the MV solutions can be placed in two broad categories – maintenance solutions (maintenance of older, pre-existing technologies) vs. upgrade solutions (upgrades to the latest technologies).
Maintenance solutions include renewal parts and accessories for normal maintenance, Class 1 reconditioning, and loaner breakers. These solutions are aimed at keeping the older technology breakers (usually magnetic air breakers) in good working order over an extended period of time. And as the description implies, the breakers will be maintained, but they will never exceed the original specifications.
Upgrade solutions include Vacuum Replacement Breakers (VR Series), Breaker and Starter Cell Retrofills (CR Series), Panel Upgrades and Fluidized Bus Insulation. These solutions share the common thread of replacing the older technology elements with the latest in technology offerings. The latest technology permits significant improvements to be realized in longer service intervals, reductions in maintenance labor and even increases in interruption capability.
Is the old technology breaker still good enough?
That depends on the answers to the following questions. (As you are going through these question.
- Are replacement parts available for the breaker from the original manufacturer?
The issue here is the suitability of the replacement part to do its job. If the part came from a used equipment dealer, you don’t know much about the part – it may be worn, it may be reverse engineered with questionable tolerances, it may be no better than the part it is replacing. If the part came from the original breaker manufacturer, you can be confident that the part is properly made and right for your breaker.
- Are these parts cost effective?
While many parts may seem expensive, they are much less expensive than replacing the breaker. Other parts, such as replacement arc chutes, are so expensive that they can tip the scales toward replacing the breaker.
- Is the breaker experiencing excessive operations?
The classic case of a breaker experiencing excessive operations is where the breaker is used as a motor starter. Breakers can experience hundreds or even thousands of operations per year, simply wearing them out at an accelerated pace. Breakers were designed to be circuit protectors, not load switchers.
- Does the breaker reliably perform as expected?
Some circuit breakers have a history of troublesome operation. If the breaker is not a reliable performer even when properly maintained, it should be considered for replacement.
- Does the breaker represent an environmental or health hazard?
Older technology breakers used asbestos in the arc chutes. Even older oil breakers used PCP laden oil. If your breaker poses a potential health risk or environmental impact, it should be considered for replacement.
- Are the recommended maintenance intervals being followed?
There is a tendency to stretch the maintenance interval well beyond the manufacturer’s recommendations. This is dangerous. Some studies have shown that if a circuit breaker is left closed for a period of five to seven years, it may not open if called to do so.
- Does the breaker short circuit rating meet or exceed the system capability?
The switchgear lineup was no doubt properly applied within its ratings when it was first installed. If the system has grown, and in particular if the incoming transformer has been changed, a new short circuit study must be performed. If the new system capability is now greater than the circuit breaker’s ratings, the circuit breaker must be replaced. (The switchgear lineup must also be evaluated, particularly for short circuit rating).
If the answers to the above all say that the circuit breaker does not need to be replaced, then the old technology breaker is still good enough, and Maintenance Solutions are recommended:
- Maintain the breaker at 1 to 2-year intervals using original OEM parts.
- Perform Class 1 reconditioning every 5 to 8 years.
Eaton can provide loaner breakers to maintain system up time while the maintenance or reconditioning is being performed.
If any answer to the above questions indicate that the circuit breaker should be replaced, then the old technology breaker is no longer good enough, and Upgrade Solutions are recommended.
- Vacuum Replacement Breaker
- Cell Retrofill (Old Tech Breaker to Vacuum Breaker)
- Cell Retrofill (Old Tech Breaker to Vacuum Starter)
What questions can you ask to choose the right upgrade solution?
- Is an extended outage acceptable?
If the answer is “No”, this is a clear indication that a Vacuum Replacement Breaker is the appropriate solution, since it is the only solution that does not require an extended outage.
- If an outage is acceptable, the last question is:
Does the breaker experience excessive operations?
If “Yes”, then a Cell Retrofill (Old Tech Breaker to Vacuum Starter) is the preferred solution.
If “No”, then a Cell Retrofill (Old Tech Breaker to Vacuum Breaker) is likely the preferred solution.
It is worth noting that the Vacuum Replacement Breaker may still be preferred even if an outage is acceptable. The VR series provides interchangeability with the old technology breaker, whereas the Breaker CR series provides interchangeability with VCP-W breakers. Panel Upgrades and Fluidized Bus are new technology solutions that are not upgrades to the breakers per se, but upgrades to the switchgear. Panel Upgrades provide new technology tripping and metering systems in the switchgear. Fluidized Bus provides the latest in applied insulation technology to the bus system in the switchgear. These solutions can be selected independently of the breaker solutions outlined above.
