The benefits of preventative circuit breaker maintenance

It goes without saying that there’s simply no room for downtime when it comes to the running of critical infrastructure systems. After all, it’s the likes of emergency services, transport services and energy plants that are impacted if a failure occurs. Disruption in terms of the availability, integrity or delivery of essential services could have significant economic or social impacts here.

To ensure smooth operation, facilities need rock-solid physical infrastructure to back up their assets in the event of cable overloads, short circuits and insulation faults. Even the smallest electrical fault or failure can have disastrous consequences, including expensive and extensive operations downtime, damage to critical equipment in the event of a power outage, as well as the resource drain of locating and repairing malfunctioning equipment. 

When it comes to switchgear, in particular, there is the challenge around spending when it comes to maintenance and services. There is no doubt that regularly scheduled maintenance extends the life of existing switchgear. However, at some point facilities must decide whether to maintain or replace with new equipment.

Keeping up with equipment maintenance can sometimes be a challenge, especially with limited resources. But, of course, the safety and reliability of a facility depends on it and must be the priority. 

With most facility teams looking for ways to optimise the performance of their infrastructure, there’s growing interest in alternative maintenance strategies. Fortunately, advances are being made in terms of the intelligence of circuit breakers. This is enabling a more condition-based approach, based on real operational and environmental inputs. The actual health of each breaker can now be predicted, as it relates to ageing and other risks.

Based on this information, facility or contracted maintenance teams can tailor their maintenance schedules to perform servicing on each breaker when it’s needed. Risks can also be revealed that point to breakers needing more urgent attention, including replacement. It all adds up to improved safety and less downtime. But it can also mean getting longer life out of equipment while spending less time on maintenance.

What conditions cause a circuit breaker to age?

It’s important to take into the account the two different sets of conditions that cause a circuit breaker to age and require maintenance:

• Operational conditions. Mechanical wear is determined mainly by the number of times a breaker opens or closes, as well the number of times its protection mechanism trips due to an overload or short circuit. But to truly gauge the wear on a breaker’s contacts – and, therefore, service life – you also need to take into account the amount of current flowing during each of these actions. More current leads to more wear.
• Environmental conditions. Harsh environments can accelerate ageing. High ambient temperatures, high power harmonics, and high load levels all contribute to higher overall operating temperatures. There could also be corrosive elements present, such as high humidity, salt, gases, or airborne oil particles. Finally, dust and mechanical vibration each add to the stresses on a circuit breaker.

Maintenance strategy options

To fully optimise the service life and performance of a circuit breaker, a maintenance program should take into account all of these operational and environmental influences on the ageing process. But what kind of maintenance strategy is best?

• Reactive maintenance. Adopting a reactive approach to maintenance allows circuit breakers to fail before they are taken out of service and replaced. This might be a reasonable approach in situations where productivity or safety are not affected, as it can enable low maintenance time and costs. But those savings can be lost due to shorter equipment life and therefore more frequent replacement, as well as the potential damage to secondary equipment.
• Preventative maintenance. This is the most typical approach in most facilities. Periodic checks are done to reduce the probability of breaker failures and extend their life span. Specific maintenance intervals are recommended by the manufacturer, or by electrical or safety organisations. These take into account general operating and environmental conditions. The approach helps minimise failures and, in turn, maintenance and equipment costs. However, it’s more labour-intensive than the reactive approach and can sometimes result in unnecessary servicing. On the other hand, maintenance might not be done often enough if conditions affecting ageing aren’t estimated accurately, or if they change over time.
• Predictive maintenance. By acquiring a continuous stream of operational data from circuit breakers and environmental data from other facility systems, service teams can quantify real-time conditions affecting each breaker’s performance. This strategy has a number of benefits over the preventative method. Maintenance can be done only when it’s required, avoiding unnecessary shutdowns. Imminent failures can also be anticipated, avoiding downtime. 

Future ready

Clearly, preventative, condition-based maintenance can deliver greater facility uptime and savings. Fortunately, the supporting tools required for this approach are now becoming available, in the form of smart breakers such as Schneider Electric’s Masterpact MTZ. These circuit breakers provide outstanding power uptime for low voltage electrical distribution networks and are designed to support critical power installations. 

With the Masterpact MTZ, achieving safe and efficient day-to-day facility management is easier through connectivity to smartphones. The smart app reduces the safety risk for local maintenance as no direct contact is required for quick analysis and action through a secure Bluetooth connection. Quick view, self-diagnosis of protection setting and modification, energy consumption, power quality, phase balance, and health status are all available in real time. 

Advances in technology such as the Masterpact MTZ are allowing facility managers to do more with less.  Connected, intelligent controls and equipment can now deliver greater insight into the performance of buildings and provide a significant, measurable return on investment.
 

This article is written by Gary Buckingham, product and segment marketing manager, partner projects at Schneider Electric