Nothing operates without electricity, so the health of the electrical infrastructure that works behind the scenes should be a vital concern to your plant. Like any engineered system, electrical power distribution systems cannot be designed and constructed to operate 100% of the time indeﬁnitely. To help ensure electrical reliability, facility management should:
- make room in the op-ex budget for planned maintenance activities, and
- put a strategy in place to optimize the budget and reduce unplanned downtime.
A properly planned and executed electrical maintenance strategy is a vital component in supporting electrical workplace safety, business continuity, and optimized total cost of ownership. Plant managers should schedule proactively and employ a variety of approaches to maintain electrical distribution equipment. Even though reactive maintenance activities typically cost three to four times more, planned maintenance activities often are deferred because of high productivity objectives and tight maintenance budgets. NFPA 70B-2016 Annex Q-2 provides an example of costly reactive maintenance:
An industrial plant experienced damage totaling $100,000 (USD), not counting the cost of downtime. It was discovered that dirt, gummy deposits and iron filings in the main switchgear caused the failure. The cost of this event would have supported a compre¬hensive electrical preventive maintenance program covering all of the plant's electrical distribution system for several years.
The best way to avoid such a major financial loss is to reduce the risk of an unplanned outage. This requires time, effort, planning, and money. A comprehensive maintenance strategy should incorporate all electrical power distribution equipment, regardless of the manufacturer, to ensure that electrical equipment and components operate safely and reliably as they were originally designed and intended.
It is important to keep in mind that any individual maintenance on separate pieces of equipment or components does not ensure a completely coordinated and reliable power system. In a basic, everyday example, you probably have your vehicle’s tires rotated and balanced on a routine basis and purchase new tires when it’s time to do so. Does that ensure that your vehicle is reliable? A holistic view is required when electrical reliability is the goal.
Preventive maintenance is the traditional time-based maintenance strategy, typically built around a manufacturer’s recommended guidelines. For electrical distribution equipment, the industry-accepted OEM frequency is once every three years. If equipment is installed in harsh or extreme operating environments, the maintenance schedule is most likely more frequent.
Fast-forward to today’s increasingly complex, automated, and connected systems. Developing the proper maintenance strategy can be a quite an undertaking, given the different types and manufacturers of equipment within a facility.
When budgets are tight and processes are critical, a reliability-centered maintenance (RCM) strategy may be a viable consideration. RCM focuses on the operation of the power system as a whole by identifying the functions and failure modes of the most critical assets. Maintenance tasks are then determined and prioritized to minimize the possibility of failures. RCM lets facility management make quantifiable decisions on maintenance costs while increasing power system reliability.
RCM integrates preventive maintenance, predictive testing and inspection, run-to-fail, and proactive maintenance techniques. Companies looking to implement RCM should refer to the SAE standard JA1011, Evaluation Criteria for Reliability-Centered Maintenance (RCM) Processes for guidance.
Whether the selected maintenance strategy is preventive, predictive, condition-based, or reliability-centered, proper planning and adequate resources are crucial. Most planned maintenance activities are conducted during a scheduled shutdown to minimize the impact on business operations. Following are key preparedness steps to take to help ensure a smooth, productive shutdown.
Ensure that electric maintenance personnel are qualified, as defined by OSHA/NFPA 70E. Facility personnel are rarely knowledgeable or effectively trained in the speciﬁc electrical equipment or power distribution systems that make up the electrical infrastructure of their respective facilities. Therefore, routine electrical equipment maintenance often is outsourced to outside maintenance contractors or local electrical contractors. Service personnel should be experienced in the specific electrical equipment or power system to be maintained.
Have updated one-line diagrams available. This type of diagram provides clear and precise information concerning the exact interconnections of all pieces of electrical equipment that make up the entire power distribution system. If a current diagram does not exist, a professional electrical engineer should be contracted and commissioned to create and maintain current electrical one-line diagrams and equipment name-plate data, including the location of each piece of electrical equipment.
Obtain OEM operations and maintenance manuals. If this documentation has been discarded, misplaced or lost, contact the manufacturer (or manufacturer’s rep) and request replacement copies. An internet search for these documents may yield positive results, as well.
Verify that equipment to be maintained is properly rated, set, and labeled. Before any maintenance program is initiated or contracted, it's strongly recommended that a licensed professional electrical engineer perform a short circuit analysis, a time/current coordination study, and an arc ﬂash analysis of the power distribution system. The electrical engineer can also identify safety concerns, power system deﬁciencies, and/or circuit protection issues that might need to be addressed before any maintenance is performed.
Arrange for power during shutdown. Temporary electrical power during a planned maintenance shutdown might take the form of the use of the onsite optional standby generators.
Communicate expectations with service provider. Facility management needs to be very clear as to exactly which equipment is to be cleaned, inspected, maintained, serviced, and tested, as well the speciﬁc order in which each piece of electrical equipment is to be removed from service for inspections, maintenance, or testing.
With very few exceptions, electrical equipment should not be cleaned, inspected, maintained, serviced, or tested while it is energized. Performing maintenance tasks on energized equipment exposes personnel to the risk of shock, burns, or death.
Section 4.2.1 of NFPA 70B-2016 best sums up the case for having a maintenance strategy in place: "A well-administered electrical preventive maintenance (EPM) program reduces accidents, saves lives, and minimizes costly breakdowns and unplanned shutdowns of production equipment." Impending troubles can be identified – and solutions applied – before they become major problems requiring more-expensive, time-consuming solutions.