- Aging gracefully... or not
- Maintenance can extend life
- The results of maintenance mistakes
- Update wisely to create safer, more efficient systems
- More intelligent maintenance
- Straighten the sags, kill the spikes
At the end of 2010, OSHA charged an employer with “willful and serious” electrical safety violations at 30 of its facilities across the US. The employer had exposed workers to the potentially fatal hazards of shock, electrocution and arc flash.2
Do I have your attention? Your plant’s electrical systems is a little like your body’s cardiovascular system. It’s often forgotten until something goes wrong, and then, it’s catastrophic. But with sensible maintenance and planning for growth and expansion, you can ensure your electrical system and its components will go about their work behind the scenes, keeping your plant humming along without downtime or more serious consequences. And today, just like we monitor our cardio functions while we exercise, a bevy of new, smart and networked equipment can let you know when and where a problem exists in your plant’s electrical system.
The electrical system often is taken for granted until it’s time to upgrade or replace a major component. “For the most part, I think it falls under ‘out of sight, out of mind,’” says Jake Ten Haken, director of integrated services, Interstates Companies, a member of the Control System Integrators Association (CSIA). “Most of these [systems’] electric rooms don’t have people going into them. The rooms are relatively clean, and the equipment is working. But because of the age of the equipment, the owners run into reliability problems and issues with finding replacement parts. At 20 years, you’re starting to get to the end of the useful life of most equipment.”
“We’re finding many facilities with electrical systems that are 30 to 40 years old,” adds Jaron Vande Hoef, Interstates senior project manager/principal. “A lot of these facilities are still operating on their original electrical systems. The equipment has been maintained but never upgraded or improved.”
The issue of locating replacement parts is a real stumbling block, if not a downtime creator. “It affects the processor’s reliability because, as things start to fail, [processors] no longer have the parts on hand to make a quick replacement. Also, aged equipment is generally less safe than equipment that has been designed according to more modern standards and codes,” adds Vande Hoef.
Vande Hoef points out another problem for processors, depending on their facility’s location and municipal electrical codes. Older facilities designed and built under older generations of electrical codes are typically grandfathered in. So, while they technically meet newer code standards, the entire room/system must meet all the new codes or be out of compliance as soon as new equipment is added to the mix.
“Many installations do not meet the most recent electrical codes,” says Mark Redmond, Food Plant Engineering president. “This doesn’t necessarily mean they were not installed according to the electrical codes at the time, but more than likely, these systems have not been modified to meet the new codes.”
Redmond sees processors adding seemingly insignificant loads to the electrical system over the years, gradually pushing it beyond its limits. “By the time the plants get to be 20 or 30 years old, it becomes apparent the original design of the electrical system was not meant to support the amount of expansion the industry has demanded.” This is when processors need to decide whether to overhaul their existing electrical services or relocate to accommodate their expansion needs, according to Redmond.
“We inspect the existing systems for any undue wear and tear or lack of maintenance,” says Bob Haffeman, Haskell director—group lead electrical engineer. “When we see issues, we note needed repairs. Then, we audit the facility’s electrical consumption by analyzing power bills. This helps us determine what load factor to consider for the power consumption and how much spare capacity might be in an electrical utility feed for a new process.”
Neglect is usually the cause for a big surprise when old systems can no longer support a plant’s evolving needs. “Often, the electrical system upgrade is driven by the need to install additional process equipment with microprocessor control,” says Larry Ray, Schneider Electric director, consulting services. “That’s when many facilities discover the limitations of their neglected power systems such as outdated designs. Other issues may be age related such as loose connections and a lack of or deteriorated bonding conductors.”
“Generally, equipment 20 or more years old can be upgraded, and there are many ways to do this,” says John Weihing, global operations leader, GE Industrial Solutions. Unless major system limitations exist, additional process/packing lines can be added by augmenting existing equipment instead of replacing entire systems. Additionally, older equipment can be upgraded to meet new code requirements, improve data gathering/reporting and reduce risks such as arc flash hazard levels.
“New lines typically require an upgraded distribution system or components,” says Brian Barr, ABB/Thomas & Betts/low voltage market development manager, food and beverage. “However, it is on a case-by-case basis; not all lines require upgrades. Any food or beverage processing facility that implements a preventive maintenance [PM] program has well-maintained equipment.”
“One of the biggest maintenance mistakes we see is a lack of maintenance itself,” says Mohamed Shishani, Schneider Electric/Partner Projects go-to-market and launch manager. “Electrical equipment gets installed and is forgotten.” But regular maintenance is essential for the upkeep and longevity of any system. While in maintenance mode, engineers and technicians need to follow specific guidelines and procedures. For example, torque settings can cause financial and human injuries. “Lockout/tagout [LOTO] is fundamental to any maintenance procedure,” adds Shishani.
Ultimately, maintenance is a management issue. “[In one plant], due to the lack of an experienced maintenance staff, the aged electrical switchgear/motor control centers were not properly maintained or updated,” recalls Ken Viradia, Siemens Energy low-voltage system marketing manager. “Vintage breakers, fuses and switches were supplying power to the electrical systems.” Another problem at a number of existing plants is the lack of documentation or accurate drawings that reflect updated protective device sizes and settings. Plant electricians tend to fix short-term problems without considering the codes of compliance or updating plant documentation, concludes Viradia.
Well-maintained electrical equipment can last more than 20 years, provided it’s not overloaded, according to Jud Walker, Stellar senior electrical engineer, food and beverage design. But location within the plant also has a lot to do with the equipment’s longevity. “Locating electrical equipment either in production spaces or adjacent areas with little protection typically results in failure at one point or another. This primarily applies to wet-type process areas with heavy washdown requirements.”
On the other hand, locating electrical equipment in dusty/dirty areas without routine maintenance and cleaning is a sure way to shut down a line or plant. “For example, at a certain facility, a main piece of switchgear was located in a room with mechanical ventilation near product silos, eventually accumulating enough dust buildup inside to cause a large circuit breaker to fail,” remembers Walker. “This shut down part of the production for more than 24 hours.”
The possibility of a dust explosion is another reason why locating electrical equipment in a dusty area is a dangerous practice. The combination of dust in the air and an errant spark is a recipe for a catastrophic explosion, capable of destroying the plant and killing people.
According to Haskell’s Haffeman, “If dust, water, steam or chemicals are in the environment, it is best to have properly rated components—or locate the components in another room with a more stable atmosphere.”
While a proper PM program can extend the life of an electrical system and its components, small oversights can cause damage and equipment costs. Thomas & Betts’ Barr lists a few examples of these oversights:
- Missing conduit body covers
- Missing while-in-use covers
- Temporary fixes that turn into permanent fixes
- Components being used in the wrong environmental-rated area
- Mating two dissimilar metals, causing corrosion due to galvanic differences.
Poor maintenance in general increases the likelihood of unplanned downtime and the risk of a catastrophic failure due to an arc flash incident, explains GE’s Weihing. Plus, in extreme situations, protective devices may not work. For example, if breakers can’t operate as designed, a short circuit can occur, resulting in infrastructure damage and extended downtime. Lacking or not following LOTO procedures, switching circuits inside arc flash hazard areas and performing work on or near energized circuits can create extreme danger for personnel and equipment.
Common maintenance mistakes include bypassing overcurrent protection and/or having inadequate overcurrent protection when updating a motor control center (MCC) bucket (the metal structure that contains components such as a circuit breaker, motor starter, etc.), states Siemens’ Viradia. These factors, compounded with inadequate surrounding environments (such as dust and/or humidity), have resulted in outages and a loss of production.
Consequently, Vande Hoef instructs processors to look carefully at component ratings. For example, if a circuit breaker needs to trip due to a ground fault or a short circuit, it could seriously malfunction if it is not designed to handle the amount of fault current that could flow through the system. “We see this all the time in older facilities that were originally designed with smaller transformers,” he says. Over time, processors add capacity and increase transformer sizes to allow more fault current to flow, but suddenly, the equipment is not rated for it anymore. “It’s not something that affects operations, but it leads to dangerous situations just waiting to happen.”
“When processors know they have to increase the capacity of their electrical system,” says Interstates’ Ten Haken, “they’ll frequently go to the front end of their electrical systems and put in a new transformer along with one or two pieces of new equipment. But this gives them much more capacity than their existing equipment can handle.” Ten Haken likens it to the person who puts an oversized engine into a pickup truck without pairing it with a new transmission designed to handle the extra power transfer.
“When we survey existing facilities, we often find prior expansions did not include a properly permitted and designed electrical system,” says Food Plant Engineering’s Redmond. “This is a major safety concern and introduces the risk of potentially damaging expensive equipment. When dealing with any kind of electrical work, it’s extremely important that the facility consult with licensed engineers, code officials and equipment manufacturers,” adds Redmond.
Intelligent devices, when used as part of an overall control and application system, can add levels of protection from electrical incidents such as arc flash, according to John Kay, Rockwell Automation senior product specialist for medium voltage technologies. “In some cases, a simple reconfiguration of the system design can lower the amount of arc energy at given points within a power distribution system,” says Kay.
Several technologies are now available to aid in the reduction of electrical incidents. However, each system and technology needs to be reviewed for fit within a site’s existing control and protection strategy. “Most of these newer systems can be provided with networking capabilities to facilitate continuous online monitoring and programmable, reactive trigger points. Users can be notified of any changes of steady state or imminent failure detection, permitting more logical and controlled process shutdowns,” explains Kay.
The makeup of the basic parts of an electrical distribution system hasn’t changed much in the last 30 to 40 years. “However, all manufacturers now offer larger circuit breakers with electronic tripping and metering systems,” says Stellar’s Walker. “For example, today’s switchboards can be specified with all circuit breakers, which have electronic metering to include the main and distribution breakers. With proper design, such as segregating loads into lighting, process, HVAC, refrigeration, etc., owners can review different building loads at any time and determine where the largest energy users are.”
GE’s Weihing suggests some specific changes to equipment to minimize the dangerous effects of arc flash. Protective relays on medium-voltage systems should be upgraded from electromechanical- to microprocessor-based systems. Fuse protection on step-down transformers should be changed to breakers for faster action. Older low-voltage breakers can be retrofitted with new trip units (e.g., GE’s EntelliGuard) that provide zone-select interlocking and reduced energy let-through (RELT) features to protect personnel, improve breaker coordination and maintain high levels of system reliability. Finally, Weihing suggests installing equipment, such as GE’s Arc Vault product, to shunt arc flash incidents.
One major improvement brought about by smart systems is a shift from preventive to predictive maintenance. “Today’s intelligent power monitoring and controls systems can support migration from time-based to condition-based maintenance, where maintenance cycles can be based on actual circuit conditions instead of specific time intervals,” says Schneider’s Ray.
“A smarter intelligent system provides control, configuration and monitoring locally away from the energized equipment,” says Siemens’ Viradia. Additionally, a local HMI-based system reduces search and repair time when a breaker is tripped on a fault; the operator can assess the situation and implement remedial steps faster, improving the system’s reliability. Smarter HMI-based local monitoring also keeps operators away from arc flash hazards.
“The most important advancements made in electrical distribution are in the ubiquitous circuit breaker,” says Schneider’s Shishani. “Although some people initially thought of it as ‘dumb,’ Schneider’s Powerpact device with micrologic has redefined the circuit breaker. Embedded intelligence in circuit breakers allows processors to know exactly what is going on at the branch level.”
This new technology allows for remote communications and operations—and, most importantly, preventive maintenance. With it, users know exactly when to change a breaker via the contact wear indication; pre-alarming provides insight on the health of the electrical circuits; and energy consumption can be metered through the breaker for precise usage and optimization, says Shishani.
Many manufacturers are also coming out with overcurrent devices with a normal operating mode and a maintenance mode, according to Vande Hoef. “This [having two modes in a single device] allows you to remotely toggle the mode of your circuit breaker to maintenance mode, which changes all the settings to the safest possible to minimize arc flash while the electrical equipment is being maintained. The two modes give you the best possible scenario: a well-coordinated power system and a safe power system option if you have to maintain it while it’s energized.”
Circuit breakers and other devices aren’t unique to built-in “intelligence.” “Modern MCCs use network devices to communicate the status of the system, enable control of the system devices or facilitate advanced diagnostics,” says David Lanni, GE Industrial Systems’ global sales director—industrial field services. “With some intelligent MCCs, you can remotely monitor and control your system, helping you increase productivity and personnel safety.”
“Metering, monitoring and control are popular,” says Haskell’s Haffeman. The advent of the Internet allows a client in a remote location to actively view the load readings on a plant anywhere in the world. With a proper metering configuration, a facility also can be monitored remotely by a third party, distant headquarters or the engineering part of the facility. “Also known as data logging, this allows more precise design of future electrical installations. Plus, a plant maintenance team can monitor the electrical performance or consumption over time.”
You don’t have to look very hard to find the right equipment for remote monitoring. “It is becoming much more possible to purchase equipment that has energy monitoring built right into the overcurrent devices themselves,” says Interstates’ Vande Hoef. “This allows you to do demand monitoring or management from within your electrical equipment or with an add-on software package.”
“Users may also want to review their overall process requirements,” advises Rockwell’s Kay. They can use energy and process management tools in combination with the energy feedback data from intelligent networked control and protection devices. Correlating energy use versus process efficiencies can highlight areas within the process flow where optimization may reduce process idle or bottlenecked points. The use of variable frequency drives (VFDs) or reduced voltage methods of starting also reduce the peak and overall energy demands on the system.
GE’s envisage energy management system (an electrical distribution system) provides a window to analyze and control a facility’s real-time energy usage onsite through a web browser or a mobile device. The system displays real-time power and demand data from intelligent devices and facility-wide infrastructure systems; executes energy management strategies by automating load-shedding schemes; captures disturbances on the electrical network (harmonic distortion and transients); and determines where power is consumed and generates reports.
Our increasing dependency on a consistent supply of quality, reliable energy has never been higher, says Rockwell’s Kay, and most newer equipment designs are more fault tolerant in regard to power quality. But in some cases, additional support equipment, such as industrial uninterruptible power supplies (UPSs) that can be retrofitted to existing control products, may be required.
When a system-wide approach is necessary, a voltage sag protection system may need to be employed to protect against voltage sags and momentary outages that can account for a significant amount of manufacturing downtime and damaged equipment. Many of these systems do not require batteries, have no moving parts and require minimal maintenance. They are ideal for manufacturing processes and sensitive electronics that require sag ride-through protection for several seconds.
Many types of modern food processing equipment come equipped with VFDs that have ride-through capability, as long as the drives are programmed correctly and set with the right parameters. With this capability, a VFD can keep operating and pick the load back up once the voltage returns to its regular level, even during a small voltage dip. Unfortunately, many facilities don’t take advantage of this feature, although it’s built into their systems, says Vande Hoef.
Voltage spikes, or transients, also can wreak havoc with equipment. “It is important to design your power system with built-in transient voltage surge suppression to handle surges and arrest them at the source [where your utility comes into your building], versus letting them get downstream into your system where they can fry some of your electronics,” suggests Vande Hoef. “Additionally, you can install a UPS to help the critical parts of your system ride through a voltage sag or dip.”
Power monitoring and control systems can support sags, transients and uneven power quality problems in a single device applied on key circuits and networked to computer workstations—or even to a smartphone, says Schneider’s Ray. “Devices like the PowerLogic PM8000 series, for example, enable a facility manager to improve power quality and reliability; reduce demand, energy and power factor costs; and support a variety of productivity enhancements.”
“Modern switchgear or software packages can help you watch your electrical demand or send alarms to your controllers or operators about meeting peak demands,” adds Vande Hoef. “You can turn things off manually, or you can even program your system to shut down things automatically to keep peak demand in check.”
In addition, isolating specific electrical loads with redundant power resources reduces the impact of power outages, brownouts or power quality issues that cause process interruptions, says GE’s Weihing. “GE’s paralleling switchgear, automatic transfer switches, UPS and related monitoring and control packages offer customers the capability to meet their specific needs. GE’s Digital Energy business also offers power quality products such as power factor correction capacitors, static VAR compensators, etc.”
With so many electrical switching components and safety devices now available with smart monitoring systems and quick-acting electronics, your plant’s electrical system can protect people, save lives and reduce operating expenses by controlling when and where power is supplied and to what plant systems.
For more information:
Jaron Vande Hoef, Interstates Companies, 712-722-1664, firstname.lastname@example.org
John Kay, Rockwell Automation, 440-646-3434, www.rockwell.com
- “Fires in U.S. Industrial and Manufacturing Facilities,” Ben Evarts, National Fire Protection Association, Fire Analysis and Research Division, April 2012.
- “The Costs and Risks Associated with Improper Service and Maintenance of Electrical Systems,” Siemens Industry Inc., Building Technologies Division, June 2012.