PQ Problems Affecting Your Processes? Ask EPRI!
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PQ Problems Affecting Your Processes? Ask EPRI! Introduction When the lights blink, and processes shut down—what happened? The lights are on, but critical systems are down, and—what just happened? Whatever the case, lost time and production result. Sound familiar? The assumption may often be “power outage,” but most often the culprit is a voltage sag due to a short circuit somewhere in the distribution system—perhaps miles away on another feeder. The problem inside the facility most often is caused by control systems that are sensitive to variations in power quality. EPRI’s Facility Assessment Team specializes in on-site Power Quality evaluations—over 300 conducted since the mid-1990s and broken down as shown in Figure 1. EPRI’s team specializes in reducing process downtime due to power quality events and maximizing client production output. Facility assessments may involve a few targeted processes or the entire plant. Our team member experience in solving power quality issues is deep—going back several decades, and broad in scope—food to pharmaceuticals, potato chip to computer chip fabrication, metal casting to machining, automotive to automation. Figure 1 Over 300 On-site Assessments in these Industries While processes may differ, all share similar electronic controls affected by power quality events. While others practice power quality as “general practitioners,” EPRI’s team has been referred to as the “neurosurgeons” in the field—with power quality (PQ) expertise with the control systems within an industrial plant and utility systems outside the facility. PQ Services group is unique EPRI’s PQ Services Group is unique—with decades of experience in laboratory PQ research and development, followed by its application in the field—even commercializing its R&D into readily available, third-party PQ mitigation products—applied research indeed!
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Transcript of PQ Problems Affecting Your Processes? Ask EPRI!
PQ Problems Affecting Your Processes? Ask EPRI!
Introduction
When the lights blink, and processes shut down—what happened? The lights are on, but critical systems are down, and—what just happened? Whatever the case, lost time and production result. Sound familiar? The assumption may often be “power outage,” but most often the culprit is a voltage sag due to a short circuit somewhere in the distribution system—perhaps miles away on another feeder. The problem inside the facility most often is caused by control systems that are sensitive to variations in power quality.
EPRI’s Facility Assessment Team specializes in on-site Power Quality evaluations—over 300 conducted since the mid-1990s and broken down as shown in Figure 1. EPRI’s team specializes in reducing process downtime due to power quality events and maximizing client production output. Facility assessments may involve a few targeted processes or the entire plant. Our team member experience in solving power quality issues is deep—going back several decades, and broad in scope—food to pharmaceuticals, potato chip to computer chip fabrication, metal casting to machining, automotive to automation.
Figure 1 Over 300 On-site Assessments in these Industries
While processes may differ, all share similar electronic controls affected by power quality events. While others practice power quality as “general practitioners,” EPRI’s team has been referred to as the “neurosurgeons” in the field—with power quality (PQ) expertise with the control systems within an industrial plant and utility systems outside the facility.
PQ Services group is unique
EPRI’s PQ Services Group is unique—with decades of experience in laboratory PQ research and development, followed by its application in the field—even commercializing its R&D into readily available, third-party PQ mitigation products—applied research indeed!
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EPRI’s experience provides unparalleled expertise in identifying the sources of process sensitivity (see Figure 2) and recommending solutions—from the utility, plant, panel, and machine to the individual control components. With our expertise in equipment and component assemblies, we enable our clients to consider options for lower-cost, targeted solutions at the control level.
Figure 2 Example Control Circuit Sensitive components include AC “ice cube” relays, PLCs and I/O, and others.
Facility Assessments for Power Quality
Every year, problems with electrical equipment cost industrial companies up to $20 billion in scrap material, down time, damaged data, and delayed orders due to shut-down events attributable to power quality. Computers in commercial offices may crash, industrial equipment may shut down, and entire processes may grind to a halt. Moreover, equipment in one facility may cause other equipment in the same facility or in a neighboring facility to malfunction, even when the quality of delivered power is perfect. EPRI follows a step-by-step approach to assist the customer in its efforts to improve the power quality and response of the manufacturing processes to PQ events.
The on-site work schedule, as illustrated in Figure 3, typically includes:
• Meeting with plant engineers and operators to discuss the specific shutdown issues that occur. • Observing control cabinet contents of identified processes after having plant personnel open
cabinet doors and take any requested voltage and current measurements for the equipment to be examined.
• Reviewing equipment electrical and control drawings and operational requirements. • Digital photography of internals of control cabinets and completion of PQ Assessment sheets. • Examination of facility’s power quality data (illustrated in Figure 4).
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Figure 3 EPRI has broad experience with PQ investigations in many industries
Figure 4 Example PQ Data Each diamond represents a voltage sag of some duration (in seconds) and at some voltage magnitude (in percent of nominal). Equipment sensitive to a 50% of nominal voltage sag, for example, will shut down for sags below 50% as well
While conducting this PQ Assessment, EPRI will look for the most economical and feasible ways to implement power quality improvements at the plant. Typical solutions can range from:
• Implementing small control-level solutions at each cabinet in a line that has vulnerable equipment
• Replacing a small component with a more robust one • Adjusting the settings on an AC motor drive • Implementing DC bus ride-through schemes for select AC motor drive systems
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• Implementing a single power conditioner for the vulnerable controls/machines associated for each line or implementing an area-wide power conditioner for vulnerable controls/machines associated for each manufacturing area.
Each option has associated tradeoffs and the best solutions in the plant may include a mixture of these options. For instance, replacing a small vulnerable component such as a relay or adjusting settings on a drive can be extremely quick and cost effective. However, other items in the control cabinet may still be vulnerable to some degree.
The assessment will evaluate the power quality characteristics of the supply along with the sensitivity characteristics of the facility loads (as illustrated in Figure 5) and identify a range of possible solutions that could be implemented to mitigate the effects of PQ events and improve the performance of electrical equipment to those events (as illustrated in Figure 6). These possible solutions can range from modifications and protection for individual devices in the process to changes in the supply system that would improve the quality of supply. The economics of these solution alternatives will then be evaluated to identify the best alternatives for the site (considering costs at all levels) and appropriate recommendations will be developed.
Figure 5 Various Control Components have their own Sensitivities Using the same PQ data shown earlier, the equipment sensitivities may be understood as being robust for the region between 100% of nominal voltage and the colored lines. Below and to the right these lines, the equipment identified above shuts down.
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Figure 6 Example Mitigation Solutions and Capabilities Mitigation devices support the mitigated equipment for voltage sags occurring above the colored lines indicating the mitigation capabilities of these identified technologies.
Facility Assessment Options
EPRI’s team has several facility assessment options that our clients may choose:
In-Plant “Boots on the Ground” PQ Assessment – one to two EPRI team members will travel to the facility to conduct a comprehensive assessment of the site. The EPRI engineers meet with the designated facility personnel, and walk down the specified equipment examining control cabinets, equipment drawings, etc. Enabled by the experience of over 300 similar projects and EPRI’s web-based expert tool called the Power Quality Investigator (PQI), EPRI engineers identify the susceptibility of the plant equipment to power quality issues, determine specific effective mitigation options, and provide economic solution metrics such as net annual return, IRR, NPV, and simple payback.
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Figure 7 EPRI Engineers Examining Industrial Control Panels for “Weak Links” (left), Using the PQ Investigator Tool (right)
Remotely Guided PQ Assessments – with functioning wireless video and audio communication signals and equipment—along with the PQI, EPRI personnel can guide designated facility personnel through the assessment process remotely—directing the facility personnel to collect the required electrical measurements and control panel images.
Figure 8 EPRI Offers Remotely Guided PQ Assessments using Computerized Integrated Audio-Visual Headsets (Photo Courtesy of Realwear®)
Power Quality and Energy Efficiency Assessment
When requested, EPRI’s Industrial Team can combine the goals of improving power quality performance and energy efficiency when conducting an assessment. Energy efficiency assessments may include traditional areas of energy efficiency Assessment areas (insulation, waste heat—see Figure 9, drive
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applications, motors, lighting, air leaks, and heat recovery). In addition, EPRI can provide initial energy-management system (EMS) activities for determining significant energy uses, determining or verifying a plant’s key performance indicators (KPIs) and energy performance indicators (EnPIs), and creating a plant baseline model that considers energy use, production, and relevant variables per ISO 50001 and the Superior Energy Performance Certification requirements.
Figure 9 EPRI’s Team Can Combine Energy Efficiency and Power Quality Assessments for a Comprehensive Analysis
Design Consulting
Known power quality sensitivities may be accounted for in the design of industrial processes. EPRI offers its knowledge of component, equipment, and process PQ sensitivities as a service to original equipment manufacturers (OEMs) through a review of process-control designs prior to manufacturing. Thus, equipment and process designs may be robust to variations in power quality as built, requiring no PQ mitigation after installation.
PQ Design Consultation may be accomplished at the Greenfield stage (not yet built—drawings only) on-site at the OEM or remotely using plant process control circuit drawings. Thus, a new machine design or an existing manufacturing cell design may be reviewed to identify and mitigate power quality sensitivity. Reducing volumes of control drawings to a single-line diagram, EPRI’s PQ team can quickly understand interrelationships of control system components and determine where mitigation may be required to harden the response of the machine to power quality events.
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Figure 10 For Complex designs, EPRI creates a Single-Line Diagram that represents power flow throughout the machine and the interrelated components.
Testing
EPRI maintains comprehensive test laboratories and mobile test tools, which enable expert power quality testing (voltage sags, line transients, and electromagnetic interference) both in the lab and onsite. We pioneered the technology behind the EPRI voltage sag generator (also called the PortoSag) and routinely test industrial equipment loads that require three-phase power (up to 200 amps of current).
Figure 11 Voltage Sag Testing EPRI can test in its laboratory or at a client’s location
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Voltage Sag Standard Certification
EPRI can quickly certify that a process component or machine complies with IEEE 1668 and/or SEMI F47 (see Figure 12). EPRI established a certification program to test manufacturer equipment per established power quality standards. PQ Star certification is available for OEMs looking to document their equipment’s robustness to voltage sag events.
Figure 12 Example Certification Test Curves Red Line Only: SEMI F47 for Single- and Two-phase Voltage Sags; IEEE Std 1668 for Single- and Two-phase Voltage Sags Green Line Only: IEEE Std 1668 for Three-phase Voltage Sags
Training
EPRI offers training in all aspects of power quality at its location in Knoxville, Tennessee, at off-site locations around the world as requested, and even online through its video series on power quality topics.
Figure 13 EPRI Provides PQ Training at its Offices or at Off-site Locations
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Autonomous Robotic Site Surveys
For indoor or outdoor locations, the PQ Team has developed robotic technology to enable comprehensive detection and analysis of radiated emissions. Electromagnetic interference or electric fields may be characterized and isolated using the EPRI “PQ Robot” (the Big Autonomous Mobile Measurement Platform, or BAMMP). Navigating with high-precision (+/- 2CM) GPS (outdoors) or LIDAR (indoors), the BAMMP, shown in Figure 14, autonomously measures several parameters, including electric fields, radio frequency interference (RFI), the lighting spectrum, and even the presence and emissivity of radioactive materials or residues. The data obtained may be visualized as a heat map on aerial imagery or a map. Characterizations can be done before and after mitigation automatically using the same path.
Figure 14 The Big Autonomous Mobile Measurement Platform (BAMMP)
Conclusion
EPRI’s PQ Team has the tools and expertise to investigate all aspects of power quality and understands how PQ sensitivities may be mitigated—from the utility level, to the facility-level—even down to the component level of individual process controls. Our experience comes from 300-plus facility investigations with multiple process mitigation recommendations at each site. We work with industrial, commercial, and governmental organizations worldwide to help them solve vexing problems in power quality. And we can help you.
For help in solving your power quality issues, contact us at [email protected] or visit http://mypq.epri.com .
July 2020
Electric Power Research Institute 3420 Hillview Avenue, Palo Alto, California 94304-1338 • PO Box 10412, Palo Alto, California 94303-0813 USA 800.313.3774 • 650.855.2121 • askepri@epri. com • www.epri.com
© 2020 Electric Power Research Institute (EPRI), Inc. All rights reserved. Electric Power Research Institute, EPRI, and TOGETHER…SHAPING THE FUTURE OF ELECTRICITY are registered service marks of the Electric Power Research Institute, Inc.
