EMC/EMI Facility Investigations


The generation, transmission and distribution of electric power requires power plants and massive electrical infrastructures. Power plants and the downstream transmission and distribution systems utilize electrical and electronic equipment to operate and monitor plant and power system performance. The electronic systems installed in plants and all across the grid measure voltages and currents, sense conditions which can impact the power system, analyze data and make critical decisions to help ensure safety, avoid interruptions and outages and provide a higher quality of power to customers.

Power plants, especially nuclear plants, have a high concentration of electronic equipment used for instrumentation and control (I&C). When most plants were built, analog equipment was the standard type of equipment installed. Today, utilities are having to upgrade analog equipment to more modern electronic equipment. Equipment installed today is primarily digital equipment. Equipment upgrades help utilities meet the requirements to help ensure safety, read electrical measurements faster, initiate and verify plant and system control and improve plant performance while taking into account additional conditions and plant operating experiences.

Because reliable and effective communications between plant engineers and technicians is a must, utilities rely on wireless devices. Traditionally, utilities used two-way radios and hard-wired phones. Today, utilities are adopting more sophisticated communications schemes relying on the increased use of wireless technologies including cellular phones, higher performance radios and electronic tablets networked to the plant. However, the use of wireless devices brings further concerns. Radiated emissions generated by wireless devices has caused electromagnetic interference (EMI) problems to occur in several power plants including nuclear power stations. Utilities must take every precaution to manage the risk of creating a condition favorable for an EMI problem to develop with digital I&C equipment, especially in nuclear plants where safety is of utmost concern.

With the use of advanced wireless communications and continuous digital I&C equipment upgrades with varying immunity to radiated (and conducted) emissions, nuclear plants frequently engage in having EMC experts conduct specialized EMC/EMI emissions and immunity testing. This includes emissions testing of wireless devices to determine the minimum separation distance (MSD) from digital I&C equipment to reduce the probability of developing an EMI proble. Options for maintaining MSDs and for using electromagnetic shielding to manage the risk of developing an EMI problem is also a critical part of testing.

Utilities also frequently require radiated and conducted emissions testing in spaces where analog equipment is slated for an upcoming digital upgrade. Electrotek uses advanced emissions measurement equipment to conduct specialized and custom EMC/EMI engineering services in all types of fossil, hydro and nuclear power plants.

Architecture & Engineering Firms

The design of an electrical system and specification of electrical and electronic equipment for end-use customers may increase the risk of developing an EMI problem in residential, commercial and industrial facilities. How a piece of equipment is powered and grounded is critical when managing this risk. The location and proximity of electronic equipment with respect to other electronic equipment may determine whether one interferes with the other. The location of a commercial or industrial facility with respect to surrounding neighbors, power lines, etc. may be critical to the design of a building and its electrical infrastructures regarding EMI risk management. Increased use of sophisticated electronic equipment in residential, commercial and industrial facilities increases the risk of developing an EMI problem. End-use customers are installing more electronic equipment while also using more advanced communications devices and infrastructures. When an EMI problem develops, facility owners and operators may turn to their A&E firms for help. 

Residential customers are using more advanced consumer electronics devices and equipment while increasing the number of potential EMI sources. The use of flat screen televisions (TVs) has increased significantly along with the use of wired and wireless networks. Networks are not only used to support communications with TVs and computers, but also to provide connectivity to smart appliances and fire protection and security systems. Nowadays, wireless networks are used to connect electronic programmable thermostats to the Internet. Every electronic device and piece of equipment utilizes at least one microprocessor and electronic switching power supply. Both the microprocessor and power supply generate radiated and conducted emissions. Both also have some susceptibility to emissions. Consumers are also rapidly increasing their use of electronic lighting devices. Most consumers are migrating to electronic LED lighting to replace electronic compact fluorescent lighting (CFLs). All LED lighting devices use at least one electronic power supply.

Increased use of electronic equipment also increases the average electrical noise level on the electrical (and communications) systems in residential, commercial and industrial facilities. Moreover, if the wiring and grounding systems in these facilities are not properly maintained, emissions (i.e., noise) generated by one piece of electronic equipment will travel to other electronic equipment. Emissions will even travel through a piece of equipment to get to another piece of equipment. The circulation of emissions current through an electrical system increases the likelihood of causing a piece of equipment to malfunction and fail.

The grounding of a facility to outside utility (power and communications) systems is also key when maintaining electrical systems. Noise from neighboring facilities can travel through the utility power distribution system and find its way into another facility with poor wiring and grounding practices not suitable to support electronic consumer and networking equipment. 

The same is true for commercial facilities, except the problem is more complex with higher risks of developing an EMI problem. Commercial facilities not only use more electronic equipment and network systems per square foot, but they also use higher-power electronic equipment like copy machines, fax machines and variable frequency drives (VFDs) to operate motors. The increased usage of security systems and wireless devices also adds to the risk. The use of LED lighting in commercial facilities is increasing. New equipment installations frequently rely on older electrical systems which may not be sufficient to support LED lighting with respect to grounding and noise control. Neighbors in a building may be operating old or faulty equipment or equipment not authorized for use in commercial facilities which may lead to an EMI problem.

Industrial facilities use the most electronic equipment per square foot and use the highest power electronic devices and systems. High-power electrical and electronic equipment used in industrial facilities increases the likelihood of developing an EMI problem. This is compounded by the fact that the wiring and grounding systems in these facilities receive the least amount of attention with respect to maintenance. Aged wiring and grounding systems add significant risk to the development of an EMI problem. Adding VFDs to an existing facility also adds significant risk. Moreover, the increased use of electronic-based manufacturing systems and controls increases the susceptibility of this equipment to malfunction and to the cause of plant shutdowns.

Electrotek maintains the capabilities necessary to

  • Identify the cause(s) of an EMI problem and eliminate them
  • Understand the EMI mechanism(s) causing the problems to occur
  • Develop guidelines to avoid EMI problems beginning with the equipment specification process down to the process for installing and maintaining electronic equipment
  • Characterize a facility for radiated and conducted emissions, so end users and plant operators better understand their electromagnetic environments and the risks of developing an EMI problem as most problems are expensive to solve.

The message here is that steps to avoid the development of EMI problems start at the facility design level under the auspices of A&E design firms. 

Equipment Manufacturers

Aside from managing power quality, equipment manufacturers must also manage their electromagnetic environment (EME). Why is this important? 

  • The EME in a manufacturing plant is constantly changing with equipment upgrades, replacing, moving and adding manufacturing processes and capabilities.
  • Plants are adding internal / external communications capabilities with increases in the number of wireless devices, connectivity to equipment and the exchange of data among plant management, plant operators and customers to help ensure the right product gets built, shipped and delivered to the customer on time.

Plant workers are becoming more inter-connected to plant equipment and operating systems. The exchange of real-time information among plant workers, manufacturing engineers and plant managers is becoming more critical as budgets shrink and schedules become more compressed.

Having the right part at the right place at the right time is becoming more dependent upon one manufacturing process being able to efficiently and effectively communicate with another process. Whether the communication scheme is hard-wired or wireless, an unmanaged EME will increase the risk of developing an EMI problem.

Managing risk means understanding the emissions sources—natural or man-made, intentional or unintentional—and understanding the immunity of equipment to radiated electric and magnetic fields and how that immunity varies with equipment age and use. Every piece of electronic equipment has aspects of its design geared towards the prevention of EMI problems. AC line filters are used at the front end to reduce conducted emissions generated by operation of the equipment and to reduce incoming emissions from getting to sensitive semi-conductor components. Specialized materials like plastics, rubber and metals are used to prevent (i.e., shield) radiated emissions from "getting through the cracks" of the equipment enclosure to the sensitive components. Normal wear and tear of equipment causes the filters and shields to weaken. Over time, emissions begin to leak into and outside of equipment, increasing the probability of developing an EMI problem. 

Plants are still engaged in reducing energy consumption and improving processes, capabilities and manufacturing time. These require an increased use of high-efficiency electronic equipment whether a new plant communication system is installed or 10 new VFDs are installed to reduce the power used to operate 10 electric motors rather than use a direct AC or DC connection to power the motors.

Cases involving EMI problem identification and resolution by Electrotek show that every EMI problem could have been prevented through better planning before equipment in specified, procured and installed and better understanding and managing the EME. Every case also shows that the cost of understanding and managing the risks far outweigh the cost of resolving an EMI problem—some by as much as a factor of 100.

Electrotek maintains the expertise and capabilities to investigate any manufacturing-related EMI problem regardless of its extent or complexity. Advanced investigative techniques developed by Electrotek engineers not only minimize the cost and time required to perform an EMI investigation, but also uncover other potential causes of future EMI sources and equipment susceptibilities.

End Users

End users are defined as anyone who uses an electrical or electronic device in any environment—indoor or outdoor. An end user may be a plant worker, contract employee working in a facility or plant for long-term or an independent contractor working out in the field as a part of a small business. With lots of independent contractors working inside facilities and outside on stand-alone systems, the likelihood of EMI problem develop can also be high.

For example, an independent contractor working inside a plant may require the use of a specialized electronic system designed for portable use. Such a system may not be electromagnetically compatible with the plant's electromagnetic environment or compatible with another fixed system used in a facility or plant or a stand-alone system out in the field. In this case, the contractor may require some assistance from an expert EMC/EMI engineer at Electrotek to understand and resolve an EMI problem. Electrotek's fleet of EMC/EMI test and measurement equipment is designed for portable use in any situation. 

A good example of this is the welder in the photo on the right. The use of welding equipment in active customer facilities sometimes causes EMI problems with other equipment currently in use to develop. When these problems occur, the use of the welding equipment is temporarily suspended until a means to reduce emissions from the welding equipment can be determined, installed and verified for performance. 

Whether wireless or hard-wired, two electrical / electronic devices or systems may not get along electromagnetically when brought close together or powered from the same AC or DC bus. Cases show that the equipment that contractors use can cause EMI problems with existing equipment in customer facilities.

Electrotek maintains the expertise and capabilities to help end users understand and manage the risk of EMI problem development whether the concern is indoors or outdoors with any type of portable and fixed equipment in any customer environment.