Conducting a PQ investigation is key to understanding what’s going on within a PQ problem. Investigations may be conducted on utility systems—generation, transmission, distribution (including substations), and on customer electrical systems (residential, commercial, industrial and outdoor). Electrotek’s vast amount of experience in conducting PQ facility investigations places us at the top of the list regarding experience, and know-how. Our PQ engineering experts have investigated 1000’s of facilities, finding the cause of the PQ problem in every facility. No two facilities are alike, and no two PQ problems are alike either. Electrotek’s expert approach and the custom tools we’ve developed to investigate PQ problems in any facility and at any voltage level leaves no stone unturned.
Sometimes it is necessary to go beyond what one can see by visiting a customer facility. PQ monitoring is one tool that helps us do that. Modeling and simulating a PQ phenomenon in a facility is another tool. Electrotek’s expert PQ modeling and simulation engineers are able to take what is learned from a facility investigation, plus PQ monitoring data, and verify the characteristics of a PQ problem, plus determine the likelihood of it happening again, as well as, what might happen if the problem is not solved. Modeling and simulation also helps us to select and verify the PQ mitigation measure is best suited for the problem at hand ... read more
Electromagnetic compatibility (EMC) is the term used to describe how well a device or system can function in an electromagnetic environment without introducing electromagnetic disturbances that interfere with the operation of other electrical products in the environment. Electromagnetic interference (EMI) is a term used to describe an undesirable condition that has developed between a source of emissions and a receptor. One classic example is the static you hear on your cordless phone when trying to have a conversation. The source is the piece of equipment or electrical condition causing the static, and the receptor is the cordless phone.
Increased usage of electronical and electronic equipment has led to the increased development of EMI problems. Customers who use electronic equipment are likely to experience an EMI problem at some point. When an EMI problem occurs, it renders a piece of equipment inoperable. This often affects the customer’s business (i.e., their bottom line), or a customer’s quality of life (i.e., can’t use a piece of equipment in my house). If a piece of equipment at a business cannot be used, it will likely affect a process or production line in some negative way.
Solving EMI problems is similar to solving PQ problems, but the frequencies of interest are much higher—ranging from a few Hertz, to the GHz range. The frequencies for traditional PQ phenomena start at DC and extend to about 3 kHz. Nowadays, the upper end extends to about 150 kHz. Why is this? This is because of the conducted emissions generated by electronic switch-mode power supplies. Every electronic device uses some type of electronic power supply. Power supplies operate on the basis of switching energy. Capacitors and inductors are charged and discharged using a power electronic switch (i.e., power transistor). This switching action and the movement of high-frequency energy generates radiated and conducted emissions. Conducted emissions extend well beyond the 150-kHz point, but the increased use of power supplies and other devices (e.g., photovoltaic inverters) is causing an increase in conducted energy up to 150 kHz.
EMI problems which have been investigated by Electrotek include those involving electronic lighting, variable frequency drives, battery chargers (including electric vehicle chargers), photovoltaic (solar) farms, medical equipment, hospitals, data centers, and many more.
Electrotek also serves on IEEE and IEC standards bodies regarding EMC standards .... read more
The performance of wiring and grounding (W&G) systems in customer facilities critical to achieving good power quality performance for equipment. Errors and deficiencies in W&G systems will exacerbate PQ disturbances that might not otherwise affect the performance of electrical and electronic equipment. Every existing plant older than 10 years will have serious W&G issues that will impact the delivery of good PQ to their equipment. Most W&G problems go undetected, and many are not identifiable with the naked eye. W&G issues that are left undetected will worsen, placing staff at the risk of electric shock, and equipment at the risk of malfunction and permanent damage.
Often, proper interpretation of PQ monitoring data will lead to the identification of W&G issues that need further attention by a PQ expert. Sometimes a facility PQ investigation will include a detailed investigation of W&G systems. When PQ investigations do include W&G, expert PQ engineers have the opportunity to identify W&G issues that might need attention immediately. This is especially important for certain types of equipment malfunctions and damage.
W&G systems are often the victim of frequent changes to electrical systems by electricians. Facilities are constantly receiving attention from electricians. One of the first things a newly commissioned facility experiences is changes to the electrical system. Customers often want new loads installed and new circuits added for future loads. Existing plants receive the most attention from electricians. Specific areas in a plant often undergo upgrades, requiring the removal of loads and circuits followed by the installation of new ones. Most of the time experienced electricians knowledgeable of the National Electrical Code (NEC) do the right thing to follow the code and know the things that are likely to impact PQ delivered to equipment. It’s the individuals who don’t know enough about the code or PQ that end up creating a problem when they attempt to do electrical work.
Regardless of the situation, Electrotek’s expert PQ engineers know the ins and outs of facility electrical systems, no matter the configuration, and have the equipment, tools, and knowledge to identify hidden W&G issues in all types of facilities at all voltage levels ... read more
It is not uncommon for utilities, building managers, and end users to add electric capacity and equipment to an existing electrical system. Utilities are frequently adding substations, circuits, and new customers, as well as distributed generation (DG) to offset the construction of new power plants. Based on experience, utilities know that it is critical to understand how significant changes to the grid at specific points should be modeled and simulated before plans are solidified. PQ impact studies are often carried out when DG resources—PV solar farms, microturbines, fuel cells, and generators are added to a power system. Electrotek’s expert PQ engineers are well-versed in DG technologies, modeling, and simulation of DG systems.
Customers are also frequently adding new loads and extensions onto their plants. PQ impact studies can determine how the addition of new loads will impact the existing electrical system. Sometimes a plant expansion requires a completely new facility and a new electric service off the same utility feeder to power the new plant. Depending on the size of the new electrical load, its electrical characteristics, and the level of power reliability, availability, and quality required, an impact study may be needed. Impact studies can determine the effects of new loads on existing plant loads and utility services and vice versa. Customers may have had bad PQ experiences with existing loads, electric services, and also desire to know the effects of such issues on a new plant extension and its new loads ... read more
The protection of electrical and electronic equipment to ensure it functions properly not only include all facets of PQ immunity—it also may include that a lightning study (i.e., risk analysis) be done. PQ immunity addresses voltage surges caused by the combination, and ring waves which are used to simulate the disturbances which occur in a facility when lightning or other PQ phenomena occur at or near a building.
In some cases, a lightning risk analysis (LRA) may be needed if a building is suddenly experiencing a lot of equipment failures caused by lightning. In other situations a facility that is being redesigned may require an LRA, or if the building is a mission-critical facility, an LRA is required by the NEC. LRAs can also help determine where to install surge protective devices (SPDs) and what type to install.
Electrotek expert PQ engineers can carry out a comprehensive lightning risk assessment, and develop lightning protection plans that will help to ensure that a lightning strike will not cause catastrophic failures, injuries, or fatalities at facilities that must house, and protect equipment. Our lightning risk assessment and proposed lightning protection plans illustrate the current risks, and necessary steps that should be taken in order to meet the guidelines as set out in NFPA 780 and IEEE 998.
NFPA 780 provides lightning protection system installation requirements to safeguard people and property from fire risk, and related hazards associated with lightning exposure. While NFPA 780 has no force in law, it is generally recognized as the primary lightning protection document in the USA. The purpose of NFPA 780 is to safeguard persons and property from lightning.
NFPA 780 has two risk assessments, a simplified version and a detailed version. The simplified tells you if your site needs a lightning protection system, while the detailed tells you if a partial lightning protection system will work, or if you need a full system. We typically run both versions in order to determine where cost savings can be made ... read more
As end users of electricity, we all tend to hear more about electrical shock than arc-flash hazards. Arc-flash hazards are caused by electrical short circuits, when an arc-flash ionizes in the air around the electrical equipment. When this occurs, the environment can be extremely hazardous for nearby personnel working on or near the energized electrical equipment. The arc-flash produces large amounts of heat that can burn the skin of the nearby personnel and actually set clothing on fire. From the fault location, the arc-flash can emit a flash of light, a loud noise, ionized gases, metal vapors, molten metal droplets, shrapnel, and shock waves, that can blow the person off his or her feet. Arc-flash hazards can cause serious injury or death if the right protective clothing is not worn, if the right precautions are not taken, and if facility owners and occupants alike are not aware of the potential hazards that exist with arc-flash events.
Basically, an arc-flash hazard study is an analysis of the arc-flash hazards at a facility in order to identify for personnel around the facility the appropriate Personal Protection Equipment (PPE) and safe distances at various pieces of electrical equipment around the facility including substations, switchboards, panel boards, and motor control centers. The Arc-Flash Hazard Analysis (AFHA) takes the short circuit and protective device coordination study another step by determining incident energy levels, needed PPE, and boundary distances for personnel when working on energized electrical equipment. This information is printed on a label that can be attached to the electrical equipment and enables the facility owner or manager to comply with the NFPA/IEEE guidelines that are enforced by OSHA inspectors.
Many governing institutions have added language to their requirements for Arc-Flash Hazard Analysis. Here is a synopsis: NFPA 70E-2002 and the National Electrical Code (NEC) require that electrical equipment be marked in the field to indicate where an arc-flash exists. OSHA’S Electrical Safety Require-ments for Employee Workplaces [OSHA 29CFR 1910.132(d)] requires employers to “assess the work-place to determine if hazards are present, or are likely to be present, which necessitate the use of personal protective equipment (PPE).” If this type of hazard exists or is likely to exist, the employer shall “verify that the workplace hazard assessment has been performed through a written certification that identifies the workplace evaluated.”
Recently IEEE Standard 1584™–2002 reviewed many arc-hazard studies, and determined the importance of conducting an arc-flash hazard analysis. They determined that the arc-flash hazard analysis allows design changes to electrical systems that have high incident energy levels in order to implement changes that make incident energy levels more manageable. They maintain that only a study can identify buses with high incident energy levels and only a study can determine the rating of PPE needed at each location.
Electrotek expert PQ engineers are certified to conduct Arc-Flash Hazard Analyses and can conduct these analyses on any type of facility—utility owned or end user owned ... read more