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With an additional wave of Ameren employees headed to Florida, Ameren now has approximately 1,000 employees and contractors assisting in the restoration and rebuilding efforts in response to Hurricane Irma.

The company also announced today an additional $25,000 donation to aid Red Cross relief efforts in Florida, following a similar donation last week for Texas after Hurricane Harvey.

"Historic storms such as Harvey and Irma require a large collaborative response effort from utilities and relief organizations," said Warner Baxter, chairman, president and CEO of Ameren Corporation. "Being able to assist in power restoration efforts and offer resources to organizations that help those in need can make a real difference in recovery efforts – which is why we are providing both. For those who have been affected by these devastating storms, our hope is to help get these communities back on their feet as quickly as possible."

Ameren resources working in Florida or headed that way include those from Ameren Missouri, Ameren Illinois and Ameren Transmission.

According to the Edison Electric Institute, Hurricane Irma is likely to be one of the largest and most complex power-restoration efforts in U.S. history.

Ameren participates in the electric industry's mutual assistance network through Edison Electric Institute, which means the company is available to help with emergencies in other parts of the country such as Superstorm Sandy in 2012 and Hurricane Katrina in 2005. Customers of Ameren Illinois and Ameren Missouri have benefited from past assistance from other utilities following severe weather in the Midwest, including tornados, ice storms and other weather events.

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Addressing the surge environment.
The Institute of Electrical and Electronics Engineers, IEEE, has produced a set of standards known as the “trilogy” to address the surge environment, characterize surges, and define surge testing in low-voltage AC power circuits. The following standards constitute the trilogy.

  • IEEE C62.41.1, “Guide on the Surge Environment in Low-Voltage (1000 V and less) AC Power Circuits”
  • IEEE C62.41.2, “Recommended Practice on characterization of Surges in Low-Voltage (1000 V and less) AC Power Circuits”
  • IEEE C62.45, “Recommended Practice on Surge Testing for Equipment Connected to Low-Voltage (1000 V and Less) AC Power Circuits”

In addition IEEE has produced the following standards for the application and testing of SPDs.

  • IEEE C62.47-1992, “IEEE Guide on Electrostatic Discharge (ESD): Characterization of the ESD Environment”
  • IEEE C62.48, “Guide on Interactions Between Power System Disturbances and Surge-Protective Devices”
  • IEEE C62.62, “Test Specifications for Surge-Protective Devices (SPDs) for Use on the Load Side of the Service Equipment in Low-Voltage (1000 V and Less) AC Power Circuits”
  • IEEE C62.72, “Guide for the Application of Surge-Protective Devices for Low-Voltage (1000 V or Less) AC Power Circuits”

These standards have been developed from many years of scientific research and are recognized by American National Standards Institute (ANSI). They are intended for use primarily by surge equipment manufacturers and provide valuable reference for consulting engineers that specify surrge protection devices (SPDs).

IEEE C62.41.1

Guide on the Surge Environment in Low-Voltage (1000 V and less) AC Power Circuits.

This guide, the first in the trilogy, provides readers with a comprehensive information on surges, the environment in which they occur and is a reference for the second document of the trilogy. The surge environment is described using:

  • Three location categories (C, B or A) according to their position from the building service entrance.
  • Level of exposure to major sources of surges: lightning and load switching.
  • Representative waveforms of surge voltages and surge currents are described for each category.

This guide should not be used as a testing document to define performance, survivability or any other related test criteria. Any statement that a SPD “meets the requirement of” or “is certified to”, this document is inappropriate and misleading.

IEEE C62.41.2

Recommended Practice on characterization of Surges in Low-Voltage (1000 V and less) AC Power Circuits.

This guide, the second in the trilogy, presents recommendations on the selection of surge waveforms, amplitudes of surge voltages and currents used to evaluate equipment immunity and performance of SPDs. Two recommended “standard” waveforms are used as a simplified representation of the surge environment:

  • 0.5µs/100kHZ ringwave
  • 1.2/50/8-20µs combination wave

IEEE C62.45

Recommended Practice on Surge Testing for Equipment Connected to Low-Voltage (1000 V and Less) AC Power Circuits.

This guide, the third in the trilogy, focuses on surge testing procedures (using the simplified waveform representations) for obtaining reliable measurements and enhancing operator safety. The intent is to provide background that can help determine whether equipment or a circuit has adequate ‘withstand’ capability.

  • Signal and data lines are not addressed in this document.
  • The document does not indicate withstand levels that might be assigned to specific equipment.
  • An important objective of the document is to call attention to the safety aspects of surge testing.
  • Underwriters Laboratories, Inc. uses these guidelines as a reference in their performance and safety testing of SPDs.

IEEE C62.48

IEEE Guide on Interactions Between Power System Disturbances and Surge-Protective Devices

This guide applies to surge-protective devices (SPDs) manufactured to be connected to 50 Hz or 60 Hz ac power circuits rated at 100–1000 V rms. It describes the effects on SPDs of power system disturbances occurring in these low-voltage ac power circuits. The disturbances are not limited to surges. The effects of the presence and operation of SPDs on the quality of power available to the connected loads are described. The interaction among multiple SPDs on the same circuit is also described. This guide discusses both voltage and current surges. The current surges discussed in this guide are the result of voltage surges. Current surges that are solely the result of load changes and do not result in voltage increases, such as a short circuit, are not discussed in this guide.

An SPD’s primary purpose is to provide surge protection. Devices discussed in this guide contain at least one nonlinear component for diverting surge current and/or dissipating surge energy, such as a metal oxide varistor (MOV), silicon avalanche diode (SAD), thyristor, or spark gap. Uninterruptible power supplies (UPSs), ferroresonators, motor-generators, and filters containing only inductive and/or capacitive components are not considered SPDs in this guide.

IEEE C62.62

IEEE Standard Test Specifications for Surge-Protective Devices (SPDs) for Use on the Load Side of the Service Equipment in Low-Voltage (1000 V and Less) AC Power Circuits

This standard applies to surge-protective devices (SPDs) intended to be installed on the load side of the service equipment connected to 50 Hz or 60 Hz alternating current (ac) power circuits rated at 1000 V (root mean squared [rms]) or less. Performance characteristics and standard methods for testing and rating are established for these devices, which may be composed of any combination of components. The tests in this standard are aimed at providing comparisons among the variety of surge-protective devices available.

IEEE C62.72

IEEE Guide for the Application of Surge-Protective Devices for Low-Voltage (1000 V or Less) AC Power Circuits

The transient overvoltages or surge events that are described and discussed in this guide are those that originate outside of a building or facility and impinge on a power distribution system (PDS) through the service entrance conductors. Transient overvoltages or surge events that originate from equipment within a specific facility are not within the scope of this document.

This guide applies to surge-protective devices (SPDs) that are manufactured for connections to 50 Hz or 60 Hz ac power circuits that are rated between 100 V rms and 1000 V rms. This guide applies to SPDs that are specifically identified, labeled, or listed for connections on the load side of the service entrance main overcurrent protective device. This guide does not cover those SPDs identified, labeled, or tested as a secondary surge arrester intended for connections on the line side of the service entrance main overcurrent protective device. The SPDs covered in this guide are those manufactured for use in an association with electrical power distribution equipment such as load centers, motor control centers, panelboards, switchboards, switchgear, and end-use equipment installed in commercial and industrial facilities. This guide excludes SPDs associated with retail and consumer appliances and components for residential use.

The SPDs discussed in this guide contain at least one nonlinear component for either diverting surge currents and/or dissipating surge energy. Examples of such nonlinear components are metal-oxide varistors (MOVs), silicon avalanche diodes (SADs), spark gap tubes, or thyristors. Ferroresonators, motor-generators, uninterruptible power supplies, and filters containing only inductive or capacitive components are not considered SPDs in the guide.

IEEE C62.47-1992

IEEE Guide on Electrostatic Discharge (ESD): Characterization of the ESD Environment

The purpose of this guide is to describe the electromagnetic threat posed to electronic equipment and subassemblies by actual Electrostatic Discharge (ESD) events from humans and mobile furnishings. This guide organizes existing data on the subject of ESD in order to characterize the ESD surge environment. This guide is not an ESD test standard. An appropriate ESD test standard should be selected for equipment testing. The manufacturing, handling, packaging, and transportation of individual electronic components, including integrated circuits, are not discussed, and this guide does not deal with mobile items such as automobiles, aircraft, or other masses of comparable size. ESD results in a sudden transfer of charge between bodies of differing electrostatic potentials. In this guide, the term ESD includes charge transfer whether or not an arc occurs or is perceived.

ESD phenomena generate electromagnetic fields over a broad range of frequencies, from direct current (dc) to low gigahertz. The term ESD event includes not only the discharge current, but also the electromagnetic fields and corona effects before and during a discharge. In this guide the intruder is often a human, but it may be any object that is moved, such as a chair, an equipment cart, a vacuum cleaner, or the equipment victim itself, whether or not it is in conductive contact with a human. The equipment victim is usually a fabricated electronic equipment or subassembly and is generally, although not necessarily, at local electrostatic ground potential.

The equipment victim may be the receptor to which the discharge takes place from the intruder; less frequently, the equipment victim may be the intruder. Alternatively, the equipment victim may be affected by the electromagnetic fields generated by a discharge between an intruder and a receptor. Receptors and intruders that may not themselves are equipment victims include furniture such as metal chairs, carts, tables and file cabinets, as well as other electronic equipment.

This guide discusses and cites references that describe the ways in which a body builds up charge and the characteristics of discharge currents and fields. Descriptions and references are also given for electrical equivalent circuits to be used in understanding and simulating the discharge current between intruder and receptor masses. Publications that are specifically referenced in the text of the guide are listed in the Section 3, while Section 9 cites additional publications in both ESD and related areas.

Most of the work that has been published in connection with actual ESD is related to discharges from humans, usually grasping or in association with a metal object. Far less published data exists for discharges from humans without metal objects, and from mobile furnishings, and virtually no data exists for discharges from human torsos or clothing. For this reason, primary emphasis is placed on discharges from humans with associated metal objects, with some additional material relating to ESDs from mobile furnishings. All discharges are assumed to take place in an air environment.

Finally, all of the published time-domain data on which this guide relies were taken using instrumentation with either a 400 MHz or a 1 GHz bandwidth.

IEEE Std 1100™-2005

IEEE Recommended Practice for Powering and Grounding Electronic Equipment

This document presents recommended design, installation, and maintenance practices for electrical power and grounding (including both safety and noise control) and protection of electronic loads such as industrial controllers, computers, and other information technology equipment (ITE) used in commercial and industrial applications.

IEEE Std. 142-2007

IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems

The problems of system grounding, that is, connection to ground of neutral, of the corner of the delta, or of the midtap of one phase, are covered. The advantages and disadvantages of grounded vs. ungrounded systems are discussed. Information is given on how to ground the system, where the system should be grounded, and how to select equipment for the ground of the neutral circuits. Connecting the frames and enclosures of electric apparatus, such as motors, switchgear, transformers, buses, cables, conduits, building frames, and portable equipment, to a ground system is addressed. The fundamentals of making the interconnection of a ground conductor system between electric equipment and the ground rods, water pipes, etc., are outlined. The problems of static electricity— how it is generated, what processes may produce it, how it is measured, and what should be done to prevent its generation or to drain the static charges to earth to prevent sparking—are treated. Methods of protecting structures against the effects of lightning are also covered. Obtaining a low-resistance connection to earth, use of ground rods, connections to water pipes, etc., are discussed. A separate chapter on electronic equipment is included.

How to Buy IEEE Standards:
IEEE standards can be obtained online in the IEEE Standards Store

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How to know what kA rating to use

Selecting the appropriate surge protective device (SPD) can seem like a daunting task, especially with all of the different types on the market today. The surge rating or kA rating of an SPD is one of the most misunderstood ratings. Customers commonly ask for an SPD to protect their 200A panel. There¡¯s also a tendency to think that the larger the panel, the larger the kA device rating needs to be for protection. As you will see in this article, this is a common misconception.

When a surge enters a panel, it does not care or know the size of the panel. So how do you know if you should use a 50kA, 100kA, or 200kA SPD? As discussed in the IEEE standard C62.41, a building's wiring adds impedance that will limit the surge current. The standard also states that 10kA devices have been adequately limiting surge currents at the service entrance for several years. Therefore, it's reasonable to say the largest surge that can enter a building's wiring system is 10kA; however, a direct lightning strike would produce a much larger surge. The extremely high voltage associated with a direct lightning strike would most likely flashover, thereby "self-limiting" the surge. So why would you ever need an SPD rated for 200kA? Simply stated — for longevity.

You might think: If 200kA is good, then 600kA must be three times better, right? Not necessarily. At some point, the rating diminishes its return, only adding extra cost and no substantial benefit.

Because most SPDs on the market use a metal-oxide varistor (MOV) as the main limiting device, we can explore how/why higher kA ratings are achieved. If an MOV is rated for 10kA and sees a 10kA surge, it would use 100% of its capacity. This can be viewed somewhat like a gas tank, where the surge will degrade the MOV a little bit (no longer is it 100% full).

If the SPD has two 10kA MOVs in parallel, it would be rated for 20kA. Theoretically, the MOVs will evenly split the 10kA surge, so each would take 5kA. In this case, each MOV has only used 50% of its capacity, which degrades the MOV much less — leaving more left in the tank for future surges.

Does this translate into surge "stopping power"? No. Just because an SPD has two or 20 MOVs in parallel doesn't mean it will limit the 10kA surge any better than a single SPD of the same rating. The main objective of having MOVs in parallel is to increase the longevity of the SPD. Again, keep in mind that this is subjective — at some point you are only adding cost by incorporating more MOVs and receiving little benefit.

As mentioned before, panel size does not really play a role in the selection of a kA rating. The location of the panel within the facility is much more important. IEEE C62.41.2 defines the categories of expected surges within a facility as:

Category C: Service entrance, more severe environment: 10kV, 10kA surge.
Category B: Downstream, greater than or equal to 30 ft from category C, less severe environment: 6kV, 3kA surge.
Category A: Further downstream, greater than or equal to 60 ft from category C, least severe environment: 6kV, 0.5kA surge.

Category C devices can be used in Category B or A locations; however, a Category C device would be excessive for a Category B location. Some engineers may decide to specify Category C devices to have a conservative design, but this will also only add cost while adding little to no benefit.

Although UL 1449 third edition does not use the exact category terminology as IEEE C62.41.2, it does define three major types. Type 1 can be installed on the line side of the service entrance overcurrent device (no extra overcurrent device needed), which is similar to Category C. Type 2 is similar to Category B and can only be installed on the load side of the service entrance overcurrent device. Type 3 and Category A are point of utilization devices like a surge power strip that is plugged into a wall outlet. While UL types and IEEE categories are similar, they are not 100% interchangeable. UL Type 1 devices are often used in Type 2 locations. The benefit of doing this is that there is no extra overcurrent device needed.

How do you know what kA rating to use? The IEEE categories provide a good base for selecting kA ratings. There are many "right" sizes for each category, but there must be a balance between redundancy and added cost. Qualified judgment should always be used when selecting the appropriate kA rating for an SPD.

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destroyed computer

Surges or transients can damage, degrade or destroy the sensitive electronic equipment in offices or businesses resulting in:

  • Equipment damage
  • Equipment downtime
  • Losses in resulting revenues
  • Productivity losses due to downtime

Page content:

What is at risk?
What are signs of damage?

There are three main types of effects that transients have on your electronic equipment:

Disruptive effects:

These effects are usually encountered when a transient enters the equipment by inductive coupling. The energy source for this inductive coupling can act on the data output lines that integrate an electronic installation. The electronic components then try to process the transient as a valid logic command. The result is system lock-up, malfunction, erroneous output, lost or corrupted files, and a variety of other undesirable effects.

Dissipative effects:

These effects are associated with repeated stresses to IC components. The materials used to fabricate IC’s can only withstand a certain number of repeated energy level surges. After long-term degradation, the device fails to operate properly. The failure is due to the cumulative build-up of transient-created stresses which result in arc-overs, shorts, open circuits, or semiconductor junction failures within the IC.

Burned Circuit Board

Destructive effects:

These effects include all conditions where transients with high levels of energy cause equipment to fail instantaneously. Very often, there is actual physical damage apparent, like burnt PC boards or melting of electronic components.
Destructive effects can occur when noise pulses are too fast for power supply regulator circuits to respond by limiting transient voltage to acceptable levels. Also, transients on the power line may subject electronic components to overwhelming voltage levels. For example, components like rectifier diodes can fail immediately when their Peak Inverse Voltage (PIV) rating is exceeded. PIV diode ratings in a well-designed computer can be in the 1 kV – 1.5 kV range. Transients on AC lines can easily exceed 1.5 kV.
What are the Symptoms of Surge Damage?

There are several possible symptoms to look for to determine whether surges are affecting your office or business.

  • Computer lock-ups or latch-ups
  • Unexplainable data corruption
  • Equipment shutdown
  • Flickering lights
  • Premature failure of electronic ballasts or printed circuit boards

surge damage

There is no such thing as a transient free facility. Many people do not realize that their company’s productivity and profitability is being significantly impacted by the effects of transients. The problems described above result in billions of dollars of lost profits to U.S. businesses every year.

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ThinkstockPhotos 616899444ProcessHeatSystemWebVersion 0

Actively search out sources of waste heat and pursue techniques to recover the wasted heat.

What kind of gas mileage would you expect if you were driving your car with one foot on the gas and the other on the brake? The results from this approach would be pretty poor.

Many facilities have a similar dynamic going on with “waste heat.” Continuing on with the car example, if you look under the hood (and understand what you’re looking at), you’ll see some waste heat recovery techniques in play.

What kinds of techniques might your facility use? Before you can really answer that question, you need to identify the waste heat sources and quantify the amount of waste heat from each source.

Once you have that information, look at processes or equipment that requires additional heat. Many waste heat recovery techniques involve providing at least some of that heat by redirecting waste heat.

Consider a plant that had a small annealing furnace. This furnace used outside air, which had to be preheated in the winter just to get up to the inside air temperature. Meanwhile, several hot process situated nearby were ducting their waste heat air to the outside (and pulling already heated ambient air out as well). Some reducting (along with pressure controls and approval by the boiler inspector prior to actual implementation) changed much of the waste heat into process-used heat.

Another plant had a row of small cooling towers outside the building. A closed piping system ran through the towers. The water cooled a manufacturing process and was simply circulated through the pipes. Hot water ran to the cooling towers, and cooled water ran back to the equipment that needed cooling. This system is very much like the cooling system in a car, except the car has a radiator instead of a row of cooling towers.

The plant had recently hired a new plant engineer, and he noticed almost none of the pipes in the ceiling were color coded or even labeled. So he hired an industrial services firm to identify the pipes. In the process of identifying these, they were amazed to discover that the uninsulated cooling tower return pipe was run between two hot water pipes for about thirty feet. And the pipes were touching each other, causing a loss of energy in the heated water while degrading the cooling system.

Don’t wait to incidentally find instances of gas and brake. Actively look for them. Where are you running hot air, water, etc., and where are you running cooling air or water supply? Where are you generating heat for use, and where are you exhausting heat instead of using it?

 

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