The Institute of Integrated Electrical Engineers (IIEE) in the Philippines publishes a magazine quarterly, The Electrical Engineer. Copies of the issues are provided with hard copies to residences of members and soft copies at their website. Of course, I am a member of IIEE that's why I get copies on-line. I have called the attention of IIEE Technical Department on this but I can't understand why they keep on repeating this ethical mistake.
Below are tables of comparison I made, from where IIEE technical authors might have sourced their technical articles. I ranked them for fun but the issue is not.
Honorable Mention
GE Tech Note | IIEE Article |
Control Error – Loss of control power results in the inability to control the process. This may well be the most pervasive voltage interruption problem, especially among commercial users. Contactor Dropout – Many industrial controls employ magnetically-latched contactors as motor control devices. A voltage sip or sag can cause a momentary collapse of the magnetic field which holds the contacts closed. When the contacts open, the motor stops. Voltage Flicker – In the strictest sense, flicker is the repetitive variation in intensity of lighting, and is more of a human irritation factor than a direct cause of process disruption. However, it can also be used in a more literal sense to describe a set of problems in which lighting is extinguished due to voltage dips. Machine Dynamics – Since voltage magnitude is essential to transmitting power, voltage dips and sags limit the ability of a power system to distribute power from sources to loads. This limitation in power transfer can lead to generators not being able to maintain stability. Stall and Reacceleration – Motors will stall if the supply voltage is depressed for a prolonged period. This may be a problem if the motor is not properly protected. Furthermore, motors must reaccelerate when normal voltage is restored. Reacceleration involves higher than normal motor currents which may result in further voltage sag problems. | Control Error – Loss of control power results in the inability to control the process. Contactor Dropout – Many industrial controls employ magnetically-latched contactors as motor control devices. A voltage dip or sag can cause a momentary collapse of the magnetic field which holds the contacts closed. When the contacts open, the motor stops. Voltage Flicker – In the practical sense, flicker is the repetitive variation in intensity of lighting, and is more of a human irritation factor (threshold of perception, or threshold of human objection) than a direct cause of process disruption. However, it can also be used in a more literal sense to describe a set of problems in which lighting is extinguished due to voltage dips. Machine Dynamics – Since voltage magnitude is essential to transmitting power, voltage dips and sags limit the ability of a power system to distribute power from sources to loads. This limitation in power transfer can lead to generators not being able to maintain stability. Stall & Re-Acceleration – Motors will stall if the supply voltage is depressed for a prolonged period. Furthermore, motors must reaccelerate when normal voltage is restored. Reacceleration involves higher than normal motor currents which may result in further voltage sag problems. |
Voltage sag is a partial reduction in the magnitude of voltage that often persists for extended periods and is usually related to system loading conditions Voltage dip is a significant reduction in voltage for a relatively short duration, often caused by power system faults. Voltage interruption is a complete loss of input voltage, lasting from seconds to much longer. | Voltage Sag is a partial reduction in the magnitude of voltage that often persists for extended periods and is usually related to system loading conditions. Voltage Dip is a significant reduction in voltage for a relatively short duration, often caused by power system faults, or as frequently in events of large motor starts-up. Voltage Interruption is a complete loss of input voltage, lasting from seconds to a much longer time. |
The actual economic justification for prevent production interruptions due to voltage disturbances must consider the following elements: 1. How vulnerable is the process to various types of voltage disturbances? 2. What is the net cost of production outages due to these disturbances? 3. How effective is a particular solution in avoiding these outages? 4. How does the cost of the solution compare to the savings which can be realized? There are several elements of cost associated with a voltage interruption that should be recognized and quantified in the economic evaluation. Cost of Lost Production – In the simplest case, this is the incremental margin on product that is not manufactured and therefore cannot be sold. Cost of Damaged Product – If the interruption damages a partially completed product, the cost of repairing that product must be recognized. In some cases, the product cannot be repaired, so the value of the raw materials (including the consumed energy up to the point where the disruption occurred) must be accounted for together with the cost of the incremental value added to the product. In the commercial arena, a major source of concern is lost computer data. Cost of Maintenance – The cost of reacting to a voltage disruption experience. This includes everything involved in restoring production, including diagnosing and correcting the problem, cleanup and repair, disposing of damaged product, and environmental costs. In some industries (e.g., plastics and electronics), an interruption for several hours may result in the need to invest many days and thousands of dollars in cleaning up the process system before it can be returned to service. Hidden Costs – This factor may be the most difficult to quantify but it can easily be the most significant. If the impact of the voltage dip or sag is control error, it is possible that the impact on product may not be apparent until the product is in the hands of the consumer. Product recall and/or public relations costs can be significant. | The actual economic justification in preventing production interruptions due to voltage disturbances must therefore consider the following elements: 1) How vulnerable is the process to various types of voltage disturbances? 2) What is the net cost of production outages due to these disturbances? 3) How effective is a particular solution in avoiding these outages? 4) How does the cost of the solution compare to the savings which can be realized? As to the cost associated with voltage interruptions the following elements should be recognized and quantified: Cost of Lost Production – In the simplest case, this is the incremental margin on products that cannot be sold because they are not manufactured. Cost of Damaged Product – If the interruption damages a partially completed product, the cost of repairing that product must be recognized. In some cases, the product cannot be repaired, so the value of the raw materials (including the consumed energy and other manufacturing costs up to the point where the disruption occurred) must be accounted for together with the cost of the incremental value added to the product. In other environments, a major source of concern is lost computer data. Cost of Maintenance – This is the cost of reacting to a voltage disruption. This includes everything involved in restoring production, including trouble-shooting and correcting the problem, cleanup and repair, disposing of damaged product, and environmental costs. In some industries (e.g., plastics, glass manufacturing, cement manufacturing, electronics, etc), an interruption may result in the need to invest many days and a significant amount of money in cleaning up the process system before it can be returned to service. Hidden Costs – This factor may be the most difficult to quantify but it can easily be the most significant. If the impact of the voltage dip or sag is control error, it is possible that the impact on product may not be apparent until the product is in the hands of the consumer. As business nightmare, product recall and the subsequent public relations costs can be significant or may even cause bankruptcies. |
Salutatorian
Pure Power Article | IIEE Article |
Effects of voltage-wave distortion, however, are evident throughout the distribution system. This condition results when instantaneous current demand exceeds the distribution system’s ability to deliver power to the load. | Voltage-wave distortion, which is evident throughout the distribution system, results when instantaneous current demand exceeds the distribution system's ability to deliver power to the load. |
Equipment with the potential for generating voltage-wave distortion includes UPS systems, VFDs, solid-state elevator drives, arc heating units, and other devices with very large, short term current demands. | Equipment with the potential for generating voltage-wave distortion includes UPS systems, VFDs, solid-state elevator drives, arc heating units, and spot welding machines. |
There are two primary ways to eliminate voltage harmonics: by incorporating harmonic filters at selected locations, or by eliminating devices that produce voltage wave distortion by purchasing devices that produce lower levels of harmonics. | The two basic ways to eliminate voltage harmonics are: by harmonic filters placed at selected locations, and by eliminating devices that produce voltage-wave distortion by using devices that produce lower levels of harmonics. |
Active filters incorporate microprocessors to eliminate harmonics by rapidly compensating for sine-wave deviations from ideal wave forms by inverting the harmonic distortion and reinserting it into the feeder to cancel the harmonics. These models can correct all harmonic magnitudes up to their maximum capability and can eliminate harmonics concerns in electrical-distribution design. | Active filters incorporate microprocessors to eliminate harmonics by rapidly compensating for sine-wave deviations from ideal wave forms by inverting the harmonic distortion and reinserting it into the feeder to cancel the harmonics These models can correct all harmonic magnitudes up to their maximum capability and can eliminate harmonics concerns in electrical-distribution design |
SUMMARY Without careful design considerations, harmonics can cause expensive & damaging problems. As a result, each potential harmonic producer should be investigated to determine the frequency and level of harmonics so the appropriate type of filtering may be specified. Doubled neutral conductors and k-factor transformers should be used only as a last resort in existing installations to mitigate large triplen harmonic levels; and not as a routine procedure for every facility. Judicious use of harmonic filters for either a dedicated, device-specific application or on a group basis. Incorporating a single filter to handle a number of harmonic-producing loads, can be the most cost-effective way to limit harmonics in the distribution system. | A SYSTEMS APPROACH Without careful design considerations, harmonics can cause expensive, damaging problems. As a result, each potential harmonic producer should be investigated to determine the frequency and level of harmonics so the appropriate type of filtering may be specified. Doubled neutral conductors and k-factor transformers should be used only as a last resort in existing installations to mitigate large triplen harmonic levels, not as a routine procedure for every facility. Judicious use of harmonic filters for either a dedicated, device-specific application or on a group basis, incorporating a single filter to handle a number of harmonic producing loads, can be the most cost effective way to limit harmonics in the distribution system. |
Valedictorian
See word for word imitations by clicking title | |
Book | IIEE Article |
Integrated Solutions for Energy & Facility Management By Association of Energy Engineers, Sioros/Assoc En, Donna Sioros | |
