Introduction to Power Quality
Mohammad A.S. Masoum, Ewald F. Fuchs, in Power Quality in Power Systems and Electrical Machines [Second Edition], 2015
1.6.2 IEEE-519 Standard
The United States [ANSI and IEEE] do not have such a comprehensive and complete set of power quality standards as the IEC. However, their standards are more practical and provide theoretical background on the phenomena. This has made them very useful reference documents, even outside of the United States. IEEE-Std 519 [1] is the IEEE recommended practices and requirements for harmonic control in electric power systems. It is one of the well-known documents for power quality limits. IEEE-519 is more comprehensive than IEC 61000-3-2 [2], but it is not a product standard. The first official version of this document was published in 1981. Product testing standards for the United States are now considered within TC77A/WG1 [TF5b] but are also discussed in IEEE. The current direction of the TC-77 working group is toward a global IEC standard for both 50/60Hz and 115/230V.
IEEE-519 contains thirteen sections, each with standards and technical reports [11]:
Section 1 [Introduction and Scope]. Includes application of the standards.
Section 2 [Definition and Letter Symbols].
Section 3 [References]. Includes standard references.
Section 4 [Converter Theory and Harmonic Generation]. Includes documents for converters, arc furnaces, static VAr compensators, inverters for dispersed generation, electronic control, transformers, and generators.
Section 5 [System Response Characteristics]. Includes resonance conditions, effect of system loading, and typical characteristics of industrial, distribution, and transmission systems.
Section 6 [Effect of Harmonics]. Detrimental effects of harmonics on motors, generators, transformers, capacitors, electronic equipments, meters, relaying, communication systems, and converters.
Section 7 [Reactive Power Compensation and Harmonic Control]. Discusses converter power factor, reactive power compensation, and control of harmonics.
Section 8 [Calculation Methods]. Includes calculations of harmonic currents, telephone interference, line notching, distortion factor, and power factor.
Section 9 [Measurements]. For line notching, harmonic voltage and current, telephone interface, flicker, power factor improvement, instrumentation, and statistical characteristics of harmonics.
Section 10 [Recommended Practices for Individual Consumers]. Addresses standard impedance, customer voltage distortion limits, customer application of capacitors and filters, effect of multiple sources at a single customer, and line notching calculations.
Section 11 [Recommended Harmonic Limits on the System]. Recommends voltage distortion limits on various voltage levels, TIF limits versus voltage level, and IT products.
Section 12 [Recommended Methodology for Evaluation of New Harmonic Sources].
Section 13 [Bibliography]. Includes books and general discussions.
IEEE-519 sets limits on the voltage and current harmonics distortion at the point of common coupling [PCC, usually the secondary of the supply transformer]. The total harmonic distortion at the PCC is dependent on the percentage of harmonic distortion from each nonlinear device with respect to the total capacity of the transformer and the relative load of the system. There are two criteria that are used in IEEE-519 to evaluate harmonics distortion:
limitation of the harmonic current that a user can transmit/inject into utility system [THDi], and
limitation of the voltage distortion that the utility must furnish the user [THDv].
The interrelationship of these two criteria shows that the harmonic problem is a system problem and not tied just to the individual load that generates the harmonic current.
Tables 1.7 and 1.8 list the harmonic current and voltage limits based on the size of the user with respect to the size of the power system to which the user is connected [1,64].
Table 1.7. IEEE-519 Harmonic Current Limits [1,64] for Nonlinear Loads at the Point of Common Coupling [PCC] with Other Loads at Voltages of 2.4 to 69kV
| <20b | 4.0 | 2.0 | 1.5 | 0.6 | 0.3 | 5.0 |
| 2050 | 7.0 | 3.5 | 2.5 | 1.0 | 0.5 | 8.0 |
| 50100 | 10.0 | 4.5 | 4.0 | 1.5 | 0.7 | 12.0 |
| 1001000 | 12.0 | 5.5 | 5.0 | 2.0 | 1.0 | 15.0 |
| >1000 | 15.0 | 7.0 | 6.0 | 2.5 | 1.4 | 20.0 |
Here Isc=maximum short circuit current at PCC,
IL=maximum load current [fundamental frequency] at PCC.
For PCCs from 69 to 138kV, the limits are 50% of the limits above. A case-by-case evaluation is required for PCCs of 138kV and above.
aEven harmonics are limited to 25% of the odd harmonic limits above.bAll power generation equipment is limited to these values of current distortion, regardless of the actual Isc/IL.Table 1.8. IEEE-519 Harmonic Voltage Limits [1,64] for Power Producers [Public Utilities or Cogenerators]
| Maximum for individual harmonics | 3.0 | 1.5 | 1.0 |
| Total harmonic distortion [THDv] | 5.0 | 2.5 | 1.5 |
The short-circuit current ratio [RSC] is defined as the ratio of the short-circuit current [available at the point of common coupling] to the nominal fundamental load current [Fig. 1.23]:
Figure 1.23. Equivalent circuit of power system and nonlinear load. ZS is small [or ISC is large] for strong systems, and ZS is large [or ISC is small] for weak systems.
Thus the size of the permissible nonlinear user load increases with the size of the system; that is, the stronger the system, the larger the percentage of harmonic current the user is allowed to inject into the utility system.
Table 1.8 lists the amount of voltage distortion [1,64] specified by IEEE-519 that is acceptable for a user as provided by a utility. To meet the power quality values of Tables 1.7 and 1.8, cooperation among all users and the utility is needed to ensure that no one user deteriorates the power quality beyond these limits. The values in Table 1.8 are low enough to ensure that equipment will operate correctly.
Introduction
Joseph Yiu, in The Definitive Guide to Arm® Cortex®-M0 and Cortex-M0+ Processors [Second Edition], 2015
1.1.4 What Type of Skills Do I Need to Start Learning Microcontroller Programming?
In this book, I assumed that you already know a bit of C programming. Some experiences of using any microcontrollers will certainly help a lot.
Knowledge on electronic engineering areas like digital interface circuits can help you to understand some of the examples in this book and enable you to start creating your own electronics projects. It is possible to create your own microcontroller boards, but this often requires more design experience. To make the learning process easier, for beginners, or people who are not familiar with electronic engineering should consider starting off with off-the-shelve microcontroller development boards. They are ready to use and this will save a lot of time in debugging hardware issues.
Engineering and Engineering Sciences*
Hsue-shen Tsien, in Collected Works of H.S. Tsien [19381956], 2012
b] Electronics
The electronics engineering can be divided in to two main divisions: The division which deals with electronic tubes themselves and the division which treats the circuits and the radiation fields. The second division mainly involves an application of the classical Maxwell theory.The general character of the results is expected, in spite of the fact that such calculations may be very complicated and may require advance mathematical technique. The performance of tubes is, however, seldom comprehensively analyzed. The design of these tubes is generally worked out by numerous tests, guided by a few basic principles. However, the electronics engineering has now passed its heroic age of invention and creation and has entered the age of engineering development. The empirical approach may not be the most economical one in this new situation where detailed improvement of the various devices has to be carried out. This is especially true for very high frequency tubes where the electron inertia effect can no longer be neglected. It seems necessary to develop an engineering method of calculating such flow fields of electron cloud under the combined effect of rapidly varying external electric and magnetic fields. If this is done, then the characteristics of electronic tubes or other similar devices can be analyzed and the experimental data coordinated.
Radio Navigation Systems
Revised by D.G. Jablonski, in Reference Data for Engineers [Ninth Edition], 2002
INTRODUCTION
Electromagnetic waves at radio and microwave frequencies can be used for the precise measurement of time, distance, and direction. Several factors make this possible. First, one can generate extremely accurate timing signals using a variety of techniques, including atomic clocks. In addition, radio and microwave signals can be generated coherently, so that their frequency and phase are well controlled and easily measured. Because of the low ambient thermal noise at these frequencies, radio signals can be detected at extraordinarily low power levels [ 160 dBW using time integration techniques]. In addition, the diverse propagation characteristics of radio waves, as a function of frequency, permit engineers to exploit over-the-horizon transmission at low frequencies, and sight-limited propagation at high frequencies. The high resolution afforded by the short signal wavelengths at higher microwave frequencies, the effects of constructive interference at all frequencies, and the always useful Doppler effect are also utilized to good advantage in modern radio navigation systems.
However, in recent years, there has been considerable change in the radio navigation systems deployed throughout the world. In particular, several time-honored systems, including Omega and the Transit satellite system, are no longer operational. Efforts to develop the Microwave Landing System [MLS], which was intended to replace the existing Instrument Landing System [ILS] used by aircraft, have been reduced greatly, at least in the United States. In their stead, the Global Positioning System [GPS] has been deployed and declared operational, and is now the system of choice for worldwide radio navigation. The Russian counterpart to GPS, the GLONASS system, is also operational, and an additional worldwide satellite-based radio navigation system, called Galileo, is under development in Europe. In addition, various military communications systems, such as the Joint Tactical Information Distribution System, or JTIDS, have an incipient radio navigation capability for their users.
In addition to the new systems, the venerable VOR, TACAN, DME, and Air Traffic Control Radar Beacon System [ATCRBS] remain stalwarts of the commercial and military aircraft navigation infrastructure.
Major Navigation Agencies
Airlines Electronic Engineering Committee [AEEC], Annapolis Science Center, Annapolis, Maryland: A division of Aeronautical Radio, Inc. [ARINC] and owned by the scheduled US airlines. Publishes technical standards for avionics purchased by the scheduled airlines.
Airline Owners and Pilots Association [AOPA], Washington, DC: Defends the needs of the airline industry and pilots with regard to safety-of-life issues, frequency allocation that affects radio navigation systems, etc.
Department of Transportation, United States Coast Guard [USCG], Washington, DC: Operates the Loran-C navigation system for marine and aeronautical navigation; operates and maintains a beacon system for differential GPS in the coastal regions of the United States and along the Mississippi River.
Federal Aviation Administration [FAA], Washington, DC: Operates navigation aids and air traffic control systems for both civil and military aircraft in the US and its possessions.
Federal Communications Commission [FCC], Washington, DC: The agency that licenses transmitters and operators in the United States and aboard US registered ships and aircraft.
International Air Transport Association [IATA], Montreal, Canada: The international association representing scheduled airlines.
International Civil Aviation Organization [ICASO], Montreal, Canada: A United Nations agency that formulates standards and recommended practices, including navigation aids, for all civil aviation.
International Telecommunication Union [ITU], Geneva, Switzerland: An agency of the United Nations that allocates frequencies for best use of the radio spectrum.
RTCA, formerly Radio Technical Commission for Aeronautics, Washington, DC: Supported by contributions from industry and government agencies. Participation by manufacturers, users, and others in the recommended standards for aviation electronics. The ICAO and the FAA adopt many of these standards, at least in part.
Radio Technical Commission for Maritime Services [RTCM], Washington, DC: Functions similar to those of RTCA; however, addresses primarily marine issues.
Human-aware localization using linear-frequency-modulated continuous-wave radars
J.-M. Muñoz-Ferreras, ... C. Li, in Principles and Applications of RF/Microwave in Healthcare and Biosensing, 2017
Abstract
Electrical and electronic engineering is moving forward to improve the quality of life of people. In particular, electromagnetic sensors can be used to detect and localize persons indoors and outdoors. The range of applications is vast, going from the fall detection of elderly people at home to the monitoring of vital signs for healthcare applications, the detection of trapped persons after avalanches or earthquakes, and human-aware localization gaming.
Radars have emerged as interesting noncontact devices which can contribute to the implementation of these ideas. In particular, coherent linear-frequency-modulated continuous-wave [LFMCW] radars are short-range devices with unique features. This chapter reviews these advantages in terms of architecture, cost, signal processing issues, resolution, accuracy, phase-based precision, clutter isolation, and so forth.
Simulations and experimental data are also provided to confirm the suitability of LFMCW radar prototypes to human-aware localization applications.
Electrical
Ray Tricker, Samantha Tricker, in Environmental Requirements for Electromechanical and Electronic Equipment, 1999
9.1 Guidance
9.1.1 What is electrical?
Electrical and electronic engineering is recognised as probably the largest and most diverse field of engineering and is concerned with the development, design, application and manufacture of systems and devices that use electric power and signals. Among the most important subjects in the field are electric power and machinery, electronic circuits, control systems, computer design, superconductors, solid state electronics, medical imaging systems, robotics, lasers, radar, consumer electronics and fibre optics.
9.1.2 Introduction
Electrical engineering can be divided into two main branches: electric power and electronics.
Electric power is concerned with the design and operation of systems for generating, transmitting and distributing electric power.
One of the most important developments in the last 30 years has been the ability to transmit power at extremely high voltages in both the direct current [d.c.] and alternating current [a.c.] modes, reducing power losses proportionately.
Electronic engineering deals with the research, design, integration and application of circuits and devices used in the transmission and processing of information.
Electronic engineers design circuits to perform specific tasks, such as amplifying electronic signals, adding binary numbers and demodulating radio signals to recover the information they carry.
9.1.3 Test categories
This sort of test requires the electronic assembly, or its subassemblies, to be subjected to a complete examination of its/their performance in order to determine whether it/they correspond to the specification.
Correct operation of all the electronic control equipment should be checked within the normal limits of system voltage, battery voltage and air pressure.
In particular, checks should be made to see that the operation of the equipment is not disturbed during start-up of any auxiliary services [e.g. lighting, an auxiliary set, compressor, etc.] and power circuits [e.g. a chopper, combustion engine, etc.]. Checks should also be made to establish whether any interference produced by electronic control devices disturbs other equipment, in particular data transmission installations, safety devices, etc. [e.g. see EN 50155].
The aim of this test which is carried out on printed board assemblies [by sampling] is to ensure components are not mounted too close to surrounding metal parts.
The test has to be carried out with the printed board connected in its place of operation. The test voltage [of a nominal frequency of 50 Hz or 60 Hz] is then applied for 1 minute between all the terminals [with the printed board short-circuited] and the metal rack of the electronic assembly.
For dielectric tests the r.m.s. value of the test voltage is as follows:
Table 9.1. r.m.s. test voltage values
| 500 V | For rated supply voltages up to and including 72 V |
| 1000 V | For rated supply voltages between 72 V and 125 V |
Note: The test is considered satisfactory if neither a disruptive discharge nor a flashover occurs.
All terminals of the electronic equipment which are directly connected magnetically or statically coupled to external circuits and which are likely to produce voltage surges that could cause damage to electronic equipment are normally subjected to a voltage surge test.
During this test a surge voltage of an agreed waveform [see Table 9.2] is applied at the points of connection between the electronic equipment and external circuits of the operating equipment.
Table 9.2. Waveform of normally permitted voltage surges
| Û | 1.5kV ± 3% |
| Impedance [resistive] | 100Ω ± 20% |
| D | 50μs ± 20% |
The surge voltage should be applied in both directions [positive and negative] and in the case of power supply connections, the surge voltages should be superimposed on the nominal supply voltage.
The waveform parameters are normally agreed between the user and the manufacturer and are typically:
The test should be considered as satisfactory if the equipment continues to operate without malfunction or damage both during and following application of the voltage surge.
The electronic assembly under test is placed, without any voltage applied, in a room where the temperature is progressively lowered from the ambient temperature [25°C ± 10°C] to 25°C, or to the lowest agreed temperature over a period of time equal to or greater than 30 minutes.
The assembly is then kept for a further period of 2 hours at this low temperature with a permitted tolerance of ± 3°C.
At the end of this period, a performance test [see 9.1.3.1] needs to be carried out with the equipment kept at this low temperature.
For this particular test, the electronic assembly [which is normally supplied with power] is placed in a room where the temperature is progressively raised from the ambient temperature [25°C ± 10°C] to 70°C [with a tolerance of ± 2°C] or to the highest agreed temperature over a period of time equal to or greater than 30 minutes.
The assembly should then be kept for 6 hours at this temperature, at the end of which a performance test should be carried out.
The electronic assembly is placed, without any voltage being applied, in a chamber where the temperature is raised from the ambient temperature [25°C ± 10°C] to 55°C ± 2°C over a period of time between 1½] hours and 2½ hours. The relative humidity being stabilised between 80% and 100%.
The temperature is then maintained for a further period of 10 hours within the limits of 55°C ± 2°C, with a relative humidity of 95% to 100%.
At the end of this time, the temperature is lowered to the ambient temperature [25°C ± 10°C], over a period of 3 hours, with the relative humidity being between 80% and 100%. After this cycle, a performance test and a dielectric test needs to be completed.
Note: IEC Test 68.2.30: Damp heat, cyclic [12 + 12 hour] is the preferred test as it more closely represents those conditions in which equipment will be stored or operated. [See paragraph 4.4.3.]
In this test the test chamber is kept tightly closed and if the test includes the necessity for a salt solution, it should continue without interruption during the whole conditioning period. The duration of the test is chosen so as to suit the intended purpose and should be subject to an agreement between the user and the manufacturer.
At the end of the test, the equipment is then washed under a running tap for 5 minutes or rinsed in distilled or demineralised water. It is then shaken by hand [to remove any droplets of water] and stored under standard atmospheric conditions in the testing area for not less than 1 and not more than 2 hours.
After this storage period, the components are then subjected to a visual examination, followed by measurements and verification tests necessary to check their correct operation.
Note: IEC 68.2.11 and 68.2.52 are the recommended tests for salt mist and cyclic salt mist environmental parameters. [See paragraphs 6.4.1 and 6.4.3.]
The electronic assembly, in operating condition, is placed in a room where the temperature is progressively raised from the ambient temperature [25°C ± 10°C] to 70°C or to the highest agreed temperature [with a tolerance of ±2°C] for between 1½ hours and 2½ hours [depending on the customer], with a relative humidity of 80% to 100%.
Dust [which is normally specified and, if necessary, provided by the user at the time of specifying the item] is sprayed over the electronic assembly. The quantity and the method of application are subject to an agreement between the user and the manufacturer.
At the end of this test, a performance test and a dielectric test should be carried out.
Note: IEC 68.2.68: Environmental testing procedures Dust and sand is a more stringent test than this basic test and is recommended [see paragraph 7.4.4].
The complete electronic assembly [or subassembly] together with any auxiliaries and mounting arrangements [including its shock absorbing devices if the equipment is designed for mounting on such devices] should be subjected to the tests in three orthogonal planes under the ambient temperature condition of the testing area.
For these tests, the equipment should be secured in a suitable position to a machine producing sinusoidal vibrations with an adjustable amplitude and frequency.
In order to determine the possible existence of critical resonant frequencies producing resonance during this test, the frequency should be varied progressively from 1 Hz to 100 Hz within a time of not less than 4 minutes. The amplitude of the oscillations being a function of the frequency.
If resonance is produced, the corresponding frequency should be maintained for a few minutes in each case.
The equipment is then subjected to a test with sustained vibrations for not less than 15 minutes [to be agreed between the user and the manufacturer], either at the critical frequencies or, otherwise, at a frequency of 10 Hz.
As electronic equipment is generally mounted either inside a room or a vehicle or in external boxes, there is no real need to carry out watertightness tests. In exceptional cases, however, tests can be carried out in accordance with clause 7 of IEC 165 and clause 8 of IEC 490.
Note: Current thinking suggests that watertightness tests are, however, very relevant in some circumstances [e.g. equipment exposed to rain, water jets, etc.] and the reader is referred to Section 6.4 for the appropriate tests.
9.1.4 Other related tests and standards
This book, by its very nature, recommends numerous alternative tests to those shown above and the reader's attention is drawn to the relevant chapters.
INTRODUCTION TO ELECTROMAGNETICS
Hung-Yu David Yang, in The Electrical Engineering Handbook, 2005
Electromagnetics is fundamental in electrical and electronic engineering. Electromagnetic theory based on Maxwell's equations establishes the basic principle of electrical and electronic circuits over the entire frequency spectrum from dc to optics. It is the basis of Kirchhoff's current and voltage laws for low-frequency circuits and Snell's law of reflection in optics. For low-frequency applications, the physics of electricity and magnetism are uncoupled. Coulomb's law for electric field and potential and Ampere's law for magnetic field govern the physical principles. Infrared and optical applications are usually described in the content of photonics or optics as separate subjects. This section emphasizes the engineering applications of electromagnetic field theory that relate directly to the coupling of space and time-dependent vector electric and magnetic fields, and, therefore, most of the subjects focus on microwave and millimeter-wave regimes. The eleven chapters in this section cover a broad area of applied electromagnetics, including fundamental electromagnetic field theory, guided waves, antennas and radiation, microwave components, numerical methods, and radar and inverse scattering.
OPTIMIZING POLYMERIC STRUCTURES OF ORGANIC ELECTRONIC PACKAGES
Sulaiman Khalifeh, in Polymers in Organic Electronics, 2020
9.1 OVERVIEW
The organic electronic packaging is a field of electronic engineering, focusing on enclosing and protecting polymer-based electronic, microelectronic, and nanoelectronic systems from mechanical damage, cooling, radio frequency noise emission, electrostatic discharge, moisture, and other environmental conditions. The main packaging technologies are casting, potting, encapsulation, impregnation, filling, sealing, and coating. The selection of packaging technology depends on maintenance, thermal dissipation, electrical performance, operator convenience, reliability, and cost. The optimized polymers that can be selected for electronic packaging are adhesives, solid machinable products, liquids, or conductive polymer composites. The application of polymer adhesives includes die attachment, underfills, and encapsulation. Based on the polymeric structure, polymer packaging can be divided into electronic, microelectronic, microelectromechanical MEMS, nanoelectronic, and optoelectronic packaging, and polymer adhesives. Based on the use of material, the packaging of electronic systems is divided into ceramic and polymeric types [Figure 9.1197198]. Packaging classification also recognizes different mounting methods, such as through-hole mount surface THD, surface-mount packaging SMD, and custom packaging techniques.16,48,276277
Figure 9.1. Classification of polymers used with organic electronic packaging.197198
The through-hole mount surface technique includes insertion of lead pins and soldering them into holes of 0.8-1.0 mm in diameter, which were drilled through the organic printed circuit board. The surface-mount packaging technique includes soldering lead pins directly to a soldered pattern provided on the organic printed circuit board. The soldered pattern is called mount pad. The custom packaging techniques include mounting of memory integrated circuits ICs on an organic printed circuit board. The polymer packaging systems can be divided into polymer dual in-line package, single in-line package, and zigzag in-line package ZIP.3,6 Examples of through-hole mount surface THD packaging include7,8 dual in-line package DIP and pin grid array P-GA package. Examples of surface-mount packaging SMD packaging include10 quad flat package QFP and quad flat J-leaded QFJ package. Examples of custom packaging techniques include tape carrier package TCP and tape automated bonding TAB techniques.