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Showing papers on "Harmonics published in 1982"


Book
01 Jan 1982
TL;DR: Theory of load compensation and reactive power control in electric transmission systems has been studied in this article, with a focus on the effects of reactive power on the dynamic performance of transmission systems.
Abstract: Theory of Load Compensation. Theory of Steady--State Reactive Power Control in Electric Transmission Systems. Reactive Power Compensation and the Dynamic Performance of Transmission Systems. Principles of Static Compensators. Design of Thyristor Controllers. An Example of a Modern Static Compensator. Series Capacitors. Synchronous Condensers. Reactive Compensation and the Electric Arc Furnace. Harmonics. Reactive Power Coordination. Selected Bibliography. Index.

697 citations


Journal ArticleDOI
TL;DR: In this paper, the conventional Newton-Raphson power flow study has been reformulated to permit the inclusion of nonlinear loads, which give rise to harmonic signals which propagate throughout the power system.
Abstract: The conventional Newton-Raphson power flow study has been reformulated to permit the inclusion of nonlinear loads. These loads give rise to harmonic signals which propagate throughout the power system. The reformulation is based on the reduction to zero of the mismatch active power and reactive voltamperes, the imbalance current at harmonic frequencies, and the mismatch apparent Voltamperes. Conclusions on the existence of positive, negative, and zero sequence signals are made for harmonic frequencies. The harmonic power flow study formulation is illustrated for a three phase full wave bridge rectifier. A companion paper presents a discussion of the actual computer implementation and several practical examples.

256 citations


Journal ArticleDOI
TL;DR: In this paper, a statistical analysis of power spectra demonstrates that at least 10-30% of Pc 3 pulsations can be classified as harmonic events, which can be explained by a standing Alfven wave consisting of many discrete harmonic frequencies.
Abstract: Power spectra of magnetic pulsations observed at synchronous orbit by the ATS 6 satellite often show several spectral peaks simultaneously. Such pulsations, called harmonic events because of the nearly constant separation between successive peaks, are continuously observed in the dayside in the Pc 3-4 frequency range (6.6-100 mHz). The harmonic events are seen clearly only in the east-west magnetic field component. The spectral peaks are regularly spaced with a typical minimum separation of 14 mHz in the morning gradually decreasing to 10 mHz in the afternoon. In the dynamic spectra of harmonic events, the fundamental mode is usually absent. In addition, the relative amplitudes of the higher harmonics depend on the magnetic latitude. These observed features can be explained by a standing Alfven wave consisting of many discrete harmonic frequencies. A statistical analysis of power spectra demonstrates that at least 10-30% of Pc 3 pulsations can be classified as harmonic events. For a selected event on August 7, 1975, the plasma mass density at the synchronous orbit is estimated to be 3-8 hydrogen mass/cu cm.

161 citations


Journal ArticleDOI
TL;DR: In this article, the authors reviewed a number of artefactual limitations in the current EXAFS analysis and suggested an efficient correction of the effects of X-ray leakage is suggested whereas the presence or the elimination of harmonics can be assessed by monitoring the reproducibility of the edge jump when calibrated metallic foils of different nature are inserted behind the sample.
Abstract: This paper is reviewing a number of artefactual limitations in the current EXAFS analysis. In conventional absorption measurements, the major sources of errors are the transmission of harmonics by the monochromator and inevitable leakages of radiation around or through the sample. The consequences are an alteration of the amplitude of the signal but also some harmonic distortion of the EXAFS oscillations and a systematic perturbation of the measured Debye-Waller terms. An efficient correction of the effects of X-ray leakage is suggested whereas the presence or the elimination of harmonics can be assessed by monitoring the reproducibility of the edge jump when calibrated metallic foils of different nature are inserted behind the sample. The basic analysis developed for absorption measurements has been successively extended to the case of REFLEXAFS and various emission techniques : X-ray fluorescence/scattering, optical luminescence and total electron yield. It became possible to rationalize a number of experimental observations and to determine appropriate operating conditions.

152 citations


Journal ArticleDOI
TL;DR: In this paper, the eLectric power flow problem is reformulated to account for harmonic signals which arise from nonLinear loads, and the problem of initialization of bus voltages (including harmonics) is considered and convergence of the algorithm is assessed from the theoretical viewpoint and from the results of actual studies.
Abstract: This is a companion paper to a paper of the same title, Part I, in which the eLectric power flow problem is reformulated to account for harmonic signals which arise from nonLinear loads. In this paper, implementation and practical applications are discussed. The problem of initialization of bus voltages (including harmonics) is considered and convergence of the algorithm is assessed from the theoretical viewpoint and from the results of actual studies. The principal content of this paper is two examples both containing nonlinear loads (rectifiers).

125 citations


Journal ArticleDOI
TL;DR: In this article, the contribution to the errors of a regularly sampling wattmeter caused by using n distinct instantaneous samples of the input signals taken at equal intervals of time is evaluated and discussed.
Abstract: The contribution to the errors of a regularly sampling wattmeter caused by using n distinct instantaneous samples of the input signals taken at equal intervals of time is evaluated and discussed. It is shown that although most of the possible harmonic products are handled correctly, a significant number of harmonic autoproducts and particularly of harmonic cross products are not, namely all the components of the nth, 2nth, 3nth, ... product harmonics. Sinusoidal waveforms are handled correctly, and the errors with near-sinusoidal waveforms are generally negligible. Two particular classes of non-sinusoidal waveforms are examined, those controlled by phase-angle switching and those associated with discharge lamps.

104 citations


Journal ArticleDOI
TL;DR: In this article, the harmonic currents, apparent, active, reactive and distortion power associated with a cluster of taper-current type battery chargers, connected to a common bus, were analyzed.
Abstract: This work analyzes the harmonic currents, apparent, active, reactive and distortion power associated with a cluster of electric vehicle taper-current type battery chargers, connected to a common bus. A Monte Carlo simulation using pseudorandum number generators taking into consideration the statistical distribution of the states of charge of the batteries and starting times of the chargers is the primary tool employed in this study.

70 citations


Journal ArticleDOI
D. J. Jackson1, James J. Wynne1
TL;DR: In this paper, it was shown that destructive interference between two coherent excitation pathways from different optical harmonics, a fundamental and a third harmonic, inhibits resonance-enhanced multiphoton ionization.
Abstract: It is shown that destructive interference between two coherent excitation pathways from different optical harmonics, a fundamental and a third harmonic, inhibits resonance-enhanced multiphoton ionization. Once the role of the third harmonic is realized, the interference follows naturally from simple considerations of Fermi's "golden rule" and Maxwell's equations.

64 citations


Journal ArticleDOI
TL;DR: A general method for computing the coefficients, at any order, of the Lame's functions used to define a set of orthogonal polynomials called ellipsoi, illustrated by the calculation of the free energy of a molecule seperated from a dielectric.

59 citations


Journal ArticleDOI
TL;DR: In this paper, simple recursive expressions for the harmonics using a sampling rate of 12 times a cycle were given for a three-phase, three-winding power transformer, which were used as the basis for a one cycle algorithm which was compatible with proposed digital line protection schemes.
Abstract: This paper presents an algorithm for digital protection of a three-phase, three-winding power transformer. Simple recursive expressions are given for the harmonics using a sampling rate of 12 times a cycle. These expressions are used as the basis for a one cycle algorithm which is compatible with proposed digital line protection schemes. The algorithm was tested on data obtained from a model transformer. Test results are given for 19 cases of energizations and faults.

59 citations


Proceedings ArticleDOI
14 Jun 1982
TL;DR: In this paper, an ac to dc converter which draws sinusoidal and in phase current waveforms from the ac power source is described, and a stability analysis and design methodology is given.
Abstract: An ac to dc converter which draws sinusoidal and in phase current waveforms from the ac power source is described. Harmonic and power factor measurements obtained from an FET converter operating at 45 kHz for a single phase and a three phase connection are presented. A stability analysis and design methodology is given.

Patent
30 Apr 1982
TL;DR: In this paper, the authors proposed a test and method for nondestructively detecting nonlinearity faults in conductors, including the application of a composite AC and DC drive signal to the device under test in such manner that nonlinearities in the devices under test produce fault signals including second harmonics, due to local changes of resistance caused by ohmic heating.
Abstract: The tester and method for nondestructively detecting nonlinearity faults in conductors includes the application of a composite AC and DC drive signal to the device under test in such manner that nonlinearities in the device under test produce fault signals including second harmonics, due to local changes of resistance caused by ohmic heating. Electronic filters are used to select out and amplify the second harmonic only, eliminating the direct current and fundamental frequency components of the initial test pulse, plus third and subsequent harmonics. The filtered second harmonic signals from the device under test are then phase-compared to a phase-shifted second harmonic signal produced by a frequency doubler from the test signal generator oscillator to cancel out the second harmonic signals from the good conductor; the remaining phase anomaly signals control a threshold detector remaining to provide fault indication.

Journal ArticleDOI
TL;DR: In this article, the ISIS 1 satellite passes through the auroral kilometric radiation (AKR) source region and the sounder receiver often detects harmonic bands of radiation associated with the fundamental AKR band.
Abstract: When the ISIS 1 satellite passes through the auroral kilometric radiation (AKR) source region the sounder receiver often detects harmonic bands of radiation associated with the fundamental AKR band. These harmonic components were earlier attributed to a nonlinear instrumental response to the strong wide-band bursty AKR fundamental signal. Evidence is here presented that indicates that these harmonics are of natural origin, namely: (1) all the harmonic signals are sometimes observed to have nearly the same bandwidth, (2) when the fundamental signal has two components the harmonic signal sometimes corresponds to the weaker rather than the stronger component, (3) a weak harmonic can be observed to be associated with a weak fundamental, and (4) a 'harmonic' signal can be observed when there is no fundamental.

Journal ArticleDOI
TL;DR: In this article, the nonlinear propagation characteristics of surface acoustic waves on an isotropic elastic solid have been studied and the solution of the harmonic boundary value problem for Rayleigh waves is obtained as a generalized Fourier series whose coefficients are proportional to the slowly varying amplitudes of the various harmonics.
Abstract: The nonlinear propagation characteristics of surface acoustic waves on an isotropic elastic solid have been studied in this paper. The solution of the harmonic boundary value problem for Rayleigh waves is obtained as a generalized Fourier series whose coefficients are proportional to the slowly varying amplitudes of the various harmonics. The infinite set of coupled equations for the amplitudes when solved exhibit an oscillatory slow variation signifying a continuous transfer of energy back and forth among the various harmonics. A conservation relation is derived among all the harmonic amplitudes.

Journal ArticleDOI
TL;DR: In this paper, a new weighted least square scheme for differential protection of power transformers using digital techniques is presented, where the differential current waveform is modeled as a sum of decaying de, fundamental and selected higher harmonic components.
Abstract: The paper presents a new weighted least-square scheme for differential protection of power transformers using digital techniques. The differential current waveform is modeled as a sum of decaying de, fundamental and selected higher harmonic components. The model coefficients are established by using a least-square filtering technique for the sampled data. A root mean square error criterion is established to select the proper harmonic orders, data window, weighting matrix and sampling rate for fast detection of internal faults and high restraint against energizing transients in transformers. A variety of simulated waveforms is presented to highlight the important features of this algorithm. The results clearly demonstrate the efficacy and weakness of the weighted least square model.

Journal ArticleDOI
N. Sasaki1
TL;DR: In this article, it was shown experimentally and theoretically that only odd harmonics are generated for the ring oscillators with an odd number of stages, and the propagation delay t pd of the nth harmonic oscillation is given by t = n \cdot T/2N where T is the observed repetition period and N the number of stage.
Abstract: Harmonic generation is found with 101-stage ring oscillators. Harmonics have not been observed for the usual ring oscillators with a small number of stages. If one mistakes the higher harmonic generation for the fundamental, he obtains a wrong propagation delay which is shorter than the real one. It is shown experimentally and theoretically that only odd harmonics are generated for the ring oscillators with an odd number of stages. The propagation delay t pd of the nth harmonic oscillation is given by t_{pd} = n \cdot T/2N where T is the observed repetition period and N the number of stages. Computer simulation shows that a ring oscillator with an even number of stages can also oscillate if every inverter is the same, and that the oscillation decays if there is asymmetry in the inverter chain. If N is large and the effects of the deviations of the transistor parameters cancel one another, the harmonic oscillation that happens to be generated can continue.

Journal ArticleDOI
TL;DR: In this paper, a general formula for angular integrations in many-dimensional spaces (derived in a previous paper) is applied to several problems connected with solution of the Schrodinger equation for many-particle systems.
Abstract: A general formula for angular integrations in many-dimensional spaces (derived in a previous paper) is applied to several problems connected with solution of the Schrodinger equation for many-particle systems. Matrix elements of the Hamiltonian are derived for cases where the potential can be expressed in terms of functions of the generalized radius multiplied by polynomials in the m coordinates. The theory of hyperspherical harmonics is reviewed, and a sum rule is derived relating the sum over all the harmonics belonging to a particular eigenvalue of angular momentum to the Gegenbauer polynomial corresponding to that eigenvalue. A formula is derived for projecting out the component of an arbitrary function corresponding to a particular eigenvalue of generalized angular momentum, and the formula is applied to polynomials in the m coordinates. An expansion is derived for expressing a many-dimensional plane wave in terms of hyperspherical harmonics and functions which might be called “hyperspherical Bessel functions.” It is shown how this expansion may be used to calculate many-dimensional Fourier transforms. A formula is derived expressing the effect of a group-theoretical projection operator acting on a many-dimensional plane wave. Finally, the techniques mentioned above are used to expand the Coulomb potential of a many-particle system in terms of Gegenbauer polynomials.

Journal ArticleDOI
01 Nov 1982
TL;DR: In this paper, a new theory of the libration of the Moon, completely analytical with respect to the harmonic coefficients of the lunar gravity field, was presented, which is represented through its third degree harmonics for the torque due to the Earth (second degree for the Sun).
Abstract: This paper presents a new theory of the libration of the Moon, completely analytical with respect to the harmonic coefficients of the lunar gravity field. This field is represented through its third degree harmonics for the torque due to the Earth (second degree for the torque due to the Sun).

Journal ArticleDOI
TL;DR: In this article, the performance of five types of battery chargers for use with electric vehicles is compared with a typical electric vehicle battery pack and an 8-hour recharge cycle based on a typical EV battery pack.
Abstract: This report compares the performance of five types of battery chargers for use with electric vehicles. Chargers with and without controlled rectifiers for maintenance of constant charging current and with and without current-smoothing inductors are analyzed. Based on a typical electric vehicle battery pack and an 8 hour recharge cycle, current and voltage waveshapes, current harmonic levels, power, reactive and distortive volt-amperes, voltage distortion factor, and power factor are reported for each charger type.

Book ChapterDOI
TL;DR: In this article, the authors have observed a sequence of periodic and chaotic regimes that alternate as a function of the flow rate in a stirred flow chemical reactor, which correspond to a smooth one-dimensional map that has a single maximum and a positive Lyapunov exponent.
Abstract: In experiments on a stirred flow chemical reactor we have observed a sequence of periodic and chaotic regimes that alternate as a function of the flow rate. The periodic regimes are characterized by power spectra consisting of a single fundamental frequency component and harmonics and by limit cycle attractors, while the chaotic regimes are characterized by broadband power spectra and strange attractors. One of the chaotic regimes has been studied in detail and has been found to correspond to a smooth one-dimensional map that has a single maximum and a positive Lyapunov exponent.

Journal ArticleDOI
TL;DR: In this paper, the effects of quantum noise on the operation of a ring-laser gyro were investigated and exact expressions for the spectrum and the mean beat frequency of the beat signal were obtained in terms of infinite continued fractions.
Abstract: This is the second of three papers dealing with the effects of quantum noise on the operation of a ring-laser gyro. Exact expressions for the spectrum and the mean beat frequency of the beat signal are obtained in terms of infinite continued fractions. The spectrum is found to be always separable into a "coherent" $\ensuremath{\delta}$-function contribution at zero frequency, representing the effects of locking, and an "incoherent" part of nonzero band-width. Computed forms for the spectrum and the frequency response curve are presented for parameter values appropriate to the ring-laser gyro. The results obtained show that for laser rotation rates corresponding to the locked zone in the absence of noise, the tendency for locking as measured by the strength of the coherent contribution continues to dominate, but this effect rapidly becomes negligibly small outside this zone. In addition, the transition in beat frequency between the locked and unlocked zones which is discontinuous in the noise-free case ceases to be well defined in the presence of noise. Finally, the higher harmonics predicted to occur in the unlocked zone in the absence of noise are found to reoccur in the presence of noise except that the individual harmonics are now found to be broadened.


Journal ArticleDOI
TL;DR: The unsteady upstream influence associated with insertion of an impingement wedge in an unstable mixing layer is shown to enhance the coherence at the fundamental frequency of vortex formation, and to produce well defined higher harmonics in a manner strikingly similar to artificial excitation of the corresponding nonimpinging flow as mentioned in this paper.
Abstract: The unsteady upstream influence associated with insertion of an impingement wedge in an unstable mixing layer is shown to enhance the coherence at the fundamental frequency of vortex formation, and to produce welldefined higher harmonics in a manner strikingly similar to artificial excitation of the corresponding nonimpinging flow. Each of the higher harmonic components grows at a rate 1.6 times that of the fundamental component, agreeing well with strong nonlinear interaction theory. Furthermore, assuming a state of quasiamplitude equilibrium at each streamwise station, the absolute value of each of the higher harmonic components was obtained from the Stuart perturbation model; the first harmonic amplitudes agree well with predicted values. At amplitude equilibrium, there is also very favorable agreement. Finally, a spectral analysis of the unsteady velocity expression of the Stuart model allowed comparison of measured and predicted velocity spectra; there is good agreement in both amplitude and shape of the spectra away from the center (y0f5) of the shear layer.

Journal ArticleDOI
TL;DR: In this paper, the authors present the techniques and measures used by Calgary Power Ltd. to mitigate inductive interference problems into communiation circuits using triple harmonic currents generated by distribution transformers.
Abstract: The paper presents the techniques and measures used by Calgary Power Ltd. to mitigate inductive interference problems into communiation circuits. Investigation of several cases of triple harmonic-noise problems indicated a new role of triple harmonies, generated by distribution transformers, in the interference mechanism. Trriple harmonic currents on distribution phases form an unbalanced set of phasors which have in general an equivalent positive, negative and zero-sequence components.

Journal ArticleDOI
TL;DR: In this paper, it was shown that the potential energy function, because of rotational invariance, can be expressed in terms of six-dimensional harmonics for J = 0 only.
Abstract: It is noted that the potential energy function, because of rotational invariance can be expressed in terms of six‐dimensional harmonics for J = 0 only. (AIP)

Journal ArticleDOI
TL;DR: In this paper, the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, the development of analytical techniques to calculate the harinonic impedance of the system, and comparison of the calculated and measured results.
Abstract: This paper is Part I of a two part series. The two papers will report part of the research project RP-1138 sponsored by EPRI and BPA on HVDC-AC System Interaction from AC Harmonics. The two papers deal with the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, the development of analytical techniques to calculate the harinonic impedance of the system, and comparison of the calculated and measured results.

Journal ArticleDOI
TL;DR: In this article, the authors describe the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, and the development of analytical techniques to calculate harmonic impedance of the system, and compare the calculated and measured results.
Abstract: This paper is Part II of a two part series. The two papers will report part of the research project RP-1138 sponsored by EPRI and BPA on HVDC-AC System Interaction from AC Harmonics. The two papers describe the harmonic impedance measurement of Bonneville Power Administration's (BPA) system as seen from the Celilo HVDC substation, the development of analytical techniques to calculate the harmonic impedance of the system, and comparison of the calculated and measured results.

Patent
17 Aug 1982
TL;DR: In this article, a frequency domain geophysical electromagnetic surveying system is provided in which intermittent primary fields having sharp terminations are generated in a cycle having a fundamental frequency by a transmitter, and a receiver includes a gate passing only secondary signals received during interruptions of the primary field, the gated signal being applied to filters tuned to harmonics of the predetermined frequency.
Abstract: A frequency domain geophysical electromagnetic surveying system is provided in which intermittent primary fields having sharp terminations are generated in a cycle having a fundamental frequency by a transmitter, and a receiver includes a gate passing only secondary signals received during interruptions of the primary field, the gated signal being applied to filters tuned to harmonics of the predetermined frequency. The filter outputs are synchronously demodulated to provide signals corresponding to at least the in-phase component of the secondary signal at the fundamental frequency, and preferably in-phase and quadrature components at at least two harmonics. The system can provide improved resolution particularly of the characteristics of in-phase secondary signals received from terrain being surveyed.


Journal ArticleDOI
TL;DR: In this paper, it is shown that the unique spectrum of information for each satellite contained within a comprehensive spherical harmonic model can be represented by simple gravitational constraint equations (lumped harmonics), all such constraints are harmonic in the argument of perigee (ω) with constants determinable directly from tracking data or reconstituted from the comprehensive solution.