Results 291 to 300 of about 10,262,280 (355)

Effects of Current Harmonics on Maximum Loading Capability for Solar Power Plant Transformers

2020 International SAUPEC/RobMech/PRASA Conference, 2020
Distribution transformers are commonly designed and manufactured to operate at fundamental frequency and to facilitate sinusoidal loads. The operation of loads that draw distorted currents culminate in higher losses, hotspot temperatures, degradation of ...
Dr Bonginkosi Thango, J. Jordaan, A. Nnachi   +2 more
semanticscholar   +1 more source

Harmonic Contributions Evaluation With the Harmonic Current Vector Method

IEEE Transactions on Power Delivery, 2008
A method to evaluate harmonic contributions at the point of common coupling is presented in this paper. The proposed approach is based on the harmonic current vector method where reference impedances are introduced. Resistance defined at fundamental frequency with measurements is used as the customer-side reference impedance.
Tomaz Pfajfar, Bostjan Blazic, Igor Papic   +2 more
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Harmonic measurements: current and voltage transducers

199 IEEE Power Engineering Society Summer Meeting. Conference Proceedings (Cat. No.99CH36364), 2003
An overview of the development of special current and voltage transducers at the National Research Council of Canada for accurate measurements of harmonics in power systems will be presented. The transducers include two-stage and electronically-aided instrument transformers, openable-core AC and AC/DC current transformers, multi-stage clamp-on current ...
openaire   +1 more source

Inductive load current harmonic injection

Proceedings of the Thirty-Fourth Southeastern Symposium on System Theory (Cat. No.02EX540), 2003
Induction motor audible noise can be related to the frequency content present in the stator winding currents. These currents produce time varying air gap fluxes which in turn produce exciting forces resulting in vibrations in the mechanical structure. By adding harmonics into the winding currents, additional frequencies can be added to the air gap flux
B. Brzezinski, J. Parker, T.A. Haskew, J. Murphree, D.J. Jackson   +4 more
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Current Harmonics Measurement by Means of Current Transformers

IEEE Transactions on Power Delivery, 2007
This paper analyzes the accuracy of current transformers (CT) when excited with nonsinusoidal currents. It uses a nonlinear model that accounts for the minor hysteresis loop of the core. It was concluded that instrument transformers with accuracy class 0.6 or better provide reasonably accurate measurements of current harmonics magnitudes, however the ...
Alexander E. Emanuel, John A. Orr
openaire   +1 more source

Current harmonics in nonlinear resistance circuits

Electrical Engineering, 1935
A semigraphical method of solving for harmonics in the input current to a network containing any number of linear and nonlinear resistances in any combination, when a sinusoidal voltage is applied across the network, is presented herewith. The treatment is restricted to nonlinear resistances in which the d-c volt-ampere characteristic is the same ...
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Harmonic-current-restrained relays for differential protection

Electrical Engineering, 1938
DIFFERENTIAL relaying is the commonly accepted means of protecting large power transformers, a-c generators, and station bus systems against internal faults.1 The methods and circuits employed in various instances, while differing in detail, are all fundamentally the same in basic principle.
L. F. Kennedy, C. D. Hayward
openaire   +1 more source

Alternating current sensor with second-harmonic detection

Applied Optics, 2000
We describe a novel optical sensor based on the Faraday effect for measuring ac. The sensing element is a piece of material of high Verdet constant placed between polarizers. When the angle between the polarizers differs by 45 degrees, a signal of twice the frequency of the ac is generated--in addition to the usual signal with the same frequency as the
J A, Ferrari, C D, Perciante, A, Dubra, A, Arnaud, E M, Frins   +4 more
openaire   +2 more sources

Divisors and Harmonic Currents

2001
In the first two sections of the present chapter we introduce a conjecture (Conjecture 7.1) which specifies the idea that the characterization of the divisor of the Selberg zeta function of the a-twisted geodesic flow proved in Chapter 3 Section 3.3 is related to its characterizations in terms of a-twisted harmonic currents on SX.
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Even harmonics in alternating-current circuits

Proceedings of the American Institute of Electrical Engineers, 1909
In the usual presentation and consideration of wave-forms in alternating-current circuits we are so used to the mathematical expressions which omit the second, fourth, sixth, etc. harmonics and so generally assume that these even harmonics can be neglected at the outset, that a short consideration of usual and special conditions, giving rise to even ...
openaire   +1 more source