The well-known and widely applied Thévenin theorem is applied to the operational analysis of ac transmission circuits. The approach is to model the transmission circuit AI as an n-port. The ...calculation of the Thévenin equivalent impedance is found by applying an n-vector of currents to AI and observing the behavior of the terminal voltages of AI. The Thévenin equivalent voltage is an n-vector and this is simply the open-circuit voltage of AI. The equivalent circuit is applied to conveniently study the transmission circuit performance for a range of different operating conditions. The treatment of controlled sources in the model is described. The application of Thévenin's theorem to a class of multiport circuits has been described before, and the application to three-phase circuits has been suggested; however, the contribution in this paper is the treatment of transformers and modeling mutual coupling between phases in transmission components, and the application to general polyphase circuits.
There is a direct analogy between the mechanical and electrical phenomena related to vibrations and electromagnetic oscillations in the RLC series AC circuits and an inverse analogy to the ...electromagnetic oscillations in the RLC parallel alternative current (AC) circuits. Direct analogy RLC series AC circuit refers to the connection between complex velocity and complex electrical intensity, mechanical impedance and electrical impedance, etc. Reverse analogy RLC parallel AC circuits refers to the connection between complex velocity and complex electrical voltage, mechanical impedance and electrical admission, etc.
Use of Phasors in Nonlinear Analysis Borys, Andrzej; Zakrzewski, Zbigniew
International Journal of Electronics and Telecommunications,
09/2013, Letnik:
59, Številka:
3
Journal Article
Recenzirano
Odprti dostop
In this paper, the well-known method of phasor analysis of linear ac circuits is extended in a rigorous mathematical way to nonlinear analysis. This fills the lack of such a theory in the literature. ...The results derived enable carrying out the needed corrections of some results published recently that regard harmonic distortion analysis of weakly nonlinear circuits.
This paper describes and demonstrates the principle and efficacy of a novel direct current fault interruption scheme using a reactor in series with a controlled rectifier and a conventional AC ...circuit breaker. The presence of the series reactor limits the capacitive discharge current from the DC filter capacitor at the output terminals of the phase-controlled rectifier. In addition, the series reactor along with the filter capacitor forms an underdamped series RLC circuit which forces the fault current to oscillate about zero. This synthetic alternating current can then be interrupted using a conventional AC circuit breaker. The selection criteria for the series reactor and overcurrent protection are presented as well. Using the proposed scheme for an example case, a DC fault current magnitude is reduced from 56 kA to 14 kA, while the interruption time is reduced from 44 ms to 25 ms.
Research efforts by the nuclear power industry and, most recently, its regulatory agency, the U.S. Nuclear Regulatory Commission (USNRC), have provided information useful for risk-informed analysis ...of the effects of spurious actuation (“hot shorting”) of alternating current (AC) electrical circuits at nuclear power plants. The results from these efforts have been integrated into a methodology to predict the likelihood of spurious actuation of AC circuits due to fires in commercial nuclear power plants.
► Three separate models for fire-induced AC circuit electrical “failure” have been integrated. ► The “Cable Failure” model predicts both the time and probability of thermally induced failure. ► The “Hot Short Probability” model estimates the likelihood of inadvertent equipment actuation. ► The “Hot Short Duration” model predicts the probability of double or triple hot short concurrence. ► The integrated model is demonstrated via an example application.
This paper will focus on single-phase ac circuits and develop the definitions for ac powers (complex power, active (real) power, and reactive power). Then, I will discuss design and development of ...interactive instructional virtual instrument (VI) for studying basic single phase ac circuits. These VI demonstrate how to take power measurements using a NI USB-6008 multifunction I/O device, which interfaces to the PC through a USB connector. PUBLICATION ABSTRACT
This book provides an understandable and effective introduction to the fundamentals of DC/AC circuits. It covers current, voltage, power, resistors, capacitors, inductors, impedance, admittance, ...dependent/independent sources, the basic circuit laws/rules (Ohm’s law, KVL/KCL, voltage/current divider rules), series/parallel and wye/delta circuits, methods of DC/AC analysis (branch current and mesh/mode analysis), the network theorems (superstition, Thevenin’s/Norton’s theorems, maximum power transfer, Millman’s and substitution theorems), transient analysis, RLC circuits and resonance, mutual inductance, transformers, and more.
Electric power and energy measurements are probably the most important and critical measurements in power systems, since they are used to quantify every energy transactions and assign an economical ...value to energy flowing through a given section of the grid. Things became even more complex when the first AC distribution systems began to be used as an alternative and more efficient way to distribute electricity and, in the end, replaced the DC systems almost completely. It is generally thought that power and energy definitions are the same for DC and AC circuits. Under time‐varying conditions, electric and magnetic fields exist in the same point of space and are related by Maxwell equations. Wattmeters and energy meters are probably among the oldest instruments built since the industrial exploitation of electric energy. Power and energy measurements are performed in power systems at all voltage levels, from low‐voltage to ultrahigh‐voltage systems.
Techniques for Solving AC Circuits Ceraolo, Massimo; Poli, Davide
Fundamentals of Electric Power Engineering,
2014, 2014-04-25
Book Chapter
This chapter is mainly devoted to the analysis of alternating current (AC) circuits, in which all the quantities (mainly currents, voltages, powers) vary as sinusoids over time. In addition, it deals ...with two kinds of circuits in which the quantities do not vary as sinusoids, namely the R L circuit (containing a resistor and an inductor) and the R C circuit (containing a resistor and a capacitor). The chapter introduces circuit branches, whose idealized behaviour can be mathematically described by other constitutive equations. Since these are differential equations, it shows that the corresponding components have some energy storage capability and are therefore called globally energy storage elements. The phasors circuit was introduced, showing that Kirchhoff's equations can be written directly in terms of phasors.
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