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In electrical circuits, reactance is the opposition presented to alternating current by inductance and capacitance. [1] Along with resistance, it is one of two elements of impedance; however, while both elements involve transfer of electrical energy, no dissipation of electrical energy as heat occurs in reactance; instead, the reactance stores energy until a quarter-cycle later when the energy ...
In electrical engineering, impedance is the opposition to alternating current presented by the combined effect of resistance and reactance in a circuit. [1]Quantitatively, the impedance of a two-terminal circuit element is the ratio of the complex representation of the sinusoidal voltage between its terminals, to the complex representation of the current flowing through it. [2]
The state is very brief, as the current in the damper winding quickly decays allowing the armature flux to enter the rotor poles only. The generator goes into transient state; in the transient state (′) the flux is still out of the field winding of the rotor. The transient state decays to steady-state in few cycles. [6]
Foster's reactance theorem is an important theorem in the fields of electrical network analysis and synthesis. The theorem states that the reactance of a passive, lossless two-terminal ( one-port ) network always strictly monotonically increases with frequency.
Inductive reactance = increases as frequency increases, while capacitive reactance = decreases with increase in frequency (defined here as a positive number). At one particular frequency, these two reactances are equal and the voltages across them are equal and opposite in sign; that frequency is called the resonant frequency f 0 for the given ...
The condition was first proposed by Wilhelm Cauer (1926) [5] who determined that it was a necessary condition. Otto Brune (1931) [2] [6] coined the term positive-real for the condition and proved that it was both necessary and sufficient for realisability.
As an example of how per-unit is used, consider a three-phase power transmission system that deals with powers of the order of 500 MW and uses a nominal voltage of 138 kV for transmission. We arbitrarily select S b a s e = 500 M V A {\displaystyle S_{\mathrm {base} }=500\,\mathrm {MVA} } , and use the nominal voltage 138 kV as the base voltage ...
Note, , the reactance in parallel, has a negative reactance because it is typically a capacitor. This gives the L-network the additional feature of harmonic suppression since it is a low pass filter too. The inverse connection (impedance step-up) is simply the reverse—for example, reactance in series with the source.