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The neutral current can be determined by adding the three phase currents together as complex numbers and then converting from rectangular to polar co-ordinates. If the three-phase root mean square (RMS) currents are I L 1 {\displaystyle I_{L1}} , I L 2 {\displaystyle I_{L2}} , and I L 3 {\displaystyle I_{L3}} , the neutral RMS current is:
Three-phase transformer with four-wire output for 208Y/120 volt service: one wire for neutral, others for A, B and C phases. Three-phase electric power (abbreviated 3ϕ [1]) is a common type of alternating current (AC) used in electricity generation, transmission, and distribution. [2]
Symmetrical components are most commonly used for analysis of three-phase electrical power systems. The voltage or current of a three-phase system at some point can be indicated by three phasors, called the three components of the voltage or the current. This article discusses voltage; however, the same considerations also apply to current.
The voltages between the three phases are the same in magnitude, however the voltage magnitudes between a particular phase and the neutral vary. The phase-to-neutral voltage of two of the phases will be half of the phase-to-phase voltage. The remaining phase-to-neutral voltage will be √ 3 /2 the phase-to-phase voltage. So if A–B, B–C and ...
With the same argument, a set of three line currents in a balanced three-wire three-phase power system cannot contain harmonics whose frequency is an integer multiple of the frequency of the third harmonics; but a four-wire system can, and the triplen harmonics of the line currents would constitute the neutral current.
One voltage cycle of a three-phase system. A polyphase system (the term coined by Silvanus Thompson) is a means of distributing alternating-current (AC) electrical power that utilizes more than one AC phase, which refers to the phase offset value (in degrees) between AC in multiple conducting wires; phases may also refer to the corresponding terminals and conductors, as in color codes.
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 ...
Weak neutral current interactions are one of the ways in which subatomic particles can interact by means of the weak force. These interactions are mediated by the Z boson . The discovery of weak neutral currents was a significant step toward the unification of electromagnetism and the weak force into the electroweak force , and led to the ...