of primary phase voltage of transformer between terminals C and C′magnitude of secondary phase voltage of transformer between terminals a and a′magnitude of secondary phase voltage of transformer between terminals b and b′magnitude of secondary phase voltage of transformer between terminals c and c′magnitude of primary phase voltage of transformer between terminals A and A′magnitude of secondary phase voltage of transformer between terminals a and a′VBAmagnitude of primary line‐to‐line voltage of transformers between terminals B and AVbamagnitude of secondary line‐to‐line voltage of transformers between terminals b and amagnitude of primary line‐to‐line voltage of transformers between terminals B and Amagnitude of primary line‐to‐line voltage of transformers between terminals C and Bmagnitude of primary line‐to‐line voltage of transformers between terminals A and Cmagnitude of secondary line‐to‐line voltage of transformers between terminals b and amagnitude of secondary line‐to‐line voltage of transformers between terminals c and bmagnitude of secondary line‐to‐line voltage of transformers between terminals a and cVArunit for imaginary/reactive power Q called volt‐ampere reactivevc(t = −0)vc(t) voltage before switching occurs at t = 0vL(t = +0)vL(t) voltage after switching occurs at t = 0vC(t = ∞)vC(t) at an infinite amount of time VMamplitude of time function v(t)VSIvoltage source inverterVCcapacitor voltage
W
wwaveshapingWwork/energy, iron‐core widthWCwork stored in capacitorWcoreenergy stored in iron coreWgapenergy stored in air gapWL(t)energy/work stored in inductor as a function of timeWswatt‐seconds
X
xx‐coordinate of x‐y spatial rectangular system, variable of integration(x, y, z)Cartesian coordinate system with x, y, z componentsx(t)x‐variable as a function of timeXreactance, variable for voltage and currentXMamplitude of time function x(ωt)Xmmagnetizing/cross‐branch reactance of transformerXlsleakage reactance of secondary windingXlineper phase reactance of distribution/transmission linesecondary leakage reactance referred to primary side of transformerXlpleakage reactance of primary windingXrms = Xeffroot‐mean‐square (rms) or effective (eff) value of a quantityXloadload reactance
Y
yy‐coordinate of x‐y spatial rectangular system, subscript refers to admittance Ywinding connected in wye/Y/star phasor admittance as a function of angular velocity or frequency ωY‐Y or Y/Yprimary and secondary windings of three‐phase transformer are connected in wye or starY‐Δ or Y/Δprimary winding of three‐phase transformer is connected in wye and secondary winding in deltacross‐branch phasor admittance of transformeradmittance phasorYMamplitude of sinusoidal/cosinusoidal time function y(ωt)
Z
zz‐coordinate of a spatial x, y, z or r, φ, z systemimpedance phasorzeros of transfer function G(jω) from 1, …, mphasor impedance as a function of angular velocity or frequency ωcapacitive phasor impedanceinductive phasor impedanceZZener diodecomplex numberphasor load impedancephasor load impedance when in Δ connectionphasor impedance of ith Y‐connected transformer loadphasor impedance of ith Δ‐connected transformer loadphasor impedance of first Δ‐connected transformer loadphasor impedance of second Δ‐connected transformer loadphasor impedance of first Y‐connected transformer loadphasor impedance of second Y‐connected transformer loadphasor impedance of Y‐connected transformer loadphasor impedance of first connected transformer loadphasor impedance of second connected transformer loadphasor transmission/distribution line impedancephasor input impedance of primary circuitphasor reflected impedance of secondary circuit as viewed from primary circuit phasor output impedance of secondary circuitimpedance of secondary winding of transformerimpedance of secondary winding referred to the primary side of the transformercross‐branch/magnetizing impedance of transformerimpedance of primary winding of transformerphasor load impedance of secondary circuit referred to primary circuit of transformerphasor total impedanceZoutoutput impedanceZininput impedanceZCSelectronic zero‐current switchzigzagzigzag transformer (a special type of three‐phase transformer)
