（低功率因数的2 Deleterious effects of poorpower factor危害)☆PTPFV.·PF1·Increasing power lossintransmission lines,transformers,generators
2 Deleterious effects of poor power factor (低功率因数的 危害)☆ •Increasing power loss in transmission lines, transformers, generators. V PF PF P 1 I = s s
3Deleteriouseffectsofharmonicdistortion（谐波的危害)☆·lncreasing power loss in transmission lines,transformers,generators.: The utility voltage waveform will also become distorted,diadversely affecting other linear loads.Vpcc= V,- Ls1dt6PCOtherequipmentFigure 5-25 Line-voltage notching and distortionFigure 5-26Voltage waveform at the point of common coupling in thecircuitofFig.5-25
8 3 Deleterious effects of harmonic distortion (谐波的危 害)☆ •Increasing power loss in transmission lines, transformers, generators. • The utility voltage waveform will also become distorted, dt dis adversely affecting other linear loads. vPCC = vs − Ls1
Maycausing resonanceconditionsbetweenthecapacitive reactance of the shunt capacitors and theinductive reactanceof thetransmission lines.·Overloading the shunt capacitors used by utilities forvoltage support.·May causing EMIidCdROther equipmentFigure5-25 Line-voltage notching and distortionFigure5-26Voltage waveform at thepoint of common coupling in thecircuit of Fig.5-25
9 •May causing resonance conditions between the capacitive reactance of the shunt capacitors and the inductive reactance of the transmission lines. •Overloading the shunt capacitors used by utilities for voltage support. • May causing EMI
（谐波准则）：IEEE5194HarmonicGuidelinesTable18-2HarmonicCurrentDistortion(l/l)TotalOddHarmonicOrderh(%)Harmonich<1117≤h<2323≤h<3535≤hDistortion (%)Iscll,11≤h<175.01.50.60.3<204.02.02.51.00.58.020-507.03.51.54.54.00.712.050-10010.05.55.02.01.015.012.0100-10002.51.47.06.020.015.0>1000Note:Harmonic current limits for nonlinear load connected to a public utility at the point of common coupling (PCC)with other loads at voltages of 2.4-69kV.Is is themaximum short-circuit current at PCC.I, is the maximumfundamental-frequency load current at PCC.Even harmonics are limited to 25% of the odd harmonic limits above.Source:Reference 1.>Commonlyusedforspecifyinglimitsontheinput current distortion
4 Harmonic Guidelines (谐波准则) : IEEE 519 ➢Commonly used for specifying limits on the input current distortion