Calculation of voltage fluctuation caused by intermittent loads

Abstract Intermittent loads, such as grinders and welders, are the main factors that degrade the power quality in the distribution system. Intermittent loads will result in voltage fluctuations with stochastic characteristics, which may lead to malfunction of other sensitive loads. This paper uses cumulant method to calculate the bus voltage fluctuation using the algebraic addition and multiplication. The probability density function of the voltage fluctuation can be further expressed by the Gram‐Charlier series expansion. Compared with traditional methods, computation complexity can be simplified and computation time can be markedly reduced by the proposed method. The simulation results from an 11‐bus industrial distribution system with grinders show the applicability of the proposed method.

[1]  F. S. Prabhakara.  A fast discrete method for voltage drop and current calculation for manufacturing facilities with intermittent loads , 1990, Conference on Industrial and Commercial Power Systems.

[2]  A. T. De Almeida.  Understanding power quality , 1993 .

[3]  X. Wang,et al.  Modern power system planning , 1994 .

[4]  D. Koval,et al.  Proposed chapter 9 for predicting voltage sags (dips) in revision to IEEE Std 493, the Gold Book , 1993, Conference Record Industrial and Commercial Power Systems Technical Conference 1993.

[5]  F. S. Prabhakara,et al.  Current calculation methodology for manufacturing facilities with intermittent loads , 1990, Conference on Industrial and Commercial Power Systems.

[6]  A. Meliopoulos,et al.  Power System Reliability Evaluation Using Stochastic Load Flows , 1984, IEEE Transactions on Power Apparatus and Systems.

[7]  J. Stremel,et al.  Production Costing Using the Cumulant Method of Representing the Equivalent Load Curve , 1980, IEEE Transactions on Power Apparatus and Systems.

[8]  Turan Gonen,et al.  Electric power distribution system engineering , 1985 .

[9]  W.E. Kazibwe,et al.  Frequency and duration of voltage drop in plants with intermittent loads , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.

[10]  George J. Cokkinides,et al.  A new probabilistic power flow analysis method , 1990 .

[11]  C. Becker,et al.  Proposed chapter 9 for predicting voltage sags (dips) in revision to IEEE Std 493, the Gold Book , 1993 .

[12]  C. D. Kemp,et al.  Kendall's Advanced Theory of Statistics, Vol. 1: Distribution Theory. , 1995 .

[13]  J.F. Dopazo,et al.  Stochastic load flows , 1975, IEEE Transactions on Power Apparatus and Systems.

[14]  Lester La Verne Helms.  Introduction to Probability Theory: With Contemporary Applications , 1996 .