Harmonic source identification in electrical power network with multiple non-linear loads

Abstract This paper presents a novel technique for identifying the sources of individual harmonics in an electrical network that contains multiple nonlinear loads. The differential in the harmonic apparent power flowing through a section of the network is used to trace the source of the harmonic. The technique is proposed as an improvement over active and reactive power flows, which have been widely used in literature for identifying harmonic sources. Analytical models are derived to justify the use of apparent power flow as a method for locating harmonic sources. A comparative analysis is performed on the reliability of applying active, reactive, and apparent power flows for each harmonic component in identifying harmonic sources in a network comprising linear and nonlinear load structures. A criterion for assessing the applicability of the developed method is developed. A case study of a transmission network that supplies electricity to an industrial area that mainly consists of steel manufacturing plants is used to validate the developed technique. The developed technique is equally implemented in a hardware laboratory test rig. Results obtained from the analysis show that the flow of apparent power proves to be the most promising in predicting the source of harmonics in a network. Knowledge of the network and source impedances is not required in the application of the method. A choice of metering point or the relative size of the source and consumer impedances does not affect the results obtained with the method, provided that the developed application criterion is met. The developed method can be used to detect harmonic sources when multiple loads are connected to a point of common coupling (PCC).