Optimal Placement of Harmonic Filters in Electric Power Networks: Eko Distribution Network as Case Study

ABSTRACT

Many researchers have proposed the attenuation of injected harmonic magnitudes with

electronic filters as the panacea for resonance problems in electric power distribution networks.

Identifying suitable ratings and locations for the filters is a subject of on-going research, and Genetic

Algorithm has been deployed on certain occasions as meta-heuristic optimization method for the

optimal location of such compensation devices. This paper has proposed a guide based on a non-linear

loop current analysis in time domain, with the total harmonic distortion and current amplification at

several parts of the network employed as parameters for filter location because they portray the danger

or risk level imposed on each section of the network by resonance. The creation of dummy loops is also

introduced to accommodate the connection of capacitor banks, filter branches and cable capacitances

during the network calculations. The developed tool has successfully been applied to a section of Eko

distribution network in Lagos Metropolis which contains induction furnaces at two load centers. A

passive filter was designed and applied in two locations where the highest current amplifications were

attained. Verification of the designed filter has revealed a significant decrease in the magnitude of 5th

order harmonic current and outright elimination of 107th order harmonic current. The proposed

technique will guide the Power Quality Engineer in identifying the resonance conditions at the design

or modification stage of electric power networks as well as undertaking adequate precautionary

measures to minimize resonance events and the associated economic losses.

Keywords — Amplification Factor; Dummy Loop; Distortion Profile; Filter; Resonance