1 Abstract-- In this paper, the validity of the single-point measurements methods and indices, which were proposed for harmonic source detection and sharing harmonic responsibility between utility and consumer, are investigated in a typical distribution system which consists of several critical load cases. A parametrical analysis by means of the variation of the utility side impedance’s X/R ratio is also undertaken. The results provide that the conventional methods and indices based on the flow direction of the harmonic active power are still the most effective tools for the harmonic source detection in the typical distribution systems. Index Terms-- harmonic source detection; sharing harmonic responsibility; harmonic source quantification. I. INTRODUCTION AND BACKGROUND RESENT day power systems invariably have nonlinear loads, which inject harmonics into the system and give rise to non sinusoidal voltages and currents. The most important effect of the harmonic distortion can be underlined as the increased losses and decreased life expectancy of the power system equipment [1]. Thus, the costs associated with harmonic disturbances and any necessary mitigation equipment should be recovered from the consumers that produce harmonic pollution [2]. However, the guidelines and standards on the limitation of harmonic pollution do not provide any tool to detect those consumers [3]-[9]. Therefore, to fulfil this gap, several methods and indices are proposed in the literature. Active Power Direction (APD) method is one of the oldest [10] and probably the most commonly used [11] method today, and based on the sign of the harmonic active power. It defines consumer side as the dominant harmonic source if the respective harmonic active power has a negative sign; otherwise, source side is the dominant for the considered harmonic orders. In addition to these, two indices were proposed by means of the same way [12], [13]: one is that Supply Load Quality (SLQ) index express the harmonic producing quantity of the load as; This work was supported in part by Turkish Scientific Council under the project number of 110E113. M. Erhan Balci is with Balikesir University, Electrical and Electronics Engineering department, Balikesir, Turkey (e-mail: mbalci@balikesir.edu.tr). M. Hakan Hocaoglu is with Gebze Institute of Technology, Electronics Engineering department, Kocaeli, Turkey (e-mail: hocaoglu@gyte.edu.tr). 1 SLQ PP = (1) where P and P 1 are the active and fundamental harmonic active powers, respectively [12]. Thus, the load is detected as the dominant source for the harmonic distortion when the value for SLQ is smaller than unity; otherwise, supply side is the dominant source for the harmonic distortion. Second index, Harmonic Global Index, is defined as; 2 2 h h h hs HG I I ∈ ∈ = ∑ ∑ ` (2) where ℓ is the harmonic orders related to the harmonic active powers, which have the negative sign, and s is vice versa [13]. A non-zero value of HG index shows that the load causes harmonic distortion. Linearity Current method [14] defines the harmonic contributions of utility and consumer sides by separating the load current into two components; namely, linear current, which is drawn by the R-L equivalent impedance part of the load, the remaining current when the linear current is subtracted from total current in time domain. The two current components can be expressed as: the linear current; () ( ) 1 1 2 h h h h h V i t sin h t Z = = ω +θ - φ ∑ ` (3) and the nonlinear current; () () () n i t it i t = - ` ` (4) Where h h h Z Z = ∠φ is the h th harmonic linear load impedance, which is equivalent with the serial connection of the resistance, ( ) 1 1 1 1 Re R V I = ∠θ ∠δ and the h th harmonic inductance, ( ) 1 1 1 1 Im h X h V I = ⋅ ∠θ ∠δ . Therefore, the index that gives the harmonic responsibility of the consumer is expressed as; ( ) % 100 n I NLC I = ⋅ ` (5) Superposition and Projection (SP) method, presented in [15], separates harmonic currents into the utility and the customer portions using Norton equivalents of the utility and the consumer sides as illustrated in Fig. 1. On the Validity of Harmonic Source Detection Methods and Indices M. Erhan Balci and M. Hakan Hocaoglu P ▀▀ ▀▀ 978-1-4244-7245-1/10/$26.00 ©2010 IEEE