METHOD TO DETERMINE CONTRIBUTION OF THE CUSTOMER AND THE POWER SYSTEM TO THE HARMONIC DISTURBANCE Paper 2.32

Regulatory context Problematic with the measurement of the currents emitted by installations Estimation methods Results Prospects and conclusions

Regulatory context Evolution of technical methods of connection In addition to limits per equipment, a tendency towards the definition of limits per installation. Commitments of network operators and customers in terms of power quality and particularly harmonics. This evolution will require measurement methods to check the network operator’s and users’ reciprocal commitments.

Problematic with the measurement of the currents emitted by installations The current measured (Ih) at the point of common coupling is the vector sum of the current emitted by the customer (Ihc) towards the network and the network towards the customer (Ihs). Purpose: Determine harmonic single-phase equivalent circuit at the point of common coupling . Vh Upstream part : S Supply or source side Downstream part : C Installation or customer side Ihs Ihc Ih=Ihs+Ihc JS JC ZS ZC Ih Vh Source Installation

Estimation method based on the sign of The ratio provides: The impedance if

Non linear regression estimation method Determination of harmonic single-phase equivalent parameters: Through error minimization based on harmonic current and voltage at PCC.

Iterative estimation method Alternated determinations by means of network equations: Stage 1: presumedly equal to the previous estimated values, estimation of Stage 2: presumedly equal to the previous estimated values, estimation of

Results The definition of algorithms and two dedicated measurement campaigns made it possible to cross a stage. The method using the sign of allowed coherent harmonic impedance estimations when significant harmonic variations occur. The iterative method enabled interest to follow on line equivalent parameters, but it requires a precise initial value. iterative method appears to be a very good complement with the precedent method The non-linear regression brought encouraging results but only in some cases.

Result example Algorithm application for the method using the sign of Harmonic variation

Result example Algorithm application for the iterative method. Scc ~ = 20 kV Measurement point Domestic loads 590 V PdN=660 kW Current (A)

Prospects and conclusions Technical objective: Define an approach scrutinizing sudden harmonic variations at the point of common coupling in order to apply the method using the sign of The iterative method makes it possible to follow-up these values over the time. General objective: Promote methods to determine contribution of the customer and power system to harmonic disturbance to check the network operator’s and users’ reciprocal commitments.