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

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

3. 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.

4. 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

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

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

7. 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

8. 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.

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

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

11. 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.