AS/NZS 61000.3.6:2001

1 - AS/NZS 61000.3.6:2001 ELECTROMAGNETIC COMPATIBILITY (EMC) - LIMITS-ASSESSMENT OF EMISSION LIMITS FOR DISTORTING LOADS IN MV A
4 - PREFACE
6 - CONTENTS
9 - 1 Scope
10 - 2 Reference documents
10 - 3 Basic concepts
10 - Compatibility levels
11 - Planning levels
12 - Assessment procedure
13 - Emission levels
13 - 4 General principles
14 - Stage 1: simplified evaluation of disturbance emission
14 - Stage 2: emission limits relative to actual network characteristics
14 - Stage 3: acceptance of higher emission levels
14 - Responsibilities
16 - 5 General guidelines for the assessment of emission levels
16 - 5.1 Assessment of harmonic injection from distorting loads
16 - Operating conditions of the distorting loads
16 - Non-ideal operating conditions
17 - 5.2 Harmonic impedance
17 - 5.2.1 Simplified assessment methods
17 - 5.2.2 Detailed manual calculations
17 - 6 Summation laws
18 - 6.1 First summation law
18 - 6.2 Second summation law
19 - 7 Emission limits for distorting loads in MV systems
19 - 7.1 Stage 1: simplified evaluation of disturbance emission
20 - 7.1.1 Weighted distorting power as a reference value
21 - 7.1.2 Relative harmonic currents as emission limits
21 - 7.2 Stage 2: emission limits relative to actual network characteristics
22 - 7.3 Stage 3: acceptance of higher emission levels
22 - 8 Emission limits for distorting loads in HV systems
22 - 8.1 Stage 1: simplified evaluation of disturbance emission
22 - 8.2 Stage 2: emission limits relative to actual network characteristics
22 - 8.2.1 Assessment of the total available power
23 - 8.2.2 Individual emission limits
23 - 8.3 Stage 3: acceptance of higher emission levels
23 - 9 Emission limits for interharmonics
24 - 10 Emission limits for telephone interference effects
25 - APPENDIX A - Harmonic impedance, Zh - Simplified assessment methods
25 - A.1 Simplified assessment methods
28 - APPENDIX B - Example of the manual calculation of the harmonic impedance of a MV network at the PCC (as used in Germany)
28 - B.1 Capacitive reactive power
29 - B.2 Load of the network PN
29 - B.3 Example of the calculation of the impedance of the network, by successive addition of the values of each element of ....
31 - B.4 Calculation of the impedance of the network with the reduced equivalent circuit
33 - APPENDIX C - Example of particular rules for stage 1 limits in MV networks
34 - APPENDIX D - Stage 2 emission limits for distorting loads in MV systems - Two possible apportioning approaches
34 - D.1 Simplified approach based on the first summation law
35 - D.2 General approach based on the second summation law
41 - APPENDIX E - Stage 2 emission limits for distorting loads in HV systems - Two possible methods of assigning total ....
41 - E.1. Stage 2: emission limits relative to actual network characteristics
44 - APPENDIX F - Examples in some typical HV cases [12]
44 - F.1 Konti-Skan 2 HVDC Link
46 - F.2 Steel factory
48 - APPENDIX G - Example of the "worst case impedance curve" approach
49 - APPENDIX H - General case of MV loads spread along the feeders: sharing of emission
49 - H.1 General
49 - H.2 Definition of the harmonic injection distribution along the feeders: the reference injection set
50 - H.3 Evaluation of the harmonic voltage response of the system to the reference injection set of harmonic currents along...
51 - H.4 Evaluation of the harmonic current emission limits
52 - H.5 HV systems
54 - APPENDIX I - Example of application of the approaches proposed for assessing emission limits
54 - I.1 Reference network and assumptions
55 - I.2 First approximation
56 - I.3 Second approximation
58 - I.4 Third approximation
61 - I.5 Summary of the main results
63 - APPENDIX J - List of principal letter symbols, subscripts and symbols
63 - Letter symbols
63 - List of subscripts
64 - List of principal symbols
66 - APPENDIX K - Bibliography

Proposes a set of principles which are intended to be used as the basis for determining the requirements for connecting large distorting loads (producing harmonics and/or interharmonics) to public power systems. This Standard provides guidance on engineering practices which will ensure adequate service quality for all connected consumers.

This Standard outlines principles which are intended to be used as the basis for determining the requirements for connecting large distorting loads (producing harmonics and/or interharmonics) to public power systems. The primary objective is to provide guidance for engineering practices which will ensure adequate service quality for all connected consumers. Since the guidelines outlined in this Standard are necessarily based on certain simplifying assumptions, there is no guarantee that this approach will always provide the optimum solution for all harmonic problems. The recommended approach should be used with flexibility and judgement as far as engineering is concerned, when applying the given assessment procedures in full or in part. The final decision regarding the connection of distorting installations will always rest with the utility. Problems related to harmonics fall into two basic categories: – The harmonic currents are injected into the supply network by converters and other harmonic sources. Both harmonic currents and resulting voltages can be considered as conducted phenomena. The objective of this Standard is to limit actual harmonic voltages on supply systems to levels (compatibility levels) that will not result in adverse effects on sensitive equipment. Since the harmonic voltages result from harmonic currents and impedances, this involves limiting the harmonic currents injected into the system. – The harmonic currents in the range 50 Hz to 5 kHz may induce interference into communication systems. This phenomenon is more pronounced at higher order harmonic frequencies because of increased coupling between the circuits and because of the higher sensitivity of the communication circuits in the audible range. This Standard primarily focuses on controlling or limiting harmonic voltages and their effects, but a clause is included to address communication interference. Appendices A, B, C, D, E, F, G, H, I, J and K are for information only. NOTES 1 The load is to be understood as the complete consumer’s installation. 2 This Standard uses the following terms for system voltage:– low voltage (LV) refers to Un <= 1 kV;– medium voltage (MV) refers to 1 kV < Un <= 35 kV;– high voltage (HV) refers to 35 kV < Un <= 230 kV;– extra high voltage (EHV) refers to 230 kV < Un.In the context of this Standard, the function of the network is more important than its nominal voltage. For example, a HV system used for distribution may be given a "planning level" (see clause 3) which is situated between those of MV and HV systems. 3 A list of principal letter symbols, subscripts and symbols is given in appendix J.

First published in Australia as AS 2279.2-1979.
Second edition 1991.
Jointly revised and redesignated as AS/NZS 61000.3.6:2001.