KNOW YOUR STANDARDS
by J. M. Woodgate B.Sc.(Eng.) C.Eng. MIET SMIEEE FAES Hon FInstSCE MIOA
We are coming to the end of the survey of the huge IEC 61000-4 series of Basic EMC standards (those defining the methods of measurement of (mostly) immunity characteristics and, in some cases, specifying the test equipment). However, because the survey began a while back, we need to look for updates to the earlier Sections as well.
As for all of the IEC 61000-4 series standards, these standards and Technical Reports apply only if normatively referenced in product or product-family EMC standards.
Immunity to conducted disturbances, induced by intentional and/or unintentional broadband signals)
This standard was published in July 2016, and is important in the context of signalling on the supply mains, although that subject seems to be fading from interest.
IEC TR 61000-4-32
High-altitude electromagnetic pulse (HEMP) simulator compendium
This has not been adopted by CENELEC or BSI. It gives information on HEMP simulators and their applicability for immunity test requirements. It includes datasheets describing 42 EMP simulators that could be available for use by the international community.
Measurement methods for high-power transient parameters
This standard provides a basic description of the methods for measuring responses arising from high-power transient electromagnetic parameters, such as: the electric (E) and/or magnetic (H) fields; the current and voltage induced by a transient field or within a system under test; and the charge Q induced on a cable or other conductor. These are generally complicated time-dependent waveforms, which can be described approximately by several "observables". It does not provide information on specific level requirements for testing.
Voltage dips, short interruptions and voltage variations immunity tests for equipment with rated input current of more than 16 A per phase
The standard applies for single and 3-phase connections at 50 Hz or 60 Hz (but it's not adopted in the Americas yet). An important Normative Reference is that to IEC 61000-2-8, a not very well-known Technical Report on the statistics of occurrence of these disturbances. Apart from the statistical data, it contains a lot of information about electricity supply networks that may be difficult to obtain elsewhere.
IEC TR 61000-4-35
HPEM simulator compendium
This comprehensive Report (88 pages) gives details of High-Power Electromagnetic (HPEM) simulators and their use for immunity testing. It includes numerous definitions of terms and a survey of the increasing use of high-power electronic systems and its implications for the prevention of interference with other, safety-critical electronic systems.
IEMI immunity test methods for equipment and systems. This was published in 2014.
It provides methods for the assessment of equipment and systems to IEMI (Intentional ElectroMagnetic Interference) environments. These environments are defined in IEC 61000-2-13 (see below). It explains the differences between natural and intentional high power electromagnetic environments and plugs a gap in the IEC series of publications defining HEMP and HPEM environments and HEMP test methods. It provide test methods for those HPEM environments that can be generated by criminals or terrorists for malicious purposes, namely IEMI.
IEC TR 61000-4-37
Calibration and verification protocol for harmonic emission compliance test systems
This was published in 2016. It is of interest to test houses who need to be sure that their testing arrangements are strictly in accordance with the applicable standards.
IEC TR 61000-4-38
Calibration and verification protocol for flicker compliance test systems
This was published in 2015. Its application is the same as for Section 37.
Radiated fields in close proximity – Immunity test
This standard was published in March 2017. It is needed to cope with things like mobile phones being very close to other equipment.
IEC TR 61000-4-40
Digital methods for the measurement of power quantities of modulated or distorted signals
Work on this Section has stopped and it may be withdrawn from the Programme of Work. It was not possible to obtain consensus on the usefulness of RMS values calculated over periods other than one or more whole cycles.
IEC 61000-2-13:2005 defines a set of typical radiated and conducted HPEM environment waveforms that may be encountered in civil facilities. For the purposes of this standard, high-power conditions are achieved when the peak electric field exceeds 100 V/m. This limits the application of this standard to EM radiated and conducted environments that are substantially higher than those considered for "normal" EMC applications, which are covered by other standards. As such, it may be of significance in the context of functional safety.
This information is accessible only to a very limited extent from the public part of the IEC web site for TC77/SC77B 'Projects/Publications' 'Work programme'. The actual documents are available only to committee members, including members of the BSI Committee. Some members may not be very familiar with parts of the BSI committee web site, which has more dark recesses than the Cheddar Gorge.
The way, or at least a way, is to go to the BSI committee front page and select 'Projects' from the 'Library Containers' menu. Scroll down to the IEC 61000 series folder and click on it, then scroll down to the IEC 61000-4 series folder and click on it. The 'Modified' column on the far right indicates the last change date, and can be used to select (by clicking on) those folders that may include new documents, but some do not. Even so, new documents associated with each Section can be found this way.
The first CD for Edition 4 was circulated to National Committees in August 2017. It gives a non-exhaustive list of the changes from Edition 3:
Testing using multi-tone signals;
New information on EUT and cable layout.
It will attract numerous editorial comments, because ISO/IEC Directives Part 2 has not been applied.
A DC was circulated in June 2017 on proposed clarification of Edition 3:
Using the 'Edition 2' surge generator
Clarification of the improvements in Edition 3;
Clarification that 'Section 5 surges' should not be applied to antenna ports.
A DC (Document for Comment) was circulated to National Committees in August 2017, concerning a fourth edition (or an amendment, if the agreed changes are not too extensive). A list of 16 detailed improvements is proposed.
A Call for Comments on the preparation of a Third Edition was circulated and resulted in six pages of proposals. However, there is no explicit statement of the next step.
An Interpretation Sheet giving a clarification of the wording of sub-clause 6.8 on rectangular voltage modulation was approved without comment.
CENELEC finally agreed to withdraw the 2000 edition, so that the latest edition can be published by European NCs.
A DC for the preparation of Edition 4 was circulated in June 2017. It lists five fairly substantial improvement proposals, including a complementary TR on power quality issues for LVDC (Low Voltage Direct Current) supplies.