# CISPR TR 16-4-4:2007/AMD2:2020

(Main)## Amendment 2 - Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: Uncertainties, statistics and limit modelling - Statistics of complaints and a model for the calculation of limits for the protection of radio services

## Amendment 2 - Specification for radio disturbance and immunity measuring apparatus and methods - Part 4-4: Uncertainties, statistics and limit modelling - Statistics of complaints and a model for the calculation of limits for the protection of radio services

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CISPR TR 16-4-4

Edition 2.0 2020-04

TECHNICAL

REPORT

colour

inside

INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

AMENDMENT 2

Specification for radio disturbance and immunity measuring apparatus and

methods –

Part 4-4: Uncertainties, statistics and limit modelling – Statistics of complaints

and a model for the calculation of limits for the protection of radio servicesCISPR TR 16-4-4:2007-07/AMD2:2020-04(en)

---------------------- Page: 1 ----------------------

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---------------------- Page: 2 ----------------------

CISPR TR 16-4-4

Edition 2.0 2020-04

TECHNICAL

REPORT

colour

inside

INTERNATIONAL SPECIAL COMMITTEE ON RADIO INTERFERENCE

AMENDMENT 2

Specification for radio disturbance and immunity measuring apparatus and

methods –

Part 4-4: Uncertainties, statistics and limit modelling – Statistics of complaints

and a model for the calculation of limits for the protection of radio servicesINTERNATIONAL

ELECTROTECHNICAL

COMMISSION

ICS 33.100.10; 33.100.20 ISBN 978-2-8322-8224-3

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission---------------------- Page: 3 ----------------------

– 2 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

FOREWORD

This amendment has been prepared by CISPR subcommittee H: Limits for the protection of

radio services.The text of this amendment is based on the following documents:

Draft TR Report on voting

CIS/H/402/DTR CIS/H/407A/RVDTR

Full information on the voting for the approval of this amendment can be found in the report on

voting indicated in the above table.The committee has decided that the contents of this amendment and the base publication will

remain unchanged until the stability date indicated on the IEC website under"http://webstore.iec.ch" in the data related to the specific publication. At this date, the

publication will be• reconfirmed,

• withdrawn,

• replaced by a revised edition, or

• amended.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct understanding

of its contents. Users should therefore print this document using a colour printer.

_____________2 Normative references

Replace the references to IEC 60050(161) and CISPR 11 with the following:

IEC 60050-161, International Electrotechnical Vocabulary (IEV) – Part 161: Electromagnetic

compatibility (available at http://www.electropedia.org)CISPR 11, Industrial, scientific and medical equipment – Radio-frequency disturbance

characteristics – Limits and methods of measurementAdd the following new reference:

CISPR 15:2018, Limits and methods of measurement of radio disturbance characteristics of

electrical lighting and similar equipment---------------------- Page: 4 ----------------------

CISPR TR 16-4-4:2007/AMD2:2020 – 3 –

© IEC 2020

3 Terms and definitions

Replace Clause 3 with the following new Clause 3:

3 Terms, definitions, symbols and abbreviated terms

3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60050-161 and the

following apply.ISO and IEC maintain terminological databases for use in standardization at the following

addresses:• IEC Electropedia: available at http://www.electropedia.org/

• ISO Online browsing platform: available at http://www.iso.org/obp

3.1.1

complaint

request for assistance made to the RFI investigation service by the user of a radio receiving

equipment who complains that reception is degraded by radio frequency interference (RFI)

3.1.2RFI investigation service

institution having the task of investigating reported cases of radio frequency interference and

which operates at the national basisEXAMPLE Radio service provider, CATV network provider, administration, regulatory authority.

3.1.3source

any type of electric or electronic equipment, system, or (part of) installation emanating

disturbances in the radio frequency (RF) range which can cause radio frequency interference

to a certain kind of radio receiving equipment3.2 Symbols and abbreviated terms

E permissible interference field strength at the point A in space where the antenna of

the victim receiver is located – without consideration of probability factorsE permissible interference field strength at the point A in space where the antenna of

Limitthe victim receiver is located – with consideration of probability factors

protection ratio

C coupling factor describing the proportionality of the field strength E with the square

root of the power P injected as common mode into the radiating structure by theapparatus (GCPC)

Group A defined PV generator group for single-family detached houses

Group B defined PV generator group for multi-storey buildings with flat roof tops

Group C defined PV generator group for sun tracking supports (“trees”)Group D defined PV generator group for large barns in the countryside

ρ probability of an individual PV generator being a member of Group i

C group-independent mean value for the coupling factor

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– 4 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

P disturbance power emitted by a GCPC with the complex source impedance Z

S S

P power injected into the PV generator eventually radiated via that installation

P disturbance power determined at the DC-AN on a standardized test site according

to CISPR 11 with fixed impedance Z = 150 ΩU permitted disturbance voltage limit

Limit

P probability for time coincidence (µ in dB)

7 P7

P probability for location coincidence (µ in dB)

8 P8

P probability for frequency coincidence inclusive harmonics(µ in dB)

4 P4

m mismatch loss in use case (between the GCPC with complex source impedance Z

L S

and the PV generator with complex load impedance Z )

m mismatch loss in test case (between the GCPC with complex source impedance Z

TC S

and the DC-AN according to CISPR 11 with measurement impedance fixed to

Z = 150 Ω)

AMN artificial mains network

CM common mode

DC-AN DC artificial network

DM differential mode

GCPC grid connected power converter

S/N noise power/signal power

5.6.5.2.10.2 Estimation for the possible range of μ

P10

Add, at the end of 5.6.5.2.10.2, added by Amendment 1, the following new Subclauses 5.6.5.3

and 5.6.5.4:5.6.5.3 Rationale for determination of CISPR limits for photovoltaic (PV) power

generating systems

For a model for the derivation of limits for photovoltaic (PV) power generating systems see

Annex C.5.6.5.4 Rationale for determination of CISPR limits for in-house extra low voltage (ELV)

lighting installationsFor a model for the estimation of radiation from in-house extra low voltage (ELV) lighting

installations see Annex D.Add, after the existing Annex B, the following new Annex C and Annex D:

---------------------- Page: 6 ----------------------

CISPR TR 16-4-4:2007/AMD2:2020 – 5 –

© IEC 2020

Annex C

(informative)

Model for estimation of radiation from photovoltaic (PV)

power generating systems

C.1 Overview

This annex presents a model for the estimation of radiation from photovoltaic (PV) power

generating systems in the radio frequency range. The model is based on theoretical

assumptions, measurement and simulation results as well as on a database with the statistical

values of relevant parameters together with appropriate model factors. The simulation results

were validated by measurement.The model was developed for verification of the limits for the LV DC power port of power

converters (GCPCs) intended for assembly into PV power generating systems specified in

CISPR 11.The subject of interest was the frequency range below 30 MHz and PV generators with a

nominal power throughput in the range up to 20 kVA. Of the two known modes of conducted

disturbances, radiation caused by conducted common mode (CM) disturbances was found to

be dominant. Therefore the model exclusively considers radiation caused by common mode RF

currents (i.e. antenna mode currents).The structure of this annex is divided into two main parts.

Clause C.2 describes the general model approach mainly consisting of physical rationale,

formulae and procedural methods needed for the characterization of the interrelation of the

relevant influence factors.The approach is based on the application of practical data for the various model input

parameters gained from measurement, simulation and statistics. Clause C.3 provides the

calculation of a resulting limit which serves the primary task of verification of the limits for the

LV DC power port of power converters specified in CISPR 11.C.2 Description of the basic model

C.2.1 Overview

To provide a model suitable for an estimation of radiation from photovoltaic (PV) power

generating systems, various influence factors have to be considered.---------------------- Page: 7 ----------------------

– 6 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

Figure C.1 gives a schematic overview of the determined influence parameters considered in

the model and their interrelation.Figure C.1 – Schematic overview of the considered model influence factors

Initially, the permissible value for the disturbance field strength limit E was determined, at

Limita given point A in space where the antenna of the victim receiver is located, with help of the

given formula for the mathematical interrelation of relevant parameters in a remote coupling

situation (see C.2.2).In a second step a model for the PV power generating system was introduced to determine the

RFI potential. Subsequently, typical classes of PV power generating systems were selected.

Sets of appropriate input parameters for modelling the radiation characteristics were

determined (see C.2.3). Those input parameters comprise all the mechanical and electrical data

of the solar generator used during its simulation, including electrical permittivity and

conductivity of the surrounding ground.Based on these conventions and assumptions, the coupling between the electromagnetic field

at the victim receiver location and the PV generator was characterized by a parameter

). By means of the field strength limit E and this coupling(introduced as coupling factor C

PV Limit

factor C the maximum permissible disturbance power P injected into the PV generator was

PV Lestimated. Thereby the basic model for the PV power generating system was completed (see

C.2.4).In addition, the effects of power mismatch losses in test site conditions and at the place of

operation of PV power generating systems were used to refine the model (see C.2.5).

---------------------- Page: 8 ----------------------CISPR TR 16-4-4:2007/AMD2:2020 – 7 –

© IEC 2020

C.2.2 Conditions at the location of the antenna of the victim receiver

Considering the technical parameters for reliable transmission and reception of the radio

service or application to be protected, the permissible interference field strength E (without

consideration of probability factors) at the point A in space where the antenna of the victim

receiver is located can be determined by subtracting the necessary protection ratio R from the

minimum wanted field strength E needed for this radio reception (see Equation (C.1), all

quantities expressed in logarithmic units).EE− R (C.1)

ir w P

The permissible interference field strength is based on the measurement bandwidth of 9 kHz

for the frequency range in question used together with the limit. If the radio service evaluated

uses the same bandwidths, as in the case of broadcast radio, no change is necessary. If

however the bandwidth of the victim radio service is lower than the measurement bandwidth, a

correction shall be applied according to 5.6.6.2 (see Equation (C.2)).b

victim

EE= +×10 log (C.2)

ir,corr ir

measurement

When the calculation of limits for the DC power port of a power converter (GCPC) intended for

assembly into a PV power generating system is considered, then only the radiation coupling

path to the victim radio receiver needs to be considered. The conductive coupling via the LV AC

mains lines is considered to be highly unlikely due to heavy filtering of the AC mains power port

of the GCPC.Equation (37) of this document is the basic calculation rule to gain the permissible disturbance

field strength limit E for use with type tests on standardized test sites. The comprehensive

Limitformula also includes the various probability factors µ and their corresponding standard

deviations σ , reflecting the likelihood of occurrence of a real disturbance in the field, as well

as the term t σ describing the predefined statistical significance of CISPR limits for type-

β iapproved appliances. Combining Equation (37), Equation (C.1) and Equation (C.2) leads to

Equation (C.3):EEtt +µ++... µ+ σσ− ++... σ (C.3)

Limit ir,corr P1 P10 βαi P1 P10

NOTE 1 Suitable probability factors for PV power generating systems are defined depending on the context of

application (see C.3.3).NOTE 2 This document is based on the assumption that the signal characteristics of disturbances caused by

PV systems in its worst case are continuous, leading to equivalent outputs of all CISPR detectors.

Once the field strength limit E is found, a coupling factor C comprising the coupling

Limit PVcharacteristics between the electromagnetic field at the victim receiver location and the PV

power generating system can be applied to estimate the maximum permissible disturbance

power P that can be injected into a given PV generator (see C.2.4).C.2.3 Characteristics of PV generators

C.2.3.1 General

In this Subclause C.2.3 a model for the PV power generating system is introduced to determine

the permissible RFI potential. Subsequently, typical classes of PV power generating systems

are selected. Sets of appropriate input parameters for modelling of their radiation characteristics

are determined.---------------------- Page: 9 ----------------------

– 8 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

C.2.3.2 Characteristic parameters of a PV generator seen as radiator of

RF disturbances

In a simplified approach, a typical PV power generator can be regarded as an ideal vertical rod

antenna with capacitive top loading. The DC power string wires are treated as antenna, while

the PV panels or modules make up its capacitive loading. This approach is applicable for

common mode radiation only, but several investigations indicated this radiation to be

predominant in the considered case.For the specified power range (i.e. up to 20 kVA) typical PV generator configurations can be

found in large numbers. On a single-family detached house some PV panels are mounted on

the inclined roof. For multiple-family houses very often a flat top roof can be found carrying

rows of PV panels on its top. A sun tracker, which is made up by a singular steel support

carrying some PV panels that always present their broad side to the sun, and fairly large

generators on barns in the countryside, are also fairly common.As consideration of every individual PV generator configuration is not feasible, group

representatives of PV generator types are introduced (see C.2.3.3).Subclause C.3.4 reveals the technical parameters that were assumed and used in the

simulation for calculation of the RF characteristics of the respective group of PV generators.

C.2.3.3 Grouping of PV generatorsFor every individual photovoltaic power generating system or installation, the individual coupling

property may assume a different value, but it can be expected that PV generators with

about the same geometric structure and size, will show a typical property allocated

somewhere in a given (predictable standard deviation) range.As PV generators occur in various different configurations in the field, it was decided to define

group representatives of PV generator types and to create a model for each group leading to

different coupling factors C (see C.3.4), describing the interrelation between the victim

PV Group ireceiver and the respective assumed group or category of PV generators.

The defined PV generator groups are:

Group A – Single-family detached houses;

Group B – Multi-storey buildings with flat roof tops;

Group C – Sun tracking supports (“trees”);

Group D – Large barns in the countryside.

Assuming the properties of all photovoltaic power generators in the world are known and that

every individual one of those can be put into one of the predefined groups which is represented

by its model or type (and thus has as a describing constant) it can be defined that

Nb of PV generators in group iρ = (C.4)

Nb of PV generators in the world

where represents the probability of an individual PV generator being a member of group i,

while the respective coupling factor describes the typical RF characteristics of this group

(see Figure C.2).---------------------- Page: 10 ----------------------

CISPR TR 16-4-4:2007/AMD2:2020 – 9 –

© IEC 2020

Figure C.2 – Schematic representation of probability of existence of PV generator

groups in the fieldStatistical data on the population density of the PV generators in the field is given in C.3.4.3.2.

From this data, a group-independent mean value for the coupling factor C and its variance

, which is valid and typical for any PV generator configuration, can be deduced (see

Figure C.3).Figure C.3 – Schematic representation of mean value C and variance σ

PV CPV

The global (or mean) value C can be calculated by Equation (C.5):

CC ×ρ (C.5)

PV i

all groups

This simplified value for the global coupling factor is needed to select the type-independent

limit U for the LV DC power port of power converters (GCPCs) specified in CISPR 11

TC Limit(see Clause C.3 of this document).

---------------------- Page: 11 ----------------------

– 10 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

C.2.3.4 Electrical input parameters of the PV generator

One intermediate step of the approach is the determination of the maximum permissible

disturbance power P that may be injected into the PV generator. In power matching conditions,

this P is identical with the permissible disturbance power P provided by the GCPC.

L SFor thorough estimation of the RFI potential, the typical power mismatch loss between the

GCPC and the DC power interface of the respective PV generator has to be taken into account

which requires knowledge of the complex impedances of GCPCs and PV generators(see C.2.5).

C.2.4 Coupling between the electromagnetic field at the victim receiver location and

PV power generating systemC.2.4.1 General

When assessing the disturbance potential of any given apparatus with any attached structure,

the relationship between the disturbance field strength E at a given point A in space and

Limitthe RF power P fed into the radiating structure by the given apparatus has to be determined.

The relevant technical parameter or characteristic of a given PV generator is its frequency

dependent coupling factor C .For this task, the disturbance source, i.e. the grid connected power converter (GCPC) can be

modelled as a common mode power generator that injects a certain power P into a radiating

structure through its DC power port. The AC power port connects directly or via the PE

conductor in the AC mains cable local ground as the counterpoise of the radiating structure. A

block scheme covering this situation is shown in Figure C.4.Figure C.4 – General model for coupling of CM disturbances of a GCPC

to an attached photovoltaic power generating system (PV generator)

In a first approach the observation point A in space is assumed to be located at a fixed distance r

from the PV generator. The electrical (disturbance) field strength E of the electromagnetic field

emanating from the radiating structure is proportional to the square root of the real power P fed

into the PV generator, due to the linearity of Maxwell's equations.For a single point in space, a fixed function C = C (f) (coupling factor) describes the

PV PVproportionality of the field strength E with the square root of the power P injected into the

radiating structure by the apparatus (GCPC), as given in Equation (C.6).---------------------- Page: 12 ----------------------

CISPR TR 16-4-4:2007/AMD2:2020 – 11 –

© IEC 2020

ECP × (C.6)

For EMC considerations the situation at a fixed distance (e.g. the CISPR protection distance of

10 m or 30 m) is needed. For real objects many points in space with the property of having a

given distance to the EUT exist, for example in different azimuth directions and at different

heights. This applies to simulation and measurement equally. Therefore the field strength used

in Equation (C.6) shall undergo some kind of maximization procedure before being used for the

covers the worst casecalculation of the coupling factor. Henceforward this parameter C

radiation properties/characteristics of the model for the fixed installation and is explicitly valid

for one given fixed distance r and one specific group (A, B, C or D) of PV generators. By means

of Equation (C.7) the maximum permissible disturbance power that may be injected into the PV

generator P can be calculated to:Limit

(C.7)

P =

Basically, it does not matter whether a victim receiver's antenna picks up either the electric or

the magnetic portion of the radiated disturbance and which of the two coupling mechanisms is

predominant for the respective distance. They differ, because for most frequencies the victim

receiver is in the near field zone of the radiating structure.Using the coupling factor for the electric field strength and the magnetic field strength to

calculate the resulting field strengths appearing at the point in question, it can be seen, that the

two coupling factors can be compared to each other in the same unit (Equation (C.8)). The

disturbance field strengths, which are compared to each other and to the field strength of the

radio service, are in the far field of the transmitter.EC ⋅ P

PV elec

E PV elec

→= (C.8)

HC ⋅ P PV mag

PV mag

By multiplying the coupling factor for the magnetic field C with the free space impedance

PV mag, the results can be compared in the same units. Note that the coupling factor for the

Ω mmagnetic fields will also be given in the unit (see Equation (C.9)).

Ω 1

CCZ ⋅

(C.9)

PV elec PVmag

m⋅ Ω

NOTE Generally electric and magnetic fields are not interrelated by the free space impedance Z in the near field.

By convention, the coupling factor for the required protection distance is defined as the mean

value of all field strengths determined for a number of points in the xy-plane at the required

distance. When only four spatial directions are assessed, the final values of the coupling factor

can be calculated byCCCCC= mean( , , , )

PV elec PV elec 0° PV elec 90°°°PV elec 180 PV elec 270

(C.10)

CCCCC= mean( , , , )

PV mag PV mag 0° PV mag 90° PV mag 180°°PV mag 270

In a last step the predominant coupling (electric or magnetic) is found by maximization.

---------------------- Page: 13 ----------------------– 12 – CISPR TR 16-4-4:2007/AMD2:2020

© IEC 2020

CCCZ max( ,× ) (C.11)

PV PV elec PV mag 0

C.2.4.2 Determination of coupling factor by simulation C

PV sim

One approach to determine the coupling factor is to carry out simulations with a Maxwell

equation solver (i.e. NEC2, FEKO, Concept).Taking a defined representative geometrical configuration for each PV generator group as

basis, a relationship between the injected disturbance power and the resulting radiated

disturbance field strength in a point A in space at a defined distance from the PV generator can

be found.The main input for the simulation is the geometry of the photovoltaic generator. This mechanical

structure needs to be programmed into the simulating engine. An example is shown in Figure

C.5.Figure C.5 – Geometric representation of a PV generator with 18 modules

In the defined structure, common mode power is injected at the feed point (indicated by a purple

circle in the middle of the feed line) and the field strength is calculated in a cuboid around the

shall be calculatedstructure. The distance from the structure at which the coupling factor C

determines the size of the cuboid in x and y directions. The protection distance in CISPR

standards is often 3 m, 10 m or 30 m. For a large structure like a photovoltaic array, calculations

for the protection distance of 3 m are not used for the example presented in this document. The

size of the cuboid in vertical z direction shall be twice the height of the structure itself.

The output of the simulation is the field strength on the surface of the pre-programmed cuboid.

Choosing a point on the xy-plane at a distance corresponding to the required protection distance

defines a vertical line (see Figure C.6).---------------------- Page: 14 ----------------------

CISPR TR 16-4-4:2007/AMD2:2020 – 13 –

© IEC 2020

Dimensions in metres

Figure C.6 – Field strength determination by maximization (height scan) along a red line

The maximum of all field strengths in the cross-section between this line and the cuboid

represents the final field strength for the distance. Ideally this procedure would be repeated for

each angular direction, however it suffices to consider only the four different orthogonal

directions in space. The coupling factor C is then derived according to Equations (C.10)

PV simand (C.11).

C.2.4.3 Determination of coupling factor by measurement C

PV meas

The coupling factor introduced by Equation (C.6) can also be determined by measurement.

However, as the coupling factor is defined in transmission mode, it is difficult to measure the

field strength distribution around a typical setup for a PV generator, since the setup is too large

for accurate measurement in most available shielded rooms. On the other hand it is not possible

to actually transmit a potential test signal on any frequency at the installation site of a PV

generator, because of national restrictions. However, under specific operating conditions (e.g.

limitation of transmission to suitable single test frequencies) a measurement on real

installations is feasible.For these measurements, the DC wires of the PV generator shall be disconnected from the

GCPC, shorted and connected to a typical antenna tuner. The tuner should be grounded the

same way an installed GCPC would be grounded. The tuner shall be able to tune the feed point

impedance of this “antenna” to the 50 Ω output of the transmitter at all test frequencies, such

that only very little RF reflection occurs. The actual forward and reflected power shall be

measured and monitored during the procedure with a power meter.The field strength shall then be measured at a pre-defined fixed distance from the outer

boundary of th**...**

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