Elec­tro­mag­netic com­pat­i­bil­ity test­ing in EMC lab

EN 61000–4–5:2014 Elec­tro­mag­netic com­pat­i­bil­ity (EMC) — Part 4–5: Test­ing and mea­sure­ment tech­niques — Surge immu­nity test

Ana­log: IEC 61000–4–5:2014 Elec­tro­mag­netic com­pat­i­bil­ity (EMC) — Part 4–5: Test­ing and mea­sure­ment tech­niques — Surge immu­nity test

Replace: EN 61000–4–5:2006 Elec­tro­mag­netic com­pat­i­bil­ity (EMC) — Part 4–5: Test­ing and mea­sure­ment tech­niques — Surge immu­nity test

New in this edi­tion: http://​www​.inter​fer​encetech​nol​ogy​.com/​w​h​a​t​s​-​n​e​w​-​i​e​c​-​6​1​0​0​0 – 4-​5-​second-​edition-​vs-​third-​edition/​

Scope
Inter­na­tional stan­dard EN 61000–4–5:2014 char­ac­terise sus­cep­ti­bil­ity test­ing regard­ing uni­di­rec­tional surges caused by over­volt­age from switch­ing and tran­sient light­ning. Inter­na­tional stan­dard defines:
• test lev­els;
• test equip­ment;
• test setups;
• test procedures.

The aim of test­ing is to ver­ify the equip­ment under test capa­bil­ity and its reac­tion to with­stand surge volt­ages caused by switch­ing and light­ning effects. It is not intended to ver­ify the equip­ment under test insu­la­tion dur­ing high volt­age stress. This test does not intend to ver­ify equip­ment abil­ity to with­stand direct light­ning strike.

Gen­eral
Surges are cre­ated by switch­ing events and insu­la­tion faults in AC power dis­tri­b­u­tion net­works and also by the switch­ing of reac­tive loads such as elec­tric motors or power fac­tor capac­i­tor blanks. These surges are essen­tially caused by the sud­den release of the energy stored in sys­tem, and in the case of power dis­tri­b­u­tion this energy is stored in the self-​inductance of its long sup­ply lines. When an insu­la­tion fault occurs, for short time the cur­rent in the power dis­tri­b­u­tion sys­tem is much higher than usual. There­fore, when pro­tec­tive device trig­gers, the “reflected” volt­age due to sys­tem induc­tance can be quite large.

Surges are also cre­ated by light­ning. Indi­rect effect– due to mutual induc­tion high volt­age surges ar injected in power lines and other cable (if long enough).

Surges are high volt­age and con­tain sig­nif­i­cant amount of energy. The main prob­lem caused by surges is elec­tri­cal over­stress, ther­mal over­stress, energy over­stress. These over stresses cre­ate phys­i­cal dam­age to elec­tron­ics com­po­nents, con­nec­tors, etc.

Test level
Inter­na­tional stan­dard EN 61000–4–5:2014 defines pre­ferred test lev­els. Test level selec­tion must be car­ried out accord­ing to generic stan­dard or prod­uct stan­dard require­ments, or test level can be selected accord­ing to instal­la­tion conditions.

Class 0 Well pro­tected envi­ron­ment (usu­ally spe­cial room).
Over­volt­age pro­tec­tion is used for all incom­ing cables. The units of the elec­tronic equip­ment are inter­con­nected by a well-​designed ground­ing sys­tem, which is not sig­nif­i­cantly influ­enced by the power instal­la­tion or lightning.

Class 1 Partly pro­tected elec­tri­cal envi­ron­ment.
Over­volt­age pro­tec­tion is used for all incom­ing cables. The units of the equip­ment are well-​interconnected by a ground con­nec­tion net­work, which is not sig­nif­i­cantly influ­enced by the power instal­la­tion or light­ning. Power sup­ply is phys­i­cally sep­a­rated from elec­tronic equip­ment. Switch­ing oper­a­tions can gen­er­ate inter­fer­ence volt­ages within the room. For this envi­ron­ment Surge Level 1 is usu­ally applied.

Class 2 Elec­tri­cal envi­ron­ment where the cables are well-​separated, even at short runs
Sep­a­rate ground­ing sys­tem is used for power instal­la­tion. Ground­ing sys­tem can be intro­duced to sig­nif­i­cant surge cur­rents lead­ing to sig­nif­i­cant inter­fer­ence volt­ages. Power sup­ply is phys­i­cally sep­a­rated from elec­tronic equip­ment and pow­ered by ded­i­cated trans­former. For this envi­ron­ment Surge Level 2 is usu­ally applied.

Class 3 Elec­tri­cal envi­ron­ment where cables run in par­al­lel for short/​long dis­tances
Com­mon ground­ing sys­tem is used for power instal­la­tion which can be sub­ject to high inter­fer­ence volt­ages gen­er­ated by instal­la­tion or light­ning. Cur­rent due to ground faults, switch­ing oper­a­tions and light­ning in the power instal­la­tion may gen­er­ate inter­fer­ence volt­ages with rel­a­tively high ampli­tudes in the ground­ing sys­tem. Pro­tected elec­tronic equip­ment and less sen­si­tive elec­tric equip­ment are con­nected to the same power sup­ply net­work. The inter­con­nec­tion cables can be partly out­door cables, but close to the ground­ing net­work. For this envi­ron­ment Surge Level 3 is usu­ally applied.

Class 4 Elec­tri­cal envi­ron­ment where the inter­con­nec­tions run as out­door cables along with power cables, and cables are used for both elec­tronic and elec­tric cir­cuits
Com­mon ground­ing sys­tem is used for power instal­la­tion which can be sub­ject to high inter­fer­ence volt­ages gen­er­ated by instal­la­tion or light­ning. Cur­rents in the kA range due to ground faults, switch­ing oper­a­tions and light­ning in the power sup­ply instal­la­tion may gen­er­ate inter­fer­ence volt­ages with rel­a­tively high ampli­tudes in the ground­ing sys­tem. Elec­tronic and other elec­tri­cal equip­ment shares the same power sys­tem. The inter­con­nect ion cables are run as out­door cables, also for high-​voltage equip­ment.
This envi­ron­ment also includes areas where elec­tronic equip­ment is con­nected to the telecom­mu­ni­ca­tion net­work within a densely pop­u­lated area. There is no sys­tem­at­i­cally con­structed ground­ing net­work out­side the elec­tronic equip­ment, and the ground­ing sys­tem con­sists only of pipes, cables, etc. For this envi­ron­ment Surge Level 4 is usu­ally applied.

Class 5 Elec­tri­cal envi­ron­ment for elec­tronic equip­ment con­nected to com­mu­ni­ca­tion cables and over­head power lines in a non-​densely pop­u­lated area.

Test pulses (over­volt­age pulses)
Over volt­age pulses are applied by com­bined wave gen­er­a­tor with defined and pre-​calibrated wave­form. Com­bined wave gen­er­a­tor out­put imped­ance is defined– 2ohms. Open cir­cuit volt­age wave­form is 1.2us rise time and 50us fall time (1.2÷50 us). Short cir­cuit cur­rent wave­form is 8us rise time and 20us fall time (8÷20 us).

Open cir­cuit volt­age wave­form is 1.2us rise time and 50us fall time (1.2÷50 us).

Short cir­cuit cur­rent wave­form is 8us rise time and 20us fall time (8÷20 us)

Injec­tion of over­volt­age pulses
For AC power lines over­volt­age 5 pos­i­tive and 5 neg­a­tive pulses are applied syn­chro­nously to mains net­work fre­quency at 0deg, 90deg, 180deg, 270deg. Time between pulses <1min. Power cable length should not exceed 2m length. Over­volt­age pulses are applied between lines (L-​N) through 18uF decou­pling capac­i­tor (it leads to injec­tion imped­ance 2ohm, lim­ited only by wave gen­er­a­tor out­put imped­ance). Over­volt­age pulses are applied between lines and ground sep­a­rately (L-​PE, N-​PE) through 9uF decou­pling capac­i­tor in series with 10ohm capac­i­tor (it leads to injec­tion imped­ance 12ohm, lim­ited by wave gen­er­a­tor out­put imped­ance + 10ohm injec­tion circuit).

Injec­tion net­work for line to line (leads to injec­tion imped­ance 2ohm, lim­ited only by wave gen­er­a­tor out­put impedance)

Injec­tion net­work for line to ground (leads to injec­tion imped­ance 12ohm, lim­ited by wave gen­er­a­tor out­put imped­ance + 10ohm injec­tion circuit).

In addi­tion to injec­tion cir­cuit decou­pling net­work is used to pro­tect aux­il­iary equip­ment and other equip­ment con­nected to mains net­work from over­volt­age pulses.

For DC power lines over­volt­age 5 pos­i­tive and 5 neg­a­tive pulses are applied. Time between pulses <1min. Power cable length should not exceed 2m length. Injec­tion cir­cuits are equiv­a­lent to AC injec­tion cir­cuits.
There exists wide array of defined cou­pling decou­pling devices for over­volt­age injec­tion in inter­con­nec­tion lines defined in EN 61000–4–5:2014.

Per­for­mance cri­te­rion
The tests results are clas­si­fied in terms of loss of func­tion or degra­da­tion of per­for­mance. Inter­na­tional stan­dard EN 61000–4–5:2014 does not define Pass/​Fail cri­te­ria. This is defined by generic or spe­cific prod­uct stan­dards. EN 61000–4–5:2014 defines per­for­mance cri­te­ria that can be used to eval­u­ate equip­ment under test performance.

Per­for­mance cri­te­rion A
Nor­mal per­for­mance within lim­its spec­i­fied by the manufacturer;

Per­for­mance cri­te­rion B
Tem­po­rary loss of func­tion or degra­da­tion of per­for­mance. Self-​recovery after the test, with­out oper­a­tor intervention;

Per­for­mance cri­te­rion C
Tem­po­rary loss of func­tion or degra­da­tion of per­for­mance. Oper­a­tor inter­ven­tion needed for recov­ery after the test;

Per­for­mance cri­te­rion D
Loss of func­tion or degra­da­tion of per­for­mance which is not recov­er­able. Dam­age
of hard­ware or soft­ware, or loss of data.

The manufacturer’s spec­i­fi­ca­tion may define effects on the EUT which may be con­sid­ered insignif­i­cant, and there­fore acceptable.

Equip­ment shall not become dan­ger­ous or unsafe as a result of the appli­ca­tion of the tests.