Analysis for Surge Immunity

    CE is a safety certified standard, and it is regarded as the passport to enter into European Market. From the date of Jan.2, 2013, all the electric and electronic equipments export to European Market must be marked with CE, and for the CE test, EMC is a very important part of it. EMC test includes EMI test, electrostatic immunity test, fast transient immunity test, voltage dips, short interruptions and voltage variations immunity tests and surge immunity test. This article mainly discusses the lightning surge immunity test.

Test Method：

    Surges are caused by over voltages from switching and lightning transients. And the purpose for surge immunity test is that build a common criterion to evaluate the performance of electric and electronic equipments suffer from surge shock. According to IEC61000-4-5 Testing and Measurement Techniques – Surge immunity test, the surge generator should be simulation the waveform of 1.2/50us voltage wave, 8/20us current wave and combination wave (voltage wave: 10/700us; current wave: 5/320us), and then coupling the wave to tested circuit to achieve the experimental purpose. The test levels include class 1, class 2, class 3, class 4 and class X; among them, X is open level. And each level has its corresponding voltage strength, like table 1. And the test level depends on the environment and installation condition, classified as below:

Class 1: Partly protected electrical environment, like factory and control room of power station.  

Class 2: Electrical environment where the cables are well-separated, even at short runs

Class 3: Electrical environment where cables run in parallel

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

Class X: Special conditions specified in the product specification

Table 2: Test Level

 

Test Result:

Surge immunity test is a destructive test; the result can be divided according to the degree of damage: 

a) Normal performance within limits specified by the manufacturer, requestor or purchaser;

b) Temporary loss of function or degradation of performance which ceases after the disturbance ceases, and from which the equipment under test recovers its normal performance, without operator intervention;

c) Temporary loss of function or degradation of performance, the correction of which requires operator intervention;

d) Loss of function or degradation of performance which is not recoverable, owing to damage to hardware or software, or loss of data.

Application Scope:

According to the newly EMC directive 2004/108/EC, Household Wireless and TVB, Mobile Radio Equipment, Medical and Science Equipment, Household Equipment, Electronic realia, R&TTE, Industrial Equipment, Mobile Wireless Equipment, ITE, Aeronautical and Maritime Mobile Radio, Communication Equipment and Lighting are requested to do the surge immunity test. See from the lighting industry, the surge immunity test should meet the following requirements (table 2) according to EN61547 Equipment for general lighting purposes EMC immunity requirements clause 5.7.

Table 2: Surges-Test levels at input AC power ports

Characteristics		Test Level
		Device
		Self-ballasted lamps	Luminaires and independent auxiliaries
			Input power
			≤25W	＞25W
Wave-sharp data		1.2/50us	1.2/50us
Test Levels	Line to Line	±0.5KV	±0.5KV	±1.0KV
	Line to ground	±1.0KV	±1.0KV	±2.0KV

 

    According to IEC61000-4-5，EN61000-4-5 and GB/T17626.5 standards, Lisun Group developed SG61000-5 surge generator, this equipment includes coupling and decoupling network (CDN), and with three models for optional:

Model	SG61000-5	SG61000-5T	SG61000-5H
Waveform	1.2/50us, 8/20us	1.2/50us, 8/20us	1.2/50us, 8/20us, 0/700us, 5/320us
Output voltage	0-6KV±10%	0-6KV±10%	0-10KV±10%，0-6KV±10%
CDN	16A, single phase	20A，three phase	20A，three phase /30A, three phase