BS EN 61000-4-5:2014 pdf free

BS EN 61000-4-5:2014 pdf free.Electromagnetic compatibility (EMC) Part 4-5: Testing and measurement techniques – Surge immunity test.
4.1  Power system switching transients
Power system switching transients can be separated into transients associated with:
a) major power system switching disturbances, such as capacitor bank switching;
b) minor local switching activity or load changes in the power distribution system:
c) resonating circuits associated with switching devices, e.g. thyristors, transistors:
d) various system faults, such as short-circuits and arcing faults to the grounding system of the installation.
4.2 Lightning transients
The major mechanisms by which lightning produces surge voltages are the following:
a) direct lightning stroke to an external (outdoor) circuit injecting high currents that produce voltages by either flowing through ground resistance or flowing through the impedance of the external circuit;
b) indirect lightning stroke (i.e. a stroke between or within clouds or to nearby objects which produces electromagnetic fields) that induces voltages/currents on the conductors outside and/or inside a building;
c) lightning ground current flow resulting from nearby direct-to-earth discharges coupling into the common ground paths of the grounding system of the installation.
The rapid change of voltage and flow of current which can occur as a result of the operation of a lightning protection device can induce electromagnetic disturbances into adjacent equipment.
4.3 Simulation of the transients
The characteristics of the test generator are defined to simulate the above-mentioned phenomena as closely as possible.
If the source of interference is in the same circuit as the victim equipment, for example in the power supply network (direct coupling), the generator may simulate a low source impedance at the ports of the EUT.
If the source of interference is not in the same circuit as the victim equipment (indirect coupling), then the generator may simulate a higher impedance source.
5 Test levels
The preferred range of test levels is given in Table 1.BS EN 61000-4-5 pdf download.