A Technical Paper on Electromagnetic Compatibility of Electric Equipment

For all electrotechnical equipment, EMC must be considered right from the initial design phase and the various principles and rules carried on through to manufacture and installation.

This means that all those involved, from the engineers and architects that design a building to the technicians that wire the electrical cabinets, including the specialists that design the various building networks and the crews that install them, must be concerned with EMC - a discipline aimed at achieving the "peaceful" coexistence of equipment sensitive to electromagnetic disturbances (which may therefore be considered as the "victim") alongside equipment emitting such disturbances (in other words, the "source" of the disturbances). This publication is a compilation of many years of acquired experience at Schneider Electric, presenting various disturbances encountered and providing some practical remedies.

Contents

1 Introduction

1.1 Electromagnetic compatibility - EMC - a characteristic and a discipline

1.2 Today, EMC is indispensable

1.3 EMC theory is complex

2 The source

2.1 The importance of identifying the source

2.2 An example of a continuous source of conducted disturbances in power electronics

2.3 An example of radiated disturbance sources: circuit closing in MV and VHV substations

3 Coupling

3.1 Different coupling modes exist

3.2 Common or differential mode field to wire coupling

3.3 Common impedance coupling

3.4 Differential mode wire to wire coupling or crosstalk

4 The victim

4.1 Equipment malfunction

4.2 Solutions to the problem

5 Installation

5.1 Installation is an important factor in the overall system EMC

5.2 Design phase

5.3 Installation phase

5.4 Practical examples

6 Standards, test facilities and tests

6.1 Standards

6.2 Test facilities

6.3 Tests

7 Conclusion

Appendix 1: Impedance of a conductor at high frequencies

Appendix 2: The different parts of a cable

Appendix 3: Tests performed at the Schneider Electric EMC laboratories

Appendix 4: Bibliography

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