PD IEC/TR 61000-2-14:2006

INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Description of overvoltages
   4.1 General
   4.2 External overvoltages
   4.3 Internal overvoltages
   4.4 Overvoltage waveshape
5 Long duration overvoltages
   5.1 Sustained earth faults
   5.2 Broken neutral on LV network
   5.3 Maloperation of voltage regulating equipment
   5.4 Overvoltages due to voltage unbalances
   5.5 Dispersed generation
6 Short duration overvoltages
   6.1 Earth faults
   6.2 Load rejection (sudden load loss)
   6.3 Self-excitation
   6.4 Resonance and ferroresonance
7 Very short duration overvoltages (transients)
   7.1 General description
   7.2 Lightning
   7.3 Switching
   7.4 Summary of surge duration and cause
8 Effects of overvoltages on equipment
   8.1 General considerations
   8.2 Reduction in life of filament lamps
   8.3 Effect of overvoltages on IT equipment
9 Case studies
   9.1 General
   9.2 Switching of LV power factor correction capacitor
   9.3 Metal fusion furnace
   9.4 Switching of MV power factor correction capacitor
   9.5 DC traction system
   9.6 Load switching
10 Protection against the effects of overvoltages
   10.1 General considerations
   10.2 Point on wave switching
   10.3 Arcing horns and spark gaps
   10.4 Overvoltage protection relays
   10.5 Snubbers (high frequency RC filter)
   10.6 Uninterruptible power supply (UPS) systems
   10.7 Surge protection device (SPD)
11 Conclusions
12 Recommendations
Bibliography
Figures
Tables

Defines electromagnetic environment with respect to the voltages in excess of normal that are found on electricity supply networks operating at low and medium nominal voltages and that can be impressed on equipment connected to those networks, without considering further effects (e.g. amplification or attenuation) within an installation.

This part of IEC 61000 describes the electromagnetic environment with respect to the voltages in excess of normal that are found on electricity supply networks operating at low and medium nominal voltages and that can be impressed on equipment connected to those networks, without considering further effects (e.g. amplification or attenuation) within an installation. Since these overvoltages have the potential to hinder the functioning of electrical and electronic equipment, they fall within the definition of electromagnetic disturbance in the field of EMC. Various categories of overvoltage are described, based on relative magnitude, duration and energy content.

This Technical Report describes the phenomena of overvoltages, it does not specify compatibility levels and does not directly specify emission and immunity levels.

The report describes the various phenomena and processes that cause overvoltages, including the transfer into the networks concerned of overvoltages that originate in or traverse other networks and installations, including higher voltage networks and the installations of electricity users. The effects of overvoltages on equipment are outlined. Some case studies of overvoltage events are presented.

Recommendations are made regarding the general technical approach to mitigating the risk of equipment being hindered from operating as intended by the effects of overvoltages. (It is not the function of IEC publications to assign responsibility for mitigating measures to any of the parties involved.)

The purpose of this report is to ensure that this important category of electromagnetic disturbance is included in the description of the environment in Part 2 of IEC 61000. For that purpose, only a brief description is provided of the various overvoltages and their causes and effects. A much more detailed treatment can be found in IEC 62066. A UIE publication – Guide to quality of electrical supply for industrial installations, Part VI: Transient and temporary overvoltages and currents – has a similar content. Measurement methods are specified in IEC 61000-4-30.

NOTE This Technical Report does not include detailed measurement results for overvoltages, therefore it is not possible to provide an assessment of the probability of occurrence.