Electric Fast Transient 5/50 Ns; Damped Oscillatory Wave 100 Khz Or 1 Mhz - EMC-PARTNER CDN2000-06-25 User Manual

CDN2000-06-25 coupling decoupling network
The same investigation put in evidence that reverse voltage applied during the conduction period of the
power frequency produces lower breakdown voltage than the application of the transient with no load or
during blocking.

1.1.3 Electric fast transient 5/50 ns

Industrial measurement and control equipment practically always operates in conjunction with conventional
control units (relays, contactors). Fluorescent lamp ballast units, insufficiently suppressed coffee grinders,
vacuum cleaners, drilling machines, hair dryers, universal motors, etc. can be found everywhere in the
power supply system. All these primarily inductive loads produce interference when switched on and off. A
wide range of switching transients, also called bursts, are produced with the following waveform.
Figure: 1.0.3.1
The parameters which define the
burst are:
The different EFT sources generate different bursts waveforms. A typical waveform of a burst is shown in
the next figure:
The impedance of the EFT source is generally high, therefore the capacitance of connected cables
influences the rise time.

1.1.4 Damped Oscillatory Wave 100 kHz or 1 MHz

Introduction:
The damped oscillatory wave is a typical oscillatory transient, induced in low voltage supply of measuring
cables due to the switching of three phase electrical networks in HV/N`MV open air station.
In electrical stations, the opening and closing operations of HV isolators give rise to sharp front-wave
transients, with time of the order of some tens of nanoseconds. The voltage front-wave has an evolution that
includes reflection, due to mismatching of the characteristic impedance of HV circuits involved. In this
10/54
Rise time of the spike Ts in ns
Repetition frequency f4 in the range of kHz up to MHz
Energy, some mJ
Voltage amplitude UBmax. up to some kV
Duration of a burst several milliseconds