Measurements of shielding effectiveness of communication tower cables

Shielded cables are used to reduce radiated interference and to protect electronic components from the effects of disturbing electromagnetic fields. The quality of the shield varies with their design.

To evaluate the quality of the cable shield the shielding effectives has to be measured. This can be done by injecting a current or voltage to the cable shield and measuring the induced voltage or current at the cable conductors. These measurements can be performed in frequency domain or in time domain. Also the test signal amplitude might influence the results.

In this work the measurements shall be performed on given types of cables using frequency domain methods and time domain methods with different amplitudes. The measurements will also include tests in high voltage laboratory. The results of both measurements shall then be compared and a measure of shielding effectiveness suitable for cables carrying high voltages and currents during a lightning strike shall be proposed.

The tasks to perform:

* Literature survey of the existing techniques for measuring shielding effectiveness
* Time domain measurements using cable generator
* Frequency domain measurements using spectrum analyser
* Time domain measurements using standard current surges (8/20 s, up to 50 kA)
* Work report with comparison of results

The work shall be performed at Division for Electricity and lightning Research, Department of Material Science, Uppsala University.