الفهرس 
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Abstract
This research outlines in detail adding a new dimension to the already
existing protection techniques, this of predicting single line to ground faults on
overhead transmission lines and underground cables. This new concept of fault
prediction ,considered to be unprecedented ,adds a fonn of Artificial
Intelligence to the already existing traditional protection schemes for overhead
transmission lines and underground cables. The prediction system is a three
stage integrated system comprising a fault prediction relay, an optical fiber
communication link to transmit the alarm signal to the main station and a
microprocessor based identification system to identify the faulty region. The
prediction theory is based on the continuous monitoring and analysis of the
leakage currents on transmission line insulators, and of internal discharges in
air voids found in underground cable junctions. The level and frequency of
leakage currents and internal discharges are considered the back bone of the
decision making process by which the insulating properties of transmission
tower insulators and cable junctions may be assessed.
The present thesis discusses in detail the following topics:
1- Performance of overhead transmission line insulators under pollution
conditions.
2- The performance and operation of an integrated fault prediction system.
3- Flashover mechanism on overhead transmission line insulators.
4- The different criteria for assessing the degree of pollution of overhead
line insulators .
5- Leakage current criterion for assessing the condition of overhead line
insulators .
6- Leakage current wave form and characteristics.
7- Analog and Digital electronics building blocks for static relays.
8- Design details of a fault prediction relay .
9- Laboratory realisation ,complete wiring scheme and testing of the fault
prediction relay.