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Glazed glass cap and pin insulators that have been removed from the transmission line, have electrical characteristics ensuring them to be reused and reinstalled on lower voltage distribution level lines. The electrical properties determination involving insulator resistance, self-capacitance, corona inception voltage and flashover voltage were measured using AC high voltage generating unit. The advantage...
Analysis of shielding failure is carried out to observe flashover of insulators parallel with phase conductors of a transmission line associated with a lightning strike on phase conductor. Peak current of different magnitude have been used to represent the multiple strokes lightning (MSL). This paper aims to simulate the worst case due to transmission shielding failure with three direct strikes to...
Analysis of induced voltages on transmission tower and conductors has been performed when a high voltage line is subjected to propagation of lightning transient. PSCAD/EMTDC software program is used to carry out the modelling and simulation works. Lightning strikes on the tower top or conductors result in large overvoltages appearing between the tower and the conductors. Two cases considered for these...
This paper reports an investigation carried out in the laboratory on 45 units of glass insulator samples. The insulator units comprise of 5 groups; new and field-aged insulators with different ageing period (>30, 20, 15 and <10 years) from 132 kV transmission line. The results revealed a correlation between the ratio of the 3rd and 5th harmonic amplitudes with the degree of degradation of the...
This work attempts to apply an artificial neural network in order to diagnose ageing transmission line insulators. The insulator leakage current harmonic components are used as the input variables of the artificial neural network. The data used to train the network and test its performance is derived from experimental measurements carried out in artificial climatic chamber. The experimental result...
Contamination flashover as a result of pollution severity leading to costly outages plagues insulator performance. Apart from the problem of flashover, failure of insulators as a result of ageing has also lead to service disruption. Leakage current (LC) is a good measure of insulator surface condition and thus its magnitude has been used as a parameter for monitoring insulator flashover and pollution...
In this paper, the effect of lightning on a gas pipelines is investigated. The metallic pipelines were modelled as a short transmission line of PI-circuit model. A switch is represented as a pair of sphere-gaps and is used to model side-flash and insulation breakdown of air. The lightning strike leader is represented by a simple high current source generation with DC source and other elements. Results...
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