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This paper presents various characteristics of frequency response analysis (FRA) plots from an HV auto-transformer. The aims of the paper are to draw attention to the characteristics, to stimulate discussion and to promote the need to understand and incorporate high-frequency phenomena that have been previously omitted from modelling techniques. This is critical for a full appreciation of the amplitudes and waveshape reconstructions of pd signals observed at the transformer terminals allowing more accurate pd quantification.

Flashover of outdoor high voltage insulating systems, e.g. string or post-type insulators, bushings, etc., can result in electrical outages with severe social and economic consequences. It is therefore imperative, within an overall condition monitoring and maintenance strategy, that effective and efficient means are developed to monitor the condition of such systems for degradation to permit refurbishment/replacement prior to catastrophic flashover. This paper reports the results of an investigation of partial discharge activity on outdoor insulation systems utilising RF antenna techniques.

Polymeric insulating materials with excellent electrical properties are widely used in electrical power equipment. These materials are degraded, however, when they are subjected to partial discharge (PD) with different polymeric materials possessing different levels of PD resistance. In this study the PD characteristics and degradation caused by PD are analysed and compared for four different polymers – poly(ether sulphone) (PES), poly(ethylene terephthalate) (PET), poly(propylene) (PP) and low-density poly(ethylene) (LDPE). An artificial void is created in each of the polymer samples and electrically stressed above PD inception voltage (PDIV) for 4 h. The simulated electric field distribution inside the void for each of the polymer materials at the respective PDIVs is modelled using COMSOL to validate the experimental results. Little work has correlated void PD characteristics with material degradation induced by PD across a range of different polymers and subsequently categorised them according to their PD resistances. This study therefore presents a comparative study of the N–Q patterns of PD pulses (a plot of the number of discharges against the measure of apparent charge), PD repetition rate and the chemical and morphological changes occurring on the void surfaces for each type of polymer. The results show that the PD resistance of these four polymers can be categorised in a decreasing order according to the following sequence: LDPE, PP, PET and PES with LDPE being most resistant to PD and PES the least resistant.

A common cause of insulation degradation in high voltage (HV) cables is due to partial discharges (PD). PD may be initiated through imperfections and contaminants present in the insulation. It can be hypothesized that a reduction in system voltage can potentially reduce PD, which will correspondingly extend the service life of the cable. Currently, industry voltage statutory requirements permit ±6% tolerance setting on nominal voltage on distribution networks. Such ±6% voltage reduction on may have little or adverse effect on PD magnitude which depends on the nature of defect. Hence the accuracy and type of measuring PD while reducing system voltage is more critical for this application. Power cable as a low pass filter which attenuates and disperse the PD pulses. In this paper effect of voltage reduction on PD is investigated using standard electrode geometries such as point-plane, point-point and point- rod using IEC60270 measurement system together with frequency domain measurements. It has been observed that PD frequency characteristics at different voltages varies in the wideband frequency spectrum.

Solar energy has become a matter of global attention in the past few years. This paper explores the use and benefit of solar concentrators in the solar photovoltaic (PV) systems. First, a short literature review of previous research on the usage of solar concentrators in improving solar PV system performance and reducing the cost of implementation is presented. This is followed by an overview of SolarBrane, an example of a Building Integrated photovoltaic (BIPV) system which uses an optical concentrator in the solar PV design. An optimised design of the SolarBrane is also discussed afterwards. A financial benefit study is conducted to compare the average return of investment of using the optimised SolarBrane and traditional solar PV installed in Malaysia’s environment. SolarBrane has proven to be a good alternative to achieve costeffective solar PV system. The financial analysis simulated under the new Malaysian Feed–In Tariff scheme indicates that the optimised SolarBrane could potentially reduce the initial cost of implementation by 40% and generate higher return, close to 20%, when compared to traditional solar PV systems. Key words: Solar photovoltaic; solar concentrator; solarBrane; dielectric totally internally reflecting concentrator; financial analysis