Existing underground cable ratings underestimate full capability of power consumption during summer. This leads to the demand of improved and more accurate ratings . An objective of this project is to look at the heat and moisture migration initiated by the heating of the medium surrounding the buried cables, which when subjected to prolonged heating under extreme condition leads to 'thermal runaway'. Identification of conditions under which 'thermal runaway' occurs will allow the improvement of the external parameters (such as soil thermal resistivity and capacitance) used in the existing cable ratings under the ground. A Philip-deVries model is used to look at the effects of drying-out.This involves looking at the changes of moisture content of the surrounding medium, the effects of native soil having different properties to that of backfill, backfills of different properties and environmental factors. A controlled environment model will be developed to monitor the changes in heat and moisture at the viccinity of the heated source.
Design and development of novel charge-on-demand liquid atomisation packaging system. Optimisation of natural charge exchange processes in single and multi-phase liquids.
Evaluation of the behaviour of electrostatically charged airborne particles. Developemnt of a method to reduce the inhalation of PM10 partilces.
Techniques evaluated for delivering new denaturing agents for the house dust mite allergen Der p1
Development of charge-on-demand domestic aerosol packaging system. System now used commercially in aerosol products marketed in Australia, New Zealand and Brazil. Patents granted in various countries. Technology awarded Millennium Product Status by Design Council.
Previous projects in conjunction with projects currently running have studied the use of capacitive couplers, Radio Frequency Current Transformers and Rogowski coils. The aim of this project is to assess the suitability of directional couplers for on line monitoring in comparison to established methods. A directional coupler is essentially a screened conducting plate placed on the outer layer of the semi-conducting material of the cable, with outputs from each end of the sensor being fed to a scope. Due to both the capacitive and inductive effects between the two plates one output from a sensor will be greater than the other, hence the direction from which the discharge emanated from can be determined. The advantage directional couplers offer over other methods is this two-channel output per each sensor, so discharge sites can be pin-pointed, however also means that twice as much data is collected and then needs to be analysed.
This project is concerned with the detection, location and pattern identification of partial discharges in high voltage cable systems. The acoustic emission technique, capacitive coupler technique and high frequency current transducer technique have been investigated. Obtained discharge signals were analysed using statistical patterns and operators, Fourier transform and Wavelet analysis. Artificial neural networks were used to identify different PD sources.
This project is concerned with the three-dimensional (3D) space charge distribution measurement in dielectrics. The pressure wave propagation (PWP) method is applied to measure the space charge distribution. Acoustic lens is used to produce intense pressure wave on a small area of the sample so that the detected signal will reflect the charge distribution in Z direction. By moving the acoustic lens on XY plane using a XY stage, the 3D space charge distribution can be measured.
Good substation earthing is essential for a safe and reliable power system. Methods to improve substation grounding with supporting measurements of earth resistance, and computational models to simulate the possible Ground Potential Rise (GPR) due to injected current surges are of particular interest.
The main objective of the initial work is to develop a reliable computational model for the impedance of substation earthing mats and the distribution of the surface potential that occurs when a power frequency fault current is injected into the earthing system. The commercial package CDEGS MALT has been found to be one of the best currently available, and part of the initial effort was to verify its performance. MALT is being tested with experimental results and also Earthing Standards and literatures formulas available. Extensive work have been done to study the effect of �proximity effect� on the surface potentials in and around the earthing system when comparing with the computer software computations.
Also, study of the potential distribution due to the insertion of a local high resistivity barrier have been carried out. The purpose of using local high resistivity is to skew the potential contours, so the earth potential rise immediately beyond the barrier can be reduced. As the power frequency current can penetrate very deep into the ground, the effectiveness of the high resistivity barrier needs to be examined. Effects of barrier geometry under various system conditions was analysed. Both solid barrier and barrier made of plates with various spacings of gaps were tested in the electrolytic tank and modelled in the CDEGS software.
Production and use of HV DC power cables cause formation of space charge within the insulating material and this can become a serious problem. One of the well known non-destrcutive techniques is the Pulsed Electro-acoustic(PEA). The method makes use of the acoustic wave generated by the charges existing in the sample under an applied pulse voltage and this wave is then detected by a piezo-electric transducer. Presently, construction of the improved Pulsed Electro-acoustic(PEA) system is capable of not only measuring space charge but also conduction current simultaneously on thin plaque specimens under a controlled temperature environment. This additional valuable piece of information enhances comprehension about their relationship. They complement each other to give details about charge carrier generation, transportation and accumulation. Such measurements allow insight into the charging processes taking place within the dielectric under study, and make it possible to select materials and interfaces which minimise the risk of breakdown in HV applications.