The design of an electric fence monitoring system : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Production Technology at Massey University

This thesis presents the design of an Electric Fence Monitoring System (EFMS) which detects and announciates fence malfunctions indicating operational ineffectiveness. The EFMS consists of a master unit and up to sixteen slave units. Each slave unit monitors a single remote point on the fence. Slave units gain their power from the electric fence pulse itself. They use a unique transmission algorithm to transmit the peak electric fence voltage, to the master unit. The electric fence wire is used to convey this transmission. The master unit uses a non-linear switched capacitor filter with variable gain control, to detect the slave unit transmissions. This unit displays the peak voltage at each monitored point and allows the setting of alarm trigger points. This thesis includes modelling of the electric fence energiser and typical electric fence line, and the detailed design of the two units that makeup the EFMS

Oscillation-Based Test Structure and Method for OTA-C Filters

“This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.”This paper describes a design for testability technique for operational transconductance amplifier and capacitor filters using an oscillation-based test topology. The oscillation-based test structure is a vectorless output test strategy easily extendable to built-in self-test. The proposed methodology converts filter under test into a quadrature oscillator using very simple techniques and measures the output frequency. The oscillation frequency may be considered as a digital signal and it can be evaluated using digital circuitry therefore the test time is very small. These characteristics imply that the proposed method is very suitable for catastrophic and parametric faults testing and also effective in detecting single and multiple faults. The validity of the proposed method has been verified using comparison between faulty and fault-free simulation results of two integrator loop and Tow-Thomas filters. Simulation results in 0.25 mum CMOS technology show that the proposed oscillation-based test strategy for OTA-C filters has 87% fault coverage and with a minimum number of extra components, requires a negligible area overhead

A design for testability study on a high performance automatic gain control circuit.

A comprehensive testability study on a commercial automatic gain control circuit is presented which aims to identify design for testability (DfT) modifications to both reduce production test cost and improve test quality. A fault simulation strategy based on layout extracted faults has been used to support the study. The paper proposes a number of DfT modifications at the layout, schematic and system levels together with testability. Guidelines that may well have generic applicability. Proposals for using the modifications to achieve partial self test are made and estimates of achieved fault coverage and quality levels presente

Fault simulation for structural testing of analogue integrated circuits

In this thesis the ANTICS analogue fault simulation software is described which provides a statistical approach to fault simulation for accurate analogue IC test evaluation. The traditional figure of fault coverage is replaced by the average probability of fault detection. This is later refined by considering the probability of fault occurrence to generate a more realistic, weighted test metric. Two techniques to reduce the fault simulation time are described, both of which show large reductions in simulation time with little loss of accuracy. The final section of the thesis presents an accurate comparison of three test techniques and an evaluation of dynamic supply current monitoring. An increase in fault detection for dynamic supply current monitoring is obtained by removing the DC component of the supply current prior to measurement

Simulation and BIM in building design, commissioning and operation: a comparison with the microelectronics industry

Analogy between the Microelectronics and Building industries is explored with the focus on design, commissioning and operation processes. Some issues found in the realisation of low energy buildings are highlighted and techniques gleaned from microelectronics proposed as possible solutions. Opportunities identified include: adoption of a more integrated process, use of standard cells, inclusion of controls and operational code in the design, generation of building commissioning tests from simulation, generation of building operational control code (including self-test) from simulation, inclusion of variation and uncertainties in the design process, use of quality processes such as indices to represent design robustness and formal continuous improvement methods. The possible integration of these techniques within a building information model (BIM) flow is discussed and some examples of enabling technologies given

Experimental set-up for investigation of fault diagnosis of a centrifugal pump

Centrifugal pumps are complex machines which can experience different types of fault. Condition monitoring can be used in centrifugal pump fault detection through vibration analysis for mechanical and hydraulic forces. Vibration analysis methods have the potential to be combined with artificial intelligence systems where an automatic diagnostic method can be approached. An automatic fault diagnosis approach could be a good option to minimize human error and to provide a precise machine fault classification. This work aims to introduce an approach to centrifugal pump fault diagnosis based on artificial intelligence and genetic algorithm systems. An overview of the future works, research methodology and proposed experimental setup is presented and discussed. The expected results and outcomes based on the experimental work are illustrated

International White Book on DER Protection : Review and Testing Procedures

This white book provides an insight into the issues surrounding the impact of increasing levels of DER on the generator and network protection and the resulting necessary improvements in protection testing practices. Particular focus is placed on ever increasing inverter-interfaced DER installations and the challenges of utility network integration. This white book should also serve as a starting point for specifying DER protection testing requirements and procedures. A comprehensive review of international DER protection practices, standards and recommendations is presented. This is accompanied by the identifi cation of the main performance challenges related to these protection schemes under varied network operational conditions and the nature of DER generator and interface technologies. Emphasis is placed on the importance of dynamic testing that can only be delivered through laboratory-based platforms such as real-time simulators, integrated substation automation infrastructure and fl exible, inverter-equipped testing microgrids. To this end, the combination of fl exible network operation and new DER technologies underlines the importance of utilising the laboratory testing facilities available within the DERlab Network of Excellence. This not only informs the shaping of new protection testing and network integration practices by end users but also enables the process of de-risking new DER protection technologies. In order to support the issues discussed in the white paper, a comparative case study between UK and German DER protection and scheme testing practices is presented. This also highlights the level of complexity associated with standardisation and approval mechanisms adopted by different countries

Piezoelectric Transformer and Hall-Effect Based Sensing and Disturbance Monitoring Methodology for High-Voltage Power Supply Lines

Advancements in relaying algorithms have led to an accurate and robust protection system widely used in power distribution. However, in low power sections of relaying systems, standard voltage and current measurement techniques are still used. These techniques have disadvantages like higher cost, size, electromagnetic interference, resistive losses and measurement errors and hence provide a number of opportunities for improvement and integration. We present a novel microsystem methodology to sense low-power voltage and current signals and detect disturbances in high-voltage power distribution lines. The system employs dual sensor architecture that consists of a piezoelectric transformer in combination with Hall-effect sensor, used to detect the disturbances whose harmonics are in the kHz frequency range. Our numerical analysis is based on three-dimensional finite element models of the piezoelectric transformer (PT) and the principle of Hall-effect based “Integrated Magnetic Concentrator (IMC)” sensor. This model is verified by using experimental data recorded in the resonant frequency and low frequency regions of operation of PT for voltage sensing. Actual measurements with the commercial IMC sensor too validate the modelling results. These results describe a characteristic low frequency behaviour of rectangular piezoelectric transformer, which enables it to withstand voltages as high as 150V. In the frequency range of 10Hz to 250Hz, the PT steps down 10-150V input with a linearity of ±1%. The recorded group delay data shows that propagation delay through PT reduces to few microseconds above 1kHz input signal frequency. Similarly, the non-intrusive current sensor detects current with a response time of 8μs and converts the current into corresponding output voltage. These properties, in addition to frequency spectrum of voltage and current input signals, have been used to develop a signal processing and fault detection system for two real-time cases of faults to produce a 6-bit decision logic capable of detecting various types of line disturbances in less than 3ms of delay

Time domain analysis of switching transient fields in high voltage substations

Switching operations of circuit breakers and disconnect switches generate transient currents propagating along the substation busbars. At the moment of switching, the busbars temporarily acts as antennae radiating transient electromagnetic fields within the substations. The radiated fields may interfere and disrupt normal operations of electronic equipment used within the substation for measurement, control and communication purposes. Hence there is the need to fully characterise the substation electromagnetic environment as early as the design stage of substation planning and operation to ensure safe operations of the electronic equipment. This paper deals with the computation of transient electromagnetic fields due to switching within a high voltage air-insulated substation (AIS) using the finite difference time domain (FDTD) metho

A Method for Specifying Complex Real-Time Systems With Application to an Experimental Variable Stability Helicopter

Engineering systems increasingly contain a significant element of embedded software. The specification of such systems causes problems because of the diversity of the sub-systems which they contain. For example, in modem aerospace systems a combination of mechanical, electrical, hydraulic and digital sub-systems need to function together in a safety-critical manner. The need is for a uniform means of specification which spans the whole diversity of sub-systems and which serves both to verify and to validate the functional aspects of the total system