This thesis presented the design and construction of an adaptive active band-pass filter by using a tachometer circuit. The main part was the multi voltage-mode filter circuit based on an operational transconductance amplifier which could automatically adjust the center frequency to adapt to the input signal frequency by the tachometer circuit. The frequency error value in the center frequency was set to be ≤ 3% of the input signal. Furthermore the proposed filter could support the input signal in the frequency range of 10 Hz - 10 kHz. From the simulation and experimental results of the proposed prototype filter it could respond to the frequency according to the theory of the band-pass filter and the error in choosing the center frequency which was 1.45 % and 2.6 % respectively (below the set error value of 3 %). Therefore the proposed filter could be used for real application. The working principles of the proposed prototype filter could also be applied to the noise attenuation circuit of an electrocardiogram machine. Moreover this research could be used as a guideline study for those who want to develop other types of adaptive active filters for higher efficiency.

In this article the construction of a high-frequency high-voltage commercial flyback transformer to supply an input voltage for a tesla transformer is proposed. The purpose of a demonstration is a breakdown through the air gap of electrode. To confirm the proposed method the design of control of a flyback converter by using a commercial flyback transformer is rated with a 10 to 15 kV output voltage to supply a tesla transformer at a rated 30 kV and 120 kHz. The experimental results of an output breakdown design of the electrode and the setting for a 1 cm space are constructed. The electrodes consisted of the following: sphere–sphere electrode plane–plane electrode sphere–plane electrode and rod–plane electrode. It was found that there was a breakdown at the output electrode in all cases. Accordingly there was a breakdown with a 2 cm sphere diameter with reference to the IEC 60052-2002 standard; after that it was compared with the standard table and the atmospheric and temperature at the laboratory were adjusted resulting to a high voltage equal to 31.5 kV.

The objectives of this research were to develop of transmission line calculation program based on usage and frequency consisting of the two-wire transmission line twisted pair transmission line and coaxial transmission line. The program was developed in the form of graphical user interface in Malta. The developing and testing results found that the program was correctly capable to calculate capacity conductance inductance resistance and impedance for each transmission line usage and frequency. The results from the program with black box testing by five experts and twenty system users found the average and the standard deviation of results form computer experts were 4.04 and 0.36 respectively while those of results form the system users were 3.88 and 0.48 respectively. Conclusion it showed that the efficiency of the calculation program was a high level and can be used as a teaching and learning as well.

The effects of load frequency control (LFC) of interconnected distribution power system in tie-line substation area load –frequency stability and the frequency respond at distribution generator (DG) are very important for interconnected control power system of tie-line area. The generating power system of solar farm and wind turbine which have interconnected distribution power system in tie-line substation area were tested using 3 simulation parameters: non-controller Automatic Voltage Regulator (AVR) and with Pl Controller. The results showed that there were 3 types of load and frequency changing in the interconnected area: load changed 0.02 p.u. had frequency of load changed 0.025 Hz and large disturbance. Comparisons of load-frequency to respond for steady state the time respond was 7.9 seconds for non-controller 5.4 seconds for AVR and 1.7 seconds for under controlled system at 0.1 p.u using Pl controller. Therefore the Pl controller has better efficiency than non-controller about 31 % and AVR about 16%. It can be concluded that the interconnected distribution power system in tie-line substation area controlling for storage for connected grid had better efficiency and optimization of generating power from renewable solar farm and wind turbine which have interconnected distribution power system in the nearby are balance of controlling of the original system.

This paper presents an analysis of transformer faults to determine the damage occurring within the transformer by the frequency response analysis (FRA) method. Enter the frequency from 10 Hz to 3 MHz and then the measured value is compared to the standard reference value. Consider the different graphs of frequency response in various frequency ranges to analyze the deformation of the iron cores and transformer coils to know the internal condition of the transformer. The tests show that the 50 MVA 115 kV/22 kV transformer has severe damage to the high voltage side and low voltage side of phase-A coil. As a result the transformer can not be used in the power system and make a reminder to repair the transformer.