The trend of energy savings has been widely interested and phase shift transformers (HMT) have been extensively used. This paper presents the investigation of the effect of harmonic currents on losses of the HMT. In this paper a 15-degree HMT with quad secondary winding is applied to find the relationship between harmonic currents and losses of the HMT. This relation can be met by testing the active power of primary and secondary sides while the HMT supplies for two and four non-linear loads at 25% 50% 75% and 100% rated currents respectively. The results reveal that harmonic currents affect winding eddy current losses significantly and the losses for loading the two secondaries 1 and 2 are the same as loading the two secondaries 1 and 3 while both %THDi are different. However for loading the secondaries 1 and 2 the %THDi is more than 15% so it is not met IEEE 519 Std. while the HMT is supplied with four loads the %THDi has met IEEE 519 Std. and the losses are less than 57% compared to one load. As a result of these if the HMT is applied to an adjustable speed drive system it is not only reduced the harmonics but also saved the energies.

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.

Ground grid design of substation is very important. It will help prevent the danger caused by the fault which causes the high step voltage and high touch voltage and may cause the operator to die. It also helps prevent damage to equipment and increases reliability for power systems as well. Currently the Gas Insulated Substation (GIS) has been built a lot especially in areas with limited space because it takes less space than the Air Insulated Substation (AIS). In order to create a substation of the GIS model instead of the AIS model. In order to create the GIS instead of AIS including the improvement or maintenance of the substation it is necessary to build another small substation to supply electricity to replace electricity from the original substation. However there are two substation stations in the same area may cause an increase of high-slope ground potential between the ground grid systems of both substations. It will cause high step voltage and high touch voltage while the fault is diminished. Therefore before improvement or maintenance of substation the ground grid distance and the size of the newly constructed substation must be analyzed that what effect on step voltage and touch voltage generation. Including studying the effects of step voltage and touch voltage that will occur.

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.

This paper presents the simulation and experimental result of class-E power amplifier. It is often used in designing a high frequency ac power source because its ability to perform the conversion efficiently even at high frequencies with significant reduction of switching losses. This paper aims to compare the transmission performance of electrical power between the air core transformer and iron core transformer which the identical input voltage of 50 VAC. Both transformers are designed to step voltage up (step up transformer) ratio of 1:4.5. The Arduino microcontroller Arduino was used to generate a pulse width modulation (PWM) with operating frequency of 3.74 kHz. IC gate drive TC4422 was used to drive the IRF510 MOSFET. Based on the simulation and experimental results the power loss in air core transformer is 75 percent while power loss in iron core transformer is 0.2 percent. The maximum distance that can transmit electric power of air core transformer is 9.3 centimeters.