Now showing 1 - 3 of 3
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Designing HV Reactor With Multiple Air Gap Structure Based on Fringing Flux Factor
    (2024-01-01) ;
    Raxsa, Jedsada
    ;
    ;
    Khumpho, Juthathip
    This paper introduces an experimental approach to determining the fringing flux factor (F), representing the leakage flux within the air gap of the magnetic core, for the design of high-voltage (HV) reactors. The formula for determining F was developed from the AC excitation experimental data using curve-fitting techniques on the proposed reactor's reduced-scale model, which features a CC shaped magnetic core with six air gaps. The significant configuration of the model includes an iron core and coil windings. The test conditions for the reduced-scale model are based on the number of turns in the winding, 85 and 300 turns for each coil winding and the length of the air gap, 2 mm. and 5 mm. for each gap. Based on experiments with the reduced-scale model, the developed formula for F demonstrates effective results, exhibiting an absolute error lower than 20 %. This F formula provides a promising guideline for designing HV reactors, with a lower absolute error value.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Resonant power frequency converter and application in high-voltage and partial discharge test of a voltage transformer
    This paper presents application of a resonant power frequency converter for high-voltage (HV) and partial discharge (PD) test of a voltage transformer. The rating voltage, power, and frequency of the system are 70 kV<inf>rms</inf>, 40 kVA, and 200 Hz, respectively. The testing system utilized the converter feeding to an HV testing transformer connected to a conventional partial discharge detection system. The converter system comprising a rectifier and insulated-gate bipolar (IGBT) switches with the H-bridge configuration was applied as a low-voltage source instead of a conventional motor-generator test set which requires large space and high cost. The requirements of the test according to the standards are quality of the test voltage and the background noise level. The required voltage must have the different voltage (DV) and total harmonic distortion (THD<inf>v</inf> ) in the acceptable values of less than 5%. The DV is defined as the difference of the root mean square and peak voltages in percent. The required background noise level must be lower than 2.5 pC. Simulations and experiments were performed for verification of the developed system performance in comparison with those of the previously developed system based on the pulse width modulation converter. It is found that the developed system can provide the testing voltage with the DV and the THD<inf>v</inf> of lower than 1% and the background noise level of lower than 1 pC. Considering this achievement of promising performance, the developed system is an attractive choice for the HV and PD testing of voltage transformers in real practice.
  • Some of the metrics are blocked by your 
    Item type:Publication,
    Accurate Circuit Parameter Determination of a Resonant Power Frequency Converter for High-Voltage and Partial Discharge Tests
    For high-voltage (HV) and partial discharge (PD) tests on high-voltage equipment, a resonant power frequency converter has recently been developed. A single-phase power frequency converter with a resonant tuning and filter circuit and an HV testing transformer comprise the developed system. A difficulty in the tuning and filter circuit design is the unknown testing system circuit parameters, including unknown parasitic inductance, capacitance, and internal resistance. In this paper, a system with a voltage rating of 75 kV<inf>rms</inf>, apparent power of 40 kVA, and an operating frequency from 50 Hz to 200 Hz is considered for determination of the equivalent circuit parameters. From the determined circuit parameters, the appropriate resonant tuning and filter circuit was designed effectively. The transfer functions of the input and output testing voltages, along with the transfer impedance of the input voltage and signal voltage of the PD measuring port, were analyzed. The system design was verified by experiments with a voltage transformer. The gain of the transfer impedance was about 15 and 4 at the testing frequencies of 50 Hz and 200 Hz, respectively. With the proper design, it is possible to generate an output voltage waveform that is almost entirely sinusoidal and has a background noise level of under 1 pC. According to the experimental results, the system design of the resonant converter and the method for determining the equivalent circuit are very helpful for the HV and PD tests of voltage transformers in actual practice.