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Modeling tools are useful for educational and industrial use. Such tools help the new engineers to simulate the power system under normal and faulty conditions. This paper presents the design and various data conversion steps of a digital negative sequence relay. The digital relay has a superiority over electromechanical relay in terms of accuracy and speed. The detection of negative sequence current...
A lot of things determine the life expectancy of a transformer such as overheating due to triplen harmonics, unbalanced loading, vibro-acoustic noise and so on. For this reason, this paper presents the investigation carried out on the magnetostrictive sound of Bauchi, 30/40 MVA, 132/33 KV substation transformer. Readings were taken using standard audio recording instrument for various loading and...
This paper presents an effective algorithm to locate Single Line to Ground (SLG) fault at a transmission line. Post fault voltages and currents from both substation terminals were used as the input parameters to the algorithm. Discrete Fourier Transform (DFT) was used to extract the magnitudes and phase angles of three phase voltages and currents. The modeling of the transmission line along with the...
Failure of vacuum metal clad switchgears often results in major load loss and long restoration time. Failure analysis is conducted with the aim to prevent future recurrence, thus an improved life of the equipment. This paper presents two failure cases of vacuum metal clad switchgears which had suffered from flashover. Both switchgears were connected to a local transformer and had exhibited similar...
An investigation of magnetizing current waveforms of single phase power transformer due to DC bias injection through simulation and experimental study is present in this paper. A method base on MATLAB simulation that is capable of predicting of magnetizing current without and with DC bias is used. The experimental study is done by the DC bias current injected simultaneously with AC source to primary...
The dc bias effects on the magnetizing and magnetic induction are analyzed through their harmonic characteristics. A model transformer in order to analyzed the harmonic characteristic of the single phase power transformer under dc bias condition. The effect of dc bias will seen by the dc current injected on the winding of experiment system. Effect of that the linear value is changed with the ac excitation...
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