this paper presents the application of the fuzzy-neuro method toinvestigate transformer inrush current. recently, the frequency environment ofpower systems has been made more complicated and the magnitude of the secondharmonic in inrush current has been decreased because of the improvement of caststeel. therefore, traditional approaches will likely mal-operate in the case ofmagnetizing inrush w...

(Received: October 30, 2011; Accepted: December 8, 2011) Abstract: This paper presents a novel technique for transformer differential protection to prevent incorrect operation due to inrush current. The proposed method in this paper is based on time-frequency transform known as the Wavelet transform. The discrete Wavelet transform is used for analysis the differential current signals in time an...

Magnetizing inrush currents are known as the most critical potential threat in maloperation of transformer differential protection. Therefore, there is a need to detect current from internal fault avoid protection maloperation. Due possibility (CT) saturation at high level and current, discrimination algorithm should function appropriately CT conditions. Here, method developed based on rate pha...

During the transient period at the start of transformer energization, it experiences a flux linkage that is up to twice its nominal steady state value and saturates the core. This causes a large inrush current to flow which affects the power system stability and power quality especially when the source is weak. Sequential phase energization technique and addition of neutral resistor are the maj...

Abstract China has built the largest power network in world, forming a pattern of “nationwide interconnection, sending from west to east, mutual supply between south and north.” As user-oriented terminal network, safe operation distribution is basis system stability. However, huge, widely distributed prone failure. In order quickly accurately judge fault category, improve efficiency location re...

This paper presents the characterization of transients resulting from faults in transformers using discrete wavelet transform (DWT). This characterization will aid in the development of an automatic detection method for internal incipient faults in the transformers. The detection method can provide information to predict failures ahead of time so that the necessary corrective actions are taken ...

Numerical field solutions may be used to predict the magnetizing current waveform of power transformers for a giving value of sinusoidal voltage supply. This note concerns the sequence of operations necessary to estimate the magnetizing current waveform of power transformers employing a set of numerically simulated open-circuit tests.

This paper presents a novel power transformer differential protection scheme by using combined Wavelet Transform and Artificial Neural Network which provide the means to enhance the classical protection principles and facilitate faster, more secure and dependable differential protection for power transformer. Wavelet transform is used to extract the feature from transient signal and the neural ...

In the power system voltage sag become the important issue for industries. According to the survey 92% of the interruptions at industrial installations are voltage sag related. In various companies voltage sag may affect many manufactures and introduce sufficient losses in the power system. The voltage sag compensator, based on a transformer coupled series connected voltage source inverter, is ...