This paper presents an efficient wavelet and neural network (WNN) based approach for distinguishing magnetizing inrush currents from internal fault currents in three phase power transformers. The wavelet transform is applied first to decompose the current signals of the power transformer into a series of detailed wavelet components. The values of the detailed coefficients obtained can discrimin...

In this paper, according to theoretical diagnosis of fault tree, the author builds a diagnosis model based on dynamic fault tree and illustrates the model’s construction method and diagnosis logic in detail. According to case analysis, compared with conventional fault tree diagnosis, the above-mentioned method is advanced in fault-tolerant ability. Plus, the diagnosis results record some interm...

High power and high voltage gain DC-DC converters are key to high-voltage DC (HVDC) power transmission for offshore wind power. This paper presents an isolated ultra-high step-up DC-DC converter in matrix transformer configuration. A flyback-forward converter is adopted as the power cell and the secondary side matrix connection is introduced to increase the power level and to improve fault tole...

Current and voltage transducers provide instrument level signals to protective relays. Protective relay accuracy and performance are directly related to the steady state and transient performance of the instrument transformers. Protective relays are designed to operate in a shorter time than the time period of the transient disturbance during a system fault. Large instrument transformer transie...

Protection systems have vital role in network reliability in short circuit mode and proper operating for relays. Current transformer often in transient and saturation under short circuit mode causes mal-operation of relays which will have undesirable effects. Therefore, proper and quick identification of Current transformer saturation is so important. In this paper, an Artificial Neural Network...

A method of modeling internal turn-to-earth and turn-toturn faults in distribution transformer is discussed in this paper. The models are entirely compatible with the Alternative Transients Program(ATP). The simulation of the faults is based on known leakage factors between the various coils of the transformer. These leakage factors are evaluated by using a simple method implemented in this pap...

Transformer is one of the most important and costly apparatus in a power system. The reliable and efficient fault free operation of transformer has a decisive role in the availability of electricity supply. In recent years, there has been growing interest in the condition assessment of transformer insulation. In this paper we concerned about the condition monitoring of transformer, benefit of c...

Transformer fault detection and diagnosis is becoming more important due to the restructuring of the electric power industry. In this era of deregulation, loading transformers to their optimum capacity is becoming normal practice, which in turn applies high stresses on the insulation of the transformers and increases the probability of occurrence of internal incipient faults. Such faults can le...

Transformer fault diagnosis is an interesting subject for plant operators due to its criticality in power systems. There are several international standards available to interpret power transformer faults based on dissolved gas analysis. In certain cases these standards are not able to provide correct diagnosis. There are several soft computing techniques available for modelling transformer fau...