Transformer is the power equipment of power system core. Intelligent monitoring and operation of transformer can not only monitor the full range of the transformer, the realization of state evaluation, it should be required repair, maintenance required good, but also on the latent fault early diagnosis and prediction. Research on transformer intelligent monitoring and operating technology of sa...

(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...

Power transformers are one of the most critical devices in power systems. It is responsible for voltage conversion, power distribution and transmission, and provides power services. Therefore, the normal operation of the transformer is an important guarantee for the safe, reliable, high quality and economical operation of the power system. It is necessary to minimize and reduce the occurrence o...

The restricted earth fault (REF) relay is a type of differential protection which is used for detection of internal ground faults of power transformers. But, during external faults and transformer energization conditions, the probability of current transformer (CT) saturation increases. Thus, the spurious differential current due to CT saturation, can lead to REF relay maloperation. In this pap...

Power transformer is one of the most important equipments in the electric system. Dissolved Gases Analysis is an important method in the diagnosis of internal fault of transformers. Because the signs and types of fault have complicated nonlinear relations, the traditional methods cannot exactly meet the requirements of engineer application. This paper proposes synthesis of relational grey incid...

This paper presents an algorithm based on a combination of Discrete Wavelet Transforms and neural networks for detection and classification of internal faults in a twowinding three-phase transformer. Fault conditions of the transformer are simulated using ATP/EMTP in order to obtain current signals. The training process for the neural network and fault diagnosis decision are implemented using t...

This paper proposes a novel Fault Current Limiter (FCL) for the application on distribution networks to control voltage sags at the Point of Common Coupling (PCC) during faults. This new FCL is based on series resonance including resonance transformer and series capacitor. So, by proper design of the series resonance LC tank, the fault current is limited to an acceptable level. The FCL operatio...

Theoretical research and equipment development of traveling-wave fault location seriously depend on digital simulation. Meanwhile, the fault-generated transient traveling wave must be transferred through transmission line, mutual inductor and secondary circuit before it is used. So this paper would maily analyze and summarize the modeling technology of transmission line and mutual inductor on t...

This paper proposes a novel continuous sparse autoencoder (CSAE) which can be used in unsupervised feature learning. The CSAE adds Gaussian stochastic unit into activation function to extract features of nonlinear data. In this paper, CSAE is applied to solve the problem of transformer fault recognition. Firstly, based on dissolved gas analysis method, IEC three ratios are calculated by the con...

A new approach for protection of power transformer is presented using a time-frequency transform known as Wavelet transform. Different operating conditions such as inrush, Normal, load, External fault and internal fault current are sampled and processed to obtain wavelet coefficients. Different Operating conditions provide variation in wavelet coefficients. Features like energy and Standard dev...