Precise detection and localization of faults in power transformer windings for ultimate protection is the key issue. The insulation quality in windings majorly determines the enduring transformers function. Achieving as accurate and efficient detection method of partial discharge (PD) in transformer windings is challenging. The occurrence of PD being primarily responsible for the transformers f...

The insulation of power transformer i.e. oil and paper decomposition recognized by means of dissolved gas-in-oil analysis (DGA). To detect incipient faults in a transformer, standard key gas method of DGA is employed on the basis of quantity of gases released from the oil. This primary information also reflects the overall condition of a transformer. In this paper, condition assessment of power...

This paper develops a novel dynamic correction method for the reliability assessment of large oil-immersed power transformers. First, with the transformer oil-paper insulation system (TOPIS) as the target of evaluation and the winding hot spot temperature (HST) as the core point, an HST-based static ageing failure model is built according to the Weibull distribution and Arrhenius reaction law, ...

Generation, transmission and distribution of electric energy are to be characterized by a very high degree of reliability. Reliability level is directly related to the quality of the equipment used and the periodic maintenance carried out on the system. In our country, the distribution system is the most neglected part, which is being given some importance only in the recent years. Distribution...

Smart grid technology is a new approach for promoting the energy efficiency and for accomplishing the environment objectives. In this context, the lifetime of transformers have a great impact on the quality of the delivered energy. The paper deals with a mathematical statistic method for estimation of winding insulation lifetime of the power transformers, based on Rayleigh distribution. The con...

Analyzing the concentration of low molecular acids dissolved in oil is vital in the oil-paper insulation aging diagnostic procedure of power transformers. The existing methods cannot distinguish between different acid types and their strengths. In this study, an improved solution Raman detection platform is fabricated. The direct measurement of dissolved acetic acid, a kind of low molecular aci...

This paper introduces a high precise direct current (DC) negative high voltage power supply. The supply’s output voltage is 25kV and its maximal output current is 100mA. The power supply uses BOOST converter for power factor correction and voltage regulation. It converts DC to high frequency (HF) alternating current (AC) square wave with phase-shifted full bridge. The voltage of the AC square w...

Frequent Switching of arc furnace in steel company causes a great effect on the insulation of arc furnace transformer winding which in turn may causes a shutdown of production for long periods of time. Therefore, it is necessary to study and analyze the causes of these outages and design an adequate protective device. In this paper the transient overvoltage resulted from vacuum circuit breaker ...

The need for economic, reliable and effective delivery of electric power has lead to the search for new, efficient and effective methods for diagnosing the insulation of the HV equipments in the industries all over the world. One of the methods currently being investigated as a potential nondestructive diagnostic tool for condition monitoring of the oilpaper insulation of power transformers is ...

Dissolved gas analysis (DGA) has been widely applied to diagnose internal faults in transformer insulation systems. However, the accuracy of DGA technique is limited because of the lack of positive correlation of the fault-identifying gases with faults found in power transformers. This paper presents a laboratory study on the correlation between oil dissolved gas formation and partial discharge...