The most common cause of power transformer failures is mechanical defect brought about by excessive vibration, which is formed by the combination of multiples of a frequency of 120 Hz. In this paper, the types of mechanical exciting forces applied to the power transformer were classified, and the mechanical damage mechanism of the power transformer was identified using the vibration transfer ro...

Electromagnetic forces in power transformer windings are produced by interaction between the leakage fluxes and current passing them. Since the leakage flux distribution along the windings height is in two axial and radial directions, so the electromagnetic forces have two components, radial and axial. There is a risk that a large electromagnetic force due to the short circuit or inrush current...

Reactive energy and power factor L2 1.1 The nature of reactive energy L2 1.2 Equipment and appliances requiring reactive energy L2 1.3 The power factor L3 1.4 Practical values of power factor L4 Why to improve the power factor? L5 2.1 Reduction in the cost of electricity L5 2.2 Technical/economic optimization L5 How to improve the power factor? L7 3.1 Theoretical principles L7 3.2 By using what...

In this paper, a novel pulsed power generator based on IGBT stacks is proposed for wide pulsed power applications. Because it can generate high voltage pulsed output without any step-up transformer or pulse forming network, it has advantages of fast rising time, easiness of pulse width variation, high repetition rate and rectangular pulse shapes. Proposed scheme consists of multiple power stage...

This paper is concerned with the protection of wind energy systems against the direct effects of lightning. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded as a serious problem. Nevertheless, very few studies exist yet in Portugal regarding lightning protection of wind energy systems using numerical codes. A new case study is p...

This article provides a description of protection based on the transformer model. The described by authors does not require calculations and depend operating mode power system. sensitivity ensures detection internal coil short circuits in case transformer. compares proposed algorithm with an improved version differential protection, which is capable fixing most

The electronic current transformer plays an irreplaceable position in the field of relay protection and current measurement of the power system. Rogowski coils are used as sensor parts, and in order to improve the measurement accuracy and reliability, the circuits at the high voltage system are introduced and improved in this paper, including the analog integral element, the filtering circuit a...

This paper is concerned with lightning surge propagation on wind turbines. As wind power generation undergoes rapid growth, lightning incidents involving wind turbines have come to be regarded as a serious problem. Nevertheless, no known studies exist yet in Portugal regarding lightning protection of wind turbines. Hence, we present a case study, based on a wind turbine with an interconnecting ...

There are some deficiencies in the improved three-ratio method even though it has been widely used in power transformer fault diagnosis. Using artificial neural networks, the power transformer fault diagnosis is improved in this article. With Matlab programming, three different kinds of neural networks, which are Radial Basis Function (RBF) neural network, Learning Vector Quantization (LVQ) neu...