This article presents a novel technique to distinguish between magnetizing inrush current and internal fault current of power transformer. An algorithm has been developed around the theme of the conventional differential protection method in which parallel combination of Probabilistic Neural Network (PNN) and Power Differential Protection (PDP) methods have been used. Both PNN and PDP method ar...

Intriguing mal-operations and fail-to-trip of the differential protection of the converter transformer in the HVDC system are reported. In this paper, the mechanism of these abnormal operation behaviors is analyzed. By virtue of deliberately designed models of the converter transformer and the HVDC transmission system, a variety of simulation tests are carried out and above mentioned strange op...

A new approach for power combining several low-voltage CMOS amplifiers using a new on-chip transmission line transformer structure is presented. The power combiner utilises the interconnection of short sections of integrated differential lines and has an efficiency independent of the transformation ratio. Full-wave electromagnetic simulation confirms the operation and low insertion loss of the ...

Energization of a transformer results in sudden flow of current which is an effect of core magnetization. This current will be dominated by the presence of second harmonic, which in turn is used to segregate fault and inrush current, thus guaranteeing proper operation of the relay. This additional security in the relay sometimes obstructs or delays differential protection in a specific scenario...

rotection schemes employing the differential relaying principle exhibit certain limitations in applications with power transformers. This is because the detection of a differential current does not clearly distinquish between internal faults and other possible conditions. Among the phenomena most likely to upset the current balance and cause the relay to malfunction are inrush magnetizing curre...

(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...

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...

Power transformers are key components for electrical energy transfer in a Power system. In order to protect the transformers from these faults different protective methods are adopted. Some of them are differential protection, over excitation Protection, etc. In this Paper Over Voltage protection is established for the protection of the transformer. Microcontroller is used for the Power Transfo...

There are two main approaches to realize a receiver front-end. However, they have drawbacks when fully-integrated on a single chip. One direction to realize this front-end is to use a transformer that can convert the single RF output of the LNA to the differential input of mixer [4]. Another way to do this is to use a narrow-band two stage tuned LNA [5] that can provide a differential output. H...