A fully integrated X-Band quadrature VCO is presented. The VCO is implemented using transformer-coupled resonator in 0.18 μm CMOS technology, in which two VCOs are coupled by direct current modulation method to generate I-Q signals. The VCO is realized employing the drain-gate transformer feedback configuration proposed here. This allows VCO to use the quality factor enhancement in coupled reso...

Line current differential (87L) protection schemes face extra challenges compared with other forms of differential protection, in addition to the traditional requirements of sensitivity, speed, and immunity to current transformer saturation. Some of these challenges include data communication, alignment, and security; line charging current; and limited communications bandwidth. To address these...

With the rapid development of wind energy, relay protection for large-scale wind farms has been attracting some researchers, due to the absence of standards. Based on the large-scale doubly fed induction generator (DFIG)-based wind farms located in Gansu Province, China, this paper studies the differential protection for the outgoing power transformer of large-scale DFIG-based wind farms. Accor...

proper operations of transformer have several issues such as; preventing of unscheduled removal’s, increasing of reliability and continues supply of consumer demand. this result would be obtained that load and harmonic orders of sensitivity transformer at intervals appropriate for next hours and days is predicted to by selecting optimal utilization coefficient, reduction life of transformer is ...

This paper presents an improvement of digital differential relay reliability for protecting a large power transfer is discussed. First, the Fourier sine and cosine coefficients required for fundamental, second third and fifth harmonies determination have been calculated using rectangular transfer technique. Then, these harmonics have been used in harmonics restrain and blocking techniques used ...