DC fault clearance is one of the critical issues for modular-multilevel-converter-based high voltage direct current (MMC-HVDC) systems. Employing a hybrid circuit breaker (H-DCCB) to isolate faulty line typical method achieve fast clearance. However, H-DCCB has interrupt and absorb energy up tens megawatts in several milliseconds. Through theoretical analysis interruption process using H-DCCB, ...

objectives: the purpose of this study was to evaluate whether intra-canal application of controlled direct electric current (dec) could accelerate the amount of orthodontic tooth movement (otm) in young adult mixed breed dogs. methods: fourth premolars of both jaws of five young adult mixed breed dogs were divided into two groups of control and experimental groups. orthodontic force was applied...

Metal oxide surge arresters (ZNO) are used widely in power system to protect equipments from over voltages. Non uniform potential distribution leads to the depressed service life and low safe reliability, so grading ring is applied on HV surge arrester order to uniform the electric field distribution. One of the problems of arresters is leakage current in power frequency that different paramet...

The electrical field arising around an inhomogeneous conductor when an electrical current passes through it is not screened, as distinct from 3D conductors, in low-dimensional conductors. As a result, the electrical field depends on the global distribution of the conductivity sigma(x) rather than on the local value of it, inhomogeneities of sigma(x) produce giant capacitances C(omega) that show...

Currently most modern dc rapid transit systems around the world use running rails or a negative rail as the negative return circuit for the dc traction current. These rails are intentionally kept ungrounded from ground (earth) by using insulating material between the rail and earth to minimize dc stray current. This configuration of return current rail develops varying voltage with respect to g...

the idea of this paper is designing an automatic fault detection system based on fuzzy logic, therefore two signals of pmsm in fault condition are analyzed for inter turn fault detection: current and torque. in this fault type there is some distortion in these signals, but it is not good enough to detecting with fuzzy logic solely, so with combination of wavelet transform and fcm a new method f...

As the electric power systems in the United States become increasingly large, complex, and interconnected, the conventional relays and protection systems are proving to be inadequate during some abnormal conditions. In particular, there exists a significant history of relay protection schemes malfunctioning and, ultimately, leading to the infamous system-wide failures, known as electric power b...

Characteristics of ground motions close to the earthquake source can be considerably different from those of far-field motions which should be considered in design process of structures. The current study aimed to present new design response spectra for Iranian seismic design code taking into account the near-fault effects. For this purpose, a new attenuation relation based on the ground motion...