When current transformer is saturated, mainly due to the presence of an exponentially decaying DC component in fault current, its secondary has a distinctive distorted waveform which significantly differs from primary (true) waveform. It leads underestimation value calculated by relay protection compared true value. Thus, turn, results trip time delay or even devices operation failure, since se...

This paper consist of two sections: control and stabilizing approach for chaotic behaviour of converter is introduced in first section of this paper for the removal of harmonic caused by the chaotic behaviour in current converter. For this work, a Time- Delayed Feedback Controller (TDFC) control method for stability chaotic behaviour of buck converter for switching courses in current control mo...

Mining operations in China are often threatened by frequent water inrushes from confined karst aquifers, We need to evaluate the risk from water-inrush from coal floors in order to have safe production in mines. water inrush risk assessment method based on fuzzy comprehensive evaluation is introduced in this paper. A secondary fuzzy comprehensive evaluation system is constructed to evaluate the...

Alternating current power supplies and rolling stock with 25 kV (50 or 60 Hz) 15 (16.7 traction systems do not have the characteristics behaviour of a typical three-phase medium-voltage distribution system. Switching inductive loads vacuum circuit breaker (VCB) in MV poses familiar challenges as well some unique challenges, such crossing phase change neutral sections. Transformers represent hig...

In many text books and papers such as [1]-[5], it is possible to find descriptions about shunt fault calculations and about the influence of the three-phase transformer connection Dyn on the fault currents distribution through distribution transformers. In [6] is described a method for digitally simulating a three-phase power system which is subjected to a fault at one location with blown fuse ...

A platform implemented with Digital Signal Controllers (DSCs) developed for real time studies of the dynamic behavior of the air-gapped current transformers (CTs) used in power grid protection and measurement systems is presented. The implemented algorithms simulate the fault current in an electric power system as well as the transient response of the current transformer. It is also presented a...