Symmetrical nature of mean of electrical signals during normal operating conditions is used in the fault detection task for dependable, robust, and simple fault detector implementation is presented in this work. Every fourth cycle of the instantaneous current signal, the mean is computed and carried into the next cycle to discover nonlinearities in the signal. A fault detection task is complete...

A novel fault phase selector for double-circuit transmission lines is presented. The fault type is determined with the superimposed components and steady state components of fault voltage. According to the determined fault type, auxiliary criteria based on the magnitude and phase difference of fault phase current is applied to judge whether inter-line fault happens or not. If inter-line fault h...

During non-severe fault conditions, crowbar protection is not activated and the rotor windings of a doubly-fed induction generator (DFIG) are excited by the AC/DC/AC converter. Meanwhile, under asymmetrical fault conditions, the electrical variables oscillate at twice the grid frequency in synchronous dq frame. In the engineering practice, notch filters are usually used to extract the positive ...

In order to ensure the safety of DFIG when severe fault happens, crowbar protection is adopted. But during slight fault condition, the crowbar protection will not trip, and the DFIG is still excited by AC-DCAC converter. In this condition, operation characteristics of the converter have large influence on the fault current characteristics of DFIG. By theoretical analysis and digital simulation,...

The fault current development in a circuit breaker during a pole-to-ground fault is analyzed for a generic multiterminal HVDC system based on Voltage Source Converters. The paper aims to contribute to the current discussion of which requirements on breaking time and peak current HVDC circuit breakers need to fulfill in such networks either based on OHLs or cables. Therefore, the fault current i...

Conventionally, the current flow control and DC fault protection issues of HVDC grids are supposed to be solved by controller (CFC) circuit breaker (DCCB) separately, which may result in a high capital cost. This paper proposes CFC topology with limiting interrupting capabilities. The operating principle presented theoretical analysis. strategies under normal conditions described. In order redu...