Fuzzy Logic Based Scheme for Directional Earth Fault Detection and Classification

Abstract

This paper presents a fuzzy-logic-based protection scheme for detecting the direction of earth faults in a transmission network using polarized voltage. The IEEE 9-Bus transmission network has been used to test the fuzzy logic scheme in MATLAB/Simulink. The proposed scheme involves the measurement of RMS value of each phase voltage in order to detect occurrence of a fault; the direction of fault is determined by measuring the phase angle between the fault current and the polarized or reference voltage. The proposed scheme has been tested in six earth fault cases, faults in the forward and reverse direction per phase. The simulation results demonstrate that the proposed protection scheme is able to detect earth fault and classify the fault direction accurately within one cycle time. Index Terms-Fuzzy logic, three phase transmission line, fault directional detection

Detecting development scenarios of dynamic events in electric power network smart-grids.Part two“Selective Protection”

“…But, according to the simulation, the criterion is effective only in the case of a regular repetition of semantic events specified in the relay. However, with short-term irregular events, the criterion does not correspond to the problem being solved [10], [11,12], [13,14], [15,16], [17,18], [19,20].…”

“…To implement the developed method of selective search SP of the amount of information Q when detecting SсеN scenarios, let us consider examples of the synthesis of elementary information sensors TS, in relation to the improvement of known detectors of selective relays [4,10], [11,13], [14,15], [16,17], [18,19], [20].…”

“…The time for making a decision TCHECK from the moment of the beginning of the development of the EFP to the moment of issuing the resultant signal of the relay operation, can be very long, e.g. TCHECK=0.1-1.5 s and can last up to 4 hours [10,11], [12,13], [14,15], [16,17]. The time TCHECK can be automatically reduced, depending on the meaning of the events occurring and the possibility of stable formation of the results of the relay operation [4].…”