In this paper, the traveling wave protection issue of a hybrid high-voltage direct-current transmission line based on line-commutated converter and modular multilevel is investigated. Generally, voltage variation criterion, rate criterion current applied lines as primary protection. There are two issues that should be addressed: (i) it has no fault direction identification capability which may ...

This paper proposes a new approach to the distributed generation system protection coordination based on directional overcurrent protections with inverse-time characteristics. The key question of protection coordination is the determination of correct values of all inverse-time characteristics coefficients. The coefficients must be correctly chosen considering the sufficiently short tripping ti...

it is well-known that severe deformation to metals causes a direct grain refinement of the matrix without special heat-treatments due to the mechanism of dynamic continuous recrystallization (dcr). however, the microstructural revolution during severe deformation is seemed to be different depending on the deformation mode, namely the direction of deformation. in general, multi-directional defor...

economic and environmental logging is important for sustainable wood production in the caspian forests, north of iran. predetermination of the skid trail network and directional felling is a usual recommended method to reduce logging impact. the aim of this study was evaluation of directional felling and finding factors effective on felling error. totally 135 trees were selected randomly for di...

post-mineralization activities may cause difficulties in the process of ore modeling in porphyry deposits. sungun, nw iran, is one of the porphyry copper deposits, in which dyke intrusions have made ore modeling more complicated than expected. among different kinds of dykes, two types were chosen and the consequent geostatistical analyses were applied on. in this study, simple directional vario...

the efficiency measurement is a subject of great interest. the majority of studies on dea models have been carried out using radial or non-radial approaches regarding the application of dea for the efficiency measurement. this paper, based on the directional distance function, proposes a new generalized hybrid measure of efficiency under generalized returns to scale with the existence of both r...

The effects of using both directions and directional subdividing on adaptive gridembedding on the computational time and the number of grid points required for the same accuracy are considered. Directional subdividing is used from the beginning of the adaptation procedure without any restriction. To avoid the complication of unstructured grid, the semi-structured grid was used. It is used to so...

Inverter-based resources (IBRs) exhibit different short-circuit characteristics compared to traditional synchronous generators (SGs). Hence, increased uptake of IBRs in the power system is expected impact performance protective relay schemes—set under assumption a SG-dominated system. Protection engineers need study these challenges and develop remedial solutions ensuring effectiveness protecti...

This paper presents a hybrid optimization approach for the optimal coordination of Inverse Definite Minimum Time (IDMT) directional overcurrent relays in meshed power systems, namely Immune Algorithm and Particle Swarm Optimization (IA-PSO) algorithm. The algorithm is employed by coupling the immune information processing mechanism with the particle swarm optimization algorithm in order to achi...