Investigation of the Effect of Current Protections in Conditions of Single-Phase Ground Fault through Transient Resistance in the Electrical Networks of Mining Enterprises

Abstract

The efficiency of electrical complexes depends directly on the level of power supply system reliability, which comprises extensive and branched distribution networks. A complex of single-phase ground fault (SPGF) relay protection and automation devices (RPA) is used to reduce the economic losses from the failure of the electrical receivers’ distribution networks. This paper presents a study of the protection sensitivity factor, taking into account the influence of the network capacity and the resistance during a fault. The results of this study determined the minimum permissible values of the sensitivity factor that ensures the stable operation of the protection device. This was achieved by taking into account the influence of the transient resistance at the point of short circuit. The practical significance of the study is as follows: the obtained characteristics will allow for the development of new functional logic circuits for SPGF protection. The practical implementation of the obtained results will allow for the following: to increase the sensitivity and selectivity of current non-directional protections in conditions of incomplete short circuits; to ensure the reliable functioning of technological equipment and responsible consumers; to reduce the level of electrical injuries of service personnel; and to reduce economic losses associated with the repair of damaged electrical receivers.

Method for Assessing Damage to Gas Distribution Network Pipelines based on Nonlinear Guided Wave

“…There are two kinds of velocities for nonlinear directional wave propagation in polyethylene pipe, group velocity, and relative velocity. With the extension of propagation distance, directional waves with different frequencies will be separated (39), which will cause large-area dissipation of directional waves in a certain time domain and cause interference with the extraction of characteristic signals (40,41). Therefore, when choosing non-directional waves, try to choose directional waves with slow speed changes (42).…”

Improving the Efficiency of Radar Method for Monitoring Oil Spills on the Water Surface through the Use of an Active Antenna Array and Cosecant-squared Pattern

“…Decrease in cost of element base has allowed in the last decade to start serial production of radio systems with APAA not only for military but also for commercial purposes, for example, automotive radars for traffic safety [22,23] and earth terminals of satellite communication via low Earth orbit satellites [24,25].…”

“…. In addition, such ICs are significantly cheaper than gallium arsenide IC, which reduces the cost of the APAA.Decrease in cost of element base has allowed in the last decade to start serial production of radio systems with APAA not only for military but also for commercial purposes, for example, automotive radars for traffic safety[22,23] and earth terminals of satellite communication via low Earth orbit satellites[24,25].Along with the emergence of a new element base, APAA circuitry has also improved. Modern APAA increasingly use digital framing, which provides significant functional capabilities and flexible tuning of radio systems[26].…”

Off-line location strategy for single-phase ground fault of distribution line

“…At present, domestic distribution lines cover a wide area, long lines and many branches, and operating environment is complex and changeable. With the advancement of national policy orientation and urban construction, the growth rate of distribution network cable lines is close to 10%, which leads to a significant increase in the probability of failure [1][2][3][4] . According to statistics, 70% of faults in distribution system are caused directly or indirectly by single-phase grounding faults, which are often accompanied by overvoltage burnout or breakdown of equipment in stations.…”