Improving the functioning efficiency of 6-10 kV electrical networks with isolated neutral in conditions of single-phase ground faults

Abstract

The main objectives of this publication are: 1) to attract the attention of energy specialists to the problems of reliability and electrical safety of 6-10 kV overhead electrical networks with isolated neutral, operating in conditions of single-phase insulation damage; 2) substantiation of the feasibility of introducing a fundamentally new way to improve the efficiency of 6-10 kV distribution networks, based on the resonanceless limitation of the single-phase ground fault current arising from the breakdown of the insulator and the use of its own infrastructure of the electrical network for remote identification of the place of its occurrence. The expediency of including a nonlinear surge suppressor between the traverse and the grounding outlet of the reinforced concrete support is confirmed by the positive results of experimental studies carried out on the basis of high-voltage testing laboratories of IDGC of Center PJSC - Orelenergo and EnerGarant LLC. The use of deductive analysis allowed the authors to select a reliable and affordable electrical insulating material installed between the support and the traverse, as well as to formulate the main requirements for it, including taking into account weather and climatic factors. The analysis of various methods of transmitting information about the place of occurrence of the insulator damage made it possible to establish the predominant advantage of a wired communication channel using its own 6-10 kV electric network infrastructure. The authors have developed an original circuitry solution that provides remote identification of the insulator damage location using a thyristor shunting the nonlinear surge suppressor, according to a given switching algorithm, and also provides local identification of the insulator breakdown by means of special signaling devices with volatile power supply. It is expected that the proposed method, with relatively low investment, will significantly reduce the level of accidents and electrical hazards in overhead distribution networks of 6-10 kV, as well as minimize the costs associated with their operation and undersupply of electrical energy.

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

“…In addition, as noted earlier, the calculation of the current setpoints of the directional and nondirectional ground fault protections of 6-35 kV networks considers the mode of stable Combining heat and the high sensitivity of the SPGF protection devices, along with the desire of the MRC enterprises operating at 6-35 kV networks to maintain the power supply to their consumers under the conditions of SPGF mode until the damage location is reliably determined, create the conditions for the development of an accident. Despite the immutability of linear voltages values in SPGF mode with electric receivers switched on in medium-voltage networks, the long-existing single-phase short circuit mode increases the probability of intact phases insulation damage due to overvoltage and contributes to the transition to more serious damage-phase-to-phase short circuit, followed by immediate disconnection of the damaged line, shutdown of the technological process and an increase in economic losses [17][18][19].…”

Ensuring effective transit of electrical energy using the laws of environmental cybernetics and the foundations of automatic control

“…Introduction. In turn, the large-scale growth of overhead power lines has a very adverse effect on naturally formed natural landscapes, often leading to the displacement of wildlife from their natural habitat and the suppression of the growth of tree and bush vegetation [1]. Unfortunately, the reality is that the growth of the length and branching of overhead power lines, accompanied by a multiple increase in the amount of energy transmitted, is not always ensured by timely and complete repair and restoration work [2].…”