ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ЗАЩИТЫ ЛИНИЙ ЭЛЕКТРОПЕРЕДАЧИ 0,4 КВ С ОТПАЙКАМИ ОТ ОДНОФАЗНЫХ КОРОТКИХ ЗАМЫКАНИЙ ЗА СЧЁТ ПРИМЕНЕНИЯ МУЛЬТИКОНТАКТНОЙ КОММУТАЦИОННОЙ СИСТЕМЫ МКС-2-3В

Abstract

The purpose of the work is to increase the protection efficiency of 0.4 kV power lines with branch lines from single-phase short circuits by means of using the multi-contact switching system MSS-2-3. It can be not possible to provide the necessary sensitivity of protecting 0.4 kV power lines against one-phase short circuits when the power line length is too high and when the wire cross section does not provide the necessary value of the phase-zero loop resistance. Power line sectionalizing helps to solve this problem. It allows dividing power lines into sections, each is protected by its protective device. The settings of the protective devices installed at the beginning of a power transmission line and at the sectioning units (SU) are different. It provides the necessary selectivity of their work. At the same time, many power transmission lines (PTL) have long branch lines. The choice of the installation site of SU in such lines is difficult since a short circuit or other damage can occur both on a trunk line section and on a branch line. When installing SU both before a branch line and behind it, there might be the cases of unjustified power supply outages. Therefore, it is necessary to develop devices allowing for sectionalizing such power lines at the installation site of SU while ensuring the possibility of disconnecting both a trunk line section and a branch line directly. Such a device is a multi-contact switching system having two independent contact groups and three outputs (MSS-2-3). Installing the MSS-2-3 at a branch line point increases the security of the power transmission line against short circuits including single-phase ones and also increases power supply reliability to consumers since only a damaged section is disconnected in case of damage to the power transmission line. The feature of choosing the settings for the operation of switching devices installed in the MKS-2-3 to protect the switched power line sections is the need to take into account the parameters of a trunk line section and a branch line