The idea of system control and monitoring of a complete medium-voltage switchgear with solid insulation

Abstract

The idea of the system control and monitoring of a complete 35-kV switchgear with the shielded solid insulation is presented. The switchgear is constructed in the form of two cells. One of the cells, which has a three-position sulphur hexafluoride load break–disconnecting–grounding switch with a motor-spring drive is incorporated into the switch module and includes bus and cable modules, a cell cabinet, and a control and monitoring system. The other cell contains the same elements, plus a fuse and a high-speed grounding switch. The control and monitoring system is developed in two forms, one for standard and one for digital substations. Technical characteristics and the structure of the system, as well as the execution algorithms, are given. Monitoring of the electromagnetic fields and partial discharges with the use of the various indicators and sensors, monitoring of insulation, and its temperature, as well as residual life of the switching devices and drives, are of great significance. Modbus is usually used as the automation protocol for standard substations. It allows carrying out the dispatching control and data integration into the control system, but it does not allow real-time transmission of the instantaneous values of current and voltage, RPA discrete signals, etc. In accordance with the IEC 61850 standards, all real-time commutation processes are carried out by the Ethernet technology, which is described by the IEEE 802.3 protocol and provides digital data transfer in accordance with stringent RPA requirements. Structural implementation of two system modifications in the form of the nonstandard telecommunication equipment with a temperature–humidity control system located on the top of the switchgear cabinet with the arrangement of the control, indication, and alarm element is described.