Earthing Switch Technical Parameters for 24kV and 36kV Systems

An earthing switch is an essential component in medium and high voltage switchgear systems, providing a safe grounding path for electrical circuits during maintenance or emergencies. In 24kV and 36kV systems, the performance of an earthing switch directly influences operational safety, insulation coordination, and overall reliability of the power distribution network.

For 24kV and 36kV systems, the earthing switch must be rated to handle the system voltage under both normal and fault conditions. Typical rated voltages include 12kV, 24kV, and 36kV, with rated short-time withstand currents ranging from 16kA to 31.5kA for 1–3 seconds. This ensures the device can safely ground the circuit during fault clearing or isolation procedures.

The making capacity defines the maximum current the earthing switch can safely close against during an energized condition. High-performance models for 36kV applications often feature making capacities up to 80kA peak, ensuring robust performance under severe fault scenarios.

The insulation coordination between phases and to earth is critical. For 24kV systems, the power frequency withstand voltage is typically 65kV, while for 36kV systems it reaches up to 95kV. These values are designed to comply with IEC 62271 standards, ensuring safe operation even during voltage surges or lightning impulses.

A high-quality earthing switch should provide at least 2,000 mechanical operations without degradation. Manual, motorized, or spring-operated mechanisms are selected based on system configuration and automation level. Durability and smooth operation are key indicators of long-term reliability in switchgear assemblies.

Application and Mounting Options:

Earthing switches are widely used in ring main units (RMUs), gas-insulated switchgear (GIS), and air-insulated switchgear (AIS). Depending on the installation, they can be panel-mounted or integrated directly into switchgear compartments to minimize maintenance and improve safety.

For utilities and industrial users seeking dependable grounding solutions, Putai offers a comprehensive range of earthing switches designed for 12kV, 24kV, and 36kV applications. Each product is built with reliable insulation, strong making capacity, and durable mechanical performance to meet global standards.