Design of High Voltage Switchgear

1. The shells of all switch cabinets must be metal shells and have a certain mechanical strength. The circuit breaker room, busbar room and cable room in the cabinet are equipped with pressure release channels, and the laying of secondary lines is beautiful and easy to check. . The installation beams of all primary electrical components in the switch cabinet must be metal and should be grounded reliably.

2. 10KV and 35KV high-voltage switch cabinets are high-voltage live equipment. In order to prevent the human body from approaching the high-voltage live parts of the high-voltage switch cabinet and touching the moving parts, we must consider the requirements of the cabinet protection level when designing the switch cabinet.

3. The 10Kv and 35KV switchgear are used to distribute the three-phase alternating current. Therefore, a certain insulation distance must be ensured between the phases and the relative ground, otherwise it will cause a short circuit and cause harm to the entire power system.

4. The external insulation creepage distance (the ratio of the creepage distance of the external insulation of the high-voltage electrical components to the rated voltage) of the components and their supporting insulators (pure porcelain and organic insulation) in the high-voltage switchgear. Porcelain insulation is 18mm/kV, and for organic insulation it is 20mm/kV. In order to meet the above requirements, the measures we have taken are to increase the number of umbrella groups with insulators. In addition, in places where the switch cabinet is used in a humid environment, in order to prevent condensation, add belts in the cable room and circuit breaker room of the switch cabinet. The heater of the temperature control device.

5. Five-prevention interlocking function. We must abide by the following principles when designing and manufacturing switch cabinets: High-voltage switch cabinets are equipped to prevent accidental opening and closing of the circuit breaker, prevent the disconnection switch with load, prevent the power supply of the grounding switch (or grounding wire), and prevent the live connection of the grounding knife. Five kinds of anti-mistake measures such as the gate (or hang the grounding wire) to prevent the mis-entry with the point interval.

6. Temperature rise. In order to achieve the temperature rise limit, the following points must be done: Strengthen the manufacturing process of the switch cabinet (such as silver plating on the busbar lap surface, hot tin); design to avoid the occurrence of eddy current phenomenon or use non-inverted magnetic materials; large The current is increased by the air-cooled device.

7. All electrical components in the switch cabinet are live parts. In order to ensure personal safety during maintenance, all electrical components must be safely and reliably grounded.