What is the creepage distance of an insulator

The creepage distance for polymer insulators is the shortest distance along the insulator surface between the metal parts at each end of the insulator,which is critical for preventing electrical arcing and ensuring safety against electrocution or fire hazards in electrical circuits. It varies based on the application and is influenced by factors such as working voltage and environmental conditions. However, Creepage distance can also be refer as leakage distance for insulators.

If the creepage distance is too short, contaminants such as dust, salt, or moisture can cause surface discharge or electrical breakdown, leading to insulation failure and power outages. Therefore, selecting the correct creepage distance according to the pollution level, system voltage, and environmental conditions is essential for the safety and reliability of power transmission and distribution systems.

The selection of appropriate creepage distances and clearances in a converter station is a key aspect of insulation coordination. The required creepage distance for a particular piece of equipment largely depends on the environmental conditions in which it operates. Generally, the creepage length increases in proportion to the maximum continuous voltage.

In a clean, air-conditioned valve hall environment, a creepage distance of approximately 14 mm per kV (peak) is typically sufficient. However, in polluted environments-such as those encountered on DC overhead lines or outdoor converter equipment located in industrial areas-a longer creepage distance of up to 40 mm per kV (peak), or even more, may be necessary to ensure reliable performance.

The electrical clearances within a converter station are mainly governed by the lightning impulse and switching impulse withstand voltage requirements.

Wuhan Line Power, as one of the qualified suppliers of the State Grid Corporation of China, offers a wide range of composite insulator molds. Our factory can provide customized insulator lengths according to customers' specific application environments to meet various requirements.

Typical creepage values for either cap and pin insulator strings or post insulators at 132 kV under very heavy pollution, classification IV, would be determined as follows: