Power System Operation Risks: Potential Hazards Due To Poor Conductive Circuit Structure Of High-voltage Disconnect Switches

In the daily operation and maintenance of substations, the reliability of current-carrying components directly affects the stability of the power grid. As a frequently operated switching device, High Voltage Disconnect Switch often suffers from various failures due to external environmental corrosion and mechanical wear.

Analysis of Excessive Contact Resistance in Internal Contacts of High-Voltage Disconnect Switches

The contact state of each connection point in the current-carrying component determines the degree of heat generation. High-voltage disconnectors exposed to the elements for extended periods are prone to corrosion or fatigue deformation of the stationary contact springs, leading to reduced pressure.

• Contact pressure attenuation: The elasticity of the spring weakens under long-term thermal cycling, causing a sharp increase in contact surface resistance.
• Surface oxidation and corrosion: Insufficient silver plating or wear exposing the copper material easily leads to the formation of an oxide film that hinders current flow.
• Loose fasteners: Insufficient torque of the outlet bolts due to operating vibration or temperature fluctuations can induce localized high temperatures.

Affects High-Voltage Disconnect Switch Performance by Misalignment in the Transmission Mechanism

The accuracy of the mechanism's operation is crucial for the coordination of the current-carrying system. If the moving contact of the high-voltage disconnector is not accurately inserted to the predetermined depth, the contact area will be reduced.

Contact Closing Position Misalignment

During installation and commissioning, if the linkage rod stroke is not properly adjusted, the moving contact may be in a non-ideal closed position. This misalignment increases the tendency for point contact on the contact surface, and local current density overload can cause metal softening or even welding.

Rotating Shaft Pin Wear Resistance

Drying or dust accumulation in mechanical rotating parts increases resistance during operation, often preventing the contacts from reaching their proper position.

So how to improve the operational stability of high-voltage disconnect switches?

Infrared thermal imaging is a direct method for identifying potential temperature rise hazards. Regularly measure the main circuit resistance of the high-voltage disconnect switch to ensure its value is within the specified range. For older equipment, replacing contact components with those having stronger oxidation resistance can significantly reduce the probability of accidental tripping.