The following factors are usually considered when selecting materials for capacitor casings:

High temperature resistance:
Capacitors generate heat when working, and the ambient temperature may also rise. Therefore, the casing material needs to be able to withstand high temperature conditions to ensure that the capacitor maintains stable performance under rated working conditions.

Corrosion resistance:
The working environment of the capacitor may contain acids, alkalis or other corrosive substances. Therefore, the casing material needs to have good corrosion resistance to prevent the capacitor from being damaged by corrosion. Common corrosion-resistant materials include steel, aluminum and stainless steel.

Seismic resistance:
Capacitors are usually installed inside or outside the switch cabinet of the power system and may be affected by natural disasters such as earthquakes. Therefore, the casing material needs to have certain seismic resistance to ensure that the capacitor is not damaged when disasters such as earthquakes occur.

Insulation performance:
The casing material should have good insulation performance to prevent charge leakage and short circuit. This is essential for the safe operation of the capacitor.

Mechanical strength:
The casing material needs to have a certain mechanical strength to withstand the mechanical stress that may be generated during installation, transportation and use.

Thermal conductivity:
Good thermal conductivity can help the capacitor dissipate heat and ensure that the capacitor does not overheat during continuous operation. Aluminum alloy materials have good performance in this regard.

Sealing and insulation: The sealing material should have good sealing and insulation to prevent moisture and dust from entering the capacitor and affecting its performance.

Cost and processing performance: Material selection also needs to consider cost and processing performance. On the premise of ensuring performance, choosing low-cost and easy-to-process materials can reduce production costs and improve production efficiency.

Environmental friendliness: With the improvement of environmental awareness, material selection also needs to consider its environmental friendliness. Recyclable, degradable or less environmentally friendly materials are preferred.

Taking the above factors into consideration, the shell material of power capacitors usually chooses materials with good insulation, high temperature resistance, corrosion resistance and other characteristics, such as epoxy resin, glass fiber, aluminum alloy, etc. These materials can meet the considerations of production cost and environmental requirements while maintaining the stable performance and reliability of the capacitor.