What is the primary function of anchor bolts in substation foundations?

The primary function of anchor bolts in substation foundations is to hold down structures. Anchor bolts are used to secure various components of the electrical substation, such as transformer bases, bus supports, and other structural elements, ensuring they remain stable and secure during operations. This stability is crucial for safety and functionality, as the components need to withstand environmental conditions such as wind, seismic activity, and vibrations.

The other options address functions that are not directly related to the purpose of anchor bolts. Supporting electrical equipment pertains to structural integrity, which is influenced by anchor bolts, but it is not the bolts' primary function. Providing insulation does not relate to anchor bolts, as they are typically made of metal and designed for structural connectivity rather than electrical isolation. Improving air circulation, while relevant in the context of overall substation design, is not a function of anchor bolts, which are focused on securing structures rather than facilitating airflow.