What is one of the two most common foundations used in building a substation?

Grillage foundations are specifically designed to distribute the load of heavy electrical equipment over a broader area, which minimizes soil settlement and enhances the stability of the substation. This type of foundation typically consists of a framework of beams and girders that provide a strong base for substations and other similar structures, allowing them to support the weight of transformers, switchgear, and other systems effectively.

In contrast to other foundation types, grillage foundations are particularly favored in substation construction due to their ability to handle the significant loads while ensuring that the structures remain level and secure over time. This resilience is critical in ensuring the safety and operational integrity of substations, as they often face harsh operating conditions.

Other foundation options, such as drilled shafts, open pits, and tunneling, while useful in certain contexts, do not offer the same level of load distribution or stability required specifically for substations. Each of these has its own applications in construction, typically for different types of structures or ground conditions, but grillage remains one of the preferred and common choices in substation design for its effectiveness in load management.