A substation is a critical node in the electricity grid where voltage levels are changed, and the flow of power is controlled and protected. It is not just one device but an assembly of various types of equipment. The key components include power transformers for voltage transformation, circuit breakers and isolators for switching and protection, and busbars for distributing power to different circuits. Additionally, substations contain protective relays, current and voltage transformers, and lightning arresters. Ningbo Changshi provides the necessary tools for the construction, maintenance, and repair of this essential substation equipment.