Coordination and Selection Principles of Power Distribution Equipment

Dry-type transformers, oil-immersed transformers, high and low voltage switchgear, box-type substations, and power distribution boxes do not operate independently. Instead, they form a well-hierarchized and coordinated integrated system within the power distribution network. High-voltage power from the grid passes through high-voltage switchgear into transformers (or the built-in transformers in box-type substations) for voltage reduction. It is then distributed via low-voltage switchgear and finally delivered to various end-use electrical equipment through power distribution boxes, realizing the full-process power transmission from the grid to end users.

In practical projects, the selection of power distribution equipment shall follow three core principles:First, adapt to the application scenario. For indoor and densely populated areas, dry-type transformers and indoor power distribution boxes are preferred; for outdoor power distribution, oil-immersed transformers, box-type substations and outdoor power distribution boxes are prioritized.Second, match the load demand. Determine the transformer capacity, specifications of switchgear and branch configurations of distribution boxes based on the magnitude and nature of the power load, while reserving a certain margin for capacity expansion.Third, balance safety and cost. For scenarios with stringent safety requirements, equipment with high safety performance and maintenance-free features shall be given priority. For large-scale outdoor power distribution, equipment with lower cost and larger capacity can be adopted to strike a balance between upfront procurement costs and later operation and maintenance expenses.

With the development of smart grids and new energy generation, power distribution equipment is being upgraded toward intelligence, energy efficiency and modularization. For instance, smart distribution boxes enable remote power consumption monitoring and intelligent switching; box-type substations integrate reactive power compensation and new energy grid-connection functions; and the energy efficiency levels of dry-type and oil-immersed transformers keep improving.The continuous upgrading of various power distribution equipment will further enhance the operational efficiency, safety and intelligence of power distribution systems, providing more reliable power support for urban construction, industrial production and residential living.