As highly integrated power equipment, compact substations require efficient heat dissipation systems to address the heat accumulation issue caused by high-density equipment within a limited space. This challenge stems from the limited airflow due to the compact equipment layout and the increased heat flux density resulting from the increased power density of power electronic components. To solve this problem, the heat dissipation system needs to be optimized collaboratively across multiple dimensions, including ventilation design, heat dissipation structure, material application, and intelligent temperature control.
Ventilation design is fundamental to compact substation heat dissipation. A common strategy is to combine natural and mechanical ventilation: by rationally planning the positions of air inlets and outlets, natural convection is created using the principle of rising hot air to reduce the base temperature; simultaneously, low-noise DC fans are added in key areas to force and accelerate airflow, overcoming the limitations of natural ventilation. For example, some designs incorporate air ducts above transformers to guide hot air outwards, preventing heat accumulation at the top of the enclosure; or axial fans are installed at the back of high-voltage switchgear to create a "front intake, rear exhaust" through-flow airflow, ensuring uniform heat dissipation.
Innovation in heat dissipation structure is key to improving heat dissipation efficiency. Modular design enables optimized heat dissipation structures: high-heat-generating equipment (such as transformers and rectifiers) can be independently placed in dedicated heat dissipation chambers, isolated from other modules by partitions to reduce heat transfer. Simultaneously, a three-dimensional heat dissipation layout can be employed within the chamber, such as vertically mounting heat sinks to increase the heat dissipation area, or utilizing gaps between equipment to install heat dissipation fins, forming a multi-stage heat dissipation chain of "equipment-fins-air". Furthermore, some designs incorporate heat pipe technology, using phase change heat transfer to rapidly conduct heat from the heat source to the heat dissipation end, significantly improving local heat dissipation capacity.
The application of heat dissipation materials directly affects heat dissipation performance. High thermal conductivity materials are key: aluminum alloys are the mainstream choice for heat sink substrates due to their good thermal conductivity, light weight, and low cost; while for high heat flux density areas, copper or graphene composite materials are used to further reduce thermal resistance. Surface treatment technologies are also widely used: anodizing or spraying thermally conductive coatings increases the surface roughness of the heat sink, improving radiative heat dissipation efficiency; or thermally conductive silicone grease is applied to the contact surfaces of the equipment to eliminate micro-gaps and reduce contact thermal resistance.
The introduction of intelligent temperature control systems enables more precise heat dissipation management. By deploying temperature sensors in key areas, equipment temperature is monitored in real time, and the system dynamically adjusts the heat dissipation intensity based on parameters such as ambient temperature and load rate. For example, when the temperature exceeds a threshold, the system automatically starts a backup fan or increases the fan speed; in low-temperature environments or under light load conditions, fan power is reduced to save energy. Some designs also employ zoned control strategies, implementing differentiated heat dissipation for modules with different heat outputs, avoiding energy waste caused by a "one-size-fits-all" approach.
The exploration of liquid cooling technology has provided a new direction for compact substation heat dissipation. Cold plate liquid cooling directly contacts the heat-generating elements with coolant circulation pipes, utilizing the high specific heat capacity of the liquid to quickly remove heat, making it suitable for high heat flux density scenarios; immersion liquid cooling completely submerges the equipment in insulating coolant, achieving all-around heat dissipation, but requires solving sealing and maintenance challenges. Although liquid cooling technology is more expensive, its superior heat dissipation performance has led to its increasing application in high-end fields such as data centers and new energy power generation.
The cooling system of a compact substation requires the comprehensive application of ventilation design, heat dissipation structure, material application, intelligent temperature control, and liquid cooling technology to construct a multi-layered, adaptive cooling system. This system can not only effectively cope with the heat accumulation of high-density equipment, but also achieve a balance between energy saving and environmental protection while ensuring reliable equipment operation.
