## 1 Introduction  
A critical priority in achieving sustainable development involves tackling climate change through greenhouse gas emission mitigation [1, 2]. Globally, building energy consumption exceeds 40% of the total usage in developed nations, while this share continues to climb across developing countries [3]. In 2022, the total energy consumption of China's building and construction sector reached 2.42 billion tons of standard coal equivalent (tce), accounting for 44.8% of the country's total energy consumption [4]. Following the Paris Agreement, China subsequently set targets to peak carbon emissions by 2030 and achieve nationwide carbon neutrality by 2060 [5]. The construction industry, particularly industrial buildings, plays a crucial role in achieving this decarbonization goal [6; 7]. In the context of the United Nations' Sustainable Development Goals and China's dual carbon goal, industrial buildings are facing a wide range of green transformation needs [8; 9]. The power industry is one of the major contributors to global carbon emissions, making its development a key area of focus. Substations are a crucial part of the power industry, playing a key role in the reception and distribution of electricity. Their operation inevitably generates a significant amount of carbon emissions, making the construction of low-carbon substations a major development trend for the future [10]. The spacious flat roofs of industrial buildings are highly suitable for the installation of rooftop-distributed PV systems. This topic has attracted extensive research attention and has been widely implemented in practice [11]. The installation of PV systems on the roofs of urban substations is one of the approaches to promoting green, low-carbon development and enhancing energy conservation and emission reduction. This practice has already been implemented in China [12]. Urban substations are essential power infrastructure for cities. As urban development progresses, the number of substations continues to increase [13]. Therefore, in the future, more urban substations will require green retrofitting, and rooftop PV systems will be a key topic worthy of focus and discussion [14]. When PV systems are integrated into the building envelope, they expand the surface area available for power generation, reduce the need for additional land, and mitigate the environmental impact [15]. However, it is important to note that the PV system may obstruct the open space above the semi-indoor substation originally intended for natural ventilation, which could negatively impact the safe operation of the substation. The unique structural characteristics of semi-indoor substations, such as partially enclosed walls and rooftop exposure, create a complex thermal environment that necessitates advanced thermal management strategies [16]. Insufficient heat dissipation can lead to elevated temperatures, negatively impacting operational efficiency and the lifespan of equipment. Additionally, excessive heat accumulation increases the risk of safety incidents, posing a threat to the stability and reliability of the power supply network [17]. When the PV system is installed in this type of substation, it is necessary to discuss the impact of the PV system on the wind environment. Natural ventilation is the process of introducing fresh air into indoor spaces using natural forces (such as wind and/or thermal buoyancy) rather than mechanical energy. These natural forces typically influence the efficiency of natural ventilation; they may act independently, oppose each other, reinforce one another, or sometimes work in synergy [18]. Rooftop natural ventilation and cooling are well-established methods for optimizing indoor environmental quality in buildings [19]. Through numerical studies, the impact of various influencing factors on the thermal performance of naturally ventilated roofs has been analyzed, leading to the identification of optimal design parameters and their adaptability [20].