Box type substations (abbreviated as box substations) are widely used in urban power grids due to their compact structure and convenient installation. However, the noise and electromagnetic radiation generated during their operation have gradually become key factors restricting their further development. With the improvement of environmental protection requirements and residents' attention to electromagnetic safety, traditional noise reduction and shielding technologies can no longer meet the needs, and innovative solutions are urgently needed. This article analyzes the new progress in noise reduction and electromagnetic shielding technologies of box substations from the dimensions of materials, structure, and intelligent control.
Traditional sound-absorbing materials (such as rock wool and glass fiber) rely on porous structures to consume sound energy, but have defects such as narrow sound absorption frequency band and easy aging. New composite materials embed metal particles into porous matrices through nanotechnology to form a dual mechanism of "resonance-dissipation". For example, the aluminum powder-polyurethane composite material developed by a research institute has a 40% increase in sound absorption coefficient in the 100-5000Hz frequency band, and has fireproof and corrosion-resistant properties, making it suitable for long-term outdoor operation.
Active noise reduction (ANC) technology offsets noise through the principle of sound wave interference. Noise sensors and speaker arrays are installed in the box type substation to monitor noise characteristics in real time and generate reverse sound waves. For example, the intelligent noise reduction system launched by a certain enterprise can reduce the vibration noise of the transformer by 15dB (A), which is particularly suitable for the treatment of low-frequency noise (50-200Hz). This technology needs to be combined with an adaptive algorithm to optimize the phase of the sound wave, but it is sensitive to the dynamic changes of the ambient noise.
Traditional shielding solutions rely on fully enclosed metal shells, but there are problems of poor heat dissipation and high cost. The layered shielding structure uses the inner layer of highly conductive materials (such as copper mesh) to shield high-frequency electromagnetic waves, and the outer layer of ferromagnetic materials (such as silicon steel sheets) to suppress low-frequency leakage magnetic flux. For example, a new type of box type substation adopts a three-layer composite structure of "copper mesh-silicon steel sheet-insulating coating", with a shielding effectiveness of 80dB in the 10kHz-1GHz frequency band, while reducing the shell thickness by 30%.
Combined with the Internet of Things (IoT) technology, the box type substation can monitor the noise and electromagnetic radiation intensity in real time and analyze the data through the cloud platform. When the noise exceeds the standard, the system automatically adjusts the fan speed or starts the active noise reduction module; when the electromagnetic radiation approaches the limit, the local shielding enhancement mechanism is triggered. For example, a smart box transformer system uses AI algorithms to predict the impact of equipment aging on noise and optimizes the operation and maintenance strategy in advance.
Box transformers can be customized to configure noise reduction and shielding modules for different scenarios. For example, residential areas use a combination of "soundproof cabin + low-noise transformer", while industrial areas focus on "high-strength shielding + corrosion-resistant shell". The modular box transformer launched by a certain company supports the rapid replacement of noise reduction components, and the operation and maintenance time is shortened to 1/3 of the traditional solution.
New environmentally friendly materials (such as bio-based polyurethane and recycled metal) reduce noise while reducing carbon footprint. For example, the carbon emissions of a bio-based sound-absorbing material are 60% lower than those of traditional materials, and it is biodegradable after being discarded. In addition, by optimizing the thermal conductivity of the material, the heat dissipation efficiency of the box transformer can be improved, and the noise can be indirectly reduced (high temperature aggravates equipment vibration).
With the improvement of regulations such as the "Law on the Prevention and Control of Environmental Noise Pollution", the noise limit of box transformers has become stricter (such as ≤55dB (A) in residential areas during the day). EU CE certification and China GB/T standards have put forward higher requirements for electromagnetic shielding effectiveness. Technology upgrades need to take into account both compliance and economy, such as reducing material usage through simulation optimization, or shortening the construction period by adopting prefabrication.
The noise reduction and electromagnetic shielding technology of box type substation is changing from single physical isolation to "material-structure-intelligence" collaborative innovation. In the future, with the integration of metamaterials, artificial intelligence and other technologies, box type substations are expected to achieve the ultimate goal of "zero noise, zero radiation" while reducing the cost of the entire life cycle. The industry needs to strengthen industry-university-research cooperation, promote technology standardization and industrialization, and provide support for the construction of green power grids.
