地铁越江隧道风机配电变压器容量的选择

在地铁线路设计中,遇到穿越江河的超长隧道,必须配置大功率隧道风机保障隧道通风系统的安全可靠运行。由于隧道风机负荷大,而风井变电所其余负荷较小,故风机负荷占风井变电所总负荷的比例高达90%,因此,在区间风井配电变压器容量选取时将面临两难困境。在满足启动电压降的同时还要注意下级配电开关的合理匹配;另外需要从经济性、工程可实施的角度选择适合的配电变压器。以实际工程设计为例,计算分析越江隧道风机的电压降并进行校验,分析选择下级开关的额定电流并根据隧道风机启动电流配置保护整定值,以供同行设计人员参考。

Selection of Fan Distribution Transformer Capacity for Subway Crossing River Tunnel

In the design of metro line, the air blower must be equipped with large power to ensure safe and reliable operation of the ventilation system of the tunnel when a long river tunnel is encountered. Due to the large load of the tunnel air blower and the small load of the air shaft substation, the load of the air blower occupies ~90% of the total capacity of the air shaft substation. Therefore, it is difficult to determine the distribution transformer capacity in the air shaft that meets the starting voltage drop and sufficiently matches the lower distribution switch. In this paper, a suitable distribution transformer is selected from the perspectives of economy and engineering implementation. Furthermore, the voltage drop of the cross river tunnel extension was calculated, analyzed, and verified, using an actual engineering design as an example. Finally, the rated current of lower switch was analyzed and selected while the protective setting values were configured based on starting current of the tunnel air blower, for the reference of designers within the same industry.