随着选煤厂智能化发展水平的提升，选煤厂低压供配电系统在智能化建设中面临着PLC资源消耗高，系统升级改造与维护难度大，子系统数量庞大且功能重叠等问题。针对上述问题，柠条塔矿井选煤厂提出采用基于工业现场总线的智能低压供配电系统，实现对低压供配电系统的智能化升级改造：该系统主要由低压远程停送电系统、低压电机保护器监测系统、电量数据采集系统和配电室环境监测系统组成，根据功能可划分为物理层、网络层和控制层。应用实践表明：基于工业现场总线的选煤厂智能低压供配电系统实现了低压配电室的实时数据采集与监控，其中仪表及低压综合保护器读取数据的刷新时间不超过1 s，低压塑壳断路器的停送电操作动作延时控制在3 s以内；节约了PLC资源并降低了建设成本，PLC的 I/O点配置减少了5 000个，控制电缆节约了30 000 m，同时后台监控系统减少安装2套。该升级改造可为选煤厂低压供配电系统的智能化改造提供一定借鉴。

With the ongoing development of intelligent coal preparation plants, the low-voltage power supply and distribution systems applied therein are facing a multiple of problems during this development process, such as high consumption of PLC resource, difficulties in system upgrading and maintenance, and a large number of subsystems operating with overlapping functions. To address these issues, the low-voltage power supply and distribution system used at Ningtiaota Mine′s coal preparation is upgraded with an industrial field bus-based intelligent system. The system is mainly comprised of a remote low-voltage power cut-off and supply system, a low-voltage motor protector monitoring system, an electricity quantity data collection system, and a power distribution room environment monitoring system. Functionally, it is divided into physical layer, network layer and control layer. Field application of the system shows that real-time data collection and monitoring of power supply and distribution can be effected in the power distribution room; the time required for refreshing the data relating to instruments and low-voltage integrated protection system does not exceed one second; and the plastic-cased circuit breaker′s power supply/cutoff delay time can be controlled within 3 seconds. The use of the system has led to a save of PLC resource, cut of initial capital cost, reduction of PLC′s I/O points by 5 000, a save of control cable by 30 000 meters, and decrease of background monitoring and control systems by 2 set. The upgrading practice can provide a reference for intelligent renovation of low-voltage power supply and distribution system at other plants.