为了减少接地网测试时的现场测试工作量，提高工作效率，研制了一种接地网故障诊断自动测试切换装置。 接地网故障诊断自动测试切换装置由测试主控机、可控直流电流源、可编程数字万用表和程控切换装置等部分组成。ARM微处理器芯片LPC2210、霍尔传感器、继电器、模拟多路开关和电容储能维持装置构成了程控切换装置，主要完成激励、量测位置切换、激励电流极性转换和电流大小可控等功能。 基于ARM微处理器芯片LPC2210和嵌入式实时操作系统(?C/OS-II)，采用ADS1.2为软件平台进行开发，由测试主控机通过串口向程控切换装置发送控制命令，程控切换装置根据测试主控机的不同控制命令进行相应的动作，实现了接地网故障诊断测试时激励位置和量测位置的自动切换、激励电流极性的自动转换和电流大小的控制等功能。且在自动测试切换装置突然掉电等异常情况下，电容储能维持装置能维持继电器触点状态，避免因开断直流大电流而烧毁触点。 采用所研制的装置对一个60支路的模拟接地网进行自动测试，测试其与主控机之间的通信，对激励和量测位置切换、激励极性转换和激励电流大小的控制等各项功能。结果表明装置不仅能实现正常的通信和控制功能，而且在异常情况下，电容储能维持装置能保护触点使其避免烧毁。

To reduce the manpower and improve the working efficiency in grounding grid corrosion diagnosis, an automatic test system for grounding grid corrosion diagnosis is presented. The automatic test system, which consists of four parts, such as, the host computer, the controllable DC current source, the programmable digital voltage meter and the intelligential switching device. And the hardware of intelligential switching device which includes ARM based micro-processor LPC2210、hall sensor、relay、analog multiplexer and capacitor storage based backup power supply are designed and realized. According to which, the functions of automatic shift the current excitation positions and voltage measurement positions, automatic switch the excitation polarity and control the output current level are accomplished. Based on the micro-processor LPC2210 and the embedded operating system(?C/OS-II), the software of the system is developed on the platform ADS1.2. The host computer sends the control commands through the UART to the intelligential switching device. After which, the intelligential switching device take the relevant actions according to the commands. Even on the condition of sudden outage, the contacts of the relay can be kept stable by the capacitor storage based backup power supply till the current returns to zero. The software Modules includes the communication with the host computer, auto-control of the excitation and measurement positions, excitation polarity and the output current level. An experimental grounding grid with 60 branches is tested by the proposed system. The functions of communicate with the host computer, auto shift of the current excitation and voltage measurement position and the control of the output current are tested. The results show not only the common functions of communication and control are accomplished but also the contacts of the relay can be kept stable by the capacitor storage backup power supply during the outage, so that the relays won’t be damaged due to the non-zero current.