与常规变电站扩建时电缆点对点联系的清晰可见不同，数字化变电站中所有智能电子设备(IED)的面向通用对象的变电站事件(GOOSE)信息交互都是通过交换机实现，待联调的设备与其他运行设备可能接入到同一台交换机。扩建过程中必须要消除新设备对运行GOOSE网的影响，但又要保证新设备的二次试验完整性。以芝堰变500 kV信安I线间隔扩建为例，对扩建过程中新设备的安全措施及运行调试方案的实施进行了深入的探讨。

The extension of digital substation is different with the conventional, where the generic object oriented substation event (GOOSE) information of the entire intelligent electronic device (IED) is exchanged through switch, and the debugging device may access to same switch with other operating device. So it must eliminate the impact of the new equipment to operating GOOSE network and ensure the integrity of the secondary experiment for new devices, in the expansion process. Taking the interval extension of Xin’an I line in Zhiyan 500 kV substation for an example, this paper discussed the safety measures of new equipment and the implementation of debugging program in substation extension process.