第一步：检查电压回路、电流回路
Step 1: Check the voltage and current circuits
高压电力计量箱基本应用于三相中性点不接地系统的电力负荷计量，采用三相三线的接线方式
The high-voltage power metering box is basically used in the power load metering of three-phase neutral ungrounded system, which adopts three-phase and three-wire connection mode.
在分析接线之前，必须检查电压回路、电流是否有开断和无负荷的情况，确认的方式是将万用表切换到电压量程，万用表的（黑笔）对电能表的2孔，（红笔）分别对应电能表的5、8孔，电压是否均为100V，如出现57V或173V左右，互感器可能存在反极性或开断的情况；再将相位伏安表却换到电流量程，将电流钳分别夹在电能表的1、7孔进线上，电流应该满足0.1A以上，并确认电能表1、7孔进线的电流是否平衡。
Before analysis of wiring, it is necessary to check whether the voltage circuit and current are interrupted and no load. The way to confirm is to switch the multimeter to the voltage range. The two holes of the multimeter (black pen) correspond to the 5 and 8 holes of the meter respectively. Whether the voltage is 100 V, such as 57V or 173V, mutually, the two holes of the multimeter (red pen) correspond to the 5 and 8 holes of the meter respectively. Sensors may have anti-polarity or interruption; then phase volt-ampere meters are changed to current range, and current clamps are clamped on the 1-hole and 7-hole feeds of the meter respectively. The current should be above 0.1A, and the current balance of the 1-hole and 7-hole feeds of the meter is confirmed.