保护接零的原理是当设备某相带电体碰连设备外壳时,通过设备外壳形成相线对保护零线的单相短路,短路电流促使线路上的短路保护迅速动作,消除安全风险。下列4种供电系统中
A <img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20250414/22944994_0.png"> B
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20250414/22944994_0_1.png"> C
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20250414/22944994_0_2.png"> D
<img border="0" alt="" src="https://tuku.weimei168.com/uploads/upimg/20250414/22944994_0_3.png">