In view of the shortcoming of the traditional definition of electricaldistance, a new way to calculate the electricaldistance is proposed in this paper called spatial electricaldistance.
针对传统分区方法电气距离定义的缺点，提出一种新的电气距离即空间电气距离。
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The influence of load characteristics to the relative electricaldistance index is discussed and compared with the voltage stability load bus index. The equivalence of both indexes is proved.
For Shanghai power grid, which has large short circuit capacity and short electricaldistance, a method using imported instrument to test power frequency variation distance protection is presented.