Abstract: Abstract:The principle and specific calculation method of electrical geometric model were introduced, the exposure distances of all varieties of electrical geometric structure were discussed in categories. Based on this, electrical geometric model was adopted to calculate shielding failure tripout rate of the circuit, and the result was compared with that calculated by order method. According to data derived though the operation, calculations of electrical geometric model are more reliable.

Key words: Keywords:electrical geometric model, exposure distance, striking distance factor, trip around the strike rate