Electromagnetic Force Calculation of Parallel Bus in Three-Phase Symmetrical Short-Circuit

This paper introduces in detail the calculation process of the electric power of the parallel bus bar in the three-phase symmetrical short circuit. The three-phase short circuit is two or more short circuits in the three-phase four phases, including three-phase short circuit, two-phase short circuit, single-phase short circuit and two-phase ground short circuit. Two-phase grounding short circuit is the two-phase short circuit caused by single-phase grounding under the condition of ungrounding. Two-phase short circuit occurring between the two-phase wires of three-phase power supply and distribution network; Three-phase short circuit is the fault of the three-phase wire in the supply and supply lines. According to the necessary conditions of the extreme value of quadratic function, the calculation method of maximum electrodynamic force can be put forward, and the correct calculation result can be obtained, which can be a powerful supplement to the existing teaching.