短路是电力系统中最常见、最严重的故障。短路故障将大大降低系统电压，增加

Short circuit is the most common and serious fault in power system. Short circuit fault will greatly reduce the system voltage and increase the loop current. It will not only affect the normal power supply of users, but also destroy the stability of the power system and damage electrical equipment. Therefore, in the design and operation of the power station substation and the entire power system, the short-circuit current must be calculated. <br>The short-circuit types of three-phase AC systems mainly include three-phase short circuit, two-phase short circuit, single-phase short circuit and two-phase ground short circuit. Three-phase short circuit refers to the short circuit between the three-phase conductors in the power supply and distribution system; two-phase short circuit refers to the short circuit between any two-phase conductors in the power distribution system; single-phase short circuit refers to any one phase in the power supply and distribution system Short circuit between ground and neutral or neutral. Among the above short circuits, three-phase short circuits are symmetric short circuits, and other short circuits are asymmetric short circuits. In the power system, the possibility of single-phase short-circuit is the largest, and the possibility of three-phase short-circuit is the smallest, but in general, the short-circuit current of the three-phase short-circuit is the largest and the hazard is the most serious. The calculation of current.

Short circuitise is the most common and serious fault in power systems. Short-circuit faults will significantly reduce the system voltage and increase the circuit current. It will not only affect the normal power supply of users, but also damage the stability of the power system, damage electrical equipment. Therefore, in the design and operation of power station substation and even the whole power system, the short-circuit current must be calculated.<br>The short-circuit types of three-phase AC system are mainly three-phase short-circuit, two-phase short-circuit, single-phase short circuit and two-phase short-circuit. A three-phase short circuit is a short circuit between a three-phase conductor in a power distribution system, a two-phase short circuit is a short circuit between any two-phase conductor in a power distribution system, and a single-phase short circuit is a short circuit between any one-phase ground and neutral or midline in a power distribution system. In the above short circuit, the three-phase short circuit is a symmetrical short circuit, and the other short circuit is an asymmetric short circuit. In the power system, the single-phase short-circuit is the most likely, the three-phase short-circuit is the least likely, but in general, the three-phase short-circuit short-circuit current is the most powerful and the most harmful, therefore, the calculation of short-circuit current mainly focuses on the calculation of three-phase short-circuit current.

Short circuit is the most common and serious fault in power system. Short circuit fault will greatly reduce system voltage and increase loop current. It will not only affect the normal power supply of users, but also damage the stability of the power system and electrical equipment. Therefore, the short-circuit current must be calculated in the design and operation of substation and even the whole power system.<br>The short circuit types of three-phase AC system mainly include three-phase short circuit, two-phase short circuit, single-phase short circuit and two-phase ground short circuit. Three phase short circuit refers to the short circuit between three-phase wires in the power supply and distribution system; two-phase short circuit refers to the short circuit between any two-phase wires in the power supply and distribution system; single-phase short circuit refers to the short circuit between any phase of the power supply and distribution system and the neutral point or the middle line through the grounding. In the above short circuit, the three-phase short circuit belongs to symmetrical short circuit and the other short circuits belong to asymmetric short circuit. In the power system, the single-phase short circuit is the most likely, the three-phase short circuit is the least likely, but generally speaking, the three-phase short circuit current is the largest, the harm is the most serious, therefore, the calculation of the short circuit current mainly focuses on the calculation of the three-phase short circuit current.<br>