Study On The Two-phase Circuit Method Of Multi-circuit Transmission Lines On The Same Tower For Complex Fault Calculation

The multi-circuit line on the same tower has many advantages of narrow transmission corridor,covering small area,investment saving,fast construction,etc.It is used more and more in our country.As the continuous expansion of power grid and the use of one-way reclosure devices,complex failure probability is more and more high.Two-phase circuit method can decouple the circuit and makes fault calculation more simply.As a result,the study on the two-phase circuit method of complex fault calculation of multi-circuit line on the same tower has practical significance.Two-phase circuit theory is currently only being used in decoupling two-circuit line on the same tower and calculating easy fault of two-circuit line on the same tower.As a result,the study on the two-phase circuit method of complex fault calculation of multi-circuit line on the same tower is necessary.This paper firstly introduces the principle of two-phase circuit method and analyses the process of its decoupling two-circuit line on the same tower and forming independent circuits.Then this paper improves two-phase circuit method.This paper gets improved two-phase circuit components and two-phase circuits of each sequence.This paper generalizes it to multi-circuit line on the same tower and makes it decouple multi-circuit line on the same tower.This paper also lists the step of calculating simple fault multi-circuit line on the same tower via improved two-phase circuit method.Then this paper introduces the principle of two-port network method.This paper combines improved two-phase circuit method with two-port network method and gets two-port network method of two-phase circuit method coordinates.This paper generalizes it to the multi-port network method and lists voltage equations of each fault port after an in-depth analysis.This paper gets two-port network method of two-phase circuit method coordinates.Then this paper lists the step of calculating complex fault of multi-circuit line on the same tower via two-phase circuit method and makes it be able to calculate any multiplicity of complex fault of multi-circuit line on the same tower.So it gets the principle of two-phase circuit method of multi-circuit line on the same tower complex fault calculation.This paper finally sets up a power transmission system of three-circuit line on the same tower and builds its model in PSCAD/EMTDC.Then this paper lists the process of double fault of a three-circuit line on the same tower via the improved two-phase circuit method calculation and simulation analysis in PSCAD/EMTDC.Then this paper changes the line parameters and compares fault data of many double fault of the three-circuit line on the same tower under the condition of three kinds of circuit parameters comprehensively.It verifies that the study of this paper of two-phase circuit method of multi-circuit line on the same tower complex fault calculation is correct.