A new algorithm for faults on double-circuit lines in phase coordinates

The paper presents a new phase coordinate algorithm for analysis faulted AC double-circuit lines. Different topologies of double-circuit lines are considered. Different types of short circuit faults, inter-circuit faults and open conductor faults are treated in a general fault conditions. The development of the algorithm is based on the matrix transformation and port network theory in phase coordinates. The former is used to improve the efficiency of the new algorithm and the latter is used to describe faulted network since it is suitable to put all kinds of short circuit faults and open conductor faults in AC double-circuit lines into one general form, including faults with various fault impedances. With the new algorithm, the sequence network constitution can be avoid, the sparse technology can still be applied for calculation efficiency, short circuit faults and open conductor of double-circuit lines with different topologies can be simulated easily, and no restriction is imposed on the symmetry of power system parameters. Theoretical analysis and computer test results show the effectiveness and efficiency of the new method clearly.