Research on a new method to measure unbalance of multiple-circuit transmission lines on the same tower considering the impact of ground wire

In order to provide theoretical guidance for optimized design and operation of multiple-circuit transmission lines on the same tower, a new method for measuring the line unbalance is proposed, which characterized its physical nature. Using PSCAD, the unbalance factors of the six-circuit transmission lines on the same tower are simulated and calculated, under different line lengths and different phase sequence layouts, the influence of connection patterns of the ground wires on line unbalance are comparatively analyzed. Results show the method is applicable and convenient, accurately reflecting the property of the line unbalance; the connection pattern of ground wires is the main factor that influences zero-sequence unbalance.