Variable Parameter Equivalent Model of Transmission Line Based on Dual-port Norton Equivalence

Firstly, this paper proposes a variable parameter equivalent model based on dual-port Norton equivalence for the loadability of transmission line under operation condition, which can very well reflect the non-linearity and timevarying properties of power systems. And the changes in the equivalent parameters reflect the effect of parallel flow on the transmission line loadability in interconnected system. This equivalent model is inferred firstly in theory. And then, a practical method is given for forecasting equivalent parameters and obtaining the loadability of transmission line under operation. At last, the feasibility and effectiveness of the equivalent model and the method are testified by continuous power flow in IEEE-39 system.