Determination of interface flow margin using the modified continuation power flow in voltage stability analysis

A new concept of interface flow margin in terms of steady-state voltage sta bility is introduced. The interface flow margin is the active power flow ma rgin of the key transmission lines between one region and others under a fi xed load demand condition. In addition, a technique is proposed to trace in terface flow-voltage (f-V) curves by applying a continuation method. From t he f-V curves, the interface flow margin can be easily obtained, which is u seful to determine the secure flow limit of the specified interface. In the case study, an illustrative example with the New England 39-bus system is shown.