Research on optimal variable pairing selection for multivariate uniform power flow controller

Unified power flow controller;  multivariable controller;  optimal variable pairing;  Relative gain analysis

The Unified Power Flow Controller (UPFC) is a multivariable controller with multiple control input and output variables, so cross-connection and coupling inevitably exist between multiple control channels formed by these input and output variables. It can be seen from the control theory that the variable pairing selection is closely related to the coupling degree of the multivariable unified power flow control system. The relative gain analysis method in control theory is used to determine the optimal variable pairing relationship for UPFC, and the coupling between UPFC control channels is very weak under this variable pairing control scheme, so that decoupling measures are not required, which simplifies the controller design. The simulation results on the New England system show that under the optimal variable pairing control scheme,