NONLINEAR TIE-LINE BIAS CONTROL OF INTERCONNECTED POWER SYSTEMS

Tie-line bias is a power system control characteristic that determines how much an area of an interconnected power system should respond to system frequency variation. Interconnected power operation is optimum when each control area operating in parallel with other control areas has the tie-line bias set to the natural frequency response characteristic. Linear tie-line bias is the present state of the art and it is an approximation of a control area natural governing characteristic.; The natural response characteristic of a power system cannot be determined absolutely due to system nonlinearities. Improvement in interconnected power system operations can be achieved by using nonlinear function to approximate system natural response characteristic.; Pre-defined power system nonlinearities including load voltage and frequency sensitivities and governor deadband were incorporated in one control area of a hybrid simulated power system model. The natural response characteristic of the control area was experimentally determined and used as the nonlinear tie-line bias characteristic of the control area.; Quantitative power system performance indices were developed. Tests were conducted to compare interconnected power system performances of three different linear tie-line bias characteristics with nonlinear tie-line bias characteristic.