Shrinking stability regions and voltage collapse in power systems

The dynamic process of voltage collapse is analyzed based on three mechanisms: on-load tap-changing, load dynamics, and generator excitation limiting. The interaction among these mechanisms and how the voltage collapse takes place are thoroughly investigated in a general interconnected network model under the assumption that system frequency remains unchanged. It is found that, so long as an equilibrium exists, there is a maximal equilibrium. It is also established that there is a region in the state space corresponding to a monotonic fall of system voltages. When the reactive capability of generator(s) is reached, this region expands, whereas the voltage stability region shrinks. The system trajectory may eventually exit the stability region, whereupon the voltage begins to drop monotonically. It is shown that locking the tap-changers at an appropriate time helps the system voltage to reach a steady state, and therefore avoid the collapse. Numerical examples for a realistic power system are given to illustrate the theory. >

[1]  Ian Dobson,et al.  Towards a theory of voltage collapse in electric power systems , 1989 .

[2]  F. Galiana,et al.  Load flow feasibility and the voltage collapse problem , 1984, The 23rd IEEE Conference on Decision and Control.

[3]  Robert Thomas,et al.  Dynamic voltage instability , 1987, 26th IEEE Conference on Decision and Control.

[4]  A. Kurita,et al.  The power system failure on July 23, 1987 in Tokyo , 1988, Proceedings of the 27th IEEE Conference on Decision and Control.

[5]  Thierry Van Cutsem,et al.  Dynamic and static aspects of voltage collapse , 1988 .

[6]  K. T. Vu,et al.  Analysis of tap-changer dynamics and construction of voltage stability regions , 1989 .

[7]  Felix F. Wu,et al.  Steady-state voltage stability regions of power systems , 1985 .

[8]  F. Illicico,et al.  Behavior of Loads During Voltage Dips Encountered in Stability Studies Field and Laboratory Tests , 1972 .

[9]  W. R. Lachs.  Insecure System Reactive Power Balance Analysis and Counter Measures , 1985, IEEE Power Engineering Review.

[10]  Robert A. Schlueter,et al.  Methods for determining proximity to voltage collapse , 1991 .

[11]  Felix F. Wu,et al.  Stability regions of nonlinear autonomous dynamical systems , 1988 .

[12]  H. Ohtsuki,et al.  Reverse action of on-load tap changer in association with voltage collapse , 1991, IEEE Power Engineering Review.

[13]  J. Carpentier,et al.  VOLTAGE COLLAPSE PROXIMITY INDICATORS COMPUTED FROM AN OPTIMAL POWER FLOW , 1984 .

[14]  Felix F. Wu,et al.  Characterization of power system small disturbance stability with models incorporating voltage variation , 1986 .

[15]  C.-C. Liu,et al.  Dynamic mechanisms of voltage collapse , 1990 .

[16]  Thomas J. Overbye,et al.  Voltage security enhancement using energy based sensitivities , 1991 .

[17]  A. J. Calvaer,et al.  Quasi Steady State Synchronous Machine Linearization Around an Operating Point and Applications , 1984, IEEE Power Engineering Review.

[18]  Y. Tayama,et al.  Voltage instability proximity index (VIPI) based on multiple load flow solutions in ill-conditioned power systems , 1988, Proceedings of the 27th IEEE Conference on Decision and Control.

[19]  J. Zaborszky,et al.  Exploration of the conceptual structure of voltage stability , 1989, Proceedings of the 28th IEEE Conference on Decision and Control,.

[20]  H. Glavitsch,et al.  Estimating the Voltage Stability of a Power System , 1986, IEEE Transactions on Power Delivery.

[21]  Marija Ilic-Spong,et al.  Discrete Models of Slow Voltage Dynamics for Under Load Tap-Changing Transformer Coordination , 1987, IEEE Power Engineering Review.

[22]  Y. Sekine,et al.  Cascaded voltage collapse , 1990 .

[23]  Leon Y. Bahar,et al.  Static bifurcations in electric power networks: Loss of steady-state stability and voltage collapse , 1986 .

[24]  M. Pai,et al.  CRITICAL MODES AND VOLTAGE INSTABILITY IN POWER SYSTEMS. , 1986 .

[25]  R. Fischl,et al.  An extended study of dynamic voltage collapse mechanisms , 1989, Proceedings of the 28th IEEE Conference on Decision and Control,.