A quantitative assessment method of integral static stability for large scale power grid based on generalized source-grid-load equivalent model

Abstract

The on-line quantitative assessment of the static stability for large-scale power grid which based on wide-area measurement system(WAMS) data is the key to realize grid intelligent monitoring. A quantitative assessment method of the static stability for large-scale power grid based on the generalized Source-Grid-Load(SGL) equivalent model is proposed. All power generation nodes and load nodes are equivalent to ‘Source’ point and ‘Load’ point respectively according to SGL equivalent model. The SGL branches which the power factor angle, voltage phase angle and impedance angle of the equivalent grid are obtained by simple calculation. Aiming at the static domain boundary of the power grid, the static stability margin index of large scale power grid is established on the basis of the derivation of the static voltage stability margin index and the power angle stability margin index. The generalized SGL equivalent model is combined with the static stability margin index to realize the rapid quantitative assessment of the static stability for large scale power grid. The effectiveness and practicability of the proposed method is verified by the simulation tests on IEEE14 bus system. This method is fast and reliable that using algebraic calculation of WAMS information, avoiding the uncertainty of Thevenin's equivalent parameter identification. The method was used in Wind Farm and Hydro Power Plant Coordinating Operation (WHCO) for assessing the max value of power coordination.