Improving voltage stability limits of transmission lines

An approach is described which can allow the development an arrangement for automatically dealing with the threat to system voltage stability. The approach utilises pattern recognition to provide adaptive and timely responses throughout the entire grid. Pattern recognition offers an intrinsically simple (minimal computation) and reliable method, an essential for a practical protection which must function whenever it is needed. To allow an affordable solution against multiple contingencies to the grid, load shedding is proposed, as it avoids the inordinante expense of redundant equipment for withstanding unpredictable situations. This offers a modest cost protection at only a tiny fraction of the tens of millions of dollar costs incurred by the 2nd July and 10th August US incidents.