2 results about "Discriminant" patented technology

The invention relates to a voltage stability assessment method based on thevenin equivalence and branch transmission power limits. The method comprises the steps of obtaining relative power margins of all load nodes of an electric system, and selecting the minimum value of the relative power margins as a voltage stability index of the electric system, wherein the larger the voltage stability index is, the higher the voltage stability of the electric system is; according to the step of obtaining the relative power margins, 1, thevenin equivalence parameters of load nodes to be assessed are obtained; 2, a two-node system containing the load nodes to be assessed is constructed by means of the thevenin equivalence parameters, a power balance equation is analyzed, and a quiescent voltage stability discriminant is obtained; 3, branch transmission power limits of the two-node system are obtained through calculation of the quiescent voltage stability discriminant, and the relative power margins of the load nodes to be assessed are obtained. Compared with the prior art, no local measurement data is needed, calculation is rapid and convenient, assessment indexes containing the limit transmission power are given, and online voltage stability assessment of a power grid is achieved.

The invention relates to a three-point circle method parameter self-adaptive interpolation algorithm applied to a numerical control machine tool. The three-point circle method parameter self-adaptive interpolation algorithm comprises the steps of: expressing a non-circle curve equation with parameter formulas, and ensuring that each parameter is corresponding to each function value; successively getting three points D, E and F on the curve in an isoparametric manner; calculating coordinates of a circle center point of an arc passing the three points and the radius R of the arc; then deriving a discriminant for determining whether the arc is clockwise or anticlockwise, and determining whether arc interpolation at this time is clockwise or anticlockwise; finding an intermediate point H between the D point and the E point, calculating the distance [Rho]1 from the point H to the circle center, and similarly, finding an intermediate point I between the E point and the F point, and calculating the distance [Rho]2 from the point H to the circle center; respectively calculating [delta]1 and [delta]2, wherein [delta]1=absolute([Rho]1-R), [delta]2=absolute([Rho]2-R), and [delta]1 and [delta]2 are used as interpolation errors; and comparing [delta]1 and [delta]2 with an allowable error [delta]<allowable>. The three-point circle method parameter self-adaptive interpolation algorithm has the advantages that the interpolation calculation is simplified, the solving process is simple, the solving difficulty is small, the interpolation quality and efficiency are improved, etc.