Abb Research Ltd.

John Dennis Finney

Reynaldo Nuqui

Ernst Scholtz

Mats Larsson

Xiaoming Feng

Mani Subramanian

Gordon Lin

Yuan Liao

Adolfo Fonseca

A method and computer program product for optimization of large scale resource scheduling problems. Large scale resource scheduling problems are computationally very hard and extremely time consuming to solve. This invention provides a Lagrangian relaxation based solution method. The method has two distinct characteristics. First, the method is formal. It is completely structure-based and does not use any problem domain specific knowledge in the solution process, either in the dual optimization or the primal feasibility enforcement process. Second, updating the Lagrangian multipliers after solution of every sub-problem without using penalty factors results in fast and smooth convergence in the dual optimization. The combination of high quality dual solution and the structure-based primal feasibility enforcement produces a high quality primal solution with very small solution gap. An optimal solution is first found to the dual of the resource scheduling problem by sequentially finding a solution to a plurality of sub-problems and updating a set of values used in the dual problem formulation after each sub-problem solution is obtained. Coupling constraint violations are systematically reduced and the set of values are updated until a feasible solution to the primal resource scheduling problem is obtained. An initial set of multiplier values is further determined by solving a relaxed version of the primal problem where most of the local constraints except the variable bounds are relaxed.

Formal structure-based algorithms for large scale resource scheduling optimization

Phasor measurement units () provide phasor data from various locations () in an electrical power system. The phasor data is referenced to a common timing signal. Non-phasor measurement data is also obtained at various locations in the power system. A phasor assisted state estimator () uses the phasor data and the non-phasor data to determine the power system state.

Estimation of real-time power system quantities using time-synchronized measurements

A sag calculator () computes sag for a span of a section of a power line based at least in part upon a temperature of conductor lines in the line section. A temperature calculator () determines the temperature by computing a resistance ascertained through augmented state estimation techniques performed by a state estimator (). A Supervisory Control and Data Acquisition (SCADA) system () acquires data used by the state estimator () to compute the resistance.

Power-line sag calculation by way of power-system state estimation

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Raleigh, NC, United States of America

John Dennis Finney