Patent ID: 9658260
Date: 2017-05-23
CPC Classifications: G01R,H02J,Y02E,Y04S

Claim:
1. A method for state estimation in a power system that comprises a first subsystem having a corresponding first state vector and corresponding first measurements for a first state estimation time, a second subsystem having a corresponding second state vector and corresponding second measurements for the first state estimation time, and a boundary connecting the first and subsystems and having a boundary state vector for the first state estimation time, the method. comprising: operating a first plurality of sensors structured to measure the first measurements of the first subsystem of the power system and a second plurality of sensors structured to measure the second measurements of the second subsystem of the power system; operating a first microprocessor-based state estimation unit configured to receive the first measurements from the first plurality of sensors but not able to receive the second measurements from the second plurality of sensors and a second microprocessor-based state estimation unit configured to receive the second measurements from the second plurality of sensors but not able to receive the first measurements from the first plurality of sensors; operating a third microprocessor-based state estimation unit configured to communicate with the first microprocessor-based state estimation unit and the second microprocessor-based state estimation unit; for a first iteration, setting a working estimate of the boundary state vector to equal an initial estimate with the third state estimation unit; for the first iteration and for one or more subsequent iterations, calculating, with the first state estimation unit, an estimate of the first state vector, based on the working estimate of the boundary state vector, the first measurements, and a first subsystem measurement function, and separately calculating, with the second state estimation unit, an estimate of the second state vector, based on the working estimate of the boundary state vector, the second measurements, and a second subsystem measurement function; for the first iteration and for one or more subsequent iterations, computing, with the first state estimation unit, a first state estimate sensitivity and computing, with the second state estimation unit, a second state estimate sensitivity, the first and second state estimate sensitivities representing sensitivities of the estimates of the first and second state vectors to the initial estimate of the boundary state vectors, respectively; revising, with the third state estimation unit, the working estimate of the boundary state vector, based on the first and second state estimate sensitivities; and repeating, with the first state estimation unit, the second state estimation unit, and the third first state estimation unit the calculating, computing, and revising operations until a convergence criterion is met.