A Memory-Efficient Parallelizable Method for Computation of Thévenin Equivalents Used in Real-Time Stability Assessment

TY - JOUR

T1 - A Memory-Efficient Parallelizable Method for Computation of Thévenin Equivalents Used in Real-Time Stability Assessment

AU - Jorgensen, Christina Hildebrandt Luthje

AU - Moller, Jakob Glarbo

AU - Sommer, Stefan

AU - Johannsson, Hjortur

PY - 2019

Y1 - 2019

N2 - This paper introduces a factor-solve method that efficiently computes Thévenin equivalents for all buses in the power system. A range of real-time stability assessment methods relies on Thévenin equivalents, and it is therefore essential that these methods can be determined fast and efficiently. The factor-solve method has runtime for computing Thévenin voltage that scales linearly with system size resulting in runtime of only a few milliseconds even for systems with several thousand buses. The computations only need the sparse admittance matrix for the power system and a sparse factorization resulting in low memory requirements, and furthermore, Thévenin impedances can be determined in parallel. The factor-solve method is compared to a reference method that uses coefficients for super-position to determine the Thévenin equivalents. The reference method is shown to have unsatisfactory runtime and complexity. The factor-solve method is tested, parallelized, and analyzed, which shows a considerable speedup in computations of Thévenin equivalents enabling them to be computed in real time.

AB - This paper introduces a factor-solve method that efficiently computes Thévenin equivalents for all buses in the power system. A range of real-time stability assessment methods relies on Thévenin equivalents, and it is therefore essential that these methods can be determined fast and efficiently. The factor-solve method has runtime for computing Thévenin voltage that scales linearly with system size resulting in runtime of only a few milliseconds even for systems with several thousand buses. The computations only need the sparse admittance matrix for the power system and a sparse factorization resulting in low memory requirements, and furthermore, Thévenin impedances can be determined in parallel. The factor-solve method is compared to a reference method that uses coefficients for super-position to determine the Thévenin equivalents. The reference method is shown to have unsatisfactory runtime and complexity. The factor-solve method is tested, parallelized, and analyzed, which shows a considerable speedup in computations of Thévenin equivalents enabling them to be computed in real time.

KW - Algorithms

KW - power system analysis computing

KW - real-time assessment

KW - Thévenin equivalent

UR - http://www.scopus.com/inward/record.url?scp=85067828578&partnerID=8YFLogxK

U2 - 10.1109/TPWRS.2019.2900560

DO - 10.1109/TPWRS.2019.2900560

M3 - Journal article

AN - SCOPUS:85067828578

SN - 0885-8950

VL - 34

SP - 2675

EP - 2684

JO - IEEE Transactions on Power Systems

JF - IEEE Transactions on Power Systems

IS - 4

M1 - 8645670

ER -