METHOD FOR ESTIMATING HIGHER HARMONICS VOLTAGE OF POWER SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a method for simply and highly accurately estimating a higher harmonic voltage of the lower system of a power system. SOLUTION: An n-th harmonic equivalent circuit of a simplified power system is formed at a first process. An upper system n-th harmonic voltage En of an upper system 2, an n-th harmonic current In which flows into a lower system 6, an n-th harmonic voltage Vn and a fundamental wave voltage V1 of the lower system are measured at a second process. A calculated value of the n-th harmonic voltage Vn is found with the use of the actually measured values. Moreover, a standard deviation of the calculated value from the actually measured value of the n-th harmonic voltage Vn is found. Sizes and phases of an n-th harmonic conductance Gn, an n-th harmonic susceptance Bcn, an n-th harmonic current source current Ign, when the standard deviation is minimum, are found. A target n-th harmonic voltage Vn is calculated at a third process with the use of the values found at the second process and the actually measured upper system n-th harmonic voltage En or the n-th harmonic current In.