An Intuitive Approach to Fit A frequency Dependent Equivalent Circuit for Transmission Line Models

Gurrala, Gurunath; Baviskar, Aeishwarya; Challa, Kiran Kumar

doi:10.1109/npsc.2018.8771794

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Fitting an equivalent circuit for a rational function is addressed by several researchers in the literature [11–15]. Fitting the frequency dependent impedance to a higher order R‐L circuit by vector fitting and Pade approximation via the Lanczos (PVL) process is proposed in [11, 12].…”

Section: Introductionmentioning

confidence: 99%

“…A single step methodology is proposed in [15], which drastically reduces the number of passive elements required for fitting the frequency response of the characteristic impedance. This method is shown to produce same accuracy as that of vector fitting used in Marti's model of EMTP-RV.…”

Section: Introductionmentioning

confidence: 99%

“…Even though [10] rightly represented frequency dependent line, it resulted in higher number of passive elements in fitted circuit which increased the order of state space matrix. Fitting an equivalent circuit for a rational function is addressed by several researchers in the literature [11][12][13][14][15]. Fitting the frequency dependent impedance to a higher order R-L circuit by vector fitting and Pade approximation via the Lanczos (PVL) process is proposed in [11,12].…”

Section: Introductionmentioning

confidence: 99%

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An algorithm for fitting passive equivalent circuits for lumped parameter frequency dependent transmission line models

Challa

Gurrala

Mukherjee

2021

IET Generation Trans & Dist

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Accurately fitting rational functions to the frequency response of modal impedances is crucial for including frequency dependency in lumped parameter models of transmission lines. Vector fitting is widely used for fitting rational functions to the frequency response of modal impedances and then an R-L equivalent circuit is obtained from the rational functions. A single-step method based on the properties of Foster equivalent circuit is proposed to directly fit an R-L equivalent circuit to the frequency response of modal impedances. The positive peaks, negative peaks and the positive zero crossings of the slope change plot of the frequency response are found to provide a good approximation of zeros, poles and the flat region locations of the frequency response. An enhanced fitting algorithm is proposed based on these observations. A close enough fitting is achieved using the proposed method with less number of passive elements. Using the proposed model in EMTP-RV, 400, 765, 1200 kV transmission lines and a 11-bus 500 kV network are simulated for switching transients. The results are compared with the constant parameter cascaded-model and the Frequency-dependent line model in EMTP-RV. The switching transient results of the proposed model are found to be comparable to the Marti's model in EMTP-RV.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%