Abstract
Incorrect values of cable harmonic impedance can lead to wrong conclusions when assessing an impact of current distortion on the power network. A theoretical derivation of resistance and reactance for harmonic frequencies is not sufficient as it neglects operating conditions of cables as well as their configuration and actual installation pattern. In this paper, a noninvasive procedure for estimating parameters of the low-voltage cable is proposed. On contrary to invasive methods, the proposed technique does not require any external sources of harmonic excitation, and consequently, it does not introduce additional disturbances to the system. A disconnection of the cable is not required as the procedure meant to be performed online. The methodology employs natural variations of harmonic currents and voltages; however, the impedance angle is preserved due to the utilization of synchronized measurement samples. The developed signal processing algorithm provides noise reduction capabilities and smoothing of the output in presence of fluctuating harmonics. In addition, an attention is given to the metrological characterization of the measurement system and evaluation of uncertainty of impedance values. The results of the laboratory experiment indicate that for selective harmonics the variations of impedance estimates are no more than 10 $\text{m}\Omega $ , which is in the range of calculated uncertainty values. The practical applicability of the method is discussed together with its limitations.
Highlights
T HE harmonic impedance of cables and transmission lines plays a critical role in harmonic analysis
The online estimation of cable harmonic impedance value was performed in the laboratory
The proposed procedure utilizes synchronized two-point measurements which provide an advantage of accurately resolving imaginary part of cable harmonic impedance in presence of fluctuating harmonics
Summary
T HE harmonic impedance of cables and transmission lines plays a critical role in harmonic analysis. Accurate impedances at all frequencies of interest are necessary for evaluation of harmonic emission levels, identification of potential resonance problems and design of adequate mitigation measures. It is known that cable impedance under nonsinusoidal conditions can deviate significantly from theoretical values derived from 50-Hz resistance and reactance. The analytical expressions and finite element methods presented in Manuscript received February 14, 2019; revised June 17, 2019; accepted June 22, 2019. Date of publication July 3, 2019; date of current version May 12, 2020. The Associate Editor coordinating the review process was Daniele Fontanelli. The Associate Editor coordinating the review process was Daniele Fontanelli. (Corresponding author: Stanislav Babaev)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: IEEE Transactions on Instrumentation and Measurement
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
