Electromagnetic dispersion modeling and measurements for HVDC power cables
Författare
Summary, in English
This paper provides a general framework for electromagnetic modeling, computation and measurements regarding the wave propagation characteristics of High-Voltage Direct Current (HVDC) power cables. The modeling is focused on very long (10 km or more) HVDC power cables and the relevant frequency range is therefore in the low-frequency regime of about 0-100 kHz.
An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant and the related characteristic impedance. Experimental time-domain measurement data from an 80 km long HVDC power cable is used to validate the model.
It is concluded that a single-mode transmission line model is not adequate to account for the mismatch between the power cable and the instrumentation.
A mismatch calibration procedure is therefore devised to account for the connection between the measurement equipment and the cable. A dispersion model is thus obtained that is accurate for early times of pulse arrival.
To highlight the potential of accurate electromagnetic modeling, an example of high-resolution length-estimation is discussed and analyzed using statistical methods based on the Cramer-Rao lower bound. The analysis reveals that the estimation accuracy based on the present model (and its related model error) is in the order of 100 m for an 80 km long power cable, and that the potential accuracy using a perfect model based on the given measurement data is in the order of centimeters.
An exact dispersion relation is formulated together with a discussion on practical aspects regarding the computation of the propagation constant and the related characteristic impedance. Experimental time-domain measurement data from an 80 km long HVDC power cable is used to validate the model.
It is concluded that a single-mode transmission line model is not adequate to account for the mismatch between the power cable and the instrumentation.
A mismatch calibration procedure is therefore devised to account for the connection between the measurement equipment and the cable. A dispersion model is thus obtained that is accurate for early times of pulse arrival.
To highlight the potential of accurate electromagnetic modeling, an example of high-resolution length-estimation is discussed and analyzed using statistical methods based on the Cramer-Rao lower bound. The analysis reveals that the estimation accuracy based on the present model (and its related model error) is in the order of 100 m for an 80 km long power cable, and that the potential accuracy using a perfect model based on the given measurement data is in the order of centimeters.
Publiceringsår
2011
Språk
Engelska
Publikation/Tidskrift/Serie
Technical Report LUTEDX/(TEAT-7211)/1-32/(2011)
Fulltext
Dokumenttyp
Rapport
Förlag
[Publisher information missing]
Ämne
- Electrical Engineering, Electronic Engineering, Information Engineering
Status
Published
Report number
TEAT-7211
Forskningsgrupp
- Electromagnetic theory