TY  - BOOK
AU  - Muhammad Shaban
ED  - Universiti Teknologi Brunei
TI  - Analysis of Induced Sheath Voltage in High Tension Cables Under Different Forms of Bonding and Configurations / 
PY  - 2016///
CY  - Bandar Seri Begawan
PB  - Universiti Teknologi Brunei , 
KW  - Thesis
KW  - Universiti Teknologi Brunei
KW  - Thesis writing
KW  - Electric cables
KW  - Sheaths
KW  - High tension cables
KW  - Electric properties
N1  - Thesis submitted to Universiti Teknologi Brunei in fulfilment of the requirements for the award of Electrical and Electronic Engineering; ABSTRACT

The behavior of voltage and current transients when a high voltage (HV) cable is first energized is a problem of practical significance to power utilities. Modelling of this behavior on a suitable simulation platform could be an effective approach, in many cases, provided that the result is consistent with the rules of current inventions. The objective of this thesis is to examine the modelling of transients resulting from the energization of cables using the ATP/EMTP simulation software. The applicability of the existing frequency-dependent (FD) cable models is assessed. The impact of transients on a simulated cable system is also presented and discussed. In cable system modelling, system components are expected to be accurately modelled, primarily the underground cables. The FD-Phase model was used in this study to analyze the distribution of overvoltage at sending and receiving ends of the cable system. Specifically, statistical analysis has been carried out in correlating the induced overvoltage magnitudes and the closing behavior of the circuit breaker (CB).

This thesis is an attempt to understand the different phenomena associated with the use of underground cables. More precisely, the focus is to accurately describe the sheath voltage phenomenon in providing the necessary guidelines for the performance of proper simulations and in presenting the respective countermeasures that can be used in real systems. The methodology of the research is to review the analytical techniques so far used to calculate induced sheath voltage in underground cables and overhead lines. It is argued that when two parallel cables are fairly close together it becomes difficult to calculate the electromagnetic coupling effect between adjacent cables. Research not only describes the influence of different arrangements of cables but also considers the distance between the cables to calculate their effect on the magnitude of the induced voltage. This research also examines the results of different arrangements of cables and bonding in comparative perspectives with the aim of accessing their effectiveness in a given scenario.

The main findings of the thesis resulted in an interesting analysis done on the energization of cables in parallel, an operation that can result in overvoltage. Equation derivation for different arrangements when cables are arranged in double circuits and induced sheath voltage analysis of the cables when they are operating in tri circuit arrangement are also one of the main findings of this thesis. An IEEE standard gives the guidelines on how to analyze this phenomenon of overvoltage and provides formulae that can be used in the estimation of the worst case scenario. However, the formulae do not always provide accurate results. A detailed and long mathematical analysis resulted in new formulas that can replace with higher accuracy the standard formulae.

In conclusion, induced sheath voltage is calculated in multi circuit cable lines and equations are derived for the computation of induced voltage in various arrangements of double circuit. Underground cable is modelled in ATP/EMTP and the transient studies including switching and lightening strokes is done. It is also shown both by means of simulations and mathematical analysis on how the type of the bonding used, both-ends or cross-bond, may alter both the magnitude of overvoltage. To finish, in this thesis a comprehensive analysis is done on computation and reduction techniques of induced sheath voltage in the metallic sheaths of underground cables. The transients study suggests guidelines that can be used for a methodical step-by-step simulation of electromagnetic transients, in function of the grid and cable characteristics. The recommendations regarding the spacing used between the cables and the induced sheath voltage limitations are also discussed at the later part of the thesis.

Keywords: Induced sheath voltage, transients, cable modelling, cross bonding, overvoltage, lightning strike, ATP/EMTP; Thesis (Master’s degree) - Universiti Teknologi Brunei; Includes in bibliographical references
ER  -