Relevant Characteristics of Power Lines Passing through Urban Areas

Description

Relevant Characteristics of Power Lines Passing through Urban Areas covers a variety of problems in electric-power delivery that were considered for a long time in professional and scientific circles unsolvable. Taking into account the influence of all surrounding metal installations on the relevant characteristics of HV and EHV lines passing through urban and/or suburban areas, this reference provides safe and economical solutions on how to check and achieve prescribed safety conditions, determine the dangerous and harmful inductive influence of HV and EHV lines, enable compensation of deficiency for all unknowns, understand relevant data concerning surrounding metal installations, and more. This book is necessary for properly dimensioning cable systems, considering the existing underground structures near substations and providing engineers with the necessary information they need to design normal operations and determine fault events. Front Cover Relevant Characteristics of Power Lines Passing Through Urban Areas Copyright Page Dedication Contents Preface 1 Introductory considerations 1.1 Problem description 1.2 The methodology that enables solving the problem 1.2.1 Brief description of the methodology 1.2.2 Carsons’s modified equations and current return path through the ground 1.2.3 Simplified calculation of the series impedance of HV and EHV lines 1.3 Benefits of the methodology application 1.3.1 Grounding problem of HV substations located in urban areas 1.3.2 Problem of the inductive influence of HV and EHV lines 1.3.3 Influence of surrounding metal installations on transfer capacity of power lines References 2 Calculated reduction factor of feeding cable lines 2.1 Introduction 2.1.1 Definition and significance of the feeding line reduction factor 2.1.2 A brief review of the existing methods 2.2 Analytical expressions for the reduction factor 2.2.1 Lines consisting of one single-core or one three-core cable 2.2.2 Relevant characteristics of lines consisting of three single-core cables 2.2.3 Reduction factor of lines consisting of three single-core cables 2.2.4 Reduction factor of cable lines with applied cross-bonding 2.3 Ground-fault current distribution for any fault place along a cable line 2.3.1 Lines consisting of one single-core cable 2.3.2 Lines consisting of three single-core cables 2.3.3 Supplied substations with the grounded neutral point(s) 2.4 Quantitative analysis 2.4.1 Reduction factor calculated values 2.4.2 Fault place critical for the metal sheaths of cable lines 2.5 General observations References 3 Actual reduction factor of power distribution lines 3.1 Introduction 3.2 Cable lines with no applied cross-bonding 3.2.1 Complete equivalent circuit 3.2.2 Relevant parameters of the equivalent conductor 3.2.3 Critical ground-fault position 3.3 Cable lines with applied cross-bonding 3.3.1 Measurement procedure 3.3.2 Relevant parameters of the equivalent sheath 3.4 Overhead lines 3.5 Theoretical foundations for introducing equivalent sheath 3.5.1 Electromagnetic interpretation of the methodology 3.5.2 Cable sheath parameter expressing the influence of surrounding metal installations 3.5.3 Mathematical interpretation of the methodology 3.6 Quantitative analysis 3.7 Methodology application at the design stage 3.8 General observations concerning the methodology application References Further reading 4 Reduction factor of lines consisting of one overhead and one cable section 4.1 Introduction 4.2 Calculated reduction factor 4.2.1 Cable having uncovered metal sheath 4.2.2 Special cases 4.2.3 Cable(s) having covered metal sheaths 4.3 Actual reduction factor 4.4 Quantitative analysis 4.4.1 Influence of cable section length 4.4.2 Lines consisting of different overhead sections References 5 Measures for improving reduction factor of a feeding line 5.1 Overhead lines 5.1.1 Problem description 5.1.2 Calculated reduction factor 5.2 Cable lines 5.2.1 Introduction 5.2.2 Simplified equivalent circuit 5.3 Actual reduction factor 5.4 Quantitative analysis and general observations 5.4.1 Overhead lines 5.4.2 Cable lines References 6 Preliminary testing of safety conditions of high voltage substations located in urban areas 6.1 Introduction 6.2 Problem description 6.3 Relevant parameters of the introduced equivalent sheath 6.3.1 Cable lines with applied cross-bonding 6.3.2 Test circuit formed by using overhead section of feeding line 6.3.3 Line section composed of one overhead and one cable subsection 6.3.4 Method applicability 6.4 Actual grounding system impedance of a tested substation 6.5 Preliminary estimation of the tested grounding system 6.5.1 Procedure description 6.5.2 A practical example 6.6 General observations References 7 Inductive influence of high-voltage and extra-high voltage lines on surrounding metal installations 7.1 Inductive influence on the nearby metal installation 7.1.1 Introduction 7.1.2 Problem description 7.2 Exposure to inductive influence along the whole cable line 7.2.1 Complete equivalent circuit of an HV or EHV cable line 7.2.2 Equivalent cable line screen 7.2.3 Cable line with no applied cross-bonding 7.2.3.1 Ground-fault conditions 7.2.3.2 Normal operation conditions 7.2.4 Cable line with applied cross-bonding 7.2.4.1 Ground-fault conditions 7.2.4.2 Normal operation conditions 7.3 Exposure to inductive influence along any section of a cable line 7.3.1 Critical ground-fault position 7.3.2 On-site measurements and resulting screening factor 7.3.3 Relevant parameters of equivalent screening conductor 7.3.4 Determination of compensating conductor 7.4 Quantitative analysis 7.4.1 Methodology verification 7.4.2 Screening effects of the surrounding metal installations 7.5 General observations References 8 Transfer characteristics of power lines passing through urban areas 8.1 Introduction 8.1.1 Historical development of power systems 8.1.2 Contemporary tendencies in utilization of high-voltage and extra high-voltage lines 8.2 Problem description 8.3 Complete equivalent circuit of an high-voltage or extra high-voltage cable line 8.4 The additional neutral conductor 8.4.1 Overhead lines and cable lines with no applied cross-bonding 8.4.2 Cable lines with applied cross-bonding 8.4.2.1 Problem description 8.4.2.2 Measurement procedure 8.4.2.3 Analytical part of the methodology 8.4.2.4 Actual series impedance 8.4.2.5 Methodology applicability 8.5 Quantitative analysis 8.5.1 General data 8.5.2 Overhead lines and cable lines with no applied cross-bonding 8.5.2.1 The first example of overhead lines 8.5.2.2 The second example of overhead lines 8.5.2.3 The third example of overhead lines 8.5.2.4 The first example of cable lines 8.5.2.5 The second example of cable lines 8.5.3 Comments on the obtained results 8.5.4 Cable line with applied cross-bonding 8.5.5 Comments on the obtained results 8.6 General observations References Index Back Cover