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The only book containing a complete treatment on the construction of electric power lines. Reflecting the changing economic and technical environment of the industry, this publication introduces beginners to the full range of relevant topics of line design and implementation.

Overhead Power Lines: Planning, Design, Construction

1 Overall planning.- 1.0 Symbols.- 1.1 Development stages of a transmission project.- 1.2 Transmission planning.- 1.2.1 Objective.- 1.2.2 Planning stages.- 1.2.3 Planning aspects regarding transmission lines.- 1.3 Planning methods.- 1.3.1 Data acquisition and preparation.- 1.3.2 Formulation and preselection of alternatives.- 1.3.3 Electrical studies.- 1.3.4 Economic studies and final evaluation.- 1.4 Planning criteria.- 1.4.1 General.- 1.4.2 Criteria for steady-state conditions.- 1.4.3 Criteria for temporary and transient conditions.- 1.5 Evolution and selection of voltage levels.- 1.5.1 Evolution of transmission voltages.- 1.5.2 Introduction of transmission voltages.- 1.6 Conductor selection.- 1.7 Selection of line configuration.- 1.8 Direct current transmission.- 1.8.1 Aspects of DC transmission components.- 1.8.2 Economic comparison of DC and AC lines.- 1.8.3 Technical comparison of AC and DC transmission.- 1.8.4 Practical use of DC transmission.- 1.9 Transmission with higher order phase lines.- 1.9.1 Options.- 1.9.2 Properties of multiple-phase systems.- 1.9.3 Present experience.- 1.10 Investments.- 1.11 Licences and permit procedures.- 1.12 Underground transmission versus overhead lines.- 1.12.1 Application and planning aspects.- 1.12.2 Environmental constraints.- 1.12.3 Technical limitations.- 1.12.4 Comparative investments.- 1.12.5 Perspectives.- 1.13 Results of overall planning.- 1.14 References.- 2 Electric requirements and design.- 2.0 Symbols.- 2.1 Overhead lines as components of electric systems.- 2.1.1 Surge impedance and surge impedance load (natural power).- 2.1.2 Stability.- 2.1.3 Voltage regulation and maximum permissible losses.- 2.1.4 Capability of a line.- 2.1.5 Reliability and availability.- 2.1.6 Reactive power compensation.- 2.1.7 Power transmitted versus right-of-way width.- 2.2 Current-related phenomena.- 2.2.1 Normal and emergency conditions.- 2.2.2 Ohmic losses.- 2.2.3 Short circuit condition.- 2.3 Voltage and current-related phenomena.- 2.3.1 Introduction.- 2.3.2 Electrical and magnetic fields.- 2.3.3 Corona phenomena and related effects.- 2.3.4 Audible noise (AN).- 2.3.5 Impact of line design on voltage- and current-depending phenomena.- 2.4 Line performance and insulation requirements.- 2.4.1 Introduction.- 2.4.2 Power frequency voltages and temporary overvoltages.- 2.4.3 Slow-front overvoltages.- 2.4.4 Fast-front overvoltages.- 2.4.5 Principles of insulation coordination..- 2.4.6 Live-line maintenance.- 2.5 Clearances.- 2.5.1 Clearance requirements.- 2.5.2 Internal and external clearances.- 2.6 References.- 3 Electric parameters.- 3.0 Symbols.- 3.1 Introduction.- 3.2 Resistance.- 3.3 Positive-sequence impedance.- 3.3.1 Introduction.- 3.3.2 Inductance and inductive Reactance.- 3.4 Zero-sequence impedance.- 3.4.1 Introduction.- 3.4.2 Simplified approach for the determination of zero-sequence impedances.- 3.5 Capacitance and capacitive reactance.- 3.5.1 General considerations.- 3.5.2 Single-circuit lines.- 3.5.3 Double-circuit lines.- 3.6 Admittance.- 3.7 Electric representation of lines.- 3.7.1 Goals and basic conditions.- 3.7.2 Short- and medium-length lines.- 3.7.3 Long-length transmission lines..- 3.8 References.- 4 Lightning protection.- 4.0 Symbols.- 4.1 Significance of lightning.- 4.2 Formation of lightning strokes.- 4.2.1 Mechanism of lightning discharge.- 4.2.2 Impulse behaviour of lightning discharges.- 4.2.3 Electric characteristics of the discharges.- 4.3 Frequency and intensity of lightning strokes.- 4.3.1 Keraunic levels and earth flash density.- 4.3.2 Magnitude of lightning stroke currents.- 4.3.3 Direct and indirect lightning strokes.- 4.4 Arrangement and efficiency of earth wires.- 4.4.1 Theoretical background.- 4.4.2 Effective shielding by earth wires.- 4.4.3 Surge arresters.- 4.4.4 Assessment of lightning performance of overhead lines.- 4.5 Earthing in view of lightning protection.- 4.5.1 Significance of earthing for lightning protection.- 4.5.2 Surge impedance of earthing systems.- 4.6 References.- 5 Earthing.- 5.0 Symbols.- 5.1 Purpose of earthing.- 5.2 Definitions and basic principles.- 5.3 Requirements.- 5.3.1 Standards.- 5.3.2 Safety of persons.- 5.3.3 Thermal short-circuit strength.- 5.3.4 Mechanical strength and corrosion resistance.- 5.3.5 Currents to be considered.- 5.4 Earthing for personal safety purposes.- 5.5 Operational earthing.- 5.6 Lightning protection earthing.- 5.7 Rating for short-term currents.- 5.8 Soil resistivity and conductivity.- 5.9 Calculation of earthing resistance.- 5.9.1 Spherical electrode.- 5.9.2 Earthing rods.- 5.9.3 Horizontally arranged electrode wires (counterpoises).- 5.10 Measurements of soil resistivity.- 5.10.1 Basic principles.- 5.10.2 Measuring methods.- 5.11 Measurement of earthing resistance.- 5.12 Earthing resistance in non-homogeneous soils.- 5.12.1 Soil resistivity in a two-layer soil structure.- 5.12.2 Computation of earthing resistance in a two-layer soil structure.- 5.12.3 Computation of earthing resistance by means of the apparent resistivity.- 5.12.4 Computation of earthing resistance of three-dimensional structures.- 5.12.5 Example for computation of earthing resistance.- 5.13 Practical rules for installation of earthing systems.- 5.13.1 Radial and ring-type earthing counterpoises.- 5.13.2 Vertically or obliquely driven earthing rods.- 5.13.3 Bonding between earthing electrodes.- 5.13.4 Earthing connections.- 5.14 References.- 6 Requirements on loading and strength.- 6.0 Symbols.- 6.1 Mechanical design of the overhead line system.- 6.1.1 Components and elements of an overhead line.- 6.1.2 Reliability.- 6.1.3 Calculation of reliability.- 6.1.4 Strength coordination and selection of reliability.- 6.1.5 Effect of maximum load intensity on a high number of components.- 6.1.6 Use factor and its effect on the design.- 6.2 Strengths of line components and elements.- 6.2.1 Strength limits.- 6.2.2 Rating of individual components and elements.- 6.2.3 Damage and failure limits.- 6.3 Wind loads.- 6.3.1 Wind measurements.- 6.3.2 Determination of meteorological reference wind velocities.- 6.3.3 Wind action on line components and elements.- 6.4 Ice loads.- 6.4.1 Atmospheric icing.- 6.4.2 Ice observations and measurements.- 6.4.3 Determination of reference ice loads.- 6.5 Combined wind and ice loads.- 6.5.1 Probability of occurrence and combination of parameters.- 6.5.2 Determination of design parameters.- 6.5.3 Wind action on the ice covered conductor.- 6.6 Climatic loads according to relevant standards.- 6.6.1 Standards for overhead power lines.- 6.6.2 Wind loads.- 6.6.3 Ice loads.- 6.6.4 Combined wind and ice action.- 6.7 Loads at construction, operation and maintenance.- 6.7.1 Introduction.- 6.7.2 Requirements according to IEC 60826.- 6.7.3 Requirements according to EN 50341-1 and EN 50341-3.- 6.8 Failure containment and other special loads.- 6.8.1 Introduction.- 6.8.2 Provisions according to IEC 60 826.- 6.8.3 Provisions according to EN 50 341-1.- 6.9 Statistical distributions.- 6.9.1 Introduction.- 6.9.2 Normal distribution (Gaussian distribution).- 6.9.3 Log-normal distribution.- 6.9.4 Gumbel distribution.- 6.10 References.- 7 Selection of conductors.- 7.0 Symbols.- 7.1 Conductor types and design.- 7.1.1 Introduction.- 7.1.2 Conductor designation.- 7.1.3 Progress in technical development.- 7.1.4 Materials.- 7.1.5 Wire testing.- 7.1.6 Conductors made of wires with the same material.- 7.1.7 Composite conductors.- 7.1.8 Conductor testing.- 7.1.9 Bundle conductors.- 7.1.10 Special conductor designs.- 7.2 Design with regard to current loading..- 7.2.1 Introduction and requirements.- 7.2.2 Principles for determination of conductor temperature.- 7.2.3 Design with regard to current carrying capacity.- 7.2.4 Design with regard to short-circuit current.- 7.2.5 Design based on economic considerations.- 7.2.6 Line capacity as a function of the weather conditions.- 7.3 Design with regard to stresses caused by voltages.- 7.3.1 Introduction and requirements.- 7.3.2 Design with respect to the electric parameters.- 7.3.3 Design with respect to conductor surface gradients and corona effects.- 7.3.4 Corona losses.- 7.4 Mechanical design of conductors.- 7.4.1 Introduction and requirements.- 7.4.2 Stresses under extreme load conditions.- 7.4.3 Stresses under everyday conditions.- 7.4.4 Impact of the conductor tensile load on line investment.- 7.4.5 Conductor creep.- 7.4.6 Recommendations for selection of conductor tensile stresses.- 7.5 References.- 8 Earth wire selection.- 8.0 Symbols.- 8.1 Types of earth wires.- 8.2 Electric and thermal design.- 8.2.1 Requirements.- 8.2.2 Earth wire design under short-circuit conditions.- 8.2.3 Temperature limits of earth wires in case of short circuits.- 8.2.4 Fault clearing and reclosing operations.- 8.2.5 Examples of earth wire current carrying capacity in case of short circuits.- 8.3 Mechanical design.- 8.3.1 Loss of mechanical strength during heating process.- 8.3.2 Establishing tensile stresses and forces.- 8.4 Steps for selection of conventional earth wires.- 8.5 Earth wires comprising optical fibres (OPGW).- 8.5.1 Generalities and design.- 8.5.2 Installation conditions.- 8.5.3 Accessories..- 8.5.4 Tests.- 8.6 References.- 9 Insulators.- 9.0 Symbols.- 9.1 Introduction.- 9.2 Ceramic insulators.- 9.2.1 Insulator types and their application.- 9.2.2 Raw materials.- 9.2.3 Production.- 9.3 Glass insulators.- 9.3.1 Raw materials and production.- 9.3.2 Insulator types and application.- 9.4 Composite insulators.- 9.4.1 Raw materials, design and production.- 9.4.2 Types of composite insulators and their application.- 9.5 Comparison of insulator types.- 9.6 Tests on insulator units.- 9.6.1 Basic information.- 9.6.2 Tests on ceramic and glass insulators.- 9.6.3 Tests on composite insulators.- 9.7 Design of insulator sets.- 9.7.1 Suspension insulator sets.- 9.7.2 Tension insulator sets.- 9.8 Requirements for insulator sets.- 9.8.1 Electric requirements for AC lines.- 9.8.2 Particularities for DC lines.- 9.8.3 Audible noise (AN) performance.- 9.8.4 Mechanical design.- 9.9 Operational performance of insulator strings.- 9.9.1 Introduction.- 9.9.2 Voltage stresses.- 9.9.3 Behaviour of individual insulator types.- 9.9.4 Behaviour under pollution layers.- 9.10 Testing of insulator sets.- 9.10.1 Basic information and assumptions.- 9.10.2 Standard atmospheric conditions.- 9.10.3 Artificial rain.- 9.10.4 Testing arrangements.- 9.10.5 Power frequency voltage test.- 9.10.6 Fast-front and slow-front overvoltage tests.- 9.10.7 Power arc behaviour.- 9.10.8 Radio interference strength test.- 9.10.9 Corona onset or extinction voltage test.- 9.11 Example for insulator selection.- 9.12 References.- 10 Overhead line fittings.- 10.1 Definitions.- 10.2 Fittings for conductors.- 10.2.1 Conductor attachment at suspension insulator sets.- 10.2.2 Conductor attachments at dead-end terminations.- 10.2.3 Turn buckles.- 10.2.4 Connectors.- 10.2.5 Spacers for bundle conductors.- 10.2.6 Vibration dampers for single conductors.- 10.2.7 Spacer dampers for bundle conductors.- 10.3 Fittings for insulator sets.- 10.4 Rating and tests.- 10.4.1 General.- 10.4.2 Electric requirements.- 10.4.3 Mechanical requirements.- 10.4.4 Corrosion protection.- 10.4.5 Selection of material.- 10.4.6 Tests.- 10.5 References.- 11 Conductor vibrations.- 11.0 Symbols.- 11.1 Overview and types of vibration.- 11.2 Aeolian vibrations.- 11.2.1 Basic physical aspects, mathematic-mechanic model of a line.- 11.2.2 Conductor free-span amplitude.- 11.2.3 Conductor strains and stresses.- 11.2.4 Bending stiffness of a conductor.- 11.2.5 Origin of vibrations.- 11.2.6 Consequences of vibrations.- 11.2.7 Consequences for line design.- 11.2.8 Verification of vibration intensity and effectiveness of damping measures.- 11.2.9 Evaluation of vibration measurements.- 11.3 Subspan oscillations.- 11.3.1 Origin and consequences.- 11.3.2 Remedy measures.- 11.4 Galloping.- 11.4.1 Origin and consequences.- 11.4.2 Remedy measures.- 11.5 Short-circuit oscillations.- 11.5.1 Origin and consequences.- 11.5.2 Remedy measures.- 11.6 References.- 12 Supports.- 12.0 Symbols.- 12.1 Support types and their applications.- 12.1.1 Definitions.- 12.1.2 Tasks of supports in an overhead line.- 12.1.3 Support design and application.- 12.2 Tower top geometry.- 12.2.1 Requirements.- 12.2.2 Electrical clearances according to relevant standards.- 12.2.3 Clearance between conductors.- 12.2.4 Clearances at supports.- 12.3 Basic design requirements.- 12.3.1 Introduction.- 12.3.2 Static design.- 12.3.3 Design values and verification methods.- 12.4 Load cases and partial factors.- 12.4.1 Combination of loads.- 12.4.2 Extreme wind load.- 12.4.3 Wind load at minimum temperature.- 12.4.4 Uniform and unbalanced ice loads without wind.- 12.4.5 Combined wind and ice load.- 12.4.6 Construction and maintenance loads.- 12.4.7 Security loads.- 12.4.8 Partial factors for actions on supports.- 12.4.9 Partial factors for materials.- 12.5 Lattice steel towers.- 12.5.1 Structural design.- 12.5.2 Materials.- 12.5.3 Analysis of member forces.- 12.5.4 Calculation of the member forces at a plane system.- 12.5.5 Analysis of member forces at a three-dimensional system.- 12.5.6 Comparison of computations at plane and three-dimensional systems.- 12.5.7 General format of verification of members and connections.- 12.5.8 Design of compression members.- 12.5.9 Design of compound members.- 12.5.10 Design of tensile-loaded members.- 12.5.11 Design of connections.- 12.5.12 Design for bending due to transverse loads.- 12.5.13 Design of redundant members.- 12.5.14 Deformation.- 12.5.15 Calculation of foundation loads.- 12.5.16 Application of computer programs for calculation of lattice steel towers.- 12.5.17 Upgrading the support strength.- 12.5.18 Example: Static calculation of a 110 kV suspension support.- 12.5.19 Example: Calculation guy wire and mast loads in a guyed-V tower.- 12.6 Steel poles.- 12.6.1 Structural design.- 12.6.2 Analysis of loads.- 12.6.3 Rating.- 12.6.4 Example for design of a conical solid-wall steel pole.- 12.7 Steel-reinforced concrete poles.- 12.7.1 Selection of cross sections.- 12.7.2 Spun concrete poles.- 12.7.3 Vibrated concrete poles.- 12.7.4 Structural design.- 12.7.5 Production.- 12.7.6 Rating.- 12.7.7 Example for design of a spun concrete pole.- 12.8 Wood poles.- 12.8.1 Application and design.- 12.8.2 Rating.- 12.8.3 Treatment of wood poles.- 12.9 Loading and failing tests.- 12.9.1 Introduction.- 12.9.2 Foundations for support under test.- 12.9.3 Material for the tower under test.- 12.9.4 Fabrication of the prototype tower under test.- 12.9.5 Strain measurements.- 12.9.6 Assembly and erection.- 12.9.7 Test loads.- 12.9.8 Load application.- 12.9.9 Load procedure.- 12.9.10 Load measurement.- 12.9.11 Deflections.- 12.9.12 Acceptance and failures.- 12.9.13 Destruction test.- 12.9.14 Disposition of test tower.- 12.9.15 Test report.- 12.10 References.- 13 Foundations.- 13.0 Symbols.- 13.1 Requirements and preconditions.- 13.2 Types of subsoils.- 13.2.1 Classification of soil.- 13.2.2 Undisturbed natural soil.- 13.2.3 Rock.- 13.2.4 Filled-up soil.- 13.3 Subsoil investigation.- 13.3.1 Purpose of subsoil investigation.- 13.3.2 Methods for obtaining soil samples.- 13.3.3 Probes.- 13.3.4 Evaluation of soil investigation..- 13.4 Design and calculation of foundations.- 13.4.1 Type of foundation and load.- 13.4.2 Soil characteristics.- 13.4.3 Compact foundations.- 13.4.4 Separate foundations.- 13.4.5 Anchoring of leg member stubs.- 13.4.6 Foundation for guyed towers.- 13.5 Testing of foundations.- 13.5.1 Definitions and object.- 13.5.2 Categories of tests.- 13.5.3 Foundation installation.- 13.5.4 Testing equipment.- 13.5.5 Testing procedure.- 13.5.6 Test evaluation and acceptance criteria.- 13.5.7 Uplift load tests on construction and test piles.- 13.6 References.- 14 Sag and tension calculations.- 14.0 Symbols.- 14.1 Basis.- 14.2 Sags described by the catenary curve.- 14.3 Conductor sagging curve as a parabola.- 14.4 Span with differing attachment levels.- 14.5 Conductor state change equation.- 14.6 Span with concentrated loads.- 14.7 Span with tension insulator sets at both ends.- 14.8 Conductor forces and sags in a tensioning section.- 14.8.1 Introduction.- 14.8.2 Conductor state in spans with end points movable in line direction.- 14.8.3 Conductor stresses and sags in case of inverted V-insulator sets.- 14.8.4 Conductor state change equation for a tensioning section.- 14.8.5 Computer program for conductor state change in a tensioning section.- 14.8.6 Approximate formulae of sags at ice load in one span only.- 14.9 Clearances to ground and to objects.- 14.9.1 Requirements.- 14.9.2 Calculation of clearance to ground.- 14.9.3 Calculation of the clearance to a crossed road.- 14.9.4 Calculation of clearance to a crossed line.- 14.10 References.- 15 Route selection and detailed line design.- 15.0 Symbols.- 15.1 Introduction.- 15.1.1 Basic information.- 15.1.2 Preliminary activities.- 15.2 Route selection and licences.- 15.2.1 Introduction.- 15.2.2 Regulatory controls and permit procedures.- 15.2.3 Environmental impact assessment.- 15.2.4 Route selection and line design in view of visual impact.- 15.2.5 Route selection in view of people.- 15.2.6 Route selection and line design in view of ecological systems.- 15.2.7 Route selection in view of land use.- 15.3 Survey on site.- 15.3.1 Steps of survey.- 15.3.2 Survey procedures and instruments adopted.- 15.3.3 Survey of angle points and line alignment.- 15.3.4 Survey of terrain profile.- 15.3.5 Location of supports.- 15.3.6 Survey of existing lines.- 15.4 Line design and establishing of plans.- 15.4.1 Clearances.- 15.4.2 Determination of support locations, tower types and heights.- 15.4.3 Documentation of lines.- 15.5 Data processing for line design and administration.- 15.5.1 Data processing systems for planning of overhead lines.- 15.5.2 Establishing the longitudinal profile.- 15.5.3 Establishing the plan layout.- 15.5.4 Graphical Information System with integrated data bank.- 15.5.5 Administration of plans, lists and documents.- 15.6 References.- 16 Construction.- 16.0 Symbols.- 16.1 Construction planning.- 16.1.1 Introduction.- 16.1.2 Construction time schedule.- 16.1.3 Mobilisation and stockyard.- 16.2 Transportation.- 16.2.1 Means of transport.- 16.2.2 Access roads.- 16.2.3 Fences, gates and cattle-guards.- 16.3 Construction of foundations.- 16.3.1 Introduction.- 16.3.2 Concrete foundations black and slab foundations.- 16.3.3 Augerbored foundations.- 16.3.4 Driven pile foundations.- 16.3.5 Grillage foundations.- 16.3.6 Anchor foundations.- 16.3.7 Concrete for foundations.- 16.4 Installation of earthing.- 16.5 Setting of tower stubs or bases.- 16.5.1 Methods and tools.- 16.5.2 Inclination of angle and dead-end towers.- 16.6 Erection of supports.- 16.6.1 Introduction.- 16.6.2 Assembly and erection by elevation.- 16.6.3 Tower erection using a crane.- 16.6.4 Tower erection by means of a gin pole.- 16.6.5 Erection of guyed towers.- 16.6.6 Tower erection using helicopters.- 16.6.7 Bolts and torques.- 16.7 Installation of insulator sets and hardware.- 16.7.1 Insulator sets.- 16.7.2 Joints.- 16.8 Conductor stringing.- 16.8.1 General requirements.- 16.8.2 Stringing methods.- 16.8.3 Conductor stringing equipment.- 16.8.4 Conductor stringing.- 16.8.5 Determination of initial sags.- 16.9 References.- 17 Commissioning, operation and line management.- 17.0 Symbols.- 17.1 Commissioning.- 17.1.1 Introduction.- 17.1.2 Supervision of approval, design and manufacturing stage.- 17.1.3 Supervision and acceptance of construction.- 17.1.4 Final inspection and acceptance.- 17.1.5 Quality assurance.- 17.1.6 Performance tests.- 17.1.7 Energization and commence of operation.- 17.2 Operation.- 17.2.1 Real-time monitoring of conductor ampacity.- 17.2.2 Thunderstorm monitoring and forecast.- 17.2.3 Ice observations.- 17.2.4 Galloping alerting system.- 17.2.5 Insulator contamination and performance.- 17.3 Asset management.- 17.3.1 Definitions.- 17.3.2 Introduction and targets.- 17.3.3 Risk management of line assets.- 17.3.4 Net present value of annual expenditures.- 17.3.5 Planned expenditures.- 17.3.6 Risk of failure.- 17.3.7 Consequences of a failure.- 17.3.8 Overhead line asset management process.- 17.3.9 Data base.- 17.3.10 Management options.- 17.3.11 Example on management of risk of failure.- 17.4 Maintenance.- 17.4.1 Introduction.- 17.4.2 Inspection.- 17.4.3 Corrective maintenance.- 17.4.4 Investigation of line failures.- 17.5 Reliability and availability.- 17.5.1 Introduction and definitions.- 17.5.2 Energy availability, general description and guidelines.- 17.6 Line refurbishment, upgrading and uprating.- 17.6.1 Definitions.- 17.6.2 Uprating.- 17.6.3 Upgrading.- 17.7 References.