Almost all power systems contain a mix of overhead line and cable. The balance between the two can vary dramatically. A number of factors govern the choice between line and cable: cost, route availability, environmental aspects and electrical parameters. In terms of initial cost including installation, high-voltage cable systems are almost always more costly than overhead line systems for the same duty. Naturally, therefore, the designer's first choice is overhead line. The cable alternative is selected only when there is an overriding reason to do so.

Chapter Contents:

• 6.1 Introduction
• 6.2 Elementary theory
• 6.2.1 Voltage, electric field and capacitance
• 6.2.2 Current, magnetic field and inductance
• 6.3 Historical development
• 6.3.1 Early telegraph cables
• 6.3.2 Early lighting systems
• 6.3.3 Flexible cables
• 6.3.4 Impregnated cables and the renaissance of high voltage
• 6.3.5 Pressure-assisted (gas) cables
• 6.3.6 Fluid-filled cables
• 6.3.7 Polymeric cables
• 6.3.8 Polypropylene-paper laminate
• 6.4 Features of real cables
• 6.4.1 The conductor
• 6.4.2 The insulation system
• 6.4.3 Multi-core and multi-function cables
• 6.4.4 Outer layers
• 6.4.5 Installation
• 6.5 Current ratings
• 6.5.1 Time-dependent ratings
• 6.5.2 Factors affecting ratings
• 6.6 Accessories
• 6.6.1 Terminations
• 6.6.2 Joints
• 6.6.3 Other accessories
• 6.7 Direct current and subsea cable systems
• 6.7.1 Applications of AC and DC transmission
• 6.7.2 Subsea cable configurations
• 6.7.3 Insulation systems
• 6.7.4 Manufacture
• 6.7.5 Installation
• 6.7.6 Accessories
• 6.8 Standards
• 6.9 Testing
• 6.9.1 Development testing
• 6.9.2 Type testing
• 6.9.3 Prequalification testing
• 6.9.4 Factory acceptance testing
• 6.9.5 After-laying tests
• 6.9.6 In-service monitoring
• 6.9.7 Testing for periodic maintenance
• 6.9.8 Fault location
• 6.10 Future directions
• References

Inspec keywords: costing; power system reliability; environmental factors; power cables; power overhead lines; power system economics

Other keywords: electrical parameter; route availability; power system; environmental aspect; overhead line system; cost; installation; high-voltage cable system

Subjects: Overhead power lines; Power cables; Reliability; Power system management, operation and economics