Power Cables and their Application

Transcription

1 Power Cables and their Application Parti Materials Construction Criteria for Selection Project Planning Laying and Installation Accessories Measuring and Testing Editor: Lothar Heinhold 3rd revised edition, 1990 Siemens Aktiengesellschaft

2 Contents Constructional Elements of Insulated Cables 1 Conductors Wiring Cables and Flexible Cables Power Cables 13 2 Insulation Polymers Thermoplastics (Plastomers) Copolymers Fluoroplastics Polyvinyl Chloride (PVC) Polyethylene (PE)- Cross-Linked Polyethylene (XLPE) Elastomers 23 Thermoplastic Elastomers (TPE)-Conducting Rubber-Natural Rubber (NR)- Styrene Butadiene Rubber (SBR) Nitrile Butadiene Rubber (NBR)-Butyl Rubber (IIR)-Ethylene-Propylene Rubber (EPR)- Silicone Rubber (SiR) Ethylene Vinyl Acetate (EVA) Thermosetting Polymers (Duromers) Chemical Aging of Polymers The Influence of Moisture on Polyolefine Insulating Materials Impregnated Paper Literature Referred to in Section Protective Sheaths Thermoplastic Sheaths Elastomer Sheaths Sheathing Materials for Special Purposes Metal Sheath 39 4 Protection against Corrosion Cable with Lead Sheath Aluminium-Sheathed Cables Armour 43 6 Concentric Conductors 44 7 Electrical Screening Conducting Layers Metallic Components of Electrical Screening Longitudinally Water Proof Screens.. 47 Insulated Wires and Flexible Cables , Types of Wires and Cables 49 National and International Standards 49 VDE Specifications 49 Harmonized Standards 49 National Types 54 IEC Standards 55 Selection of Flexible Cables 55 Cables for Fixed Installations Flexible Cables 62 FLEXO Cords 74 Flexible Cables for Mining and Industry 75 Halogen-Free SIENOPYR Wiring and Flexible Cables with Improved Performance in the Event of Fire.. 79 Core Identification of Cables Definition of Locations to DIN VDE Application and Installation of Cables Rated Voltage, Operating Voltage Selection of Conductor Cross-Sectional Area 89 Power Cables 12 National and International Standards VDE Specifications Standards of Other Countries. IEC and CENELEC Standards Types of Construction of Low- and High-Voltage Cables 97 General 97 Type Designation 100 Selection of Cables and Accessories Power Cables for Special Applications Cable with Elastomer Insulation Shipboard Power Cable Construction and Characteristics.. 124

3 Application and Installation Halogen-Free Cables with Improved Characteristics in the Case of Fire Testing Performance under Conditions of Fire 125 Spread of Fire Corrosivity of Combustion Gases-Smoke Density. Insulation Retention under Conditions of Fire Construction and Characteristics Laying and Installation Cables for Mine Shafts and Galleries River and Sea Cables Airport Cables Cable with Polymer Insulation and Lead Sheath Insulated Overhead Line Cables High-and Extra-High-Voltage Cables Cable with Polymer Insulation Low-Pressure Oil-Filled Cable with Lead or Aluminium Sheath Thermally Stable Cable in Steel Pipe High-Pressure Oil-Filled Cable Internal Gas-Pressure Cable External Gas-Pressure Cable (Pressure Cable) 139 Planning of Cable Installations 16 Guide for Planning of Cable Installations Cable Rated Voltages Allocation of Cable Rated Voltages Rated Lightning Impulse Withstand Voltage Voltage Stresses in the Event of Earth Fault Current-Carrying Capacity in Normal Operation Terms, Definitions and Regulations Operating Conditions and Design Tables Operating Conditions for Installations in Ground Operating Conditions, Installation in Air Project Design Tables 159 Load Capacity Installed in Ground/Air- Rating Factors for Installation in Ground, for Differing Air Temperatures and for Groups in Air Use of Tables 180 Calculation of Load Capacity Thermal Resistances 184 Thermal Resistance of the Cable Thermal Resistance of Air 186 Horizontal Installation-Vertical Installation Atmospheric Pressure Ambient Temperature Solar Radiation Arrangement of Cables Thermal Resistance of the Soil Temperature Field of a Cable Definition of Soil-Thermal Resistance Daily Load Curve and Characteristic Diameter-Drying-Out of the Soil and Boundary Isotherm d x Fictitious Soil-Thermal Resistance 7* x and T^ Load Capacity Grouping in the Ground 207 Fictitious Additional Thermal Resistances AJ X ' and AT x ' y due to Grouping-Load Capacity-Extension of the Dry Area-Current-Carrying Capacity of Dissimilar Cables Installation in Ducts and Pipes Thermal Resistances 7^ and Tp Load Capacity for an Installation of Pipes in Ground or Air or in Ducts Banks Soil-Thermal-Resistivity 218 Cable in the Ground - Physical and Thermal Characteristics of Soil Influence of Moisture Content Measuring Basic Quantities for Calculation-Bedding Material Sand-Gravel Mixtures Sand-Cement Mixtures Calculation of Load Capacity Installation in Channels and Tunnels. 230 Unvcntilated Channels and Tunnels. 230 Arrangement of Cables in Tunnels Channels with Forced Ventilation Load Capacity of a Cable for Short- Time and Intermittent Operation General 239 Calculation with Minimum Time Value 239 Adiabatic Heat Rise 241 Root-Mean-Square Value of Current. 241 Short-Time Operation 242 Intermittent Operation 243 Symbols Used in Formulae in Section Literature Referred to in Section Short-Circuit Conditions 253 General 253 Temperature Rise of Conductor under Line-To-Earth Short Circuit Conductor and Sheat Currents under Line-To-Earth Short Circuit Load Capacity under Line-To-Earth Short-Circuit 259

4 19.3 Short-Circuit Thermal Rating Guide for Project Design 265 Performance under Short-Circuit Conditions Short-Circuit Duty Short-Circuit Capacity of Conductor, Screens, Sheaths and Armour Calculations of Short-Circuit Capacity 285 Adiabatic and Non-Adiabalic Temperature Rise Method Temperature Rise during Short-Circuit Thermo-Mechanical Forces and Expansion 292 General Effect of Thermal Expansion in Cables-Mounting of Single-Core Cables Accessories Mechanical Short-Circuit Capacity Electromagnetic Forces 297 Effect of Electromagnetic Forces Line- To-Earth, Line-To-Line and Balanced Three-Phase Short Circuit Multi-Core Cable 300 Tensile Force F^-Surface Pressure F F - Cable Construction Experience and Calculation Quantities Fixing Elements Single-Core Cables and Fixing Methods 305 Bending Stress Surface Pressure F F Stressing of Clamps and Binders Accessories Symbols used in Formulae in Section Literature Referred to in Section Resistance and Resistance per Unit Length of Conductor Resistance per Unit Length on d.c Resistance per Unit Length on a.c Current Related Losses Inductance and Inductance per Unit Length Inductance per Unit Length of a Conductor System Single-Core Cables Earthed at Both Ends Arrangement of Cables Earthing from Either One or Both Ends of Metal Sheath or Screen Cross-Bonding of the Sheaths, Transposition of the Cables Multi-Core Cables Zero-Sequence Impedance and Zero- Sequence Impedance per Unit Length Literature Referred to in Section Capacitance and Capacitance per Unit Length 331 General 331 Operating Capacitance per Unit Length C{, 331 Capacitive Current r e and Earth-Fault Current I' e of a Cable 334 Dielectric Losses 336 Insulation Resistance, Insulation Resistance per Unit Length and Leakage 337 Determination of Voltage Drop General 340 Short Cable Runs 340 Long Cable Runs 340 Economic Optimization of Cable Size 343 Symbols used in Formulae in Section Literature Referred to in Section Interference of Power Cables with Control and Telecommunication Cables 349 Inductive Interference 351 Mutual Inductance 351 Inducing Currents 352 Current Reduction Factor of the Influencing Power Cable 352 Voltage Reduction Factor of the Influenced Telecommunication Cable. 355 Reduction Factors of Compensating Conductors 357 Noise Voltage in Symmetrical Circuits 358 Ohmic Interference 358 Inductive and Ohmic Interference Details Required for Planning Calculated Example 360 Design and Calculation of Distribution Systems 362 Introduction 362 Determination of Power Requirement as a Basis for Planning 363 Load Requirement of Dwellings Load Requirements of Special Consumers 365 Total Load 366 Planning of Distribution Systems General 366 Selection of Distribution Voltage.. 367

5 Low-Voltage Systems 368 System Configuration and Types of Operation in the Public Supply-Extension of a Low-Voltage System Systems of Buildings-Industrial Supply Systems Location of Substations Component Parts of the Low-Voltage System Medium-Voltage Systems 375 Public Supply-Expansion of the Medium- Voltage System-Distribution Systems in Large Buildings Industrial Supply Systems Standby Power Supply-Component Parts of the Medium-Voltage System Charge Current Compensation and Star Point Treatment The Superimposed High-Voltage System 27.4 System Calculation Basics Calculation of a Low-Voltage System Investigations of Protective Measures Against Excessive Touch Voltage Investigation of Short-Circuit Protection and Discrimination Computer-Aided System Calculation Literature Referred to in Section Laying and Installation 28 Cable Identification Marking Manufacturers, VDE-Marking Colours of Outer Sheaths and Protective Coverings Core Identification for Power Cables up to U 0 /U=0.6/l kv Core Identification for Cables for Rated Voltages Exceeding iyt/=0.6/l kv Laying the Cables Transporting Preparation for Laying the Cable Differences in Level of the Cable Route Laying of Cables in the Ground Cable Route Laying of the Cables Laying of Cables Indoors Cables on Walls, Ceilings or Racks Cable Tunnels and Ducts Cable Clamps Types of Clamps Arrangements and Dimensions Installation Guide Preparation of Cable Ends Earthing of Metallic Sheaths and Coverings 416 Conductor Jointing 418 Repair of Damage to Outer Sheath Outer Sheath of Polyvinylchloride (PVC) and Polyethylene (PE) Jute Servings on Cables with Lead Sheath 423 Cable Accessories 424 Fundamental Objectives 424 Requirements 424 Stress Control 426 Fundamental Principles for the Construction and Installation of Accessories 427 Compound Filling Technique Cast-Resin Techniques 429 Shrink-On Technique 433 Lapping Technique 434 Push-On Technique 435 Plug Technique 437 Literature Referred to in Section Cable Plan 438 Measuring and Testing of Power Installations 34 Electrical Measurements in the Cable Installation, as Installed Voltage Tests General Testing with d.c. Voltage Testing with a.c. Voltage Locating Faults Preliminary Measurements Location Measurements by the Conventional Method Locating of Faults by Pulse Reflection Method Preparation of Fault Point by Burn- Through Locating Using Audio Frequency Testing of Thermoplastic Sheaths Construction and Resistance of Conductors Conversion Table 457 Index 458