CSA C22.3 No. 8 : 1991

Contents
Preface
1. Scope
2. Definitions and Reference Publications
    2.1 General Definitions
    2.2 Communications Definitions
    2.3 Reference Publications
3. Insulation Coordination and Electrical Clearances
    3.1 General
    3.2 Voltage Classification
    3.3 Overvoltages
    3.4 Criteria for Electrical Clearances and
         Insulation Levels
    3.5 Electrical Clearances
         3.5.1 General
         3.5.2 Static Clearance
         3.5.3 Dynamic Clearance
         3.5.4 Reductions
         3.5.5 Special Clearances
    3.6 Electrical Requirements of OCS Insulators
    3.7 Electrical Insulation Characteristics of High
         Voltage Switchgear and Transformers for Use with
         OCS Power Systems
4. Vertical and Lateral Clearances
    4.1 General
    4.2 Components of Design Clearances
         4.2.1 Load Clearance Limit (Ys)
         4.2.2 Dynamic Load Clearance Limit (Yd)
         4.2.3 Static Electrical Clearance (Cs)
         4.2.4 Dynamic Electrical Clearance (Cd)
         4.2.5 OCS Uplift (L)
         4.2.6 Pantograph Movements (Lt and S)
         4.2.7 OCS Sag (G)
         4.2.8 Live Vertical Distance of OCS
                Construction (D)
         4.2.9 Tolerances and Allowances (T, Ts, C, F1,
                and F2)
    4.3 Physical Clearances
    4.4 Determination of Total Clearance Requirements
    4.5 OCS Equipment
         4.5.1 Phase Breaks
         4.5.2 Static Insulators
    4.6 Parallel OCS Circuits
5. Overhead Contact Systems (OCS)
    5.1 General
    5.2 OCS Configurations
    5.3 Variable and Constant Tension Systems
    5.4 Pre-sag
    5.5 Pantographs
    5.6 Stagger
    5.7 Gradient
    5.8 Physical Clearance
    5.9 Wire
    5.10 System Depth (Encumbrance) and Droppers
    5.11 Cantilevers
    5.12 Poles
    5.13 Foundations
    5.14 Multiple Track Installations
    5.15 Guying
    5.16 Anchors
    5.17 Weight Tensioning Assembly
    5.18 Sectioning
    5.19 Mechanical Design
    5.20 Phase Breaks and Section Breaks
    5.21 Disconnects
    5.22 Electrification Layouts
6. Interference with Communications Systems
    6.1 General
    6.2 Sources of Interference
    6.3 Magnetic Induction
    6.4 Electric Induction
    6.5 Ground Potential Rise
    6.6 Shielding
    6.7 Susceptiveness
    6.8 Interference Limits
         6.8.1 Longitudinal Voltage
         6.8.2 Circuit Noise and Balance
         6.8.3 Electromagnetic Noise (EMI)
    6.9 Prevention and Mitigation of Interference
         6.9.1 General
         6.9.2 Route Separation
         6.9.3 Choice of Facility
         6.9.4 Ground Current and Shielding
         6.9.5 Harmonics
         6.9.6 Voltage to Ground
         6.9.7 Metallic Voltage
         6.9.8 Ground Potential Rise
7. Interference with and Protection of Railway
    Signalling and Communications Systems
    7.1 General
    7.2 Signalling and Communications Systems
    7.3 Railway Signal Systems
    7.4 Track Circuits
    7.5 Signal Control Circuits
    7.6 Automatic Grade Crossing Warning System
    7.7 Impedance Bonds
    7.8 Signal Supply Circuits
    7.9 OCS Configuration
8. Grounding, Bonding, and Fault Clearing
    8.1 General
         8.1.1 Operational Grounding
         8.1.2 Safety Grounding
         8.1.3 Classification of Grounding Requirements
         8.1.4 Grounding in Territory with Signal Track
                Circuits
         8.1.5 Relevant Standards
    8.2 Grounding of the Components of the OCS
         8.2.1 OCS Poles and Support Structures
         8.2.2 OCS Circuit Breakers, Disconnect Switches,
                and Fuses
         8.2.3 OCS Surge Arresters
         8.2.4 Detection and Clearing of Faults
         8.2.5 Traction Feeder Stations and Switching
                Stations
         8.2.6 Stub End Tracks
    8.3 Other Railway Equipment and Installations
         within the Right-of-Way
         8.3.1 Stands, Switch Mechanisms, and De-rails
         8.3.2 Station Buildings, Platforms, Yards, and
                Maintenance Shops
         8.3.3 Grade Crossings and Pedestrian Crossings
         8.3.4 Bridges
         8.3.5 Tunnels
    8.4 Grounding of Structures, Buildings, and Fences
         Adjacent to Electrified Rail Tracks
         8.4.1 Danger Zones
         8.4.2 Grounding in Zone 1
         8.4.3 Grounding in Zone 2
         8.4.4 Grounding in Zone 3
    8.5 Pipelines and Fuel Tanks
         8.5.1 Pipelines
         8.5.2 Above Ground Fuel Tanks
9. Electric Utility Interface Unbalance and Harmonics
    9.1 General
    9.2 Load Curves
    9.3 In-Rush Currents
    9.4 Negative Sequence Voltages
    9.5 Harmonics
         9.5.1 Harmonic Generation
         9.5.2 Effect of Harmonics on the Power System
         9.5.3 Mathematical Definition of the DF and I-T
                Product
         9.5.4 Tentative Limits to Harmonic Distortion
         9.5.5 Harmonic Suppression by Use of Filters
Tables
Figures
Appendix A-Bibliography

Applicable to the overhead contact system and traction power supply to the locomotive, using a single-phase alternating supply at 25 or 50 kV nominal voltage, 60 Hz. This Standard was primarily written for use in the development of conventional railway freight and passenger services, It is however, recommended for development of special services, such as rapid transit, wherever possible.