Cable Testing and Fault Location

Introduction

There are many locating methods for finding defects, coupled with new detection technologies that make this task much easier and less time-consuming. There is no single method or combination of methods that is “best.” Your selection of the appropriate method for the situation and your skill in employing that method are the keys to safely and efficiently locating cable faults without damaging the cable.

The power cable has become a staple of modern power engineering and operations, where underground power transmission keeps facilities out of sight and largely protected from external damage. Increasingly, the use of insulated cable rather than air-insulated overhead conductor is the only acceptable way for electric utilities to move power in both heavily congested urban cores and environmentally or esthetically important areas. This course is designed to present an overall understanding of the major cable system types including extruded, self-contained fluid-filled, as well as an understanding of elements of design, manufacturing, installation, and operation of underground transmission and distribution cables. Also, this course will enable delegates to become more conversant with diagnosing faults location on power cables and OHTL. The instructor will discuss topics that are relevant to both voltage classes.

Objectives

By the end of the training, participants will be able to:

• Identify and characterize the major cable system types and components
• List the major design calculations required for a new cable system
• Describe the types of tests that are required in the manufacture and installation of a cable system.
• An understanding of fault location techniques, an appreciation of equipment used in fault location, an opportunity to use fault location equipment for cable and OHTL.
• Medium-voltage cable design, construction, and operation
• Cable testing methods
• Industry standards and procedures for testing
• Causes of cable failures
• Perform insulation resistance, dielectric strength tests in the lab and evaluate results
• Locate faults

Training Methodology

This is an interactive course. There will be open question and answer sessions, regular group exercises and activities, videos, case studies, and presentations on best practice. Participants will have the opportunity to share with the facilitator and other participants on what works well and not so well for them, as well as work on issues from their own organizations. The online course is conducted online using MS-Teams/ClickMeeting.

Who Should Attend?

This course is intended for electrical staffs who are involved in the operation, maintenance, protection, and control of cables used in power utilities and industrial plants.

Course Outline

Day 1: Glossary, Definitions, and General Conditions

• Introductions, Summary of Course Goals, System
• Types and Historical Perspective, Basic Dielectric Theory of Cable, Electrical Insulation Materials Transmission vs. Distribution

Day 2: Cable Design Part I

• Cable System Planning, Selection, and Characteristics, Cable System Components, Cable Construction Terminations, Splices/Joints, Other Accessories, General
• Design Considerations, Power Transfer Requirements and Rating Criteria, Cable System Type, Route Selection & Rights-of-Way

Day 3: Cable Design Part II

• Cable Design Calculations, Ampacity & Soil Effects
• Pulling Tension, Impedances, Induced Voltages and
• Currents, Magnetic Fields, Manufacturing Considerations,
• Laminate Cables (Pipe-Type, Self-Contained)
• Extruded Dielectric (XLPE, EPR), Installation and Civil
• Design Considerations

Day 4: Cable Testing & Standards

• Prequalification Tests, Factory Acceptance Tests
• Line tracing, Cable and phase identification, Cable test vans and systems, Different maintenance strategies, Testing of PIL and XLPE cables (VLF and DC testing), Diagnosis and partial discharge measurement, Practical exercises

Day 5: Fault Location

• Fault types, electrical and physical characteristics of faults, Analyzing the fault, series or shunt fault, flashover fault, open circuit fault, ground contact fault, ingress of moisture, Principles of cable fault location Insulation resistance, and fault resistance measurement
• Cable fault pre-location: Time Domain Reflectometry
• (TDR), Arc Reflection Method (ARM), Impulse Current
• Measurement (ICE), DECAY measurement, Pinpoint the location of faults and marker location, Sheath testing and fault location, Lightning Protection of Distribution Cable Systems, OHTL Fault Location, and Identification.