Identify faults and repair low voltage underground cables and apparatus in the power industry

Overview

This standard is about identifying faults and repairing low voltage underground cables and apparatus in an electricity power utilities environment.  Repair can also apply to restoration of underground cables and apparatus. This could apply to both electrical transmission or electrical distribution networks and could typically apply to voltages from low voltage (LV) up to and including transmission voltages33,000 volts. Networks could be aligned with systems using traditional or emerging energy technologies.

This standard includes confirming instructions, carrying out risk assessments, isolating any live cables, justifying live working and confirming the system is safe to work on, establishing information about faults, carrying out fault diagnosis, carrying out repairs,  testing and checking completed work and completing documentation.

This standard is for crafts persons or technicians working for network owners or operators or their sub-contractors who are responsible for identifying faults and repairing low voltage underground cables and apparatus on electrical networks.  This could be carried out by people with different levels of network operational authorisation, but in each case, they will be required to have the degree of supervision which is required for their individual level of authority.

Performance Criteria

You must be able to:

  1. identify work location using system information and equipment in line with organisational procedures
  2. carry out all work within the remits of own authority and under the supervision of suitably authorised personnel when required
  3. receive and confirm instructions about fault diagnosis and repair activities to be carried out in line with organisational procedures
  4. carry out site specific risk assessments of work areas and condition of cables and apparatus to be worked on, identifying hazards and required control measures in line with organisational procedures
  5. isolate any live cables, check any de-energised cables and that the system is safe to work on in line with organisational operational safety rules
  6. justify when live working is required in line with organisational procedures and carry out all installation and jointing activities in line with organisational procedures for live or deenergised working
  7. communicate the status of fault diagnosis and repair activities to affected parties and designated people when required and in line with organisational procedures
  8. use approved plant, apparatus, tools, equipment and consumables to conduct fault diagnosis and carry out repairs in line with organisational procedures
  9. work in line with health and safety, environmental and other relevant regulations, directives and guidance at all times
  10. establish the position, cause and condition of faults or damage to cables and apparatus, the extent of repairs required and suitable repair methods in line with organisational procedures
  11. carry out fault diagnosis and repair cables and apparatus in line with workplan, safety instructions and organisational procedures
  12. carry out testing procedures before, during and after fault diagnosis and repair activities in line with organisational procedures
  13. check completed repairs comply with organisational specifications and no damage has occurred to nearby cables or apparatus for power or other utilities
  14. complete documentation for fault diagnosis and repair activities in line with organisational procedures
  15. confirm completed repairs meet safety requirements before reenergisation of the network
  16. leave repaired cables and apparatus and work areas in a safe condition in line with organisational procedures
  17. deal with network issues and complications in line with safety and organisational procedures
  18. escalate issues that you cannot resolve to the designated person in line with organisational procedures when required

 

 Knowledge and Understanding

You need to know and understand:

  1. Electrical power principles including three phase alternating current and direct current theories; voltage; types of earthing system on the LV network; dynamic and static engineering systems; application of electrical and electronic circuit theory and interfaces between the system voltage
  2. Electricity network design, construction, capabilities, complexities, operations, boundaries, topologies and control boundaries
  3. Apparatus which makes up the transmission or distribution network and the design, operation, function and limitations of transmission or distribution plant and equipment, substations, transformers, overhead lines, switchgear and auxiliary equipment
  4. Standard terminology, abbreviations and nomenclature in relation to cable and apparatus identification, and cable repair techniques
  5. The regulatory requirements associated with safety while carrying out work associated in power networks on low voltage underground cables and apparatus
  6. Organisational safe systems of work control measures for working on cable that have been made dead, isolating cables, proving dead, cables becoming live from alternative sources, screening from live equipment
  7. How to assess the location, size and condition of site, trenches and excavations and safe procedures for access, egress and working in confined spaces
  8. The general and inherent dangers of working with low voltage electrical systems under outage and non-outage conditions and required measures to address them
  9. Organisational procedures and safety instructions for receiving and confirming operational, network related instructions in normal and fault conditions, including remote and emerging technological advances
  10. The principles of pre task and point of work dynamic risk assessment, when they are required and how to carry them out and record findings
  11. Procedures for live or deenergised working, the steps to justify live working and the processes to follow
  12. Operational restrictions, their purpose and actions to be taken and how to recognise and use physical signage and network diagram indicators
  13. The symptoms and causes of common faults on low voltage underground cables and apparatus
  14. Fault finding techniques including visual examination, physical examination, testing and root cause analysis and how they can be used to identify faults, their position and the extent of repairs or refurbishment required
  15. The implications of repair activity for nearby cables and apparatus including those belonging to other utilities
  16. Who to notify about network related operations, when to notify them and organisational procedures for doing so
  17. Electricity network principles of operation of underground networks in normal and fault conditions and associated protective devices and their indicators in the event of system fault scenarios
  18. Sources of system information and how to interpret them to identify cables, apparatus, points of isolation, earthing arrangements and network running arrangements, fusing and discrimination including system schematic diagrams, geographical records, work instructions, fault logs, protection data
  19. The sequence of processes, procedures, stages and operational safety rules relating to fault diagnosis and repair
  20. The environmental impact of disposal, organisational decontamination procedures and what to do if things go wrong, including the use of spill kits
  21. The approved plant, apparatus, tools, equipment and consumables required for fault diagnosis and cable and apparatus repair on low voltage networks, including time domain reflectometers (TDR), faults sniffer, auto-reclose equipment and insulated tools, and how to obtain, inspect, prepare, carry out pre-use checks, use, maintain and store them
  22. Company specifications for repair including for polymeric based cables, paper insulated mains cables, and other legacy cable types and associated apparatus
  23. Safety, earthing, bonding, cable protection and joint protection materials and where and when they should be applied to prevent damage and moisture ingress
  24.  The purpose of visual, functional and electrical checks and tests for cables and apparatus, when they are required and how to carry them out including for insulation, continuity, voltage, polarity, earth loop impedance, phase rotation
  25. Organisational procedures and systems for recording and storing operational information and to meet cybersecurity and data governance requirements, including role-based access, secure storage, audit logging, data retention
  26. The route to authorisation and supervision at different levels and the training, experience and certification required for your role