Introduction
Statistically, in 1957, service interruptions were split broadly in two between power cuts for work and those due to operating incidents. These power cuts were inconvenient for customers, whose awareness to the quality of supply would increase. In France, the growing concern about quality of service and reducing the number of power cuts for work to be carried out as well as the safety of operators are the main issues that led EDF to undertake studies and then develop Live Working (LW). EDF therefore decided to begin exploratory missions in countries that already use this technique, particularly the USA, USSR and Sweden. The purpose was to examine under what conditions this work is carried out and to study the way it could be transferred to France.
Initially, EDF reproduced the techniques used in other countries but the experience gained rapidly enabled EDF to develop a different technique, unique in the world, based on risk analysis and defining a corpus of safety rules to be better suited to the operation to be carried out. The French method was born. LW in France has been structured around an LW Committee responsible for approving rules and methods and an expert body, SERECT (Design, Execution and Experimentation Section of the Live Working Committee); both were very quickly found to be effective.
LW developed very rapidly in the three voltage levels: LV, HV-A and HV-B. SERECT develops its own tools and invests in research. The behaviour of the air gap is dissected, analysed then turned into rules. This work, which has continued for many years, will give France a head start in LW, particularly working in a damp environment, behaviour of the air gap when a conductive part is inserted (concept of fractionation) or helicopter-based work.
Nowadays, when it comes to electricity, it is no longer considered possible to deprive customers of service continuity. Avoiding power cuts, maintaining a high level of availability for networks, ensuring the safety of operators and third parties, continuously adapting to technical developments: these are the issues in Live Working (LW). Invisible to users, this technique is now essential and forms an integral part of the design of electricity transmission and distribution networks.
Launching the approach in France
The development of methods and tools for carrying out LW at the beginning of the 1960s was made possible by setting up an efficient and responsive organisation with:
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a Technical Committee responsible for summarising work and authorising operating procedures as they were developed and then the rules to be followed when performing LW. This Technical Committee was renamed the Live Working Committee (CTST) in 1966
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an assessment unit supporting the Technical Committee, responsible for drafting these operating procedures then technical working rules, as well as the tools necessary for carrying out LW operations. The assessment unit is SERECT (Design, Execution and Experimentation Section of the Live Working Committee), based near Mulhouse at Wittelsheim (Haut-Rhin).
The Technical Committee is made up of representatives from Distribution, Production, Transport, Research & Development and Occupational Training, which was already considered to play the most important role. Subsequently, the Ministry for Energy was very interested by the approach and appointed a representative to this Committee.
The first studies were based on examining regulations, working methods, standards, conditions for checking equipment and conditions for training operators. Many documents were translated, coming mainly from the United States. The approach was gradual and the first step consisted of transposing methods already used in the countries visited during the exploratory missions, adapting them to the French networks. For some operations on high voltage lines, SERECT ensured the participation of demonstrators sent by American equipment manufacturers such as Chance, Kearney or Holan.
In addition, an experimental network was set up on the island of Ottmarsheim, not far from SERECT. It was used both to develop operating procedures and train personnel. A 63/90 kV network comprising 6 towers, 2 concrete poles, 2 wooden poles with stays and a concrete gantry were completed in June 1964. The ten towers to support 220 kV and 380 kV lines were erected in the same year.
From 1965, two sets of operating procedures were drawn up by SERECT and approved by the Committee:
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A first set of 12 operating procedures covering a standard range of LV connection operations.
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A second set of 28 operating procedures covering an extended range of standard operations on the VHV network.
In parallel, training was undertaken, based on approved operating procedures, at Ottmarsheim for 10 LV distribution centres and at two CRTT (Regional Transmission and Telecommunication Centres) for HV.
Teams are then trained to carry out LW systematically on operated networks. Bringing these new methods into use aroused great interest from all personnel. Health and Safety Committees (HSC) were fully involved in these broader experiments and the HSC coordination commission itself contributed to drafting the basic documents.
The regulatory framework in the history
In 1960, labour regulations regarding electricity distribution in France referred to a ministerial decree established in 1927; the provisions had been developed by the Union Technique de l'Électricité (UTE) and published as UTE 513. This publication prohibited Live Working on installations at voltage greater than 433 V between phases and only permitted restricted Live Working on installations at voltages below this limit.
Decree 62-1454 dated 14 November 1962 relating to protection of workers in establishments using electric currents specified, in article 50, Live Working as the exception and recommended de-energised working.
From 1963, the Technical Committee began to consider a 'Live Working charter' that quickly took the name of Temporary General Instruction (IGP). In 24 June 1965 the Minister for Electrical Energy approved this document, the first regulations opening the way to widespread LW. It came into force on 1 October 1965 for a period of 1 year.
On 29 April 1966, when the IGP was renewed, the Industry Ministry wrote to the UTE, asking it to submit for approval a general IGP no longer restricted to EDF, taking into account the experience gained since application of the first IGP. This update was more difficult than expected, because the first document had been drafted for EDF, a hierarchical company, and not for local distribution companies.
On 1 May 1966 the Technical Committee for Studies in LW became the LW Committee (CTST). This change of name showed the desire to undertake development of LW and progressive generalisation of the practice. The new committee's missions were stated to be: to summarise information gathered in other countries, to direct studies of operating procedures related to LW, to approve operating procedures and special LW equipment, as well as employee training programmes, to draw up drafts of regulatory texts that would appear necessary, as well as general EDF internal instructions.
In 1970, the Live Working Committee completed the regulations known by the title of General Instruction for Live Working; this was then converted to Publication 520 by UTE and approved by the Ministry for Industrial and Scientific Development on 26 October of the same year. From then on, it was no longer restricted solely to EDF use. These regulations were based on the following three fundamental points:
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The use of approved tools and equipment complying with approved operating procedures and the Working Conditions.
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Staff training by an organisation or body approved by the Ministry responsible for electrical power, following approved programmes.
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Inspection and monitoring by management.
From 1974, SERECT was approved to provide training for its operators and for operators seconded to it for experiments in the operation of new live working methods.
In 1982, decree 82-167 of 16 February 1982 relating to special measures intended to ensure the safety of workers against electrical hazards during construction, operation and maintenance of electrical power distribution equipment, confirmed the regulatory framework applicable to live working.
In article 8, it states that a body jointly designated for this purpose by the Minister for Labour and the Minister for Electrical Power approves training programmes, training centres, working methods and tools and safety equipment specially designed for live working. Furthermore, work that could not be carried out according to these working methods should not be performed 'live', unless it is experimental work carried out by a body approved by the Minister for Labour and the Minister for Electrical Power to develop new methods.
The inter-ministerial decision issued on 1 July 1983, designates the LW Committee as the body responsible for approving training programmes and equipment and working methods. SERECT itself is appointed as the body responsible for carrying out experimental work.
Today it is the 1982 decree that governs working conditions on electricity distribution grids, for Live Working or lockout working.
Key dates in the development of LW in France can be found on the timeline.