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Renascence 1985 - 1993
Starting from a higher base, in percentage terms the early years of the period of recovery did not see sales of electricity return to the halcyon days of the fifties and sixties. However, in absolute terms the average increase of nearly eight million units generated per year exceeded the average of the previous period by almost five million. The 178 million units generated in the year that ended on March 31st 1984 was still some 6 million below the record to date, set in 1978/79, but there had been a modest increase over the three years from 1981. The installed generating capacity of 72 MW was adequate to meet the 1984 maximum demand of 43 MW, as well as the highest demand to date of 50 MW, that also had been reached in early 1979.
The forecasts made in the latter months of 1984 concluded that the maximum demand could grow to as much as 60 MW by 1994/95. (It will be seen that this figure was reached a year later than forecast). As a result of the renewed interest in a cable link with EdF, the Board obtained the approval of the French authorities to carry out a survey of that part of the proposed route which would lay within their territory. Following this, in November 1985, Gardline Surveys Ltd. was awarded a contract to carry out a hydrographic survey of a route for a submarine cable between Guernsey and France.
Environmental groups opposed the investigations, primarily on the grounds that EdF obtained a substantial part of its electrical energy from nuclear power. The group maintained that the re-processing of nuclear waste at Cap de la Hague posed a threat to the island, and to buy electricity from EdF would convey the impression that the island supported nuclear generation. The importance to the island of the electricity supply and its vulnerability was probably best summarised by the President of the Advisory and Finance Committee. He commented in a letter to the States"the economic and social life of the island is now dependent upon the supply of electricity, .... the island is therefore completely dependent on the supply and price of oil - matters over which the island has no control".
Despite the protests it was agreed that the study should proceed and as a result of the survey a provisional scheme was planned. This envisaged that a land cable would run from an inverter station at the power station site to a transition connection at Bordeaux harbour. The submarine section would comprise two 60kV, single core, dc cables starting from Bordeaux Harbour and running for some 50.5 km to the bay of Sciotot, just south of Flamanville power station. From there a land cable extension would be laid to a dc/ac converter station, on the outskirts of Les Pieux. A 15-km dual circuit, 90 kV overhead line would then connect from the converter station to the 90 kV EdF grid system at Tolmer.
The survey, carried out in the early months of 1986, revealed that it would not be possible to bury the cables along the whole of the route because of the lack of seabed sediment over the bedrock. To provide the necessary protection, many tonnes of rock would have to be placed over the cable along the most vulnerable parts of the route, to protect it from boats' anchors and beam trawls. Although the high cost of burying the submarine cable remained a cause of concern, in April 1987 it was agreed that on strategic grounds, negotiations with the French authorities and site investigations should proceed, also that tenders for carrying out the work should be obtained.
In the spring of 1985 the maximum demand had risen by 10%to 47.6 MW. A link with EdF could not be commissioned before 1990 therefore, to meet the demand that was expected to develop in the interim period, consideration was given to filling the fourth engine bed in 'C' engine hall. Sulzers had recently introduced an improved version of the 9RNF generator, the 9RTA58, one of which was ordered at the beginning of 1986 with a GEC alternator with a higher output of 14.25 MW. The plant also included an exhaust gas turbine that utilised some 10% of the exhaust gases to drive an asynchronous generator, rated at 480kW when the engine was on full load. In practice, somewhat less was obtained due to the machine load pattern. The additional supply was fed back into the main generator terminals, increasing the overall efficiency of the machine. The Sulzer 9 RTA58 was commissioned in December 1987 bringing the total capacity of the power station to 73 MW of Diesel plant with 11 MW of peak load lopping gas turbine plant in support. The introduction of this new plant had the effect of raising the thermal efficiency of the power station to more than 40%.
In the early months of 1987 the maximum demand increased again, this time by nearly 15% to 55.3 MW. At the same time the units generated during the year ending March 31st reached 207 million, exceeding 200 million for the first time. The maximum demand during the following winter of 1987/88 fell to 51 MW heralding a period of six years during which it varied to an extent not previously experienced. The cold snowy weather of early February 1991 raised it to 58.8 MW, but in 1993 it dropped to as low as 53.5. The 1991 record was not exceeded until 1996.
During the early eighties the Stal Laval gas turbine was not sufficiently reliable for it to be included in the total capacity of the power station when planning future generating needs. In 1985 consideration had been given to a refurbishment program that would have cost £160,000, but even this would not guarantee a completely satisfactory outcome. Eventually, in the following year, when it failed to start on 50% of the occasions on which it was required, some £34,000 was allocated for modifications. This expenditure raised the reliability to a still less than satisfactory 80%.
Once the Sultzer 9RTA58 generating set was commissioned in December 1987 the "C" engine hall was full and the progressive concentration of the undertaking's activities on the site had taken up all of the space available. Earlier in the year Huelin's DIY stores had been purchased for the use of the Building Maintenance Section as their workshops and stores. (Later the building was used to temporarily house a preservation tank containing the remains of the Gallo-Roman vessel known as the 'Asterix'.) It was anticipated that by the year 1991 the demand for electricity would exceed the installed capacity. A final decision on the submarine cable to France awaited the results of on-going investigations, but it was apparent that any scheme to obtain power from EdF would take at least four years to implement. Whatever the outcome of the deliberations on this matter, diesel plant would be required to meet the island's energy requirements during the winter months when the EdF tariff was unattractive. Also, plant would be required in an emergency, if for any reason the link with France should fail. To accommodate this additional plant more land was required and to speed up its acquisition an estate agent was appointed to negotiate the purchase of properties on the East Side of the Hougue Jehannet. Throughout 1989 these negotiations proceeded so that in early 1990 the time had arrived when planning could proceed. In September, the Board approved the project to build"D" engine hall on the newly purchased area.
Demolition of the 18 houses purchased was well advanced by the end of the year.
One of the houses in the Hougue Jehannet being demolished and the slow speed engine being erected in the building that replaced them
The site was handed over to New Sulzer Diesel Ltd in July 1991 under the terms of a turnkey contract. This provided for the construction of a building with foundations for two generating sets. It also included the installation of one generator type 9RTA58 coupled to a GEC Alsthom alternator with an output of 14.5 MW, a gas cleaning plant and an enclosed water loop cooling system. This latter piece of plant would reduce both the water vapour emission and the water consumption. There was also an asynchronous generator connected via an exhaust turbine, similar to that fitted to generating set 4"C". In the interests of safety and to facilitate progress on the project, the Hougue Jehannet was closed to through traffic for the duration of the work. The new set was handed over for full operation in January 1994 bringing the total installed capacity of Diesel plant to a little under 88 MW. The Stal Laval gas turbine had been damaged in the previous November and was out of action and unavailable when the winter load reached almost 56 MW.
Continuing complaints from the public, that the emissions from the power station were causing a nuisance, resulted in further investigations being undertaken to ascertain its cause and extent. In 1984 the chimneys were modified and in 1985 the silencers in"B" engine hall were lagged. Three years later the Board arranged to install permanent monitoring equipment as recommended by Board of Health. In 1992 complaints that, when generators were started in 'B' engine hall particles of corroded material were ejected, prompted the Board to arrange for the chimney flues to be lined with a chrome steel casing.
In the months following the April 1987 decision, to proceed with the planning of the submarine cable link with France, the price of oil fuel fell sharply as a result of the marker price fall in the previous year to $10 per barrel. The thermal efficiency of the plant was improving with the greater use of the slow speed engines, and the cost and difficulty of burying the submarine cables in the seabed were still matters of considerable concern. The combination of these factors tended, again, to cast doubts on the viability of the proposed cable link with EdF. Work on the specifications continued throughout 1987, including a meeting between representatives of the SEB and EdF in October, but by November, when the cost of burying the cable was estimated to be more than £28 million, the Board decided to suspend work on them. In the following February EdF put forward proposals for the installation of a cable that would become operational in 1991. However, by June 1989, when the fall in the oil price had reduced the fuel cost per unit sold to 1.26p, the lowest since the first oil crisis, it was concluded that there was no financial justification for the project, even though the strategic reasons remained in its favour.
The Gulf war of 1991 was a reminder of the island's dependency on a reliable supply of oil at a stable price. Negotiations between the Board and EdF languished until early 1992, but then discussions were reopened, and at the same time talks were held with JEC on the feasibility of a cable link between the islands. EdF continued with the task of formulating a costed proposal for the direct link between Guernsey and France, but was finding it difficult to get approval for the erection of an overhead line between the converter station and the substation at Tolmer. Eventually in mid-1993 EdF, having cleared the obstacles, provisionally estimated that the cost of the project would be around £40 million. The Board considered this to be excessive, and it was decided to seek alternative quotations from submarine cable manufacturers.
While these proposals were being studied the price of oil continued to be volatile. In the year ending March 31st 1985 there were eleven changes that increased the price by 46%. They were caused by a number of factors that included, amongst other things, a decline in the Sterling/US Dollar exchange rate and an increased demand for oil. The long miners' strike resulted in coal burning power stations in the UK being shut down in favour of oil burning plant. The effect, in Guernsey, was to increase the cost of oil for each unit sold to 3.83p. This was the highest annual average fuel cost of the century, exceeding by nearly 18% the second and third highest, experienced in the years immediately before and after the peak year. Early in the second quarter of 1985 there were signs that the tide of price rises was beginning to turn. The miners were back at work thus reducing the demand for oil in the UK. This was followed by disarray among the oil producing countries. By January of the following year the marker price of North Sea Brent crude oil had dropped from US$25 per barrel to $17, and that of Arabian Light oil, from $27 to $24. The effect of these falls was to bring the oil cost per unit sold in 1986/7 down by almost 50% to 1.68p.
The fluctuations in the delivered price of oil had a knock-on effect on the tariffs. An increase of 0.3p per unit on all flat rate and block tariffs on October 1st 1984 was followed on April 1st 1985 by a further 0.4p. This brought the price of the secondary units to 7.4p each. There followed a study of the structure of the tariffs, with the object of achieving a set of charges more closely related to the cost of the service provided to each customer. The review in 1954 had drawn attention to the need for tariffs to be structured so as to ensure that the fixed costs of providing the service would be recovered, irrespective of the quantity of electricity used. That review had led to the introduction of the block tariffs, the principle of which was that the extra income from the first block of higher priced units would meet the customer-related costs. Over the years it became apparent that there were a considerable number of customers whose quarterly consumption was less than the number of units charged at the primary rate. The method in use was therefore demonstrably unsatisfactory.
The Board decided to solve this problem by introducing a standing charge, as had been recommended in the Simmons' report of 1981 and, as had been practised prior to 1954. (Then, the formula for determining the standing charge had depended on variable factors related to the property connected, and unreported modifications had resulted in it becoming defective.) There was no provision in the law allowing the Board to include a fixed charge in the tariff, therefore an amendment was required before a re-structured tariff could be introduced. The States approved the Board's proposals to abolish the two-block tariffs and to replace them with a standing charge and a single unit charge. The new unit charge of 6.9p, down from 7.4p, was introduced with effect from November 1st 1985, but the standing charge could not be introduced until the law had been amended.
This amendment was not registered in the island until March 1986, therefore, for a period of several months customers only paid the revised unit charge. The new quarterly standing charge, of £8 for domestic customers and £10 for commercial, was introduced on March 6th. Also from that date the unit charge was reduced to 6.6p. A few days later the unit charge was cut again, this time to 6.3p and from August 5th 1986 it fell to 5.8p, the lowest unit rate since 1980. The study that initiated this change also revealed that the prepayment meter surcharge had remained at the same level since 1978, it was therefore increased from £3.25 a quarter to £5.75 with effect from January 1986.
The off-peak tariff, introduced in the late fifties to increase the night load, had fulfilled its purpose up to the time of the oil shocks, but after that sales fell. In December 1986, in order to recover the lost night sales, the Economy 7 tariff, which in the UK had helped to move a part of the load from daytime to night, was introduced in Guernsey. Un-like the previous off-peak tariff that charged the normal rate on-peak but a reduced rate at other times, this tariff charged the consumption at two distinct rates, depending on the time of day. The on-peak rate was slightly higher than the normal charge, but the off-peak rate was substantially lower. To accommodate this innovation it was necessary to install special two-rate meters in customers' premises. By late 1987 these had been purchased, tested and installed and the new tariff implemented.
During the last few years of the eighties and the first half of the nineties the price of oil was relatively stable causing the average cost of oil per unit sold to stay below 1.8p for the ten years to 1995/6. However, the cost of other goods, salaries and services continued to rise, as reflected in the Guernsey index of retail prices that increased by an annual rate between 5% and 10%. As a consequence, the low price of 5.8p per unit of electricity only lasted until the end of the year. From January 1st 1987 it rose to 6.1p, a price that lasted only until October 1st, when the need to obtain an adequate return on capital led to a rise to 6.5p per unit. Thereafter, there were annual increases until August 1st 1991 when the standing charge was increased to £11.10 for domestic customers and to £13.80 for non-domestic and the unit rate was raised from 8.2p to 8.9p. From October 1st 1993 the standing charge was reduced to £10 for both classes of customer and in October of the following year the unit price was reduced to 8.75p.
The effect of the over supply of oil on its selling price gave OPEC ministers cause for concern in 1990. They cut back supplies and, at their Conference in July, set a ceiling for production and a minimum price of $21 per barrel. Over the following years the six-monthly meetings of the Conference confirmed the minimum price and attempted to control the market by making adjustments to the production ceilings. These met with only limited success, with the result that the price of Heavy Fuel Oil, which by this time was used to generate virtually all electricity in Guernsey, remained relatively stable for several years.
Over the period covered by this chapter there were a number of changes and modifications to procedures that affected the administration of the undertaking as well as its customers. In March 1985 Henry Lancaster retired from the presidency of the Board and was replaced by Deputy Roger A. Perrot who at the end of March 1988 was succeeded by Deputy Geoffrey Norman.
Also in 1985, an incident occurred that caused the Board to examine its powers under section 12 of the Electricity Law of 1933. This section permitted officers of the Board, in circumstances prescribed in the law, to forcibly enter premises for the purpose of disconnecting the supply. There was concern that the onus of determining the degree of force to be used, should not be placed on the staff who were required to carry out the task. The States, at the request of the Electricity Board, agreed to change the law in such a way as to make it necessary for a magistrate's warrant to be obtained, before an employee of the Board could use force to enter any premises to disconnect the supply.
This period also saw a revision of the Boards training policy. From the early seventies this had been limited to providing courses for existing employees. From 1987 this policy was expanded to include a bursary scheme to sponsor the training of school leavers and mature students who were considered capable of attaining professional qualifications. The intention was that they would thereafter take up appointments with the undertaking. During the following years students were sponsored for courses in Electrical and Electronic Engineering, Mechanical Engineering, Accountancy and Administration.
Over the years there had been a number of occasions in which prepayment meters were burgled, leaving the customer to make good the loss. In 1986 a scheme was introduced whereby pre-purchased cards could be inserted into special meters, thus avoiding storing money in meters that were often situated in vulnerable places. Whilst this card system achieved its primary objective of protecting the customer against loss, it suffered from the drawback of the cost of the control and sale of the cards.
A few years later, in 1993, this system was abandoned and replaced by one using electronic keys instead of cards. In this system, customers who opted for pre-payment meters were issued with a key, containing a microchip that recorded information identifying the customer's account. On payment of an amount of between £1 and £50, and presentation of the key at either of the SEB showrooms' cash desks or external key recharge points, the sum of money paid was recorded on the key. When inserted into the Key Budget meter, electrical energy to the value of the sum paid became available for use by the customer. At the same time the meter reading was recorded on the chip and transferred to the SEB computer when the key was next recharged. This system obviated the need for prepayment meters to be read quarterly, and by early 1995, the electronic key system had replaced all prepayment cash and card meters.
A change in the meter reading cycle had already been introduced in February 1990. Prior to this it had been the practise to read all meters once each quarter in a continuous cycle. As a cost saving measure, all credit meters from this time were read at six-monthly intervals. Estimated accounts, calculated on the basis of the consumption in the same quarter of the previous year, were issued in those quarters when the meter was not read.
On July 29th 1993 the Board decided to adopt with immediate effect, the title"Guernsey Electricity" (GE) as its trade name.
The Chief Fire Officer advised the Board in 1991, that due to low water pressure, in certain circumstances the Fire Brigade would not be able to deal effectively with a fire at the power station site. A new water main was installed in 1992/93, the work being carried out by the States Water Board, Ronez Ltd and Ideal Contractors Ltd. The project comprised a new 200mm water pipe, to supplement the existing 300mm pipe, to deliver water to new hydrants at strategic points, at the rate of up to 7,000 litres per minute. The new pipe, commissioned in 1994, ran in a loop from a connection to the trunk water main in Vale Avenue through the power station site, rejoining the trunk at the Bridge roundabout.
From the time that the 33kV cable link to Kings Mills was first suggested in the late seventies, it had been known that, to meet the generation and distribution needs of the future, a completely new monitoring and control system, using up-to-date techniques and equipment, would be required. The decision to extend the site to the east of the Hougue Jehannet provided the space required and in 1988 planning started. Proposals were prepared for the construction of a new control centre in a custom built two-storey building with a basement. Ewbank Preece Power and Systems Ltd prepared detailed specifications for the technical equipment, and in January 1991 CEGELEC Power Systems was awarded the contract for its supply at a cost of £3.15 million. Concurrently, MGF Ltd was awarded the contract to construct the building that would be situated on the newly cleared area adjacent to the proposed new 'D' engine hall. The basement would accommodate the cable highways, marshalling cubicles and associated control and switchgear. The ground floor would contain the computer installation and offices, with facilities for staff associated with the operation of the centre. The first floor would house the control room with the operator's desk, the generation and distribution console and the transmission and distribution network display board.
General view of the control room with the operator's desk in the foreground
It would also be equipped with monitors connected to closed circuit television security cameras situated in such a way as to provide surveillance of the whole site.
The project was designed to provide a facility for staff to continuously monitor, from large screen visual display units, the operational status of the generating plant, and of the distribution network primary substations. The availability of real-time data would detect abnormal operating conditions as soon as they occurred, enabling remedial action to be taken at an early stage. In addition the work of planning engineers would be considerably assisted by the provision of data showing the simultaneous loads on the primary substations. Prior to the introduction of this system data was acquired by visually reading the loads in substations, which could not be done simultaneously. In order to carry the cables connecting the generating plant, switch rooms and signals networks to the new control centre, a large works service tunnel with a network of ducts was constructed under the road by Miller and Baird Ltd. These would house some 600 control, telecommunication, protection and power supply cables.
In May 1992 training started at Loughborough for members of the staff who would be involved in the operation and maintenance of the control centre. They continued during the following months until commissioning of the equipment in May 1994. At this point, system control was phased out from the 'B' control room and the new centre became the sole point of control for the generation and distribution of electrical energy throughout the island.
In the mid-eighties there was a review of the policy for operating the computer bureau, and also of the equipment it used. The 1901T configuration, installed in June 1975, had been upgraded and replaced in 1981 by an ICL ME 29 computer. In the early years of the eighties commercial agencies were steadily taking over more and more of the bureau work from the Board. At the same time developments in the computer industry had reduced the size and cost of hardware. This made the installation of a computer a viable proposition for organisations that, previously, could not justify the expense of buying and operating their own equipment. In late 1985 the review concluded that a serious breakdown could occur in the accounts section unless the outdated programs, that had been written in the late sixties and early seventies, were re-designed. In addition, the review noted that pressure to obtain income to support the bureau, had caused it to overlook the growing requirements of other sections of the undertaking, for management information and control systems. Accordingly it was decided that this aspect should be given priority in the future.
In accordance with this new policy an ICL Series 3935 computer was acquired in December 1985. This was augmented in 1987 with Series 3945 equipment, with a memory of 125 Gigabytes. Whereas the earlier enhancements of the data processing equipment had done little more than upgrade the capacity of the bureau to do more of the same type of work, the latest change was fundamental. The terminals attached to the old ME29 could only be used to interrogate the computer records, whereas the demand by the mid-eighties was for terminals that could be used to access the records directly. The newly installed computers provided for this, consequently to take advantage of the facilities, the whole system had to be re-designed to accommodate radically modified operating changes, and to introduce security measures that would prevent unauthorised access to records.
Under the old system the data was entered in batches allowing the operating staff to plan the workload to meet the capacity of the main frame computer. By allowing the user departments to update records the computer operating staff lost control of the workflow and the batch processing procedure had to be replaced. The revised system would have to be designed to accept a stream of data from many sources and to make the records available for interrogation by authorised users.
Work on updating systems, that was expected to take several years to complete, began in 1985. The older type 'read only' terminal facilities were replaced with interactive workstations to bring users on-line. In 1987 the task of re-writing programs had progressed to the stage at which more than 150 terminals were in use, and to mark the change in emphasis, the title of the section was changed to Information Technology (IT) section. Over the next few years both the old and the new computers were used to operate the two procedures. There was a continuing programme of re-writing the old systems, transferring records from the old to the new computer and introducing new applications to improve the efficiency of the administrative functions. These improvements included recording personnel records, the preparation of contracting section job sheets and the control of work in progress.
In 1992 the Series 3945 computer was replaced with a DX270/20. The extra work of building enhancements into systems when re-writing them stretched the time taken to effect the changeover. As a result it was not until 1994 that the last systems, CAB (Customers and Billing) and SAM (Services and Meters), were finally transferred to the DX270/20 and the integrated MIDAS system was introduced. The IT section then ceased to provide a service to external users and the Series 3935 computer was de-commissioned.
With daytime batch processing phased out, the operations unit of the section worked to an entirely different routine. In this the interactive service closed down at 7.00pm each evening, and the automated batch service processed the data collected during the day. It then printed bills, cheques and such other information as required. On completion of this work the computer reverted to its interactive daytime service.
In 1987, ICL was no longer able to support the CARDS system, introduced in 1976, which mapped the distribution network. Considerable work had been done on both the maps and the cable records and, in order to complete the project the data was transferred to a new SUN Microsystems series 3 computer. This new equipment was independent of the IT section and was situated in the Electrical Engineering Planning office using ICL software, "Distribution Network Information System" (DINIS). The new system, that was renamed Geographic Information System (GIS), the generally accepted term for this type of project, also provided network analysis support for the planning engineers via a workstation, and assisted in minimising the high voltage, distribution system power losses. Later, in the early nineties the DINIS system was replaced by the more sophisticated SYSDECO system.
Until the mid-eighties cash balances, that were surplus to requirements for a short period, were deposited with local banks. The increased cost of major capital projects meant that larger sums were accumulated between stage payments on contracts, and were available for investment for short periods. The sums reached the level at which the facilities of the inter-bank market became available; these only dealt in large sums but yielded a higher rate of interest. In July 1985, at a time when there was a call for greater efficiency from States Committees, the Electricity Board decided to take advantage of this market and appointed brokers to advise it. One of the brokers recommended the Bank of Credit Commerce and Industry (BCCI) as a suitable recipient for deposits of cash balances that were not immediately required. After making the usual enquiries, the bank was used on a number of occasions from the late eighties. In the financial year ending March 31st 1991 the income from investments amounted to approximately £700,000.
At noon on Friday July 5th 1991 the Bank of England cancelled the authority for BCCI to accept deposits, effectively forcing it to close. It was claimed, by some sources, that at the time the bank had some 140,000 creditors, world wide, and had liabilities of up to £10 billion. At the date of closure the Electricity Board had £5.35 million on deposit with this bank, but £1 million of this had been accepted by BCCI at 2.17 p.m. on July 5th which was after it should have ceased trading. This deposit was returned in 1993 with interest to the date of return.
Liquidating the affairs of the bank was a protracted and involved affair, including civil and criminal lawsuits that went on for several years in many countries. In Britain, the House of Commons set up an official enquiry that led to criticism of the Bank of England's role in the affair, but which fell short of recommending that the British Government should compensate depositors for their losses. Geoffrey Norman, president of the Electricity Board, informed the States at its meeting on July 31st 1991 that the members of the Board, as trustees for the funds of the undertaking, accepted some responsibility for the potential loss and offered their resignation en masse. This was accepted and the States proceeded to appoint new members, with Deputy William (Bill) Bell as the president.
Although the main concern of the electrical engineering department during this period was the design and construction of the new control centre, the transmission and distribution systems were given considerable attention. The storms of early 1985 brought down several overhead power lines, interrupting the supply to a number of properties. This served as an impetus to accelerate the removal of overhead lines whenever possible, a process that had been going on for more than ten years, but without the sense of urgency that it now needed. Any doubts that may have existed about the wisdom of this new policy were dispelled on the night of the 15th/16th October 1987, when the damage caused by winds gusting to hurricane force was not fully repaired until five weeks after the event. It was then decided that a programme of work should be introduced to replace all overhead lines with underground cables over a period of the next fifteen years. Nearly 30 kilometres of overhead lines had been replaced by the end of 1993.
During the years 1984 to 1986, a series of faults occurred in sections of some 110 kilometres of 11kV cable supplied by AEI Cables and installed between 1960 and 1967. An examination revealed a breakdown of insulation in some drum lengths. Because of the cable problems experienced by the JEC some ten years earlier, when as many as fifty faults had occurred in a single year, the Board thought it prudent to carry out further investigation. The Electricity Council Research Establishment at Capenhurst examined a sample of the cable from Guernsey and advised that the faults were the result of failures of the insulation materials. Further tests carried out by Dr. Ross Mackinlay from Capenhurst, in January 1987 indicated that the cables were in a better state than had been anticipated. As a result a limited cable replacement programme followed while further tests were carried out during the years to 1993.
By the year 1987 only a few small areas, in the Vale Castle, Petit Bot and Jerbourg districts, were still supplied by 6.6kV cables. The former were changed over in 1988 but the last mentioned area was the most difficult to replace, yet was urgent since the cables were 50 years old. As the peninsular was only accessible by a single road, there was no alternative route for traffic during the time that excavations were obstructing passage, therefore the work could not be done without considerable inconvenience to local residents. After lengthy discussions with the St. Martin's constables and the residents of the road the work started in January 1989. It was carried out each Saturday and Sunday from January 7th to March 18th during the hours between 8.30 am and 5.00 p.m. To help to alleviate the inconvenience during the hours of disruption, Mr. Henry G. Goodeve allowed residents affected to park their cars at the rear of his property.
At 1.35 pm on April 9th 1987 the mercury arc rectifier at Les Amballes substation was disconnected. This being the sole remaining item of dc distribution equipment, the disconnection was another milestone for the undertaking, bringing to an end a period of eighty-seven years during which a direct current supply of electricity had been available. The dc supply had been kept in operation for the last few years to provide power to dc motors that operated the bottling plant at Randall's Brewery. Once the motors had been changed for ac plant the dc supply was no longer needed. To mark the occasion Mr. Monty Randall was invited to be present when the system was closed down. It was Mr. R H Randall, his grandfather, who had introduced electricity to the Island, in 1887. Then, to celebrate the golden jubilee of Queen Victoria's reign, he installed the first dynamo, the Silvertown, to generate electricity to illuminate lamps in St. Julian's Avenue. Later the Randall family committed the dynamo to the care of the Candie Museum, where it was placed in storage. In 1913, the brewery was connected to the public supply, which at that time was operated by the Guernsey Electric Light and Power Company.
The transforming capacity of the island's substations was increased by 31 MVA to 128 MVA between 1984 and 1993, by the addition of 38 substations, bringing the total to 329. Much of the network was upgraded, particularly in the St. Peter Port area and in the year ending March 31st 1988 two, sixty-two years old 6.6kV feeders to the town were abandoned. In the following year the main 6.6kV switchboard at the power station was decommissioned along with 5 kilometres of 6.6kV cable.
Also in 1989 a new 33kV substation was built on the old power station site at Les Amballes where two - 12/24 MVA, 11/33kV transformers were installed. This was followed by the installation of two 33kV 185 sq. mm. 3-core feeders with stranded copper conductors from the power station to Les Amballes substation. The first fibre-optic communication cable to be used by the undertaking was laid with the feeders, to provide power system protection and to transmit data to the control centre at St Sampson's.
In 1990 the reinforcement of the network in the town area continued. At the Albert Pier substation a new SF6 insulated switchboard was commissioned and two - 300sq. mm. 3-core aluminium 11 kV feeders were installed along the sea front to Les Amballes substation. Sulphur hexafluoride (SF6), an inert gas with excellent insulating properties, was one of a recently introduced type of non-volatile agent, that became available to replace potentially troublesome oil as the insulating medium in modern switchgear.
This period also saw a surge in efforts by the British regulating authorities, to improve safety in electrical installations. In 1991 the Institution of Electrical Engineers updated their 15th Edition of Wiring Regulations, issued in the early eighties, and published the 16th Edition, entitled 'Requirements for Electrical Installations'. In the following year these regulations, with minor alterations were issued as a British Standard, BS 7671:1992.
The commissioning of the"D" engine hall and the control centre in 1994 brought to an end the period of intense development of the St Sampson's site. It had been extended by the acquisition of land bounded by the Hougue Jehannet, North Side, the States Works department and Cognon Lane. The St Sampson's site had started its life as a part of the island's electricity supply system in 1902. A small plot was then acquired for the purpose of establishing a substation, from which power could be distributed initially to the stone quarries. Over the years more areas of land had been acquired, in the first place on the western side of the Hougue Jehannet but later, in 1962, the first plot on the eastern side was purchased for use for bulk oil storage.
By 1987, after further acquisitions, the programme of bringing together the operational centres of all departments of the undertaking on the one site was complete. The retail sales unit and cashier, which was still situated at its old site at the Albany, rented until the year 2002, was the only unit operating from outside the headquarters and power station complex at St Sampson's. The contracting section and the mains section of the electrical engineering department, with their workshops and stores had moved onto the site in 1984, opening the way for the sale of the Les Amballes site in 1985 and of the Bouet property in the following year. In 1989 the offices had been extended and another appliance sales outlet, with cashier, had been established at the main entrance to the headquarters building. At the time that this latter development was being planned, the Bridge sub-post office was in danger of being closed. To ensure that this facility would continue in the district, which by then was dominated by the presence of the electricity supply undertaking, the Board agreed to re-locate the sub-post office in its showroom area.