EA Technology
Ofcom Response Document
Contents
Page
1
Executive Summary
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2
EA Technology
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3
The EA Technology Lightning Location System
3.1
The “Live” Display
3.2
Historical Data Reports
3.3
Lightning Strike and Lightning Strike Density Plots
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3
4
4
Technical Information
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5
Summary
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EA Technology
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Ofcom Response Document
Executive Summary
EA Technology is one of the UK’s leading power asset management companies, based at
Capenhurst, near Chester. Its origins date back to the mid-1960s, when it was established
as the UK Electricity Industry’s Research and Development facility. The business has since
evolved and developed to its present status as an independent limited company, providing a
wide range of specialist services to the energy sector, particularly to the electricity
Distribution Network Operators and energy Supply Companies in the UK and overseas.
This document is our response to the Ofcom World Radiocommunication Conference 2012
and specifically “Agenda Item 1.16 - Passive systems for lightning detection below 20 kHz”
due to the importance of the EA Technology Lightning Location System.
EA Technology have developed a Lightning Location System which locates lightning strikes
that occur within the United Kingdom and The Republic of Ireland. The system was
originally set up in 1989 to assist the electricity companies detect when lightning had caused
damage to, or danger to personnel working on, overhead power lines. Consequently it was
designed to detect only “cloud to ground” lightning strikes.
Currently the system has a total of twelve major subscribers that include all the Transmission
and Distribution Network Operators within the United Kingdom and others within The
Republic of Ireland, together with major industrial customers.
The system utilises a total of six outstation aerials that are located around the United
Kingdom and The Republic of Ireland, with all using passive detection of electromagnetic
discharges generated by lightning strikes as its basis.
To ensure that this service continues without disruption in the future we ask that you take
into consideration the protection of the frequencies that the system utilises to gain its
information. These frequencies are 1070Hz centre frequency with a pass-band bandwidth of
370Hz, i.e. 700Hz to 1440Hz.
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EA Technology
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Ofcom Response Document
EA Technology
EA Technology is one of the UK’s leading power asset management companies, based at
Capenhurst, near Chester. Its origins date back to the mid-1960s, when it was established
as the UK Electricity Industry’s Research and Development facility. The business has since
evolved and developed to its present status as an independent limited company, providing a
wide range of specialist services to the energy sector, particularly to the electricity
Distribution Network Operators and energy Supply Companies in the UK and overseas.
3
The EA Technology Lightning Location System
EA Technology have developed a Lightning Location System which locates lightning strikes
that occur within the United Kingdom and The Republic of Ireland. The system was
originally set up to assist the electricity companies detect when lightning had caused
damage to, or danger to personnel working on, overhead power lines. Consequently it was
designed to detect only “cloud to ground” lightning. Currently the system has a total of twelve
major subscribers that include all the Distribution Network Operators within the United
Kingdom, including National Grid and others within The Republic of Ireland together with
major industrial customers.
The system is designed to allow subscribers to pinpoint the location of any “cloud to ground”
lightning strike and its possible correlation with any equipment failure/damage. As lightning
strikes can occur in different parts of the United Kingdom and Ireland in split second
succession to one another, the system is capable of detecting up to 100 strikes per second.
The EA Technology Lightning Location Service offers a number of different services to its
subscribers. These include:
•
“Live” display of lightning activity
•
Historic data reports
•
Lightning strike/lightning strike density plots
•
Database searches
3.1
The “Live” Display
All of the subscribers of the “Live” display consider this service essential for the safe
positioning of personnel, particularly in the case of the Electricity Companies who are
performing any maintenance or installation work on high voltage wood poles and steel lattice
towers.
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EA Technology
Ofcom Response Document
Due to their design, high voltage overhead lines are susceptible from both direct and indirect
lightning strikes. The “Live” display allows subscribers to monitor the presence of any
lightning activity within their operational area, any movement of lightning storms within a
specific location and for clarification that a lightning storm has ended. All this information can
increase the safety of subscribers’ staff that could be working on equipment.
A further benefit of the “Live” service facilitates forward planning for maintenance and
remedial work. By monitoring the presence of potentially damaging “cloud-to-ground”
strikes, operators can make allowances for damaged equipment which might need attention
once the storm has passed, increasing efficiency as a whole.
Figure 1 show a typical screen shot of the “Live” display.
Figure 1: Example screen shot of the EA Technology
Lightning Location System “Live” display
3.2
Historical Data Reports
EA Technology records all the strike location information onto a database that can be readily
searched using different criteria. The system has been fully functional since 1989 and the
strike information database has been continually growing since then. Historical data reports
are generated by a subscriber when the lightning strike database is interrogated.
An good example of its use would be the confirmation of correlation between lightning strike
and equipment damage. As the EA Technology Lightning Location System only records
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EA Technology
Ofcom Response Document
“cloud-to-ground” lightning strikes, if the system detected lightning in the area of the
damaged equipment at the correct time, the investigator can be more positive that the strikes
themselves may have caused the damage.
Historical strike data has also been used by both BS 6651: 1999 and BS EN 62305 to give
average lightning strike density figures (Ng) for the United Kingdom and The Republic of
Ireland. Subscribers can also gain location specific lightning strike density figures to allow a
more accurate undertaking of the risk assessment process detailed within BS EN 62305.
3.3
Lightning Strike and Lightning Strike Density Plots
The EA Technology lightning strike database can also be used to generate both country
wide and site specific plots of lightning strike activity and lightning flash density.
An example is shown in Figure 2.
Figure 2: Example plot of Lightning Strike Density
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Technical Information
The EA Technology Lightning Location System works by detecting the Ultra Low Frequency
(ULF) electromagnetic waves created by the electrical discharge when the lighting strike
occurs. ULF emissions have very good transmission characteristics around the earth’s
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EA Technology
Ofcom Response Document
atmosphere and can potentially travel for hundreds of miles before decaying to an
undetectable level.
The EA Technology lightning location system utilises a total of six outstation aerials that are
located around the United Kingdom and The Republic of Ireland. All use passive detection of
electromagnetic discharges generated by lightning strikes as its basis.
When an outstation detects a strike, it calculates the bearing to the strike and records the
exact time at which the aerial detected the strike to within 1 millisecond, using a high
accuracy clock derived from the satellite based Global Positioning system (GPS). By
analysing the waveform of the strike from each aerial, the outstation also calculates the
approximate strength of the strike and its polarity.
Each aerial has a permanent communication link to a central control centre located at the
EA Technology headquarters at Capenhurst, Chester and reports the time, bearing, strength
indication and polarity for each strike it detects. From this information, the geographical
position of the strike is calculated via triangulation.
All aerials are tuned to a centre frequency of 1070Hz, with a narrow pass-band bandwidth of
370Hz and due to the importance of the system, these are the frequencies we would be
interested in protecting from unwanted interference.
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Summary
The EA Technology Lightning Location System has been in operation since 1989 and
provides essential information on “cloud to ground” lightning strikes to its subscribers. In
addition to this, the information gained has been utilised by British Standards in relation to
average lightning strike density across the United Kingdom and The Republic of Ireland.
To ensure that this service continues without disruption in the future, we ask that you take
into consideration the protection of the frequencies that the system utilises to gain its
information. These frequencies are 1070Hz centre frequency with a pass-band bandwidth of
370Hz, i.e. 700Hz to 1440Hz.
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Care has been taken in the preparation of this Report, but all advice, analysis, calculations, information, forecasts and recommendations are
supplied for the assistance of the relevant client and are not to be relied on as authoritative or as in substitution for the exercise of judgement by
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© EA Technology Ltd
EA Technology Limited, Capenhurst Technology Park, Capenhurst, Chester, CH1 6ES; Tel: 0151 339 4181 Fax: 0151 347 2404
http://www.eatechnology.com
Registered in England number 2566313