scottish power quality of supply report 96-97
TRANSCRIPT
1996/97
Quality of Supply Report
Message from the Managing Director, Power Systems 2
Report Highlights 3
Company Profile 3
Quality of Supply Developments 4
Company Targets 10
System Performance 1996/97 11
Targeting Investments 1997/98 17
Capital Expenditure 19
Analysis of System Performance 1996/97 22
Glossary of Terms 23
How to Contact Us 25
Contents
1
A message from Alan Richardson, ManagingDirector, Power SystemsIn this third Quality of Supply report we review the quality of supply we provided to our customersduring the period 1 April 1996 to 31 March 1997 and include details of the improvements we willdeliver to our customers by the year 2000. In the report we examine the past and future capitalinvestments which are aimed at improving the quality of service experienced by customers.
1996/97 has been an eventful year in ScottishPower. Our area suffered from two of the worststorms that we can remember. On 6 November the south west of Scotland experienced one of theworst gale force storms for more than 20 years with wind gusts of more than 85 mph. Just fourweeks later, the south of Scotland suffered from a snow and ice storm which caused massivedisruption to the affected communities and caused the most damage to our network that we haveever experienced from a single event. Restoring supplies required the efforts of more than 1000staff including 300 from our Manweb division and other contractors. All these staff displayedremarkable dedication to customer service in the most arduous conditions. The effects of this stormare discussed in this report.
Our business strategy is to deliver continuous improvement in quality of supply and our target is toreduce ScottishPower Customer Minutes Lost (CML) per connected customer by around 20% fromthe 1991/92 levels by year 2000. We are well on the way to achieving this and we will continue toreview these targets to ensure our customers receive the highest possible quality of supply.
Customer service is our primary objective, this includes a strong commitment to improving thereliability of our network and the quality of supply provided to our customers through our investmentsin the distribution system. Much of this investment is targeted towards our customers who live in ruralareas and is described in detail in this report. However we are upgrading our urban networks withprogrammes to refurbish buildings and replace switchgear as equipment reaches the end of its usefullife. Our engineering group work closely with manufacturers, encouraging development of newequipment and technology to bring the best possible benefits to our customers, at stillacceptable cost.
At the time of preparing this Report we suffered a tragic accident which occurredon the evening of Tuesday 15 April 97 at Barrhead substation, south ofGlasgow. Three of my staff were carrying out routine checks at the substationwhen an explosion occurred in a piece of 11,000 volt equipment. Two staffsuffered fatal injuries and the third was seriously burned in the explosion. Theentire company was deeply shocked and saddened by this tragic incident anda full inquiry is underway to identify the cause of the event. I know that all staffjoin me in extending my deepest sympathy to the families of those involved.This cruel reminder of the power and danger of electricity strengthens myresolve to ensure our network continues to be maintained to the highestsafety and quality standards.
If you have any questions or comments following your study of this reportplease contact the Regional Manager at your local regional office. Detailsof how to contact us can be found on page 25 of this report.
2
Report highlights
Company profile
© Underlying CML per connected customer down 6.7% on 1995/6to 61.9.
© Two periods of exceptionally severe weather add 47% to supplyhours lost due to all the remaining unplanned incidents in 1996/7.
© Investment in Outage-Free working methods which allow work onlive 11,000 volt overhead lines have avoided around 60,000customer supply interruptions.
© Total outage time caused by planned work reduced by 55% since1992/3.
© First installation of insulated 11,000 volt overhead lines completed.
© As a result of the December 96 storm, stronger overhead lineconstruction specification to be piloted during 97/8.
© New incident recording and customer monitoring systemintroduced in April 97.
ScottishPower distributes electricity to
more than 1.8 million customers in 23,000
square kilometres stretching from Newport-
on-Tay and Helensburgh in the north to
Stranraer and Holy Island in the south.
This geographical area comprises
contrasting topography from the densely-
populated industrial and urban areas of the
Clyde/Forth Valley to the exposed and
sparsely-populated areas of the Borders
and Dumfries and Galloway.
The map shows our four Regions and
illustrates the differences in customer
numbers and type of network used to
provide supply.
3
413,952
16,048km
573,777
12,359km
140,353
13,823km
Customers
Overhead Network (km)
Underground Network (km)
S O U T H E R NR E G I O N
W E S T E R NR E G I O N
F O R T HR E G I O NC L Y D E
R E G I O N
675,98320,850km
4
Quality of supplydevelopment
Independent research, commissioned by ScottishPower during 1996, has
shown that 84% of ScottishPower customers are either satisfied or very
satisfied with the reliability of the supply they receive. This reflects the
effort we have made to improve the service we provide. Customers also
tell us that we should be easy to contact and should keep them informed
when there are problems. We have therefore introduced our 24 hour call
centre.
The same research confirmed that reliability of supply remains a concern
of customers and that when an incident does occur customers expect a
prompt response. Short interruptions of a few seconds are inconvenient,
although the majority of customers see them as being preferable to
longer interruptions.
This section describes some of the developments we are introducing to
improve all aspects of our service and reliability and to address customer
concerns.
Network Management When an incident occurs on our network which disrupts the supply to
customers, it is important that customers can contact us easily, advise
us of their circumstances and obtain information about what action we
are taking. Our Customer Service Centre now provides an improved
24 hour service, for customers to report problems with their supply on
0845 27 27 999. Calls to this Call Centre are dealt with quickly and
efficiently to make sure that customers are given accurate up-to-date
information.
In January 1996, we opened a new Power Systems Management Centre
(PSMC) in Hamilton at a cost of £5m to improve our efficiency and
management of all incidents and planned work. Since then we have
extended the system to our regional centres to allow us greater flexibility
in managing our network.
The PSMC includes a Control Room which uses a modern computerised
network management system to control all network operations, and a
Despatch Centre which provides dedicated staff to co-ordinate the
activities of all our emergency staff. The duration of an outage depends
on how quickly our field staff can rectify the problem, but more than 80%
of our customers affected by incidents are now restored within three
hours. To accelerate our supply restoration capacity we are investing
£7m in distribution automation which will complete the fitting of remote
control and alarm monitoring facilities at all 440 main substations. This
work is on target to be completed by the end of 1998.
5
To improve our ability to accurately record incidents and identify those
customers who suffer repeated interruptions to their supply, we are
developing a new incident recording and customer monitoring system at
a cost of more than £500,000. This system was implemented at the
beginning of April 97 and will be enhanced during 1997 to improve our
monitoring of the worst served areas.
Planned WorkScottishPower and Manweb are leaders in the field of Outage-Free
working and the Company integration has strengthened this experience.
Special equipment and techniques have been developed to keep
customers on supply while allowing us to conduct routine maintenance.
This has resulted in a 55% drop in CML due to such planned
interruptions, although we are conducting more maintenance. We now
have 10 Outage-Free teams operating which have contributed to the
significant reduction in CML shown on this graph.
Short Supply InterruptionsMore than 60% of all incidents on 11kV overhead lines cause no
damage to our equipment, providing the supply is disconnected
quickly. Following the incident, the supply can usually be restored
simply by re-energising the circuit. In the past, this required an
engineer to visit the substation and close the switch manually which
would typically have taken about one hour.
We have invested in automatic pole mounted switches which can be
programmed to re-energise the supplies. These pole mounted
switches each control relatively small sections of our network to
minimise the number of customers who are affected by a particular
incident.
Customers benefit by having their supply restored within a few seconds
where in the past they would have typically been off for at least an hour.
16
14
12
10
8
6
492/3 93/4 94/5 95/6 96/7
Financial Year
Pre-Arranged CML
Pre
-Arr
ang
ed C
ML
per
Co
nn
ecte
d C
ust
om
er
Pre-Arranged
6
Our market research tells us that customers see short-term interruptions
to their supply as preferable to a longer time without supply. However we
are aware that even a short interruption in supply is inconvenient. Modern
electronic equipment often needs to be reset if it is unable to
ride-through these short interruptions. Under European
legislation manufacturers are working to make their equipment
operate correctly during such supply interruptions.
We aim to collect accurate statistics on the performance of our
network and we are undertaking trials of equipment, similar to
that shown here, which will provide us with the ability to monitor
short-term interruptions. These Power Fail Monitors were
installed last year as part of a programme to develop a
reporting system. This work will continue during 1997/8 to
ensure our information is accurate and reliable. Many circuits have
measured no short interruptions and others have shown between 1 and
20 for the year. We wish to refine this work before reporting the results.
We plan to provide an indication of the number of short term interruptions
experienced by customers in our 1997/8 Quality of Supply Report.
Protection of Overhead NetworksDuring 1996/7 we continued installing our revised overhead line
protection which uses electronic links, in conjunction with pole mounted
automatic switches, to replace 11,000 volt fuses. These electronic links
are more reliable than fuses during transient events such as lightning
storms. The additional pole mounted switches help minimise the number
of customers affected by permanent incidents.
An example of the benefits we obtain from this targeted investment is
shown in the graph. This shows that following the application of our
overhead line protection policy to the 11,000 volt lines out of Dalbeattie
primary substation in 1993/4, the level of customer hours supply lost due
to non-damage incidents has fallen to less than 3.5% of its 1993/4 level.
5000
4000
3000
2000
1000
091/2
Overhead Protection – Applied to Dalbeattie Primary 93/4
‘No
n-D
amag
e’ C
ust
om
er H
ou
rs L
ost
92/3 93/4 94/5 95/6 96/7
120
100
80
60
40
20
091/2P
erce
nta
ge
Dam
age/
No
n-D
amag
e C
HL
92/3 93/4 94/5 95/6 96/7
Damage Non-Damage
7
By the end of 1996/7 we had installed this equipment on more than 190
circuits. Some of those which benefited from this equipment during
1996/7 are indicated on page 16 of this report. This program will be
completed during 1997/8 with a further 50 circuits being targeted.
Automation of Supply RestorationRural villages, often far from one of our 440 main substations, are
supplied by an 11,000 volt overhead line. Incidents on these high voltage
lines can result in the supply to the village being lost until staff arrive to
isolate the incident and restore supplies.
Many villages however, have an alternative supply available in the form of
a second high voltage overhead line. We have an ongoing programme of
installing new equipment to automate the restoration
of supply. This system detects the loss of supply to
the village and having checked that the incident is
not within the village network, signals the electrically
operated pole top switches, to operate and restore
supply to the village. This takes 30 - 60 seconds.
Already these schemes have avoided around
60,000 customer hours of supply loss, equivalent to
two CML for the Company, by their operations.
During 1997/8 we plan to install this equipment to
benefit 10 villages in the ScottishPower area.
GeneratorsLive working on 11,000 volt overhead lines will
substantially reduce pre-arranged interruptions to customers’ supplies but
some tasks are not possible to safely complete on live lines. Similarly
there are other types of high voltage equipment, such as cables,
transformers and switchgear which are not suitable for live working
techniques.
In these situations it may be possible to use a generator to maintain
supply to customers while working safely on equipment. We plan to
increase our use of generators in this way. We have developed
techniques which allow generators to be used at high voltage without
even a short interruption of customers’ supplies to allow the generator to
be disconnected. This approach will allow us to maintain supplies to
groups of customers affected by our rural upgrading programme.
Dunscore
Greenlaw
Aberlady
ColdinghamGifford
WanlockheadLeadhills
Colinsburgh
Crossford
Milton ofCampsie Slamannan
Pathhead
Tweedsmuir
GordonSt Boswells
8
Overhead Line Reconstruction Extreme weather events, such as the snow storm in the Borders on
3/4 December 1996 and a similar event in our Wales region of Manweb
on 19 November, are unpredictable and cause enormous disruption to
our network and to the local communities. Prolonged outages, often for
several days, while we rebuild and repair the damaged poles and
conductors are not compatible with the level of service we intend to offer
our customers.
Following these two such events an investigation was undertaken to
identify what actions could be taken to minimise the impact of future
extreme weather events. The investigation identified that, in general, the
equipment which failed during the storms did so because it was stressed
beyond its design limits by the combination of snow, ice and wind.
It concluded that to reduce such equipment failures in similar severe
storms it is necessary to build much stronger overhead lines than those
which were constructed by the nationalised electricity companies.
The bulk of lines in use today were constructed when electricity was
expanded into rural areas in the 1950-1960's era.
ScottishPower's policy to conduct a systematic refurbishment or
rebuilding of overhead lines will continue. We have identified that around
half of our overhead lines, supplying the most heavily populated areas,
will be rebuilt to a much stronger specification. This programme will take
many years to complete and we will seek agreement from OFFER for its
future funding. We have begun this programme and propose
concentrating our pilot schemes in our Borders area.
Landowner permission together with planning authority approval is
necessary for such work and this is proving ever more onerous.
However, we will continue to pursue our policy of building stronger
overhead lines to bring better supplies to rural communities.
9
Insulated Overhead LinesTraditionally UK overhead lines, as in most other countries,
have utilised bare wire construction. Although this has many
advantages, particularly cost, it can experience transient
damage due to gales, tree contact or bird strikes. We have
completed our first pilot installation of insulated conductors,
at Drummore near Stranraer, where 10.5km have been
installed. The results of this pilot will allow us to finalise
specifications and our future programme.
We believe the selective use of insulated conductors will
improve the reliability of our supply, particularly by reducing the short
interruptions experienced by customers.
Power Quality MonitoringVoltage dips occur on all power systems as a result of system incidents,
e.g. cable damage, lightning strikes, etc. The increasing sophistication
and sensitivity of computers, process control equipment and power
electronics in recent years has increased the problem of equipment
failure as a result of these voltage dips.
Modern equipment should be designed to ride-through many of these
disturbances and European legislation exists to guide equipment
manufacturers in the types of power quality problems that may occur on
a public supply system. Customers who rely on modern electronic
devices should seek guidance from
equipment suppliers on what voltage dips
the equipment can ride-through and how it
should be protected.
Voltage dips particularly affect our major
process and service industry customers
who are concerned about losing many
hours of production because of these
supply disturbances which last less than
one second. The ScottishPower area has
one of the highest concentrations of
semiconductor manufacturing facilities in
Europe, for example 38% of all European
PCs are manufactured here, and we are
addressing these customers' concerns by
monitoring power quality. Our monitoring
equipment produces power quality reports, showing the number, duration
and severity of voltage depression, which we use to ensure we deliver
high quality supplies and to assist customers in understanding their
internal protection needs.
SPline
BT line
Satelliteclock
Display Stationdatabase
NU
MB
ER
OF
DIP
S
VOLTAGE
R
ETAINED
DURATION
Our strategic goal is to deliver excellent customer service and ensure a
continuous improvement in the availability, reliability and security of
supply. We have system performance targets to demonstrate this
improvement, the most notable of which are:
© By 2000, to reduce total underlying CML per connected customer by
20% compared to 1991/2 to between 55 and 65 minutes.
© By 2000, to reduce total underlying customer interruptions to between
45 and 55 per 100 connected customers.
© By 2000, to target improvements to those customers who experience
more than an average of three unplanned incidents in each separately
protected section of HV network used to provide their supply.
These company targets are consistent with regional performance in line
with the tables below:
AvailabilityCustomer Minutes Lost per
Region connected customer by 2000
Clyde 37-43
Forth 58-70
Western 60-72
Southern 145-175
SecurityInterruptions per 100
Region connected customers by 2000
Clyde 32-36
Forth 55-65
Western 47-55
Southern 105-125
This report shows that the underlying performance of our network is well
on the way to achieving these targets. However, the unusually severe
snow and ice storms of the previous two winters have masked the
underlying improvement in our reported figures. We have described in
this report the actions we are taking to achieve our targets and reduce
the impact of future severe events. Through these efforts we expect the
improvements to continue.
We will however continue to review these targets to ensure our
customers receive the highest possible quality of supply.
10
Company targets
COMPANY SYSTEM PERFORMANCE
Key Improvements© Underlying CML per connected customer down 6.7% on 1995/6 from
66.3 to 61.9.
© Customer Interruptions (CI) per 100 connected customers down 13%
on 1995/6 from 65.5 to 57.0.
© Pre-arranged CML per connected customer down 38% on 1995/6
from 9.9 to 6.1.
© Investment in Outage-Free working methods which allow work on live
11,000 volt overhead lines have avoided around 60,000 customer
supply interruptions.
1996/7 Extreme WeatherDuring 1996/7 the ScottishPower area suffered two short, but
exceptionally severe, periods of bad weather which caused enormous
disruption to local communities and to our network. This graph plots the
number of HV and EHV incidents we experienced each day last year and
the impact of these storms is clearly visible.
On the 6 November 1996 the Western region suffered from severe winds
which gusted to more than 85 mph, amongst the worst for more than 20
years. These gales caused 188 incidents on our HV and EHV networks.
On the 3 and 4 December 1996 southern Scotland was subjected to a
severe snow and ice storm which caused extensive damage to our
network. This caused 300 incidents on the HV and EHV systems and was
centred on our Borders area as shown in the diagram overleaf. The
damage caused to overhead lines by this storm was the worst that
ScottishPower has ever experienced from a single event. The storm
caused more than 400 wooden poles and steel towers to snap or buckle
and conductors to break at 800 locations.
11
System performance 1996/7 (See also Tables 1-3 on page 22 of this report)
400
300
200
100
0April 96 March 97
3 & 4/12/96Ice Storm
6/11/96Gales
Number of HV & EHV Incidents per day
The region's emergency plan was activated and at the peak of the storm
more than 1000 staff, including 300 from Manweb and outside
contractors were involved. Our contingency planning successfully allowed
us to use these resources to restore the supplies to 40,000 customers
affected by the storm.
Despite all the efforts to restore supplies quickly during both these
storms their combined effect was to add 26.7 CML to the company's
performance, which represents 48% of the underlying CML performance
for the whole year.
AvailabilityThis graph clearly demonstrates the impact of the storms during 1996/7
which have been described earlier and which added 26.7 CML to the
1996/7 total. During 1995/6 severe lightning, wind and snow storms
including the snow storm in Dumfries and Galloway during February,
which triggered the Local Authority Emergency Plan, added 14.7 CML to
the 1995/6 total.
Over the past five years the underlying availability of supply due to
unplanned interruptions, measured in CML, has improved by 33%.
The underlying trend is shown in this graph by the 'weather corrected'
line, which shows that we are on course to achieve our year 2000 target.
12
120
100
80
60
40
20
092/3 93/4 94/5 95/6 96/7 97/8 98/9 99/00
Financial Year
Availability
CM
L p
er C
on
nec
ted
Cu
sto
mer
Total
All Faults
Pre-Arranged
Target
Weather Corrected
Edinburgh
Dumfries
Stirling
Kilmarnock
> 50,000
20,000 – 50,000
5,000 – 20,000
2,500 – 5,000
Key – CHL
CustomerHours Lost by PrimarySubstation
SecurityOver the past five years the impact on security of supply from unplanned
interruptions, measured in CI, has improved by 29%.
The graph shows we are on course to achieve our year 2000 target.
Quality of ServiceAs soon as we are aware that an incident has occurred which disrupts
supply to customers we respond as quickly as possible. To help us
monitor our speed of response we record the time it takes to restore
supply to each customer and we have a target to restore 80% of supplies
within three hours and 99% of supplies within 24 hours. During 1996/7
we exceeded both of these targets by restoring 80.6% of all supplies
within three hours and 99.1% of all supplies within 24 hours.
Voltage Complaints (See also Table 4 on page 22 of this report)
Domestic customers make up the majority of our 1.8 million customers
and receive their supply at 230V. European legislation requires this
voltage to be between minus 6% (216.2V) and plus 10% (253V).
We design our networks to maintain supply within this band under normal
circumstances. However, due to increasing load on our network for
example, customers may complain to us about voltage problems.
Last year we investigated 1005 complaints, found 521 were valid and
took action to rectify the problem. To ensure we rectify these problems
quickly we have a target to rectify 95% of verified voltage complaints
within six months. During 1996/7 we exceeded this target by rectifying
513 voltage complaints, equal to 98.5%, within six months.
13
100
80
60
40
20
092/3 93/4 94/5 95/6 96/7 97/8 98/9 99/00
Financial Year
Security
CI p
er 1
00 C
on
nec
ted
Cu
sto
mer
s
Total
All Faults
Pre-Arranged
Target
Weather Corrected
REGIONAL SYSTEM PERFORMANCE
Key Improvements© 1.66 million or 92% of ScottishPower’s 1.8 million customers
experience supply security and availability better than the national
average.
© All Regions achieve a minimum of 31% reduction in Pre-arranged CML
between 1995/6 and 1996/7.
AvailabilityThe vast majority of ScottishPowers' customers, 1.66 million or 92%,
reside in either the Clyde, Forth or Western regions. These customers
experience an availability of supply which is better than that received by
the average customer in the UK.
The graph shows that the supply reliability of the remaining 140,000
ScottishPower customers, who reside in Southern region, is extremely
dependent upon the weather. In 1996/7 the storms in November and
December accounted for more than 70% of the total CML during the
whole year.
The underlying performance of the network in Southern region is close to
the national average and the improvement due to our continued efforts
and investment can be seen. As a result of the storms we have
experienced, and their unacceptable impact on the performance of our
network, we are taking action to construct overhead lines which are more
resilient in extreme conditions. The work we are undertaking was
described on page 8 of this report.
14
400
300
200
100
0Clyde
1995/6 National Average
Forth Western Southern
Regional Unplanned CML
CM
L p
er C
on
nec
ted
Cu
sto
mer
95/6
96/7
Storm Contribution
15
SecurityIn general, our rural customers are those who are least well served.
This is demonstrated by the figures for our Southern region which serves
predominantly rural communities. It is for this reason that the majority of
our investments which are specifically aimed at improving the quality of
the supply we provide, are targeted at our rural area.
Again the impact of the storms is highlighted in the above figures
together with the national average. It is clear that the vast majority of
ScottishPower customers experience a supply reliability significantly
better than the national average.
Pre Arranged CMLThe improvement due to our investments in Outage Free working,
described earlier, can be seen in the graph with all regions showing a
minimum of a 31% reduction in CML due to pre-arranged supply
interruptions between 95/6 and 96/7.
These latest improvements continue the downward trend since 93/4
when we started Outage Free working. Southern region have halved the
supply minutes lost to our rural customers over this period.
200
150
100
50
0Clyde
1995/6 National Average
Forth Western Southern
Regional Unplanned CI
CI p
er 1
00 C
on
nec
ted
Cu
sto
mer
s
95/6
96/7
Storm Contribution
100
80
60
40
20
0Clyde Forth Western Southern
Regional Pre-Arranged CML
CM
L p
er C
on
nec
ted
Cu
sto
mer
93/4
94/5
95/6
96/7
16
Region Circuit Proposed Work Update
Forth Blackburn Overhead line protection Completed
Forth Menstrie Overhead line protection Completion July 97
Forth Carberry Rebuild overhead line Almost complete, remainder by+ protection October 97 following cropping
season
Forth Collingsburgh 11kV rural automation Completed
Western Pinwherry Overhead line protection Completion July 97
Southern Barrhill Insulated conductors Completed
Southern Oakfield Overhead line protection Completed
Southern Torthorwald Rebuild overhead line + protection Completed
Southern Craig – Port William Rebuild overhead line + protection Completed
Southern St. Boswells 33kV primary automation Completion September 97
UPDATE ON 1996/7 QOS CIRCUITSIn our Report last year we detailed a list of localities where we would be
targeting quality of supply initiatives. The table below gives an update of
progress on this work. It is too early to measure the effect of this work
on these circuits but we fully expect the results to improve the regional
performance statistics.
Least Well Served CustomersOur target is to ensure that by the year 2000 we target improvements to
those customers who experience more than an average of three
unplanned HV incidents in each protection zone providing their supply.
To ensure we can identify such customers we implemented a new
incident recording and customer monitoring system in April 97 at a cost
of more than £500,000.
The chart shown here indicates that in 1996/7, 36.6% of all CML were
due to high voltage overhead line incidents. The majority of the
pre-arranged CML were also due to planned work on high voltage
overhead lines. Whilst high voltage underground cables account for
24.2% of CML, this is spread over a larger number of customers who live
in more densely-populated areas. The impact on individual customers is
therefore much smaller.
We have described in this Report how we plan to improve the reliability of
our overhead lines. We target those circuits where we can expect
maximum benefits taking into account the number of incidents on a
circuit, the number of customers affected and the duration of the
interruptions.
We have a duty to maintain our system in a safe condition and our assets
are upgraded based on condition as well as CML. Much of our capital
investment therefore does not have a measurable effect on performance,
but is designed to avoid deterioration of our network. The work
programme described on page 18 is drawn from the specific programme
we have for the improvement of quality of supply.
Targeting investments andgetting results
17
LV Incidents
Pre-arranged
Transmission
EHV IncidentsHV–U/G Incidents
HV–O/H Incidents
HV – RestIncidents
Percentage of Customer Minutes Lost
36.6%
24.2%
10.9%
6.8%
8.8%11.8%
0.8%
18
Least Well Served areas to be targeted during 1997/8
No ofRegion Circuit CHL CI Incidents Proposed Work
Southern Selkirk - Ettrick Bridge, 4125 1419 8 Line rebuild & overheadDeloraine, Tushielaw, Ettrick protection policy
Southern Duns Castle, Borthwick Quarry, 1302 296 5 Overhead protection policyHardens, Gavinton, Polwarth
Southern Denholm - Bonchester Bridge, 4792 713 4 Line rebuild and refurbishmentFodderlee, Bedrule
Southern Maxton, Rutherford, Roxburgh 1957 491 8 Overhead protection policyNewton, Mertoun, Clinthill,Bemersyde, Smailmolm,Mellerstain
Southern Chapel on Leader, Birkenside 1669 388 4 Overhead protection policyBlainslie
Forth Cowstrandburn, Kinnedar, 2516 1012 3 Overhead protection policySaline, Steelend
Forth Kingston, Brownrigg, 2846 489 6 Overhead protection policyWhitekirk, Leuchie, RhodesHoldings, Newmains
Forth Longniddry, Gosford, Aberlady 5778 3842 6 Overhead protection policy
Clyde Clynder, Rosneath, Kilcreggan 1865 1007 3 Overhead protection policy
Southern Crossmichael, Laurieston 8690 4001 16 Line rebuild
Southern Boreland, Sibbaldie, Millbank 664 421 3 Overhead protection policy
Southern Holywood 1418 1181 6 Line rebuild
Southern Lochfoot, Shawhead 5493 1543 14 Line rebuild
Southern Scaur Glen, Wanlockhead, 4061 1929 8 Line rebuildLeadhills, Enterkinfoot,Durisdeer
Southern Tarff - Bridge of Dee 1332 666 4 Line rebuild & overheadprotection policy
Western Killoch Colliery, Drongan, 3882 2346 5 Overhead protection policyOchiltree rural
Western Part of Troon & Barassie, 3314 2411 2 Overhead protection policyDundonald rural, Symingtonrural
Southern Biggar - Drumelier, 2829 842 7 Line rebuild and refurbishmentTweedsmuir, Kindledores
Western Corra Linn - Towers, Rigside 2038 375 3 Line rebuildLanark & Douglas rural area
Western Towers - Poneil, Lanark & 5244 1056 18 Line rebuildDouglas rural area
Western Part of Kirkintilloch, Low Moss 3169 1771 5 Overhead protection policyPrison
Western Forth, Tarbrax, Braehead 7072 1968 7 Overehad protection policy
Forth Sauchie, parts of Alloa & 1662 327 2 Overhead protection policyOakley
Forth Ecclesmachan, parts of 5273 2029 6 Overhead protection policyBroxburn & Dechmont
3 Year Annual Average
Actual & planned investment for five yearperiod 1995/6 – 1999/2000In October 1995 OFFER announced that, in setting ScottishPower's Price
Control, they had assumed it would be necessary to spend £431.8m on
the Distribution network during the five years 1995/6 to 1999/2000.
OFFER’s Published Price Control Assumptions £m (1996/7 Prices)Load Related 233
Non-Load Related 198.8
Total 431.8
We are currently spending more on quality improvement initiatives than
allowed by OFFER in the Price Control Review and our future investment
plans will deliver further service enhancements to our customers.
A range of efficiency improvements have already been delivered and
further savings are planned for the future;
© Improved procurement by taking advantage of market opportunities.
© Cost reduction through introduction of new designs, materials and
techniques.
© Implementation of new Information Technology systems providing more
detailed operational information about our network assets and enabling
more effective prioritisation and targeting of investment.
© Improved work management systems and working practices.
Against this background of cost savings, ScottishPower's latest capital
expenditure projections are:
ScottishPower’s Network Capital Expenditure (1996/7) Prices)Actual Planned
1995/6 1996/7 1997/8 1998/9-1999/00 Total
£m £m £m £m £m
Load Related 44.6 42.1 50.1 90.5 227.3
Non-Load Related 39 37.5 36.7 70.4 183.6
Total 83.6 79.6 86.8 160.9 410.9
Capital expenditure
19
20
Reasons for Network Investment© Load related expenditure is necessary to meet customer requests for
new connections or increased supply capacity and to reinforce the
distribution network to carry additional demand. Our forecasts of future
expenditure are driven by assumptions about local economic trends,
customer requirements and movements in the location of network
demand. This demand may not materialise in the future and our
forecast expenditure is subject to constant review and updating.
© The majority of the non-load related investment programme is directed
towards maintaining the existing performance and integrity of the
distribution network as its age increases. Significant levels of
expenditure are necessary to maintain security of supplies to
customers and meet our obligation to ensure the safety of our staff
and the public and comply with environmental legislation.
Achievements in 1996/7 and work plannedduring 1997/8We have made significant progress with our programme of work and
during 1996/7 we:
© spent more than £32m to ensure that supply security is maintained to
our existing customers.
© provided more than 16,200 new housing connections.
© installed more than 230MVA of additional transformer capacity to meet
increased requirements for customer demand.
© rebuilt more than 210km of 11kV overhead line.
© refurbished more than 180km of 11kV overhead line.
© replaced switchgear at more than 230 distribution substations.
© spent more than £870k on installation of anti-oil
pollution equipment at Grid Supply Points.
This programme of work will continue during 1997/8
and we will report on progress in next year's Quality of
Supply Report.
New 11kV Switchboard
A representative selection of the major projects (each with expenditure in
excess of £100k) completed during 1996/7 and planned for 1997/8 are
shown in Tables 1 & 2.
Table 1Examples of Major Projects completed during 1996/7
Region Project Description
Clyde Replacement of 11kV switchgear at Acredyke primary substation
Forth New housing development at Seafield, Kirkcaldy
Forth Replacement of 11kV switchgear & overhead line at New Inn, Kettlebridge
Southern Refurbishment of Dumfries GSP – Penpont 33 kV overhead line
Southern Rebuild of Gatehouse – Tongland 33 kV overhead line
Southern Replacement of 11kV switchgear at Newton Stewart primary substation
Southern Extension to Dumfries GSP, 33 kV substation
Southern Connection of a 21MW Windfarm at Gallowrigg
Western Replacement of 11kV switchgear at Girvan primary substation
Table 2Examples of Major Projects planned during 1997/8
Region Project Description
Clyde Replacement of 11kV switchgear at Consett Street primary substation
Clyde Replacement of 33kV switchgear at West George Street substation
Forth Reinforcement of 6.6kV system in Kingsknowe area, Edinburgh
Southern Replacement of 11kV switchgear at Cargenbridge primary substation
Southern Rebuild of Newton Stewart – Gatehouse 33kV overhead line
Southern Uprated Supply to ICI, Dumfries
Western Replacement of 33kV switchgear at Newarthill GSP
Western Replacement of 11kV switchgear at Hamilton primary substation
Western Replacement of 11kV switchgear at Newhouse primary substation
Western New supply for Chunghwa, Mossend, Bellshill
Western New supply to Egger Chipboard, Barony, Auchinleck
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Extension to 33kV Substation at Dumfries GSP
Gallowrigg Windfarm
22
Detailed analysis of systemperformance, 1996/7
Clyde Forth Western Southern Company
Table 1 - Customer Numbers
Number of customers 573,777 675,983 413,952 140,353 1,804,065
Table 2 - Security
No. of Supply Interruptionsper 100 connected customers due to:-
a) Distribution faults
LV (Inc. Services) 7.6 4.5 4.8 2.4 5.4
HV Overhead 1.5 15.0 14.1 42.5 12.7
HV Underground 19.7 16.6 15.6 15.5 17.3
HV Other 5.9 11.8 9.7 23.7 10.4
HV Total 27.1 43.4 39.5 81.7 40.3
EHV 2.0 2.9 9.1 26.7 5.9
Transmission 3.1
Total faults 36.7 50.8 53.3 110.8 54.7
b) Planned outages 0.7 2.0 1.2 14.4 2.4
Total from all causes (a) + (b) 37.4 52.8 54.5 125.2 57.0
Correction for extreme weather events 0.3 5.3 4.6 24.6 6.0
Total corrected for extremeweather events 37.1 47.5 49.9 100.5 51.0
Table 3 - Availability
No. of Supply Minutes Lost per connected customer due to:-
a) Distribution faults
LV (Inc. Services) 11.4 7.5 12.3 5.0 9.7
HV Overhead 1.5 23.0 29.2 213.7 32.4
HV Underground 22.9 23.3 18.1 16.4 21.4
HV Other 5.0 11.8 12.7 19.5 10.4
HV Total 29.4 58.1 60.0 249.7 64.3
EHV 1.3 2.9 10.3 51.0 7.8
Transmission 0.7
Total faults 42.1 68.5 82.6 305.7 82.5
b) Planned outages 1.5 4.7 3.5 38.6 6.1
Total from all causes (a) + (b) 43.6 73.2 86.1 344.3 88.6
Correction for extreme weather events 0.4 12.9 21.0 214.9 26.7
Total corrected for extreme weather events43.2 60.3 65.1 129.4 61.9
Table 4 - Voltage Complaints
Verified Voltage complaintsper 10,000 connected customers 0.89 4.16 3.21 3.99 2.89
Notes for tables 2 and 3:
132kV faults aggregated at Company level.Weather correction = 6/11/96 and 3-4/12/96 replaced by an ‘average’ day.
Availability A measure of the time the supply is not
available, generally expressed as the average
number of minutes per connected customer
the supply is NOT available.
CHL Customer Hours Lost
CI Customer Interruptions, generally expressed
as the average number of customer
interruptions per 100 connected customers.
CML Customer Minutes Lost, generally expressed
as the average number of minutes per
connected customer the supply is NOT
available.
Extra High Voltage Nominally operating at greater than 22,000
(EHV) volts but less than 132,000 volts. This usually
refers to 33,000 volts.
High Voltage (HV) Nominally operating at greater than 1000 volts
but less than 22,000 volts. This usually refers
to 11,000 volts.
Incident An event which causes an uncontrolled flow of
electrical current, followed by supply
disconnection.
Kilovolt (kV) 1000 volts
Non-damage incident An incident which causes no permanent
damage to equipment and therefore requires
no repairs to be undertaken.
Outage Free Methods of undertaking work on 11,000 volt
equipment without interrupting supplies to
customers.
Overhead protection The use of electronically controlled links
together with automated switches to restore
supplies following an incident and, where
necessary, disconnect damaged equipment
leaving the minimum number of customers
without supply.
Pre-arranged This term is used to refer to planned
interruptions in supplies to customers which
are notified to the affected customers at least
two days in advance.
23
Glossary of Terms
24
Refurbishment A planned replacement or renewal of existing
equipment as it reaches the end of its
useful life.
Security A measure of the number of supply
interruptions, generally expressed as the
number of supply interruptions per 100
customers.
Short Interruptions to customers supplies which last
interruptions less than 60 seconds. Their duration is
typically about 10 seconds.
Substation Premises containing one or more transformers
and/or switchgear.
Switchgear Automatic or manual mechanical devices for
controlling the flow of electrical energy into a
circuit or item of equipment.
Underlying A measure of the performance of the system
performance which excludes the affects of identifiable
severe events.
Voltage Dip A sudden sag in the voltage, typically in the
range 10% to 30% of the sinusoidal voltage.
If you have any questions or comments following your study of this report
please write to the Regional Manager at your local regional office.
ScottishPower plc
Clyde Region
St Vincent Crescent
Glasgow
G3 8LT
ScottishPower plc
Forth Region
10 Fishwives’ Causeway
Edinburgh
EH15 1EP
How to contact us
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Motherwell
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DG1 2DN
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