North Island 400 kV Upgrade Project
Investment Proposal
Part I – Project Description and Project Plan
© TRANSPOWER NEW ZEALAND LIMITED 2005. ALL RIGHTS RESERVED
1
SUMMARY ....................................................................................................................................... 3
2
PROJECT DESCRIPTION ............................................................................................................... 3
2.1
General..................................................................................................................... 3
2.2
400 kV Overhead Transmission Line ....................................................................... 4
2.3
400 kV Underground Cable...................................................................................... 6
2.4
400/220 kV Substations ........................................................................................... 7
3.1
Investigation Process ............................................................................................... 9
3.2
Environmental Process ............................................................................................ 9
3.3
Property Rights Acquisition Process ...................................................................... 10
3.4
Engineer/Procure/Construct Process..................................................................... 11
3.5
Critical Timeframes and Milestones ....................................................................... 11
APPENDIX IA - TRANSMISSION SCHEMATIC OF PROJECT (SIMPLIFIED) ...................................... 14
APPENDIX IB - MAP OF ROUTE OPTIONS .......................................................................................... 15
APPENDIX IC - NORTH ISLAND 400 KV PREFERRED UNDERGROUND CABLE ROUTE ................ 16
APPENDIX ID - NORTH ISLAND 400 KV GRID UPGRADE PROJECT CRITICAL PATH TIMELINE .. 17
Part I – Project Description and Project Plan
2
1 Summary
Part I introduces the proposed investment and sets out:
• the technical description of Transpower’s proposed investment;
• the various processes required to implement the proposed investment; and
• the expected timeframes of undertaking each process.
The four key processes required to be undertaken to complete the proposed
investment are:
• investigations including preliminary environmental, property and engineering
work;
• environmental processes including securing designations and consents;
• acquisition of property rights; and
• engineering design, equipment procurement, construction
.
Transpower has concluded in Part II of this submission that the proposed investment
is required to be commissioned by pre-winter 2010 to ensure Transpower’s grid
reliability standards are met in the upper North Island. The timeframes are tight for
each of the above processes if the commissioning date is to be achieved.
The critical dates required to be met to avoid delays to the commissioning of the
proposed investment are:
• registration of interest in transmission line construction:
Completed (August
2005)
• lodgement of the notice of requirement:
13 April 2006
• commencement of compulsory acquisition process for property rights if
required:
14 April 2006
• commencement of tender process for the engineering, equipment
procurement and construction contract:
10 April 2006
2 Project
Description
2.1 General
The proposed investment is the construction of a 400 kV transmission
interconnection between the existing Whakamaru and Otahuhu substations,
including:
•
A 400 kV, double circuit, steel lattice tower, overhead transmission line of
approximately 190 km from a new Whakamaru North substation to a new
underground cable to overhead line transition station near Ormiston Road
(south of Otahuhu substation).
Part I – Project Description and Project Plan
3
•
A 400 kV, double circuit, underground cable from the underground cable
to overhead line transition station near Ormiston Road into Otahuhu
substation with a route length of approximately 9 km.
•
Two new 400/220 kV 500 MVA interconnector transformers and
associated substation works at the new Whakamaru North substation.
•
Two new 400/220 kV 500 MVA interconnector transformers and
associated substation works at the existing Otahuhu substation.
•
Dismantling and removal of all the Arapuni to Pakuranga 110 kV line,
making good the affected land and consequential works at Pakuranga.
A schematic diagram of the proposed investment is included in Appendix I-A.
2.2 400 kV Overhead Transmission Line
The 400 kV overhead transmission line will run from the new Whakamaru North
substation to a new underground cable to overhead line transition station near
Ormiston Road. The transition station will connect the overhead line to underground
cables and will require the construction of a small station yard to enclose the works.
The transition station is approximately 9 route kilometres south of Otahuhu
substation.
2.2.1 Design Parameters
The anticipated key design parameters for the 400 kV overhead transmission line are
as described in Table 2-1:
Item
Value
Number of Circuits
2
Route Length
190 km
Line Rating
1200 MVA
Max Operating Temp
50 Deg C
Nominal System Voltage
400 kV
Conductors
Twin conductors @ 460mm spacing
Earthwire System
Twin earthwires: 1-OPGW and 1-SC/AC
Structure types
Double circuit lattice steel Tower types –
Standard Suspension, Angle Heavy
Suspension, Light Strain, Heavy Strain/Dead
End
Maximum Electric Field Strength
In accordance with ICNIRP1 Guidelines
Maximum Magnetic Flux Density
In accordance with ICNIRP Guidelines
Audible Noise Level
45dBA (±1 dBA)
Radio Frequency Interference (RFI)
Compliance with NZS6869:2004
Easement Width
Minimum width based on Audible Noise.
Maximum width based on Conductor Swing.
Minimum width of 65 m
Table 2-1: Key Design Parameters of 400 kV Overhead Line
1 ICNIRP - International Commission on Non-Ionizing Radiation Protection
Part I – Project Description and Project Plan
4
Typical tower outlines are as follows, with the likely proportion of each type detailed
underneath.
Short Tower (46m)
Medium Tower (55m)
Tall Tower (67m)
(40%)
(55%)
(5%)
Figure 2-1: Typical 400 kV Suspension Towers General Outline
2.2.2 Transmission Line Route
Transpower has been using the ACRE (Area, Corridor, Route, Easement) process,
described further in an appendix to Part III of this submission, to finalise a route and
easement for the proposed 400 kV overhead transmission line. In October 2004, two
route options (referred to as Eastern and Western) were publicly released. This
commenced a significant period of consultation and technical/engineering,
environmental investigation into determining the final route.
An interim route decision was made on 14 May 2005 which proposed a largely
western route for the line. Following a period of written and verbal submissions a
final route (confirming the interim decision) was announced on 19 July 2005, together
with an indicative centre-line. Detailed investigations together with landowner
negotiations are now underway with a view to determining a final easement
centreline by late November 2005.
Transpower has confirmed that the Arapuni-Pakuranga 110 kV transmission line
which follows the final route for most of its length would be removed in its entirety.
A map showing the final route can be found in Appendix IB.
Part I – Project Description and Project Plan
5
2.3 400 kV Underground Cable
The proposed investment includes a 400 kV, double circuit, underground cable from
the underground cable to overhead line transition station near Ormiston Road, via
predominantly public roads into Otahuhu substation, with a route length of
approximately 9 km.
2.3.1 Design Parameters
The anticipated key design parameters for the 400 kV underground cable are as
described in Table 2-2 below:
Item
Value
Number of circuits
2
Number of cables per circuit
3 x single phase cables
Route length
9 km
Installation method
Direct burial or in ducts as required
Depth of burial
1.5 m, nominal
Distance between cable circuits
> 3m
Circuit rating
1000 MVA continuous
Rated voltage
420 kV
Conductor material and size
Copper 2500 sq mm
Insulation
XLPE or SCFF
Metal sheath
Aluminium
Oversheath
PVC or HDPE
Method of sheath bonding
Crossbonded
Maximum Electric field strength
Zero - Except at terminations in a
restricted area where a limit of 10
kV/ m will apply.
In accordance with ICNIRP
Guidelines
Maximum Magnetic Flux Density
In accordance with ICNIRP
Guidelines
Radio frequency interference
To comply with NZS 6869
Table 2-2: Anticipated Key Design Parameters of 400 kV Underground Cable
2.3.2 Environmental and Property
Transpower considered that obtaining designations under the Resource
Management Act and securing of property rights for a 400 kV overhead transmission
line, through densely populated urban areas into Otahuhu would create significant
environmental, property, political and financial risks to the projects success. It would
also be likely to lead to unacceptable time delays in the project. The environmental
process followed has identified that, due to these reasons, the closest distance that
the 400 kV overhead line can approach to Otahuhu substation is 9 route kilometres.
An overhead line to underground cable transition station is planned to be constructed
at this point, near Ormiston Road in South Auckland.
The cables would exit this transition station and, where practicable, be direct buried
in public roads all the way into Otahuhu substation. In August 2005, Transpower
Part I – Project Description and Project Plan
6
announced a preferred underground cable route for further consultation with affected
parties. A map of the preferred underground cable route is attached as Appendix IC.
Transpower would need to secure approvals under the Resource Management Act
for the cable route by way of designation.
2.4 400/220 kV Substations
The proposed investment includes two new 3-phase, 500 MVA, 400/220 kV
interconnector transformers at a new Whakamaru North substation (WHN) and two
new 3-phase, 500 MVA, 400/220 kV interconnector transformers at the existing
Otahuhu substation (OTA) to terminate the 400 kV line and provide interconnection
to the existing transmission system.
The switching arrangement for the new 400 kV substations at Otahuhu and
Whakamaru North will be breaker and a half configuration.
2.4.1 Design parameters
The anticipated key parameters for the 400/220 kV substations are as provided
below in Table 2-3:
Item
Value
Substation Type
400 kV (OTA): Outdoor Air Insulated
Switchgear or Indoor Gas Insulated
Switchgear (to be confirmed)
400 kV (WHN): Outdoor Air Insulated
Switchgear or Indoor Gas Insulated
Switchgear (to be confirmed)
220 kV (OTA): Outdoor Air Insulated
Switchgear or Indoor Gas Insulated
Switchgear (to be confirmed)
220 kV (WKM): Outdoor Air Insulated
Switchgear
Substation switching
400 kV (OTA): 1 ½ breaker
arrangement
400 kV (WHN): 1 ½ breaker
220 kV (OTA): 1 ½ breaker
System voltage
220 kV and 400 kV Nominal
245 kV and 420 kV Maximum
No. of transformers
2 at each site
Transformer rating
500 MVA, 400/220 kV, 3-phase
No. of shunt reactors
2 (one on each circuit)
Shunt reactor rating at
75 Mvar, 400 kV, 3-phase
Otahuhu
Table 2-3: Anticipated Key Design Parameters for 400/220kV Terminal Stations
2.4.2 Whakamaru North Substation
A new substation site will be developed at Whakamaru North to accommodate the
new 400/220 kV interconnection facilities and to provide for future 400 kV expansion
Part I – Project Description and Project Plan
7
if required. The new 400/220 kV substation will be constructed approximately 1 km
to the North of the existing 220 kV substation to provide physical separation from the
existing switchyard. Two 220 kV tie-lines will be established to connect the output of
the 400/220 kV interconnector transformers to the existing Whakamaru 220 kV bus.
The new substation will be designed to provide the necessary number of connections
at 400 kV to the two new circuits and interconnector transformers. Provision will be
made for the site to be expanded to ten 400 kV bays and nine 220 kV bays in the
future if required.
Transpower plans to use outdoor air insulated switchgear at Whakamaru substation
for the 220 kV but is still investigating indoor gas-insulated switchgear (GIS) versus
air-insulated switchgear (AIS) for the 400 kV. A final decision will be made by
December 2005.
2.4.3 Otahuhu Substation
A new 400/220 kV substation will be constructed at Otahuhu substation within the
boundary of Transpower’s existing substation and ancillary facilities.
In order to provide diversity of supply at Otahuhu substation, the 400/220 kV
interconnector transformers will be connected to a new 220 kV busbar which is
physically separate from the existing 220 kV bus. The existing 220 kV circuits from
Otahuhu to Henderson and Penrose will be rearranged so that these key loads are
supplied from both the existing and new 220 kV busses to achieve this diversity.
Provision will also be made so that other key loads can be supplied from the
extended 220 kV substation in the future. The new and existing sections of the
220 kV substations at Otahuhu will be interconnected by two tie-lines.
Transpower is still finalising its switchgear arrangements at OTA. It is likely that the
400 kV will be indoor GIS switchgear, and the 220 kV will be AIS switchgear. A final
decision will be made by December 2005.
Part I – Project Description and Project Plan
8
3 Project
Plan
There are a significant number of activities and processes that need to be completed
prior to, and during, the physical construction of the proposed investment. These
form part of Transpower’s project plan and are as follows:
3.1 Investigation Process
The investigation process has included all engineering and system planning work to
identify the need for investment, identify all possible transmission options and non
transmission alternatives and to select a preferred solution to provide long term
security of supply into the upper North Island.
This process also includes environmental, property and engineering work required to
investigate and select the preferred route corridor and investigate and select two
500m wide routes within that route corridor. It also includes consultation on the
preferred routes and the preparation of the documentation required to lodge notices
of requirement (in respect of the designation process).
3.2 Environmental Process
Since October 2004 Transpower has been following a public consultation process to
gather information to assist in determining which of two 500 m wide route options will
be selected as the preferred option.
An interim decision on a preferred route was announced on 14 May 2005, and the
public were provided with a summary of the consultation process undertaken and the
data on which Transpower based its decision. The public were invited to give
submissions to Transpower (either written or oral) on this interim decision. Following
review of these submissions, Transpower announced a final route on 19 July 2005
together with an indicative centre-line.
The final easement centre-line will be confirmed by late November 2005 and
Transpower will prepare statutory Resource Management Act (RMA) documentation
for Notice of Requirement (NoR) lodgement.
The NoR process depends on whether it is ‘called in’ by the Minister for the
Environment. In the event that the NoR is ‘called in’, the Minister can either appoint a
board of enquiry, or refer the matter directly to the Environment Court for
consideration. Although ‘call in’ procedures are still being resolved by the Ministry for
the Environment, this will affect notification and timeframes for submissions.
In the event it is not ‘called in’, the NoR when lodged with the applicable Councils
must go through the public notification, recommendation and decision making
process before it is confirmed as a designation. The key steps in the designation
process are outlined in sections 168 to 179 of the RMA. As appropriate, the NoR
documentation will be accompanied by applications for resource consents, which will
need to be supported by detailed assessments of effects on the environment.
Part I – Project Description and Project Plan
9
The designation process will offer a number of opportunities for people to become
further involved in the process. Once the Councils have received the NoR, it will be
publicly notified. Any member of the public then has 20 working days within which to
lodge their support or opposition to the proposed transmission line (NoR).
A hearing will be held to consider the NoR and the Requiring Authority (Transpower)
and all those who lodge a submission in support or opposition to the NoR can speak
at the hearing. Submitters are able to speak their submission, and may also bring
along someone to represent them, and/or present evidence on their behalf.
Following the hearing, the Councils will recommend to Transpower whether it thinks
the NoR should be confirmed, should be confirmed with modifications and/or
conditions; or should be withdrawn.
Transpower will then decide whether or not to accept the Councils’ recommendation.
Once the Councils have received Transpower’s decision, it will serve a copy of the
decision on all submitters as well as landowners and occupiers whose land is directly
affected by the transmission line.
Anyone who lodged a submission, and the Councils, can appeal the decision or parts
of the decision to the Environment Court within 15 working days of when the decision
was sent out. A one-year timeframe has been estimated to resolve all Environment
Court appeals, resulting in final statutory approval in March 2008.
Other approvals that may be required include Authorities under the Historic Places
Act and permits/concessions where a line crosses Crown or Department of
Conservation land, or reserve land. Building consents may also be required for
relevant construction work coming under the Building Act 2004.
3.3 Property Rights Acquisition Process
The property acquisition process will commence in full following the determination of
the final centre-line of the 400 kV transmission line in December 2005.
To build the proposed line, Transpower will need to secure an appropriate interest
(usually an easement) in all properties the line will cross and pay fair compensation
for this interest. The compensation will reflect any loss in value to the property
arising from the presence of the new transmission line and associated easement that
crosses it.
During earlier consultations, a number of landowners indicated that their preference
would be to sell their property to Transpower rather than grant an easement.
Transpower will consider buying properties that the proposed transmission line would
cross on a case-by-case “willing buyer willing seller” basis.
For all property acquisitions (whether easement or property purchase), negotiations
in good faith will be the key objective. However, it is anticipated that there will be a
number of landowners where negotiations in good faith will not result in an
agreement being reached. In the event this occurs, Transpower as a Requiring
Authority will seek to use the compulsory acquisition processes within the Public
Works Act 1981 to secure the necessary property right so that it can construct,
operate and maintain the proposed line.
Part I – Project Description and Project Plan
10
3.4 Engineer/Procure/Construct Process
This process will include all the detailed engineering design, procurement of all
equipment, construction and commissioning of the project.
The project will be split into several implementation packages to provide programme
flexibility, and to align the individual implementation packages with their related risks
to ensure that these risks are placed where they are best managed. In general terms
the implementation packages will all be “design/build” and there are likely to be four
basic packages covering:
•
The 400 kV overhead transmission line
•
The 400/220 kV interconnecting transformers and associated substation
works at OTA and WHN (including the overhead to underground
transition station)
•
The 400 kV underground cable
•
The dismantling of relevant existing transmission lines.
The 400 kV overhead transmission line is the project critical path, and this is
therefore the implementation package that will be most intolerant of project delays. In
order to ensure that Transpower is able to secure the best engineering solution and
commercial arrangement it sought an international registration of interest (ROI)
during August 2005. The ROI process involves the receipt of detailed submissions,
their evaluation, face to face interviews, reference checking (technical and
commercial), and short listing. The ROI process closes in October 2005, with a short
list for tendering to be determined by January 2006.
It is planned that short listed tenderers be asked to bid for an engineering,
procurement and construction contract on 10 April 2006. The contract is planned to
be awarded no later than 6 November 2006.
3.5 Critical Timeframes and Milestones
A project of the proposed investment’s magnitude would normally be expected to
take a period of eight years from initial mobilisation to final commissioning.
Transpower has identified that the proposed investment is required by May 2010
therefore all major project milestones are critical to the successful implementation of
the proposed investment.
A summary of key milestones for each process is set out below and further
highlighted in the bar chart in Figure 2-2.
3.5.1 Environmental & Property
•
Preferred Route Announced: 19 July 2005
•
Easement Centre Line Confirmed: December 2005
•
Notice of Requirement (NoR - for a designation under the RMA) Lodged
with Councils, or “called in” by the Minister for Environment: April 2006
•
Designation Granted: March 2008
•
Property Rights Secured: September 2008
Part I – Project Description and Project Plan
11
3.5.2 Transmission Line Engineer/Procure/Construct
•
Commencement of Registration of Interest & Short List: 31 August 2005
(completed)
• Commencement of Tender/Evaluation/Negotiation Process for
Design/Procure/Construct: 10 April 2006
•
Commencement of Design/Procure/Construct Process: 6 November 2006
•
Final Commissioning: 27 May 2010
Part I – Project Description and Project Plan
12
Figure 2-2: Key activity timeline
Part I – Project Description and Project Plan
13
Appendix IA - Transmission Schematic of Project
(Simplified)
X
X
Otahuhu 220
kV
X
X
X
X
Two 400/220 Interconnecting
transformers rated at 500
MVA
X
X
Otahuhu 400
kV
X
X
X
X
X
X
2 switchable shunt
reactors 50 Mvar
9km of Underground
Cable rated 420 kV
1000 MVA per circuit
Cable termination
station near
Ormiston Rd
190 km of double circuit
overhead line nominal
400 kV, 1200 MVA per
circuit
X
X
Whakamaru
400 kV
X
X
X
X
Two 400/220 Interconnecting
transformers rated at 500
MVA
Whakamaru 220 kV
Part I – Project Description and Project Plan
14
Appendix IB - Map of Route Options
Part I – Project Description and Project Plan
15
Appendix IC - North Island 400 kV Preferred
Underground Cable Route
Part I – Project Description and Project Plan
16
Appendix ID - North Island 400 kV Grid Upgrade
Project Critical Path Timeline
Date
Action Comment
Lodge submission with
Triggers EC process
31 May 2005
Electricity Commission
Commence “good faith”
EC approval required prior to TP
15 July 2005
property rights acquisition
commitment to significant
negotiations
expenditure
13 April 2006
Lodge NoR
Commence compulsory
Requires Minister of Lands
property rights acquisition
approval. Will almost certainly
require unfettered approval by EC
before Minister will “sign off”
Award “Construction”
Needs to be conditional on
3 Nov 2006
contract
designations and certainty of
property rights acquisition. If there
is uncertainty about the recovery of
the cost of the risk of
cancellation/delay then TP
shareholders will need to
underwrite.
Designation granted
28 Mar 2008
Start “Field” construction
Requires designations to be
granted and property right
acquisition certainty to be in place
(ie section 23 PWA)
Property Rights secured
25 Sept 2008
27 May 2010
Commission 400 kV
project
Part I – Project Description and Project Plan
17
