Electricity Asset Management Plan 2019-2029
155
Vector Limited://
constraints on the 110kV supply to Quay St substation while reducing the common-mode failure risk of multiple 110/22kV transformers out-of-service at the same time. To increase the electrical capacity from Liverpool substation, we are looking at installing reactors on the 110/22kV T3 transformer (Liverpool - 110/22kV transformer capacity upgrade (T3)) to enable better load sharing with the two other transformers on this site. A new 110kV transformer feeder is to be installed from Hobson substation to Quay St substation (Hobson - new 110kV cable (Hobson - Quay St)). This new feeder will supplement the existing 110kV cable from Roskill GXP via Liverpool substation. Ducts have been installed between the Hobson and Quay but the challenge is to secure a window when the cable can be installed and jointing completed. Currently the Quay St Streetscape and the CRLL tunnelling project are preventing this work being carried out. The investment plan shows a number of projects designed to increase the capacity of the distribution network within the CBD. The most significant one is the progressive roll-out of a 22kV network that will, over time, replace the lower capacity 11kV network in the CBD. Its focus is to ensure sufficient coverage with the 22kV network such that redeveloped sites can connect directly to the new network. To supply this expanding 22kV network, additional distribution switchgear is required at both Quay St (Quay - second 22kV switchboard) and Hobson (Hobson - additional 22kV feeder circuit- breakers) substations and new 22kV distribution feeders from Liverpool and Hobson substations.
A new 11kV feeder is required from the Freemans Bay substation.
TARGETED OUTCOMES
CUSTOMER EXPERIENCE
SAFETY
RELIABILITY
RESILIENCE
OPERATIONAL EFFICIENCY
CYBER SECURITY AND PRIVACY
OPTIONS ASSESSMENT For major projects, i.e. above $4M (level to be confirmed), include the following in this section: Technical feasibility, economic analysis, OPEX and CAPEX costs, net present value or net present cost, service levels, risks, etc.
DESCRIPTION
DISCUSSION OF OPTION
ESTIMATED COST (NPV IF APPLICABLE)
STATUS
Relieve capacity constraints at Liverpool substation
Option 1: Upgrade 110/22kV transformer T3 at Liverpool. Installing a transformer with the same electrical characteristics as the other transformers on this site will make additional capacity available to the network Option 2: Installation of a 22kV reactor on the existing T3 110/22kV transformer. This option addresses the issue of load sharing with the other onsite transformers, but with added complexity associated with the management of Electromagnetic Fields (EMFs). This is potentially a lower cost solution Option 3: Reconfigure the 22kV network to constrain the load on Liverpool at current levels. By transferring load to adjacent Hobson substation, we will advance a major reinforcement at this substation. This option also requires an upgrade to the network connectivity with the installation of new 22kV distribution feeders to enable the load transfer. The cost of this option is expected to exceed the solutions proposed above. Option 1: Extend the 110kV switchboard at Liverpool substation. The design of the 110kV switchboard at Liverpool may require adjacent panels to be electrically isolated for intrusive maintenance of repair works. This will compromise the security of supply to the CBD should this situation arise. Secondly the supply from Roskill GXP is
$2.7M Rejected
$1.2M Selected
$5.0M Rejected
Address HILP security risks associated with the Liverpool 110kV switchboard
$2.7M Selected
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