Electricity Asset Management Plan 2019-2029
91
Vector Limited://
Key statistics of Vector’s network are given below.
Customer connections
567,009
No of GXPs
15
No of zone substations
112
Maximum coincident GXP demand - Megawatt (MW)
1,754
Energy delivered through GXPs (GWh)
8,604
Table 4-1 Key statistics for RY18
4.2 SUBTRANSMISSION The function of the subtransmission network is to transfer electrical energy from GXPs to bulk supply substations and zone substations. The 110 kV subtransmission network emanates from Transpower 110 kV GXPs to connect to Vector owned bulk supply substations in the Auckland CBD, Kingsland and Wairau Valley on the North Shore. The 110 kV subtransmission network consists of cables in the Penrose to CBD tunnel, cables buried in ducts in the ground and overhead lines. The 110 kV subtransmission network is configured as a meshed system with a mix of 33 kV and 22 kV circuits providing backstop to the 110 kV nodes. 33 kV and 22 kV subtransmission circuits run from Vector’s bulk supply substations and Transpower GXPs to Vector’s zone substations. The 33 kV and 22 kV subtransmission network consists of a mix of underground cables and overhead lines. In the Northern network the subtransmission system is configured as a meshed system. In the Auckland network the subtransmission system is configured mostly as radial line-transformer feeders that can be paralleled at the 11 kV busbars. Vector’s overhead subtransmission circuits also accommodate 11 kV and 400 V circuits on the same support structures in many instances.
4.2.1 SUBTRANSMISSION 110 KV UNDERGROUND CABLES Overview Key statistics of the 110 kV subtransmission feeder assets are shown in Table 4-2.
No of 110 kV underground subtransmission circuits
14
Length of 110 kV underground subtransmission circuits (km)
31.86
Length of 110 kV underground circuits in tunnels (km)
15.58
Table 4-2 Key statistics for 110 kV subtransmission network
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