network investment
The rapid economic growth in Marlborough over the last few years has provided challenge and opportunity. The challenge is to meet customers' increased demand within specified timeframes and the opportunity is to further improve the quality of our network to provide a greater level of reliability.
Viticulture growth has been the primary growth driver and typically has caused flow-on effects within other parts of the economy.
Viticulture growth, irrigation and the accompanying increased winery load, together with a general increase in demand, necessitated an increase in capacity at zone substations in the East Coast, Seddon, Waihopai, Renwick, Blenheim and Picton areas. And growth continues. As an example, the load of the Redwoodtown substation in Blenheim has increased by 30% over the last five years and the firm (N-1) capacity of the new substation has already been exceeded, to the extent that an additional supplementary substation is planned for construction in the current year.
In order to support local business it is imperative that Marlborough Lines continues an ongoing programme of investment. It is salient to consider that while grape planting has slowed from previous years, the situation is that winery electricity demand is increasing as production capacity catches up in order to handle the projected volume of grapes that will be harvested over the next few years.
Through the provision of quality assets customers can look forward to increased reliability of supply to meet their requirements.
Substation Upgrades
During the year work at our zone substations included:
- Commissioning the second new 16.5MVA 33/11kV transformer at Nelson Street together with the installation of new 33kV switchgear.
- Constructing a new switchroom at Springlands and commissioning new 11kV and 33kV switchgear.
- Installing an automatic switching system at the Picton substation to enable uninterrupted supply in automatic load transfers between alternative transformers.
- Redwoodtown and Nelson Street substations received an alternative 33kV supply via new underground feeder cables from the Company's point of supply at Transpower.
- Capacity of the Woodbourne transformer increased with the installation of a second 10MVA transformer.
- A transformer of 5MVA was installed at the new Ward substation after being relocated from Seddon.
Reticulation Upgrades
We continued our programme of reconstruction over the year with a number of old lines being re-conducted or entirely replaced. This work included:
- Replacing sections of the old Springlands to Waihopai tower 33kV line which was constructed in the 1920s.
- Further reconstruction in Rapaura Road.
- Extensive reconstruction of the Rapaura, Fairhall, and East Coast areas through the installation of larger conductors or complete replacement of the existing lines. A number of new tie-lines were also constructed to provide alternative supplies, increasing the reliability of the network. Similarly a number of switches were installed to extend flexibility in the network. In a number of instances the lines near intersections have been put underground to improve road safety.
Total capital expenditure was less than anticipated because of some significant overseas sourced items being delayed or arriving in an unacceptable condition.
