There are three power supplies to the holiday town of Pauanui, and the major underwater cable is required to provide supply at peak times and holiday periods. Powerco needed the cable back in service prior to Christmas to avoid disruption to residents and holiday makers. Edison were engaged to manage this unplanned urgent project and coordinate the resources required on behalf of Powerco.

Our Solution

Edison were able to quickly provide an engineer to manage the resources required to respond quickly to Powerco’s request. The repair project had three phases:

1. Quantifying the damage and identifying solutions

• Rapid mobilisation of a commercial dive team to survey the damaged cable. Transmitting footage in real-time to the engineer on the boat, confirmed that a sleeve repair would not be viable.
• The extent of the damage to the cable meant that a section would need to be replaced. The required marine specification cable and joints have an extended lead time and were not available to put the cable back into service before Christmas.

2. Delivering a temporary repair

• In order to prevent further deterioration of the damaged cable it was decided to cut out the damaged area, test both sections and then cap and return to the seabed while a temporary joint kit was developed. To do this the dive team was deployed to excavate, cut and lift the cable to the surface for testing and capping.
• In conjunction with suppliers a joint kit was put together that would allow a section of standard MDPE to be jointed into the PIL cable. Splints were also made to stiffen the joints to allow for the difference in mechanical strength between the cable types. The jointing work was carried out on barge, before the divers re-laid and buried the repaired cable.

3. Implementing a long term solution

• The long-term solution requires the replacement of a 250m length of the existing cable. Marine specification has been sourced from Malaysia and specialist joints are being fabricated in Auckland. A repair procedure has been developed that will minimise the environmental impact of the work and this is currently going through the RMA process.

Key Results and Benefits

Edison’s ability to respond quickly and deploy specialist electrical engineering expertise enabled:

1. Rapid coordination of a team to get on site and identify the scale of the problem.
2. Identification of a temporary repair and long term solution to meet Powerco’s goal of full restoration of service before Christmas 2019.
3. A temporary repair of the cable for power to be restored to full capacity in time for Christmas.