Transitional HVDC Systems Operation and Maintenance Strategy

Power Maritime Link Inc. (NSPML) to maintain HVDC system assets, facilities, and equipment and ensure optimal performance and maximum longevity. The O&M model and contracting strategy presented in this paper can be used to forecast human resource and cost requirements for new HVDC projects and can be built upon to improve its performance. Key findings related to NSPML’s strategy can also be replicated by other HVDC system owners. The information related to NSMPL’s internal structure and processes was gathered with permission through interviews with NSMPL’s staff.

NSPML uses a semi-staffed operating model, where the converter stations are occupied during business hours by 8 technicians, 4 engineers, and the administrative staff. In general, any task not being performed by the team members is contracted to third parties based on the required expertise, labour requirement, and frequency.

When the Maritime Link began commercial operation, the team structure and operation and maintenance plan and procedures were not refined. NSPML used a transitional strategy by partnering with the HVDC original equipment manufacturer (OEM) for operation and maintenance. For the first three years, 100% of the annual maintenance scope of work was the responsibility of the HVDC system supplier. To support day-to-day operation and procedure development, NSPML also contracted two resident field service engineers from the OEM to support the terminal stations. These additional team-members facilitated troubleshooting and event analysis and helped build the competency of the technicians.

They gradually adjusted their strategy over time, either by using local contractors or by taking on the work themselves. They were also able to reduce their initially high maintenance and inspection costs as planned and their current O&M contracting strategy and level of reliance on

HVDC OEM is aligned with transmission system operators (TSO) in Denmark, Finland,

Sweden and Norway.

These findings have multiple implications for potential HVDC system owners. First, they provide a reference point for O&M cost forecasts. Second, they highlight the importance of

OEM-specific HVDC expertise. Leveraging OEM services while developing internal competencies is shown to be an effective strategy. Finally, they suggest that the optimal balance between work performed by the HVDC OEM, by local contractors or by the HVDC owners is not obvious, and that there are large opportunities for cost savings over time when using a conservative, front-loaded service strategy.

A key theme in this discussion has been the importance of OEM-specific expertise to increase performance of O&M teams. The same level of performance can be obtained early on with a high level of OEM services and a less-experienced owner team, versus an experienced owner team with fewer OEM services later in the HVDC system lifecycle. This highlights the importance of knowledge sharing between the HVDC OEM and the HVDC owner. Knowledge sharing, specifically when related to OEM-specific technology, should be seen as an important intangible benefit when considering purchasing services or products from OEMs.