Management of Offshore Transmission Owner (OFTO) Systems - Practical Considerations and Lessons Learned

Alistair Parlett
Natural Power, Castle Douglas, UK


The purpose of this Abstract is to describe the key considerations for an offshore transmission owner (OFTO) for the development and application of high voltage system management procedures for control room and field staff with a view to ensuring compliance with all relevant legislation, codes and standards.
This Abstract outlines the processes, systems and procedures necessary to ensure the safe and compliant management of the OFTO system by control room and field staff. Learning outcomes are based on Natural Power's experiences over a period of three years during which a new business unit has been created specifically to provide services to OFTO clients.


Examples of the key issues that an OFTO must consider in developing and implementing suitable processes, systems and procedures are:
• understanding of the requirements of transmission system codes and standards as relevant to control room and field operations;
• installing the necessary telecommunications infrastructure to ensure reliable connectivity between control room and field, including suitable redundancy/back-up;
• developing robust procedures and systems to ensure ongoing compliance;
• identifying additional safety rules procedures to address OFTO requirements;
• selecting, training and authorising control room and field staff;
• preparing alarm handling guidance for control room staff to ensure a timely, consistent and appropriate response to system alarms and events;
• ensuring availability of competent field staff such that attendance at site can be achieved within a suitable timescale in event of emergency.


Natural Power successfully supports clients in the management of OFTO projects through the delivery of the following services:
• control room;
• access and work control;
• safety rules;
• 24/7 standby engineer;
• first response to onshore and offshore alarms and events;
• routine substation inspection;
• provision of suitably authorised personnel for planned and reactive works.

Combinations of these services are delivered on eight OFTO projects by a dedicated transmission system team and provide the foundations upon which a wider scope of services are to be developed, including general management and wet/dry operations and maintenance (O&M).


Key findings can be summarised as follows:
• the volume of work required to support projects has been seen to vary considerably and has presented major challenges in the development of resourcing and pricing models;
• the more specialised nature of OFTO systems is difficult to resource due to the relative lack of competent personnel;
• training and authorisation of control room and field staff is time-consuming but critical to success;
• efficient alarm handling is essential in order to ensure that alarms and events are properly assessed and prioritised, and that the appropriate follow-up procedures are implemented;
• requirement to attend site in response to alarms and events can be significantly greater than anticipated for a transmission system.


Conference delegates will gain an understanding of:
• practical considerations for preparing a control room for supporting OFTO projects;
• key responsibilities under transmission system codes and standards;
• challenges of upskilling staff to deal with dynamic 24/7 high voltage operations;
• potential issues around alarm management;
• requirements for deployment of competent field staff;
• application of safety rules to OFTO projects;
• typical faults and recurring issues.