Experiences in Qualification, Installation, and Operation of Wet Conductive Connectors for TOGI

Abstract

Abstract The TOGI subsea template was the first true diverless system relying on wetmateable electrical connectors of conductive type. The process of development, qualification, purchase and installation of the connectors is described, problems that arose and how they were solved. 69 wet connectors have been inoperation for more than two years, and no major failures that influence gasproduction from the subsea station have occurred. A general test programme and specification for "wet" conductiveconnectors was developed and refined. During the fabrication and test periodseveral failures of the connectors were discovered and corrected. Qualitycontrol and inspection from Company during fabrication is of utmostimportance. During installation problems of hydroxide and carbonate layers on metallicsurfaces due to the cathodic protection system were solved. Due to the serious operational consequences of failures in electricalconnectors, operators should establish inhouse expertise in this field. Introduction In the early days of subsea electrohydraulic control systems conductiveconnectors were tried with little success. Reliability of these connectors wastoo low, and the industry soon turned to using inductive couplers. In principlean inductive coupler can be regarded as a transformer cut into two halves. Itis thus obviously much easier to seal off from seawater contact the front endof such a coupler than the front end of a conductive one. However, at the backend the coupler to cable connection, the same problems are raised as forconductive connectors. But designs have been made that solve these problems. Anumber of subsea developments were made using inductive couplers, and thecouplers proved to service in great numbers for many years without problems. Inaddition the inductive coupler can have more advantages than just reliability, it serves as galvanic insulation, voltage can be transformed across thecoupler, mating operations can be made very simple, and the coupler can bedesigned in a network such that it can be left in unmated position with poweron.