An Intelligent Drive Solution to Simply Electrify Larger Subsea Valves Such as SSIV
Authors: Pfeifroth E. -M. , Kubacki M. , Orth A. , da Silva J. P. D. , Hendrix G. , Gallinella F. 
Published: April 2024

The offshore industry needs energy-efficient and cost-effective solutions to scale up the energy transition. Through the development of a series of lean, all-electric Subsea Valve Actuators (OTC-32346-MS), most processing valves can now be easily electrified. However, some critical functions are still performed by hydraulically controlled systems due to the high loads required, the safety features demanded, the fact that they are in stand-alone applications, and also because of the offshore industry standard levels of reliability and integrity. This is the case with Subsea Safety Isolation Valves (SSIV), emergency Shutdown Valves (ESDV) or the final elements of High Integrity Protection Systems (HIPPS). This paper describes a novel solution to simply electrify larger subsea valves using a standardized and intelligent drive unit.

To complete the electrification of their projects, clients asked us for a solution to electrify large ball valves (8’’ or larger) with fail-safe closure by springs and limited power available. Therefore, different concepts were evaluated considering time-to-market, engineering effort, technology maturity, standardization and industrialization aspects, usability for OEMs and operators, and total costs. Resulting as the most promising concept, a full-scale prototype of an intelligent subsea drive based on the experience of a series of lean all-electric Subsea Valve Actuators (OTC-31083-MS, OTC-32346-MS) was designed and manufactured; with Technology Readiness Level 4 (TRL4) qualification tests starting soon in a pressure chamber emulating up to 4,400 m water depth.

The paper explains the main qualification results and various benefits of electrifying large actuators with high loads, such as SSIV or pipeline valves, in different applications. It shows how such actuators can safely be operated with lower power consumption than established hydraulic systems, while enabling maximum controllability, saving costs for consumables, and simplifying the infrastructure. This enables usage in emerging industries like Carbon Capture and Storage (CCS) and offshore hydrogen production. By using proven industrial components that were already qualified in the previous developments, in combination with an embedded digital twin (OTC-31913-MS), it was possible to integrate novel control functions into the solution, like enabling traditional hydraulic-driven valves to perform partial-stroke testing with minimal impact on the production flow during routine testing of the safety function. Additionally, it shows how safety functions such as Emergency Shutdown can be implemented, based on the de-energize to trip safety principle releasing a rapid closure by the actuators’ springs. All these features are combined into a lightweight and retrievable intelligent drive that easily plugs into existing infrastructure and enables control via the existing Subsea Instrumentation Interface Standardization Level 2 (SIIS L2) interface.

This work proposes a novel solution to enable the electrification of traditionally hydraulically operated applications by using an intelligent subsea drive. This technology allows subsea actuators with high loads and high safety integrity demands, or even stand-alone functions, to be electrified easily. To accelerate and scale up the energy transition, this solution in combination with a portfolio of linear and rotative Subsea Valve Actuators, is essential to realize a lean all-electric subsea control system.