Subsea Power Switching Unit With Localized Feeder Fault Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing subsea power distribution systems face challenges in efficiently and cost-effectively distributing medium voltage power to subsea consumers over long distances, particularly due to the complexity and expense of traditional cable arrangements and the lack of effective protection mechanisms for subsea loads.
Innovation Solution
A subsea power switching unit (SPSU) with integrated protection relays and medium voltage contactors, utilizing wetmateable connectors and transformers to provide localized fault detection and protection, allowing power distribution directly to subsea consumers, including flowline heating cables, motors, and control systems, without the need for topside circuit breakers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cable arrangements and topside circuit breakers are used for subsea power distribution, then power can be delivered to subsea consumers, but the system complexity and cost increase significantly
Solution Approach 1:
The power distribution system is segmented into multiple independent feeders, each with its own contactor and protection relay. This allows individual feeder control and isolation, reducing the complexity of managing entire cable arrangements from topside while maintaining reliable power delivery to each subsea consumer independently.
Solution Approach 2:
Subsea control units are introduced as intermediary devices between the topside power source and subsea consumers. These units locally control contactors and protection relays, eliminating the need for complex topside circuit breaker arrangements and long control cables, thereby reducing system complexity while ensuring reliable power distribution.
2Reliability
If traditional topside circuit breakers are used for fault protection, then subsea loads are protected, but the system lacks localized fault detection and protection capabilities
Solution Approach 1:
Each subsea feeder is equipped with its own protection relay and control unit that can autonomously detect faults and operate contactors to isolate faulty feeders. This self-service capability eliminates the need for topside circuit breakers to provide protection, as the system now has inherent localized fault detection and protection capabilities at each subsea consumer.
Solution Approach 2:
The system implements visual or signal indicators (analogous to color changes) through the control units to indicate fault conditions at each subsea feeder. This enables easy detection and measurement of faults locally at the subsea level, improving the difficulty of detecting and measuring parameter while maintaining reliable load protection.
3Reliability
If centralized topside power distribution is used, then power can be delivered to all subsea consumers, but the system lacks adaptability for individual feeder control and protection
Solution Approach 1:
The centralized power distribution system is divided into multiple independent, controllable segments (feeders), each with its own contactor and protection relay. This segmentation enables individual feeder control and protection while maintaining the overall power distribution capability to all subsea consumers, providing both reliability and adaptability.
Solution Approach 2:
The system transitions from a static centralized distribution arrangement to a dynamic configuration where each feeder can be independently controlled, switched, and protected. The contactors and protection relays enable dynamic adaptation of power distribution to meet individual feeder requirements while maintaining overall system reliability.
4Adaptability or versatility
If subsea control units with contactors and protection relays are installed, then localized fault protection and individual feeder control are achieved, but the device complexity increases
Solution Approach 1:
Multiple control functions (contactor control, protection relay operations, fault detection) are merged into integrated subsea control units. This consolidation provides localized fault protection and individual feeder control capabilities while managing device complexity through functional integration rather than separate components for each function.
Data Source
AI summary
A power supply system for use in a subsea environment includes an external power source operable to deliver a power input. A main circuit breaker is movable between a closed position and an open position. A subsea power switching unit (SPSU) operates in response to the receipt of the power input to deliver power to a plurality of power outputs, for each power output, the SPSU includes a contactor movable between a closed position and an open position, a sensor operable to generate a measurement indicative of one of a current and a voltage of the power output, and a relay operable to compare the measurement to a first threshold and a second threshold, the relay operable in response to the measurement exceeding the first threshold to move the contactor to the open position, and in response to the measurement exceeding the second threshold to sequentially move the main circuit breaker to the open position, move the contactor to the open position, and move the main circuit breaker back to the closed position.