Dynamic Current Control for Offshore Submarine Cables
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Solution Overview
Problem
Offshore wind energy systems face challenges in maximizing power transmission through submarine cables due to temperature constraints, leading to underutilization of transmission capacity when one cable fails, as existing methods limit current to prevent temperature rises exceeding 2 Kelvin in the seabed.
Innovation Solution
A method for current regulation in offshore wind energy systems that involves detecting and regulating the current fed into submarine cables to ensure it does not exceed the maximum permissible time-dependent current, determined based on temperature parameters and cable characteristics, allowing for increased power transmission while adhering to environmental criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the current through the submarine cable is increased to maximize power transmission, then the transmission capacity is improved, but the temperature rise in the seabed exceeds the 2K criterion
Solution Approach 1:
The patent applies dynamics by transitioning from static current limiting to dynamic current control. The control device continuously adjusts the current through the submarine cable based on real-time temperature measurements from sensors in the seabed. This allows the system to operate at higher power levels when temperatures are acceptable while automatically reducing current when temperature thresholds approach, thereby maximizing transmission capacity without permanently constraining the cable's operational potential.
Solution Approach 2:
The patent implements feedback by establishing a closed-loop control system where temperature sensors in the seabed continuously monitor thermal conditions and feed this information back to a control device. The control device processes this feedback and adjusts the current accordingly, creating a self-regulating system that maintains the 2K criterion while optimizing power transmission. This feedback mechanism eliminates the need for conservative static current limits.
2Reliability
If the current is limited to 50% of maximum to comply with the 2K criterion after cable failure, then the temperature criterion is maintained, but the transmission capacity of the remaining cable is not fully utilized
Solution Approach 1:
The patent applies dynamics by replacing the static 50% current limit with dynamic current adjustment. After cable failure, the control device continuously monitors seabed temperature and adjusts the current through the remaining cable in real-time. This allows the system to operate above the conservative 50% limit when thermal conditions permit, thereby fully utilizing the remaining transmission capacity while maintaining reliability through automatic temperature-based control.
Solution Approach 2:
The patent implements feedback by using temperature sensors to continuously monitor seabed conditions and automatically adjust current levels in the remaining cable. This feedback-driven approach replaces fixed current limiting with adaptive control, enabling the system to maintain the 2K criterion while transmitting maximum possible power through the remaining cable based on actual thermal conditions rather than predetermined conservative limits.
3Temperature
If oversized submarine cables are used to prevent temperature rise during normal operation, then the 2K criterion is satisfied, but the cables operate significantly below their rated current capacity
Solution Approach 1:
The patent implements feedback by installing temperature sensors in the seabed near the cable and using this real-time temperature data to control the current through the cable. This allows the system to operate at or near the cable's rated current capacity when thermal conditions are favorable, rather than being constrained by the conservative design assumption that the cable must operate at a fraction of its capacity. The feedback loop ensures the 2K criterion is maintained while maximizing power transmission.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the operating current based on actual seabed temperature conditions rather than relying on fixed design parameters. The control device modifies the current parameter in real-time based on temperature feedback, allowing the cable to operate closer to its true thermal and electrical limits. This transforms the cable from an oversized, underutilized component to an optimally utilized transmission asset.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the submarine cables to operate closer to their maximum capacity, optimizing power transmission and reducing the need for costly upgrades or additional cables, while maintaining compliance with environmental protection requirements.
Implementation Method 1
determining, using a prognosis device, a maximum permissible time-dependent current for the submarine cable as a function of a specified value of a maximum permissible temperature parameter at a reference point which is at a specified depth of the seabed
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method for current control of an offshore wind energy system (2), wherein the offshore wind energy system (2) comprises at least one submarine cable (8, 10), comprising detecting the current fed into the submarine cable (8, 10) at a feed-in point, determining a maximum permissible current for the submarine cable (8, 10) as a function of a predetermined value of a temperature parameter at a reference point located at a predetermined depth of the seabed (26), and controlling the current fed into the submarine cable (8, 10) such that the fed-in current does not exceed the determined maximum permissible current.