Imbalance Fault Detection Based on the Integrated Analysis Strategy for Marine Current Turbines under Variable...

Area of Science:

• Renewable Energy Engineering
• Marine Renewable Energy
• Electrical Engineering

Background:

• Marine current turbines (MCTs) offer a renewable energy source but suffer from biofouling on blades, degrading reliability and power quality.
• Existing fault detection methods often rely on single-phase electrical data, which may not capture the full complexity of MCT operational issues.

Purpose of the Study:

• To develop an advanced fault detection method for marine current turbines that utilizes comprehensive three-phase electrical data.
• To enhance the reliability and power quality monitoring of marine current energy conversion systems.

Main Methods:

• A novel fault feature was created using the derivative of the current vector modulus in a Concordia reference frame.
• Adaptive proportional sampling frequency (APSF) transformation was employed to address non-stationary fault features caused by varying current speeds.
• A fault indicator was derived from the amplitude of the shaft rotating frequency's power spectrum.

Main Results:

• The proposed method successfully detected introduced imbalance faults (80-220g mass on blades) in a testbed marine current turbine.
• The three-current-based fault indicator was, on average, 2.2 times larger than indicators derived from single-phase data.
• The fault indicator showed a monotonic increase with fault severity (1.8 times higher variation rate) and robustness across flow speeds of 0.95-1.3 m/s.

Conclusions:

• The developed fault detection technique effectively identifies blade imbalance faults in marine current turbines.
• Utilizing three-phase current information significantly enhances fault detection sensitivity and reliability compared to single-phase methods.
• The method's robustness to varying current speeds makes it suitable for real-world marine energy applications.