A review on approaches for condition based maintenance in applications with induction machines located offshore

This paper presents a review of different approaches for Condition Based Maintenance (CBM) of induction machines and drive trains in offshore applications. The paper contains an overview of common failure modes, monitoring techniques, approaches for diagnostics, and an overview of typical maintenance actions. Although many papers have been written in this area before, this paper puts an emphasis on recent developments and limits the scope to induction machines and drive trains applied in applications located offshore

Toward farm-level health management of wind turbine systems: Status and scope for improvements

An outline of health management for OWFs has been detailed in this chapter with description of various important elements. The need for such farm level management is explained and benefits are discussed. Key gaps to be filled in order to realize such a system are identified. The proposed health management system is mainly based on the existing knowledge of fleet-level management in the aerospace sector. Health management is much broader than CM; there are a number of aspects beyond the prognostics capabilities that are to be designed in order to arrive at a comprehensive maintenance management scheme. A comprehensive maintenance program that is sensitive to the health of the assets and adapts maintenance schedule accordingly, depending upon resource availability, logistics and inventory, is key to cost optimization while ensuring reliability and availability. The advances in CM and diagnostics in wind energy are in the right direction, and many of them are building blocks for health management. Offshore wind faces a number of unique challenges that can be satisfactorily addressed by following a suitable systematic approach. RCM implementation appears to be the most suitable as it encompasses other maintenance strategies and is suitable for farm-level deployment

Fault diagnostics for electrically operated pitch systems in offshore wind turbines

In this chapter, the main objective is to determine the feasibility and applicability of current signature analysis for pitch motors in typical operating profiles. In order to determine pitch system operation profiles, the 5 MW reference wind turbine is simulated in FAST analysis tools developed by National Renewable Energy Laboratory [10]. The pitch systems however pose significant challenge in terms of intermittent, start-stop operating profiles and low speed operations. The main contribution of this chapter is therefore twofold: (1) to develop a detailed physical modelling of various motor faults and study their effect on motor currents in pitch system operating profiles and (2) to determine the feasibility of current signature analysis in such operating profiles. The rest of this chapter is organised as follows: In Section 8.2, determination of the typical pitch profiles from FAST analysis tool is described. Further, a detailed modelling of induction motor with implementation of various fault conditions is described in Section 8.3. In Section 8.4, the motor current signature analysis (MCSA) is tested for pitch motor diagnostics in various wind turbine operating profiles. Finally, accuracy of the fault detection algorithms and steps towards implementation in wind farms are discussed

Accelerated bearing life-Time test rig development for low speed data acquisition

Condition monitoring plays an important role in rotating machinery to ensure reliability of the equipment, and to detect fault conditions at an early stage. Although health monitoring methodologies have been thoroughly developed for rotating machinery, low-speed conditions often pose a challenge due to the low signal-To-noise ratio. To this aim, sophisticated algorithms that reduce noise and highlight the bearing faults are necessary to accurately diagnose machines undergoing this condition. In the development phase, sensor data from a healthy and damaged bearing rotating at low-speed is required to verify the performance of such algorithms. A test rig for performing accelerated life-Time testing of small rolling element bearings is designed to collect necessary sensor data. Heavy loads at high-speed conditions are applied to the test bearing to wear it out fast. Sensor data is collected in intervals during the test to capture the degeneration features. The main objective of this paper is to provide a detailed overview for the development and analysis of this test rig. A case study with experimental vibration data is also presented to illustrate the efficacy of the developed test rig

Improved child-resistant system for better side impact protection

The article presents a new solution of child-resistant systems to improve the safety of children transported in motor vehicles subjected to a side impact during a vehicle crash. The proposed concept works by means of implementation of an energy dissipation mechanism acting between a child restraint system anchorage and a restraint system seat. The effectiveness of the proposed system is evaluated using numerical analyses of a simplified basic model as well as more complex mechanical design of the mechanism. The latter is analyzed as a part of the child restraint system (CRS) together with a deformable model of an anthropomorphic test device of Q3 series. Tests outcomes clearly show a positive effect of application of the proposed energy dissipation system resulting in reduction of head and thorax acceleration and influencing a lower factor (index) of the head injury criteria. The presented solution shows that there is still a room for improvement of young passengers safety