Reliability Assessment in Motor-Driven Compressor Units Based on D-S Evidence Theory

The scientific reliability assessment is important for motor-driven compressor units, to evaluate the reliability standard, find the performance deficiency and provide references for operation and maintenance. Besides, it can reduce the test costs and accelerate the development process. Classical reliability assessment method is not suitable for the complex and reliable equipment, like motor-driven compressor units, because it is faced with the challenge of application of the multi-source information. A multi-source information based reliability assessment method is proposed in this paper. The fusion resources of this method consist of design information and operation & maintenance information. Component based and function based reliability assessment can be completed using component tests and design information. While quality evaluation based and life model based reliability assessment can be completed using operation information mainly. Finally, the unit reliability can be assessed by fusing the characteristic parameters above based on D-S evidence theory. A case study is conducted to evaluate a 20MW-class motor-driven compressor unit by this method. There are four information resources, component tests, design information, operation data and simulation data in the case. The unit reliability is assessed as 99.32% by the fusion of four reliability assessment results, acquired at different aspects. This assessment result is validated by the statistical assessment result based on long-term shutdown reports. This application points out the existing weakness in the motor-driven compressor unit and indicates directions for improving the design and operation technology. It reveals that this reliability assessment result can provide support for making a new production plan and strengthen construction of data network. Meanwhile, it has good expansibility, which may be used in more fields.