Reliability Evaluation Of Relay Protection Device Considering Chip-module-machine Structure

The core chips of relay protection devices heavily rely on imports,posing a risk of power outage and directly affecting the safety of the power grid.Building a highly reliable and high-performance protection device based on independent chips has become an important demand for the development of China’s power grid.However,compared to imported chip devices,relay protection devices with independent chips not only have differences in hardware equipment,but may also have differences in important factors(temperature)that affect the reliability of chips and protection devices.How to evaluate their reliability is a problem that needs to be solved.In view of this,this article starts from the chip module whole machine structure,analyzes the failure rate prediction method of the core chip,module,and whole machine of the temperature protection device,and proposes a health status evaluation model for the relay protection device.The main work is as follows:(1)A failure rate prediction method suitable for relay protection device chips is proposed to address the issue of unclear applicability of existing chip failure rate prediction methods to core chips of protection devices.Firstly,a method combining high acceleration with environmental factor correction was proposed based on existing chip failure rate prediction methods;Secondly,for relay protection devices,a method for estimating chip failure rate based on chip module whole machine defect statistical data is proposed;Furthermore,the adaptability of the proposed method to relay protection chips was verified through mutual verification of examples.(2)In response to the lack of consideration of internal modules and temperature effects in existing reliability models of protective devices,a reliability model for core modules and the entire machine considering thermal effects is proposed.Firstly,by analyzing the structure of relay protection devices,three main failure modes were identified:hardware failure,software failure,and human factor failure.Based on statistical data,it was determined that the failure of CPU modules,power modules,and other modules should be considered as hardware failure;Secondly,combining the Weibull timevarying failure rate model of each module with the temperature dependent Arrhenius model,an improved Weibull distributed failure rate model integrating temperature was established,and a reliability prediction model for the entire relay protection system was provided;Furthermore,the effectiveness of the proposed model was verified through an example;Finally,the impact of temperature changes on the reliability of the entire machine was analyzed based on sensitivity analysis.(3)A health status evaluation model for protection devices that integrates chip,module,and machine information is proposed to address the issue of incomplete and lack of chip information in existing protection devices.Specifically,by analyzing the failure mechanism and influencing factors of protective devices,a progressive three-level indicator evaluation system is established;In response to the deviation of operating data from the normal range,degradation degree is introduced,and the weights of each layer of indicators are dynamically adjusted based on their size,solving the problem of small constant weight indicators being submerged;In the selection of membership functions,the most suitable membership function for relay protection devices was proposed by combining theory with examples,making the evaluation results more accurate;Through examples,it is shown that the membership function and variable weight method in the constructed model are correct and effective,and can provide scientific basis for subsequent work.