Advanced Materials Research Vols. 605-607

Abstract: In order to accurately describe the equipment’ severity caused by voltage sag, the credibility measure which meets the conditions of non-additive is proposed based on their physical properties of responses. This assessment measure can avoid the deficiencies that classical probability measure needs a large number of samples and the non-duality of fuzzy measure. The membership functions of sensitive equipment voltage tolerance capability that corresponding to the characteristic quantities in the status uncertain area was determined by fuzzy statistical method and polynomial fitting method. Then the joint credibility distribution function was deduced based on uncertainty theory. Hence, the assessment model of severity of equipment failure is constructed. Based on practical samples, the PCs were simulated using the proposed method. Comparing the simulation results with methods using classical probability measure and possibility measure prove that the proposed method is proper and credible and can reflect practical condition more objectively.

Abstract: The paper proposes fault diagnosis system that simplify circuit before using D algorithm， aiming at creating detection vector inefficient. Through simplifying circuit, the hour of creating detection vector is cut and establishment of fault diagnosis databases is easy. This method is applied to diagnose fault of output circuit board on tank. In conclusion, this method of the fault diagnosis to circuit board orientates the fault accurately and quickly.

Abstract: The paper focuses on introducing the basic condition of the TEAMS and the basic design process of multi-signal modeling and diagnostic strategy. Moreover, it introduces the applications of TEAMS in fault diagnosis from three aspects: model establishment, performance analysis and diagnostic strategy. The superiority and effectiveness of above-mentioned method is verified by an instance and the results are useful to the fault diagnosis of complex electronic equipment.

Abstract: In order to improve mechanism movement reliability of galting gun, through analyzing functions at different periods of mechanism movement course and basing on reliability, mechanism kinematics and movement error analysis theory, design variables which affect mechanism movement reliability are sampled according to distribution law. Using VC++ development environment and MFC class library’s supporting and putting parametric model into ADAMS software, mechanism movement characteristic at different design parameters is emulation calculated. According to emulation results mechanism movement reliability is estimated and all design parameters’ sensibility is analyzed, which realizes mechanism movement reliability analysis based on parametric model and provides a useful exploration for galting gun’s reliability design.

Abstract: It is difficult to assess the impact of voltage sags on sensitive equipment because of the complex uncertainties involved in voltage tolerance capability. Determining the distribution regularity of voltage tolerance capability is an important step in voltage sag sensitivity assessment. Computers’ voltage tolerance capability are obtained through laboratory tests. The point-value distribution function of voltage tolerance capability is calculated by Maximum Entropy Principle and then the interval probability distribution function is derived based on confidence interval, so as to derive an interval probability of equipment failure probability. The proposed model is finally verified in the IEEE-30 bus system. The results are compared with that of stochastic estimation method, showing that the proposed method can reflect actual conditions better and obtain accurate result.

Abstract: All sorts of design variables and parameters are often regarded as fixed values in the traditional design, it cannot describe quantitatively how well the products are safe. It is necessary to make a reliability analysis of cycloidal gear, which is the key part of FA pin-cycloidal transmission, this paper uses Monte-Carlo method to simulate and test the distribution laws of the contact stress and the contact fatigue strength of cycloidal gear, which indicates that the contact stress obeys the normal distribution and the contact fatigue strength obeys the lognormal distribution, besides, makes a sensitivity analysis of the random parameters, all these work lay the foundation for the reliability analysis of the whole reducer.

Abstract: Taking the influence caused by shunt reactors into account, proposes a new fault location algorithm. Based on distributed modal, the algorithm constructs frequency spectrum equations of the faulty network with line parameters to identify, extracts fundamental wave and harmonics of transient signal to solve equations to obtain fault position and exact parameters.

Abstract: When faults happen to the power system components, the duration of voltage sags is determined by the cooperation of protection system. Many literatures have been done in analyzing the factors which influence the magnitude of voltage sags, but the impact of protection cooperation on sag duration is not considered by existing studies. In order to estimate the duration of voltage sags more precisely, the novelty of the proposed approach is in probabilistic modeling of the cooperation of the protection system using the concept of Markov state space, then voltage sag frequency and sensitive equipment trips considering protection cooperation can be estimated by utilizing the configuration and setting value of the protection system. The proposed method was applied to the IEEE 57-bus test system, and the simulation results show that the proposed method is practical, simple and adaptive.

Abstract: A steel works 210 tons basic oxygen furnace tilting mechanism senior reducer high-speed helical gear shaft fracture. In order to find fractured reason, the static strength analysis of helical gear shaft were conducted by the finite element analysis software ANSYS, get the amount of deformation and stress distribution of helical gear shaft. On the basis of this result, based on fatigue cumulative damage theory and the concept of fatigue failure ensure it is fatigue fracture. The results of Static strength analysis provides important data to calculate fatigue life of helical gear shaft by fatigue analysis software, and Provides a theoretical basis for reliability design of helical gear shaft.

Abstract: the paper mainly solves the questions of real time fault detection and diagnosis for fire control system. Function structure and fault characteristics of the fire control system be hierarchical analyzed, through fault omen character and fault reason make up of fault stylebook, use neural network training to improve the fault diagnosis accuracy, select implication operator and calculate the fuzzy membership degree matrix of fault information, through hierarchical reasoning to complete fault recognition and confirm fault source to improve the diagnosis rate. The system is multifunctional which includes of state monitoring, fault diagnosis, diagnosis opinion, the distributed principal and subordinate structure design is propitious to improve reliability and adaptability of the system.