35results about How to "Improve computing reliability" patented technology

The invention relates to a method for estimating direct current transmission system grounding electrode address resistance utilizing average values, and belongs to the technical field of electric system distance measurement. According to the method, the long time window average value of the grounding electrode measuring end voltage and the long time window average value of the grounding electrode measuring end two-loop outlet line current are calculated according to the recording data obtained before line faults of a grounding electrode circuit, then, the total equivalent resistance value shown from the measuring end is worked out according to the long time window average value of the grounding electrode measuring end voltage and the long time window average value of the grounding electrode measuring end two-loop outlet line current, and lastly, the resistance value of the grounding electrode address is worked out according to the total equivalent resistance value shown from the measuring end and the resistance value of the grounding electrode circuit. The ground electrode address is estimated based on the existing fault recording data, high-frequency sampling is not needed any more, and the estimation can be carried out in field easily.

A welding joint for a fuel tank includes a cylindrical portion and an annular weld portion. The weld portion has a multi-layer structure formed by layering an inner layer member made of a resin alloy material obtained by alloying a modified HDPE, to which a functional group having a high affinity to a hydroxyl group of EVOH is introduced, and EVOH, or by alloying the modified HDPE, normal HDPE and EVOH, and an outer layer member which uses the HDPE resin and / or modified HDPE resin and has high weldability to the fuel tank. Each of the inner and outer layer members is heat-welded to the fuel tank at a corresponding welding end surface. In a vicinity of at least one of the welding end surfaces of the inner outer layer members, a flow preventing portion that prevent a molten part of the inner layer member from flowing the outer layer member is provided.

The invention discloses a diffuse reflection light source system and a design method for visual detection, which can obtain the shape of a diffuse reflection curved surface according to the size of a target illumination area, and effectively improve the illumination uniformity of the target area. On the basis of the rectangular array light source, the illuminance distribution of the reflective surface is solved, the light intensity distribution of the reflective surface is obtained according to the principle of energy conservation, the illuminance distribution formula of the target surface is obtained, and the coordinates of a series of discrete points on the reflective surface are obtained to obtain the reflective surface. The invention has sufficient theoretical basis, simple and practical mathematical modeling, and high calculation reliability. The light source system built according to the optimal structural parameters has the characteristics of uniform illumination, high energy utilization rate, and no blocking of the lens. It can effectively Improving the imaging quality of the target object in visual inspection has important practical significance for improving the detection accuracy.

The invention discloses a fault rate evaluation method of an MMC (Modular Multilevel Converter). The fault rate evaluation method comprises the following steps: (1) acquiring a sub-module and a sub-module assembly of an MMC circuit; (2) inputting working parameters of the MMC circuit and the sub-module assembly thereof, and finishing setting of initial conditions; (3) calculating a fault rate of the sub-module assembly according to a fault model to obtain the fault rate of the sub-module; (4) establishing a Markov model of the MMC circuit and establishing a state transfer equation based on the Markov model; (5) solving the state transfer equation to obtain a variation function of the fault rate of the MMC circuit along with time and module quantity, a variation function of the reliability along with the time and the module quantity and average failure time. The calculation reliability of the fault rate of the sub-module assembly is greatly improved and the estimation reliability of the fault rate of the MMC circuit is improved; by applying the Markov model, the solved fault rate and average service life of the MMC circuit are relatively accurate and are varied along with time variation; the fault rate evaluation method has a dynamic property and high fault evaluation precision.

The invention relates to a seaborne boundary condition simulation method for an FLNG device liquidation process. The method is characterized by comprising the following steps of: (1) establishing a three-dimensional control volume unit, working mediums of which flow in an FLNG liquidation process system, under a sea condition, and carrying out analysis to obtain a momentum equation of working medium flow directions; (2) obtaining a three-dimensional motion equation of a hull or a platform on the basis of sea condition basic data of an actual operation sea area; (3) carrying out calculation to obtain a translational motion equation and an angular motion equation of working medium gravity centers; (4) establishing a one-dimensional fluid flow equation for representing flow, in the FLNG liquidation process system, of the working mediums under the actual sea condition; and (5) calculating sea condition boundary condition parameters according to the one-dimensional fluid flow equation, and loading the sea condition boundary condition parameters into a FLNG device liquidation process dynamic model so as to realize application of actual sea condition environment to FLNG device liquidation process. The method can be widely used for improving the simulation facticity and emergency working condition prediction correctness of the FLNG device liquidation process.