Reliability Study of Important Cross-Over Transmission Line System Based on Series System

Transmission lines inevitably cross railroads, highways, and other facilities, and in order to ensure the safety and reliability of the cross-crossing section, the influence of various random factors on important cross-crossing transmission lines needs to be fully considered. In this paper, the transmission line crossing section is treated as a tandem system according to the force transmission route, and the reliability calculation method of the cross-crossing transmission line system based on the tandem system is proposed. The reliability calculation method of each component and the reliability calculation method of the tandem system are given. Finally, an example of the reliability calculation of a 220kV cross-crossing transmission line system is given, and the results show that the cross-crossing section has the highest reliability of tower FSJ404, with a reliability index of 8.61, the second highest reliability of insulators, with a reliability index of 7.22, and the lowest reliability of tower FSJ302, with a reliability index of 4.28. The failure probability of the cross-crossing section is 0.000009245, and the reliability index is 4.28.

On-line Measurement Method and Technical Scheme of Transmission Line Crossing Point Based on Machine Vision

With the increasing demand for high voltage and UHV transmission, higher and higher requirements are put forward for transmission line monitoring and fault diagnosis. The traditional line measurement method has many shortcomings, which cannot ensure the measurement accuracy, measurement efficiency and high cost. Based on this, this paper first studies the principle of machine vision on-line measurement, then analyses the on-line measurement process of transmission line crossing point based on machine vision, and finally gives the error source and amelioration measures of transmission line crossing point on-line measurement.

Novel method for trisomy 21 screening in the first trimester of pregnancy: fetal brain angle

Objectives The present study was performed to examine the utility of a new first trimester marker called the “brain angle” (BA) in screening for trisomy 21. We postulate that differences in the midbrain anatomy between euploid fetuses and those that are affected by trisomy 21 are reflected in changes in BA measurements. Methods In fetuses at 11+0–13+6 weeks of gestations, which were at high risk for trisomy 21, the angle was measured between the line crossing the thalamus and mesencephalon cranial border tangentially and the line crossing the brainstem lower limit. This angle was compared between fetuses with trisomy 21 (based on karyotyping) and those with a normal karyotype. Results Trisomy 21 was detected in 45 (8%) of 560 fetuses. Receiver operating characteristic analysis showed that, at BA≥94°, the sensitivity and specificity for determining trisomy 21 were 97.8% (95% CI=88.2–99.9%) and 100% (95% CI=99.2–100%), respectively. Conclusions Fetal BA appears to be a promising new first trimester marker in screening for trisomy 21.

Optimization of design solutions for large overhead line water crossings

Safety, reliability, and transmission capacity are crucial for overhead power line waterway crossings. This paper reflects research results of multi-criteria optimization of a projected 220kV overhead line crossing across the Kama river. Five overhead line crossing options have been compared. These options differ by types of wires to be used, including ACSR, TACSR/ACS, ААСSRZ (ВП), АССС, and АСk2y wires. The additive convolution method has been used for selecting the best available option. A multi-criteria analysis has been simplified by one certain supercriterion. As a result, the option with АССС type wires was determined as the most efficient and promising. The АСk2y wires option was the secondary option.