An Elimination Method of Temperature-Induced Linear Birefringence in a Stray Current Sensor

Abstract

In this work, an elimination method of the temperature-induced linear birefringence (TILB) in a stray current sensor is proposed using the cylindrical spiral fiber (CSF), which produces a large amount of circular birefringence to eliminate the TILB based on geometric rotation effect. First, the differential equations that indicate the polarization evolution of the CSF element are derived, and the output error model is built based on the Jones matrix calculus. Then, an accurate search method is proposed to obtain the key parameters of the CSF, including the length of the cylindrical silica rod and the number of the curve spirals. The optimized results are 302 mm and 11, respectively. Moreover, an effective factor is proposed to analyze the elimination of the TILB, which should be greater than 7.42 to achieve the output error requirement that is not greater than 0.5%. Finally, temperature experiments are conducted to verify the feasibility of the elimination method. The results indicate that the output error caused by the TILB can be controlled less than 0.43% based on this elimination method within the range from −20 °C to 40 °C.

Evaluating the stray current corrosion of steel rebar in different layouts

“…In this case, the stray current flowing in the tunnel segments can be parallel or vertical to the steel rebar. To study the stray current-induced corrosion for steel in concrete, although various works reported different aspects [13][14][15][16][17][18][19], the effects of the steel rebar layout on the amount and distribution of stray current corrosion product are still not investigated sufficiently. This aspect is of significance in view of the degree of corrosion damage, and geometrical location of corrosion product accumulation on the steel rebar surface.…”

A New On‐line Monitoring Method for Stray Current ofDCMetro System

“…Nowadays, 750 or 1500 V DC power supply is usually used in metro at home and abroad [3,4], and running rail of metro is also a reflux passage of traction current. Since the rail and earth cannot reach absolute insulation, part of current leaks into the earth and forms stray current [5][6][7]. The normal operation of electrical equipment and facilities in the subway are seriously affected by long-term existing stray current, at the same time, tunnels, track bed structural steels, and nearby metal pipelines suffer from severe electrochemical corrosion, 1 A stray current will cause metal weight loss up to 9.13 kg in 1 year, so service life is shortened [8,9].…”