With the development of high speed railway traffic, the structure health monitoring for high-speed rail is necessary due to the safety issue. Optical fiber sensing technology is one of the options to solve it. Stress ...With the development of high speed railway traffic, the structure health monitoring for high-speed rail is necessary due to the safety issue. Optical fiber sensing technology is one of the options to solve it. Stress vector information is the important index to make more reasonable judgments about railway safety. However, information sensed by lots of commercial optical sensors is scalar. According to the stress filed distribution of rail, this paper proposes a new type of stress vector sensor based on optical fiber sensing cable(OFSC) with a symmetrical seven optical fibers structure and analyzes the relations between angle resolution and distance between adjacent of optical fibers through finite-element software(ANSYS) simulation. Through reasonable distance configuration, the angle resolution of the OFSC can be improved, and thus stress vector information, including the stress magnitude and the angle of stress, can be more accurately obtained. The simulation results are helpful to configure OFSC for angle resolution improvement in actual practice, and increase the safety factor in high speed railway structure health monitoring.展开更多
All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arci...All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arcing. These cables become less hydrophobic over time and become vulnerable to dry band arcing.This loss in hydrophobicity is because of the contamination formed on the outer layer due to pollution.This is one of the reasons which cause cable failure.Considerable amount of losses will be incurred on the occurrence of a cable failure as the cables are also leased to other companies.An improved equivalent circuit is used to calculate the voltage and current distribution of the double circuit line.A three-phase single circuit line and a three-phase double circuit line are used to calculate their corresponding voltage distribution and current distribution.The results could be used to predict dry band arcing on similar models.The method used considers sag,span and pollution on ADSS cable.展开更多
Novel small Raman gain measurement method for installed fiber optic cables using a modulated pump light is proposed. We have demonstrated accurate Raman gain measurement in small Raman gain less than 1dB and we also m...Novel small Raman gain measurement method for installed fiber optic cables using a modulated pump light is proposed. We have demonstrated accurate Raman gain measurement in small Raman gain less than 1dB and we also measured Raman gain for the installed fiber optic cable by using average pumping power of about only 25mW.展开更多
文摘With the development of high speed railway traffic, the structure health monitoring for high-speed rail is necessary due to the safety issue. Optical fiber sensing technology is one of the options to solve it. Stress vector information is the important index to make more reasonable judgments about railway safety. However, information sensed by lots of commercial optical sensors is scalar. According to the stress filed distribution of rail, this paper proposes a new type of stress vector sensor based on optical fiber sensing cable(OFSC) with a symmetrical seven optical fibers structure and analyzes the relations between angle resolution and distance between adjacent of optical fibers through finite-element software(ANSYS) simulation. Through reasonable distance configuration, the angle resolution of the OFSC can be improved, and thus stress vector information, including the stress magnitude and the angle of stress, can be more accurately obtained. The simulation results are helpful to configure OFSC for angle resolution improvement in actual practice, and increase the safety factor in high speed railway structure health monitoring.
文摘All-dielectric self-supporting(ADSS) cables are installed along with transmission line for the purpose of communication.During installation the outer layer of the cable is hydrophobic and is not prone to dry band arcing. These cables become less hydrophobic over time and become vulnerable to dry band arcing.This loss in hydrophobicity is because of the contamination formed on the outer layer due to pollution.This is one of the reasons which cause cable failure.Considerable amount of losses will be incurred on the occurrence of a cable failure as the cables are also leased to other companies.An improved equivalent circuit is used to calculate the voltage and current distribution of the double circuit line.A three-phase single circuit line and a three-phase double circuit line are used to calculate their corresponding voltage distribution and current distribution.The results could be used to predict dry band arcing on similar models.The method used considers sag,span and pollution on ADSS cable.
文摘Novel small Raman gain measurement method for installed fiber optic cables using a modulated pump light is proposed. We have demonstrated accurate Raman gain measurement in small Raman gain less than 1dB and we also measured Raman gain for the installed fiber optic cable by using average pumping power of about only 25mW.
