Romanenko N. G. Increasing efficiency of ship cables defectation

The ship power supply system is a complex system that supplies electrical energy to various mechanisms and devices using wires and cables. The reliability of power supply largely depends on the technical condition of the cable lines. During operation, cable lines are regularly exposed to mechanical stress, both from external factors and from people. Some of the most common causes of cable damage are: aging insulation, overvoltage, thermal stress, boat vibration, and corrosion and moisture. Leaving the operating state of the cable line can lead to emergencies. A cable with damaged insulation can cause an electric arc with a metal object. If several phases of a cable with damaged insulation, then when they touch, a phase-to-phase short circuit occurs, as a result of which a large amount of heat is released, from which the cable insulation and other nearby combustible materials can ignite. There is considered the principle of operation of DIPCEL (a device for diagnosing ship cables) and shown its main disadvantages in determining the aging and moisture indicators of cable insulation. It is proposed to use the absorption coefficient for increasing the efficiency of measuring the ship’s cable insulation moisture. For insulating materials, in which the absorption current decreases rapidly, resistance measurements should be taken after 15 sec and 60 sec. The absorption coefficient is defined by measuring the ratio of a sixty-second insulation resistance to a fifteen-second resistance. If the value of the obtained coefficient is less than 1.25, then the insulation is unsatisfactory; if the value is within 1.25 - 1.6, than the insulation is normal, if more than 1.6 - the insulation is excellent

Real-time quantitative evaluation on the cable damage of cable-stayed bridges using the correlation between girder deflection and temperature

Stayed cable is an important prestress-bearing component in cable-stayed bridges, and the cable damage will seriously threaten bridge safety. In this research, the method of real-time quantitative evaluation on cable damage is proposed through monitoring data analysis, correlation analysis, damage evaluation analysis, and validation analysis. Monitoring data analysis shows that temperature has a good linear relationship with girder deflection and cable force. Correlation analysis shows that this relationship is well described by a time-varying multiple linear regression model. In damage evaluation analysis, a new damage index is proposed for real-time quantitative evaluation. Each stay cable has a corresponding damage index, and a large value of damage index indicates a serious damage. The results of experiment and finite element analysis show that the evaluation error of this damage index is very small, which is feasible for real-time quantitative evaluation. This method can provide valuable reference for real-time quantitative evaluation on cable damage of cable-stayed bridges.

A Cost-Effective Approach to the Risk Reduction of Cable Fault Triggered by Laying Repeaters of Fiber-Optic Submarine Cable Systems in Deep-Sea

Long-distance submarine cable systems, such as the transoceanic system, generally consist of a series of cables and repeaters. Repeater units are spaced at regular intervals to boost the attenuated optical signal and presently contain optical amplifiers in a pressure vessel made of copper alloy. Since the repeater unit is more massive than the cable, it pulls the cable catenary locally toward the seabed. In the 1990s, several studies numerically simulated cable behavior in the water and showed that the seabed slack runs short, and the seabed cable tension increases just before the repeater reaches the seabed. Therefore, it has been pointed out that an unarmored cable with a polyethylene sheath can be easily damaged. However, no reports have been published regarding the actual situation of cable faults related to the laying of repeaters. This study quantitatively analyzes the mechanism of cable damage related to the laying of repeaters, based on experiments, simulations, maintenance records, and a comparative analysis between the simulation results and actual cable faults. Cost-effective methods to mitigate cable faults triggered by laying a repeater in the deep sea are also explored to ensure mechanical stability during the design lifetime.

Aircraft Arrestor System Panel Joint Improvement

Aircraft Arresting Systems (AAS) for military applications utilize sacrificial panels made of Ultra-High Molecular Weight polyethylene (UHMWPE) that are embedded into the pavement beneath the AAS cable to protect the pavement from cable damage. Problems have been observed with the materials and practices used to seal the UHMWPE panel joints from water and debris. Data obtained from laboratory and field studies were used make improvements to current practice for sealing UHMWPE panel joints. The study evaluated four joint-sealant materials, eight alternative surface treatment and preparation techniques to promote adhesion to UHMWPE, and seven joint-edge geometries. Bond-strength testing of joint-sealant specimens was conducted in the laboratory, followed by field evaluation of construction techniques. Field performance of the joint systems was monitored for 24 months after installation. Additionally, a thermal response model was developed to refine the joint design dimensions. Results confirmed that the best material to use was self-leveling silicone joint sealant. It was recommended that a dovetail groove be cut into the edge of UHMW panels to provide positive mechanical interlock and to reduce adhesive failures of the sealant. It was also recommended that the panel-to-panel joint-sealant reservoir be widened to prevent sealant compression damage.

Development of a Cable Damage Detection Deep Learning Method based on Acceleration Response of Cable-Stayed Bridge

The purpose of this thesis was to select a cable-stayed bridge to which external force may cause damage as the subject, to develop a damage detection deep learning method capable of detecting cable damage, and to test and verify the developed damage detection deep learning method. The damage detection method was developed as a system that utilizes the acceleration response of a structure measured for maintenance purposes. To extract information capable of identifying the damage locations from among the measured acceleration responses, a CNN ID was used to develop the damage detection deep learning method. The developed damage detection deep learning method was developed in a way not independently arranging 1 machine learning model per each measuring point and finally predicting the damage location based on the decision-making results collected from each machine learning model. The developed damage detection deep learning method performed the learning per each machine learning model by utilizing the acceleration response of a structure acquired based on the preliminary damage test. Finally, the damage detection deep learning method that completed the learning verified the cable damage location detection performance by utilizing the data acquired based on the cable-stayed bridge damage test. As a result, it was confirmed that the developed damage detection deep learning method predicted the damage location of a cable-stayed bridge at an average accuracy of 89%. In the current research, only the cable-stayed bridge of the Seohaegyo Bridge was studied, but in the improved study, the research will be conducted on other bridges and damage assessment will be conducted on all cables.

Study on the damage analysis of 110kV cable structure

The market application value of power cables has gradually emerged with the development of various industries. Cable laying is a basic project in the construction of power grid and a key part of power engineering construction, and a key content of power engineering construction, which is related to the safe and reliable operation of the entire power grid. With the laying process of power cable, the metal sheath is subjected to structural damage such as extrusion deformation. This paper takes a 110kV cable line as an example, The case of cable damage was introduced in detail, and targeted measures were proposed based on the defects caused by the damage. At the same time, the structural analysis of the cable damage is carried out, and the structural analysis and simulation are performed, and the partial discharge test is performed on the damaged portion of the insulation to obtain the stress received when the cable is recessed, and the partial discharge signal detected by the damage of the insulating shielding layer is collected. Provide reference for staff related to power cables.