Control Cables Research Articles

Vibration reduction of automotive transmission control cables

A reduction in the level of vibration in the gearshift lever module in the cabin of automobiles may have a positive effect on driver comfort. The vibration to the gearshift lever module is transferred through transmission control cables (TCCs) connected to the shift lever attached to the body of a transmission or transaxle. Ways to reduce vibrations are evaluated by analyzing vibration characteristics of TCCs employed in conventional gearshift lever modules. The analysis was carried out by both analytical and experimental approaches, including the construction and analysis of a finite element model of the module. By utilizing the results from the analysis, a vibration reduction method was proposed and its applicability was also investigated. It is observed from the investigation that the proposed method is a viable solution for both the reduction of vibration-related issues in gearshift level modules and improvement of ride quality.

Assessing the fire risk of electrical cables using a cone calorimeter

The presented study deals with the fire risk of electrical cables. Samples of three-core electrical power cables and two-core electrical control cables were investigated. The influence of the mutual spacing between the cables and the thermal conductivity of the material under the cables (underlying material) on fire risk was assessed in the study. The fire risk was determined using a cone calorimeter (at a heat flux of 50 kWm−2) and an oxygen bomb calorimeter. The fire risk was assessed based on parameters quantifying the released heat, toxicity and amount of combustion products and flashover category. The heat release rate, total heat release and the effective heat of combustion increase with increased spacing between the cables and decreased thermal conductivity of the underlying material. The carbon monoxide yield increases with the increase in the thermal conductivity of the underlying material. The influence of the spacing between cables on the carbon monoxide yield (in the interval 0–1800 s) depends on the thermal conductivity of the underlying material. At low thermal conductivity, the carbon monoxide yield decreases as the spacing decreases, with the opposite trend (with some exceptions) at high thermal conductivity. Smoke yield decreases with increasing thermal conductivity of the underlying material and also increases with increased spacing between cables. Neither the thermal conductivity of the underlying material nor the spacing between cables has an influence on the flashover category of the cables investigated.

Nonlinear mechanics of flexible cables in space robotic arms subject to complex physical environment

A nonlinear model of a special cable in space robotic arms is developed in space environment. The mechanic effects of control cables in powerful robots can often be neglected. However, in complex space multi-physics environments, involving ultra-low temperature, radiation, and other extreme conditions of outer space, the externally mounted cables (protected by shielding layers) can induce strong nonlinear interference to robot arms; and this can induce further small-range slow rotations or oscillations of the flexible joint of robots at a specific posture, which consequently affect the precision and operation performance of end effectors. Effective mathematical models on nonlinear mechanics of strong cables under multi-physics environments and their effects on weak robots have not been well developed yet. Complex key factors, such as low gravity, nonlinear friction, and unexpected curved surface constraints, have not been extensively investigated either. In this study, considering all these key factors, a Kirchhoff nonlinear mechanical model of cables in complex space environments is developed, and a relatively improved algorithm based on a trust-region strategy is proposed for solving this nonlinear model, based on which the geometry and terminal force of the modeled robot cable can be obtained. The validity and accuracy of the proposed algorithm and theoretical calculation results are verified via experiments. The theoretical findings revealed in this study are significant to future research on the slow rotations and oscillations of weak robot joints in space exploration with robotic arms.

2H3-5 Study on work load evaluation and reduction method for handling task of control cable in Substation

2H3-5 Study on work load evaluation and reduction method for handling task of control cable in Substation

Dynamic behavior and vibration mitigation of a spatial tensegrity beam

The present study focuses on employing an efficient control strategy to vibration mitigation for a spatial tensegrity beam composing of five typical quadruplex units. The active control approach is implemented in order to maintain the structural integrity and stability under dynamic loadings. Linear-quadratic regulator (LQR) is applied based on various actuator placement scenarios. Five scenarios are carried out for the control strategy, i.e. struts, cables and combination by change actuator positions in different regions. Various actuator placement schemes together with the system response are compared for all simulated scenarios by setting control parameters of LQR. The outcome of the proposed study highlights the significant reduction of dynamical response compared to the uncontrolled performance, succeeding in the tensegrity system control, even at low cost with only 5.26% (4 out of 76) elements controlled.

A Method of Controlling the Parameters of a Sealed Cable Gland

A methodology for timely monitoring of the electrophysical characteristics and parameters of a sealed cable gland based on inorganic materials is examined. The methodology is applied to assessing the quality of the status of the cable input during actual time of use of the cable line of nuclear physics facilities. The special features of connecting protective shielding systems (double shielding) of nuclear physics facilities are considered. A description of an experimental technique for using a gland for control cables is provided. The results of measuring wave resistance and the attenuation coefficient are analyzed using the quarter-wave short-circuit line method at the carrier frequency. It has been determined that the type of sealed cable gland that has been developed is stable with respect to electrophysical parameters under standard failure conditions and is applicable the input of control cables of nuclear physics facilities.

Material Selection for Cable Gland to Improved Reliability of the High-hazard Industries

The sealed cable glands (SCG) are available to ensure safest connection sheathed single wire for the hazard production facility (nuclear power plant and others) the same as pilot cable, control cables, radio-frequency cables et al. In this paper, we investigate the specifics of the material selection of SCG with the express aim of hazardous man-made facility. We discuss the safe working conditions for cable glands. The research indicates the sintering powdered metals cables provide the reliability growth due to their properties. A number of studies have demonstrated the verification of material selection. On the face of it, we make findings indicating that double glazed sealed units could enhance reliability. We had evaluated sample reliability under fire conditions, seismic load, and pressure containment failure. We used the samples mineral insulated thermocouple cable.

Effects of Insulating Material Ageing on Ignition Time and Heat Release Rate of the Flame Retardant Cables

Abstract The effects of insulating material ageing on the fire performance of flame retardant cables were investigated experimentally by cone calorimeter in the present study. The ageing time and ageing type of the insulating material were concerned, and the fire hazard of cables was represented by the ignition time and the heat release rate (HRR). The results show that both the ignition time and the peak of HRR increase with the ageing time first and then decrease slightly for the flame retardant control cables with polyvinyl chloride insulated and polyvinyl chloride sheathed (ZR-KVV). For the flame retardant control cables with crosslinked polyethylene insulated and polyvinyl chloride sheathed (ZR-KYJV), the ignition time increase and the peak of HRR decrease with the ageing time. The effects of ageing type of insulting material on fire hazard of cables were investigated with the ZR-KVV cables. The ignition time and the HRR of the thermal aged cables were higher than those of the xenon arc aged cables, the ozone aged cables and the hydrothermal aged cables. The results of fire hazard assessment of aged flame retardant cables according to the ignition time might be opposite to those derived from the HRR of cable fires, which should be paid attentions in cable fire safety evaluations.

Experimental Study of Combustion Characteristics of Power and Control Cables for Nuclear Power Plant in Fire Accidents

Experimental Study of Combustion Characteristics of Power and Control Cables for Nuclear Power Plant in Fire Accidents

Establishing Standard Methodologies To Improve The Production Rate Of Assembly Lines Used For Low Added-Value Products

Global competitiveness, mainly in the automobile sector, requires a constant focus on products and process innovation in order to provide consumers with a large variety of products of an excellent quality and at a low cost. In line with this philosophy, the study undertaken of the work method and its inherent activities has pointed to time measurement as a support tool of great potential in the optimization of the production process. The present case study aims to optimize the production process of an assembly line dedicated to the manufacture of control cables for the automotive industry. The ultimate objective was to adjust the output of the current line to that of the initial budget. By mapping all the activities and measuring the time spent on each of these, one was able to analyze the existing problems and inefficiencies. Subsequently, through the use of Lean tools and methodologies, one managed to find viable solutions, which resulted in a significant increase in productivity. The solutions implemented have allowed for an increase in line output of 43%, thus setting it within the values considered in the budget. One also achieved a reduction of 30% in assembly line use, which allowed for the addition of new product references on the assembly line in question. Since these gains are considerable for the company, the same methodology was standardized so that it could be applied to other assembly lines.

On the Coordination of Current Transformers and Relay Protection and Automation Operation of Electric-Power Systems in Transient Short-Circuit States

Due to the increasing number of incorrect actions of relay protection in transient processes accompanied by saturation of current-transformer (CT) cores, there is a need for developing a domestic standard for protective CTs designed to operate in transient states. The following ways to provide proper relay protection operation in transient states accompanied by saturation of CTs in operation are considered: (a) CT shedding that includes an increase in control cables’ cross sections, (b) development of relay-protection and automation algorithms based on the recognition of crash conditions in an appropriate CT transformation time interval of 2–3 ms, (c) development of relay-protection and automation algorithms with virtual CT error compensation, and (d) development and introduction of new primary-current converters. It is concluded that, for existing large power plants with installed TPX current transformers, it is advisable to use improved digital relay-protection algorithms for information processing obtained from CTs, for example, by methods (b) and/or (c).

Research and development about the mechanisms of a single point mooring system for offshore wind turbines

A new type of floating wind turbine, in which the floater itself can rotate from the wind is proposed in this paper. A new single point mooring system is necessary for the development of this new wind turbine. In this paper, the single point mooring system, which includes component such as catenary chains, the slip ring for the electric cable and the control cable were researched. This work will examine two different configurations of the single point mooring system that we developed. One uses a thrust bearing at the connecting points between the mooring parts and the floater parts. The other one uses not only a thrust bearing, but also an aligning bearing. Weather vane tests about the offshore wind turbine with each mooring system were conducted in an ocean basin. After performing wind tests of both configurations of the single point mooring system, it was concluded that the latter one functioned superior to the former one. This work discusses and clarifies the reason based on a physics model which focuses on the relation between the restoring yaw moment caused by the mooring chains and the static friction moment due to the bearing unit. We also performed a wind test at a real sea and verified that the bearing unit with not only the thrust bearing but also the aligning bearing could function properly.

An approach for reliability prediction of instrumentation & control cables by artificial neural networks and Weibull theory for probabilistic safety assessment of NPPs

The polymeric materials used for insulation and sheath in instrumentation and control (I&C) cables of nuclear power plants (NPPs) are subjected to degradation due to various stressors. The prediction of long-term aging and lifetime of cables is generally determined based on accelerated life testing (ALT) experiments which are not only expensive but also time consuming. Application of artificial neural networks (ANNs) in the field of transient diagnosis and condition assessment of electrical and other equipment has been a promising technique; however the use of ANN for reliability prediction of I&C cables has not yet been studied. This paper presents an integrated approach to predict the lifetime and reliability of I&C cables by ANN from the accelerated aging data. In order to validate the proposed methodology for use in probabilistic safety assessment (PSA) of NPP to account for the cable failures, ALT data on a typical cross-linked polyethylene (XLPE) insulated I&C cable has been referred from the literature. The time dependent reliability was predicted by considering the various failure rates. Study demonstrates that by an appropriate training algorithm with suitable network architecture, it is possible to predict the reliability of I&C cables by ANN with the minimal accelerated life testing.

The calculations of conductive noise and heating of the screen in a control cable

Lighting strokes and short circuits (SCs) are the main sources of conductive noise that propagates along control cables and can lead to the failure of microprocessor equipment in the protection and control systems of electric power substations. Two-sided grounding of the screen of a control cable substantially reduces the pulse and high-frequency conductive noise level, but leads to heating of the screen under short-circuit conditions. The existing standards determine the conductive noise and screen heating as a function of screen voltage that is suitable for a single cable. A more general case that takes into account the cable magnetic coupling with other conductors when current is used as a calculation parameter has been considered. The conductive noise at the first pulse of lightning current is determined using the transfer impedance “screen–cable core” or 3D cable model in the general case. To calculate the heating, the formula of GOST (State Standard) 28895-91, which is rejected in modern standards because of the assumption that short-circuit current is invariable (in fact, the current decreases with heating of the screen), has been used. Using this formula in a step algorithm leads to correct results. The cable magnetic coupling with other conductors is expressed as insertion impedance that increases the screen impedance and decreases the current and screen heating. A numerical experiment for a typical cable has shown that conductive noise and heating of the screen of the cable can be substantially reduced because of the parallel laying of conductors. It has been concluded that, to decrease the conductive noise and heating of the screen of a control cable, it is necessary to decrease the screen current.

Real-Time Condition Monitoring of LOCA via Time–Frequency Domain Reflectometry

The maintenance of control and instrumentation (C&I) cables is crucial to safety of operating nuclear power plants. Therefore, when an accident occurs, there is a need for an accurate assessment of the impact on the cable's integrity. Unfortunately, most cable diagnostic methods are destructive and real-time assessment of the effect of accidents is not possible. Thus, in this paper, we present an analysis of a specific type of accident, a loss of coolant accident (LOCA), on C&I cables in real-time, based on time–frequency domain reflectometry (TFDR). Because the TFDR is sensitive to the signal-to-noise ratio and distortion of a reflected signal, we apply postprocessing techniques that compensate the dispersion based on the estimated propagation constant and a denoising method using singular value decomposition. The approach is verified by experimentally monitoring condition changes of localized LOCA hot spot in different C&I cables. The results are also validated by comparing with elongation at break test results.

Well Integrity Assessment of Monitoring Wells at an Active CO2-EOR Flood

Assessment of well integrity has become more important for CCS and CO2-EOR as it has become apparent that wells represent the most likely migration pathway for CO2 to leave a CCS storage unit or a CO2-EOR reservoir. Although wells represent a migration pathway they are also the best vehicle for employing technology monitoring CO2 injection and storage. This contradiction of being a potential migration path and key monitoring technology leads to a need to understand how monitoring wells may be similar or different in comparison to other types of wells with respect to migration risk. The maturation and completion US Department of Energy sponsored research projects presents an opportunity to assess the integrity of monitoring wells that have been exposed to injected CO2. This paper discusses an integrity assessment of two monitoring wells in an operating CO2-EOR flood in Mississippi, USA. It provides an early assessment of how monitoring equipment affects well integrity and isolation capacity.Each of the monitoring wells in this study were similarly constructed using both fiberglass and conventional steel casing. Each of the wells was instrumented with multiple monitoring technologies including, electrodes, pressure gauges, and temperature sensors on the outside of the casing. Control lines and cables were run from the surface on the outside of the long-string casing in each well to communicate with the monitoring equipment.A comprehensive logging, testing, and sampling program was developed to assess integrity in both wells. Ultrasonic well mapping was used to create radial maps of the location of cement, liquid, and gas behind the casing. Cement bond logging provided information on the casing-to-cement and cement-to-formation bonds for the long-string section. The logs showed that the monitoring equipment attached to the long-string casing is visible as continuous low acoustic impedance features and may represent a leakage risk. Cased-hole sidewall cores were collected and provided some validation of the log results and provide local information on the isolation capacity of the wells.The combination of information from the log data sets and cores was used to assess isolation capacity. The results of the study show that careful design and assessment of the materials used in monitoring well construction, the types of monitoring technology, and the location of monitoring technology within a well needs to be conducted with limiting migration potential and maximizing well integrity as objectives.

Studying radiolytic ageing of nuclear power plant electric cables with FTIR spectroscopy

Due to the willingness to extend the nuclear power plants length of life, it is of prime importance to understand long term ageing effect on all constitutive materials. For this purpose gamma-irradiation effects on insulation of instrumentation and control cables are studied. Mid-infrared spectroscopy and principal components analysis (PCA) were used to highlight molecular modifications induced by gamma-irradiation under oxidizing conditions. In order to be closer to real world conditions, a low dose rate of 11Gyh−1 was used to irradiate insulations in full cable or alone with a dose up to 58 kGy. Spectral differences according to irradiation dose were extracted using PCA. It was then possible to observe different behaviors of the insulation constitutive compounds i.e. ethylene vinyl acetate (EVA), ethylene propylene diene monomer (EPDM) and aluminium trihydrate (ATH). Irradiation of insulations led to the oxidation of their constitutive polymers and a modification of filler-polymer ratio. Moreover all these modifications were observed for insulations alone or in full cable indicating that oxygen easily diffuses into the material. Spectral contributions were discussed considering different degradation mechanisms.

METHODS OF MEASURING THE EFFECTS OF LIGHTNING BY SIMULATING ITS STRIKES WITH THE INTERVAL ASSESSMENT OF THE RESULTS OF MEASUREMENTS

The article presents the results of the development of new methods aimed at more accurate interval estimate of the experimental values of voltages on grounding devices of substations and circuits in the control cables, that occur when lightning strikes to lightning rods; the abovementioned estimate made it possible to increase the accuracy of the results of the study of lightning noise by 28 %. A more accurate value of interval estimation were achieved by developing a measurement model that takes into account, along with the measured values, different measurement errors and includes the special processing of the measurement results. As a result, the interval of finding the true value of the sought voltage is determined with an accuracy of 95 %. The methods can be applied to the IK-1 and IKP-1 measurement complexes, consisting in the aperiodic pulse generator, the generator of high-frequency pulses and selective voltmeters, respectively. To evaluate the effectiveness of the developed methods series of experimental voltage assessments of grounding devices of ten active high-voltage substation have been fulfilled in accordance with the developed methods and traditional techniques. The evaluation results confirmed the possibility of finding the true values of voltage over a wide range, that ought to be considered in the process of technical diagnostics of lightning protection of substations when the analysis of the measurement results and the development of measures to reduce the effects of lightning are being fulfilled. Also, a comparative analysis of the results of measurements made in accordance with the developed methods and traditional techniques has demonstrated that the true value of the sought voltage may exceed the measured value at an average of 28 %, that ought to be considered in the further analysis of the parameters of lightning protection at the facility and in the development of corrective actions. The developed methods have been tested in surveys of the electromagnettic environment of 27 active high voltage electric substations with a 110 kV outdoor switchgear. The application of the techniques amended the accuracy of the information collected, the correctness of the evaluation of the electromagnetic environment of high-voltage substations with a 110 kV outdoor switchgear, the effectiveness of the developed adequate measures to protect against lightning effects.

In search of extendable conditions for cable environmental qualification in nuclear power plants

ABSTRACTThe environmental qualification (EQ) for cable insulators in nuclear power plants (NPPs) has been developed on the basis of the design basis accident (DBA) to prevent reactor core damage. However, the latest safety principles require extending the design concept to prepare the utilized equipment for scenarios after core damage. Thus, we propose a modification to the EQ for cables connecting utilized equipment at design extension conditions. This paper surveys all electrical components for accident management in boiling water reactor-4 (BWR-4), and identifies their connecting cables’ functional category as low-voltage power, instrumentation, and control cables. The EQ temperature profile of these cables during the incident phase was addressed for extension. This required postulating maximum temperature environments according to accident scenarios, knowledge of cable integrity degradation, and their current evaluation by the EQ. To evaluate whether these environments are suitable stressors, heat testing was conducted on flame-retardant ethylene propylene rubber (FR-EPR)-insulated cables. On the basis of those results, we suggest a maximum primary peak temperature of the EQ temperature profile of 250 °C. We also suggest increasing the primary peak period of the EQ temperature profile to 48 h without experiment, on the basis of inherent excessive margin for mechanical integrity during the ageing phase.

Reliability prediction of I&C cable insulation materials by DSC and Weibull theory for probabilistic safety assessment of NPPs

Instrumentation and control (I&C) cables used in nuclear power plants (NPPs) are exposed to various deteriorative environmental effects during their operational lifetime. The factors consisting of long-term irradiation and enhanced temperature eventually result in insulation degradation. Monitoring of the actual state of the cable insulation and the prediction of their residual service life consist of the measurement of the properties that are directly proportional to the functionality of the cables (usually, elongation at break is used as the critical parameter). Although, several condition monitoring (CM) and life estimation techniques are available, currently there is no any standard methodology or an approach towards incorporating the cable ageing effects into probabilistic safety assessment (PSA) of NPPs. In view of this, accelerated thermal and radiation ageing of I&C cable insulation materials have been carried out and the degradation due to thermal and radiation ageing has been assessed using oxidation induction time (OIT) and oxidation induction temperature (OITp) measurements by differential scanning calorimetry (DSC). As elongation at break (EAB) is considered to be a benchmark characterization technique for polymeric materials, tensile tests have also been carried out on these cable materials for correlating with DSC findings. The Fourier transform infrared (FTIR) spectroscopy has also been carried out on fresh and irradiated samples to monitor the structural changes in the insulation materials. The correlations obtained from DSC and FTIR studies are relatively in good agreement with the tensile testing results. The images of scanning electron microscopy (SEM) on fresh and aged samples support the degradation predicted from infrared spectroscopy, thermal and mechanical measurements. The time dependent reliability predicted from the OIT based on Weibull theory will be useful in incorporating the cable ageing into PSA of NPPs.