Guy Wires Research Articles

Structural Architectures for Imperfect Deployable Lunar Towers

The load-carrying performance for deployable lunar tower architectures using thin-ply composite booms is parametrically evaluated. These towers support a communications and sensor platform on the lunar surface. The primary design consists of the corrugated rollable tubular boom (COROTUB) acting as the primary tower mast that supports the payload tip mass. Guy wires connecting the boom tip to spreader bars attached at the base serve to correct lateral eccentricities and increase dimensional accuracy. The analysis compares the maximum tip mass that this primary design can carry relative to a reference design that does not contain any guy wires or spreader bars. The results provide insights into whether the additional system mass and complexity associated with the cable-stayed design are worth the increased payload mass that can be supported. By setting the design limiting condition to a maximum allowable deflection, the analysis reveals that the primary design has better performance when the spreader bar length relative to the tower height exceeds a critical value. The analysis is extended to lunar towers with collapsible tubular mast (CTM) booms, and similar trends are observed. Finally, the analytical load displacement behavior of the COROTUB and CTM reference towers is verified with finite element simulations.

The National Electrical Safety Code, powerline clearances, and wildfires

AbstractThe provisions of the National Electrical Safety Code (NESC) have a long, but undocumented history. They are the primary means by which Public Utilities Commission agencies in various States in the United States enforce requirements for electrical clearances pertinent to high‐voltage powerlines. Examination of the NESC provisions for clearances between grounded guy wires and distribution phase conductors in the context of the Woolsey Fire indicates a comprehensive lack of realism in the Code provisions. While they may be entirely sufficient to prevent sparkover under normal operating conditions, they are wholly insufficient to cope with even modest adverse events. The profession should consider explicitly assessing factors beyond sparkover that affect the adequacy of clearance requirements. The provisions of the NESC (and California's parallel General Order No. 95) should be systematically reexamined in order to ensure that safety regulations can cope with adverse events that are serious, but not extreme. Since the vast majority of the electrical power network is aging and not new construction, a scheme should be developed to establish priorities for upgrading existing facilities at the highest risk of failure.

Comparative analysis of a tubular masts with a 80 m high

The article presents the structures of guyed masts that are used as supporting structures. Masts of this type consist of a vertical shaft connected to the foundation by means of guy wires. The work focuses on two designs of measuring masts with an identical shaft, but with a different number of guy ropes at the level. The static analysis was carried out taking into account the geometric nonlinearity of the guy wires and environmental loads. The results of the analysis indicate how the static scheme of the structure affects its behavior. The conclusions from the work are applicable to specific designs of tubular masts, but may be an inspiration for further research on structures of this type

Deterioration of Telecommunication Equipment and Facilities in Salt-damage Environments--Case Studies of Corrosion in Guy Wires and Maintenance Holes

Deterioration of Telecommunication Equipment and Facilities in Salt-damage Environments--Case Studies of Corrosion in Guy Wires and Maintenance Holes

Mechanical Testing of Connections Blind Bolted to the Thick Glass-Fiber-Reinforced Polymer Spar Cap of a Decommissioned GE37 Wind Turbine Blade

Millions of tons of glass-fiber-reinforced polymer (GFRP) composite wind turbine blades are expected to age out of service over the next 30 years. Research is being conducted on repurposing these structures as new civil infrastructure products. The GFRP material in these decommissioned wind blades has been shown to retain significant strength and stiffness for second-life applications. However, for repurposing as new products, they will need to be connected to other structural members. The connections employed for this need to be designed, evaluated, and tested prior to their use. Here, we present the results of detailed testing of bolted connections for load-carrying appurtenances that will carry the phases and shield wires (e.g., insulators, crossarms, davits, guy wires, posts) to the spar cap of an 11-year-old 1.5 MW GE37 wind blade, intended for use as a repurposed transmission pole (i.e., a BladePole). Details of ASTM-type pull-out and bearing capacity tests using different types of blind bolts, and tests of a full-scale steel bracket connection called a “universal connector,” are reported. The effects of the different blind bolts, pin diameters, and loading directions relative to the composite laminate structure (longitudinal or transverse) for both the coupon- and full-scale connector bracket tests are described. The ability to design and construct robust connections for repurposed wind blade structures was demonstrated.

Effect of Protection on Guy Wire Related to Corrosion Defects

Guy wires are a powerful mechanical tool used widely in all industries. Most of the applications are employed in supporting tall structures such as antenna, communication towers, transmission lines, electric poles, and erecting flare stacks on an oil and gas platform or plant. Severe wind events such as tornadoes are the primary failurein transmitting line structure in many places worldwide. So, this research aims to investigate the effect of different types of guy wire on corrosion defects. There are many lay and strand design types in the production of guy wire. The two most common are the 7-wires and 19-wires lay. There are four samples with four conditions: the first sample is not protected with any material, the second is protected by lubrication using WD-40, the third is protected using rubber hose casing, and the last is protected by a combination of both lubrication and rubber hose casing technique. The result shows that the sample protected by a combination of lubrication and rubber hose casing has no corrosion defect.

Mitigating avian collisions with power lines through illumination with ultraviolet light

Collisions with anthropogenic structures by long-distance migrants and threatened and endangered species are a growing global conservation concern. Increasing the visibility of these structures may reduce collisions but may only be accepted by local residents if it does not create a visual disturbance. Recent research has shown the potential for ultraviolet (UV) light, which is nearly imperceptible to humans, to mitigate avian collisions with anthropogenic structures. We tested the effectiveness of two UV (390–400 nm) Avian Collision Avoidance Systems (ACASs) at reducing collisions at two 260-m spans of marked power lines at the Iain Nicolson Audubon Center at Rowe Sanctuary, an important migratory bird stopover location in Nebraska. We used a randomized design and a tiered model selection approach employing generalized linear models and the Akaike Information Criterion to assess the effectiveness of ACASs considering environmental (e.g., precipitation) and detection probability (e.g., migration chronology) variables. We found focal (assessed power line) and distal (neighboring power line) ACAS status and environmental variables were important predictors of avian collisions. Our top model suggests that the focal ACAS illumination reduced collisions by 88%, collisions were more likely at moderate (10–16 km/h) compared to lower or higher wind speeds, and collision frequency decreased with precipitation occurrence. Our top model also indicates that the distal ACAS illumination reduced collisions by 39.4% at the focal power line when that ACAS was off, suggesting a positive “neighbor effect” of power line illumination. Although future applications of ACASs would benefit from additional study to check for potential negative effects (for example, collisions involving nocturnal foragers such as bats or caprimulgiform birds drawn to insects), we suggest that illuminating power lines, guy wires, towers, wind turbines, and other anthropogenic structures with UV illumination will likely lower collision risks for birds while increasing human acceptance of mitigation measures in urban areas.

Improvements in reflectometry analysis for detecting faults on anchoring systems using particle swarm optimization

Metallic anchor rods are used to fix transmission tower guy wires. In order to perform visual inspections on the integrity of the anchor rods, electricity companies are obliged to undertake soil excavation, which is both costly and hazardous. Despite this, Frequency domain reflectometry (FDR) may be used to detect faults on anchor rods, and is enabled by a robust, high-frequency microwave device for support and connection. Impedance changes occur along the rod due to faults, thereby causing reflections, which are detected during FDR measurement analysis. However, auxiliary structures on the anchorage system also provide similar results during the analysis, and may therefore be confused with faults. An innovative, new approach is proposed in order to minimize the effects of small structures positioned at a distance from the fault, so that the fault reflection remains the same. Preliminary results have indicated reductions of up to 95% of the undesired reflection values.

Chemiluminescence “signal-on-off” dual signals ratio biosensor based on single-stranded DNA functions as guy wires to detect EcoR V

Signal output mode is the important part of biosensor. In general, “signal on” and “signal off” are two common output modes. The development of dual signals-based ratio analysis as a powerful diagnostic tool has attracted widespread attention in the biosensor field in recent years. Dual signals ratio sensors with “signal on” and “signal off” are more favored because of their low background signal and better sensitivity and selectivity. In this study, inspired by the idea that EcoR V can cut specific sites of DNA to produce two corresponding fragments, and by using the capturing probe as guy wires, a reliable and sensitive method for EcoR V assay is developed based on the ratio of dual chemiluminescence (CL) signals for the first time. In particular, in the existence of the objective EcoR V, the substrate DNA would be degraded into two double stranded oligonucleotides with blunt ends which include the sequence I and the sequence II, then they can separately compete with two different corresponding capture probes on magnetic beads (MBs). One of capture probe hybridized with the sequence I containing more guanine (G) bases that reacted with the phenylglyoxal (PG) to produce chemical reaction which triggered a positive CL signal output I + CL as “signal-on”; another capture probe is priority to hybridize the sequence II, which triggered the weaker reporter DNA linked with horseradish peroxidase (HRP) probe to fall off the MBs, thereby outputting a negative CL signal I−CL as “signal-off”. By comparing the linear relation and the correlation coefficient, the I−CL/I + CL ratio method has better linear relation (0.01–10 U/mL) and higher sensitivity (0.0045 U/mL). In addition, this developed strategy of high selectivity which can directly detect low concentration of target EcoR V in human serum, and thus this dual ratio biosensor might offer a promising detection approach for clinical diagnostics.

Study on safety management of guy wires in the construction of UHV (EHV) transmission lines

The guy wires play an important and key role in the erection of the tower. Temporary guy wires are also used extensively in the stringing engineer. This study summarizes the causes of many serious accidents caused by temporary guy wires that do not meet the requirements of use and operation. It focuses on the high-risk links in the guy wire operation, from the calculation and verification before the use of the guy wire, the construction technical plan, the control of key links, and the construction process. The implementation of management and control is analyzed and summarized, and the key monitoring links of safety management and control of guy wires are summarized. The study provides reference for the construction of other similar HUV (EHV) high voltage transmission lines.

Wave and Wind Responses of a Very-Light FOWT with Guy-Wired-Supported Tower: Numerical and Experimental Studies

A floating offshore wind turbine (FOWT) concept with a guy-wire-supported tower was investigated to obtain motion results in waves considering its elastic model characteristics. The FOWT concept studied aims to reduce the construction costs by using a light-weight structure tensioned with guy wires and a downwind type. Wave tank experiments of an elastically similar segmented backbone model in the 1:60 scale were carried out to clarify the dynamic elastic response features of the structure. The experimental results were compared with numerical simulations obtained from NK-UTWind and WAMIT codes. The bending moment measured at the tower and pontoons had two peak values for different wave periods carried out. The short-wave period peak was due to sagging/hogging when the wavelength matched the floater length. The second peak was due to the large tower top acceleration, which caused a large bending moment at the tower base and pontoon to support the inertia force. The wind force was not significant to modify the FOWT response. The sensibility analysis in pontoons and tower rigidities confirmed the importance of the guy wires to support the inertia due to the waves and wind incidence. The new concept of a very-light FOWT with a guy-wire-supported tower may be an option for future FOWT developments.

Optimized Protection of Pole-Mounted Distribution Transformers against Direct Lightning Strikes

Direct lightning strikes on overhead phase conductors result in high overvoltage stress on the medium voltage (MV) terminals of pole-mounted transformers, which may cause considerable damage. Therefore, introducing an efficient protection strategy would be a remedy for alleviating such undesirable damages. This paper investigates the optimized protection of MV transformers against direct lightning strikes on the phase conductors. To this end, first, the impacts of grounding densities (number of grounded intermediate poles between every two successive transformer poles) on the probability of overvoltage stress on transformer terminals are investigated. Then, the implications of guy wire, as a supporting device for ungrounded intermediate poles, on reducing the overvoltage stress on transformers, are studied. Finally, the role of a surge arrester in mitigating the overvoltage stress of non-surge-arrester-protected transformer poles is scrutinized. The investigations are conducted on a sample MV network with 82 wood poles comprising 17 pole-mounted transformers protected by spark gaps. To provide in-depth analysis, two different poles, namely creosote- and arsenic-impregnated poles, are considered under wet and dry weather conditions. A sensitivity analysis is performed on grounding distances and on a combination of guy wire and grounded intermediate poles while taking into account soil ionization. The results provide a clear picture for the system operator in deciding how many grounded intermediate poles might be required for a system to reach the desired probabilities of transformers experiencing overvoltage stress and how the surge arrester and guy wires contribute to mitigating undesirable overvoltage stress.

Magnetic Nondestructive Testing as an Effective Instrument for Monitoring Conductors and Ground Wires of Overhead Transmission Lines

Magnetic nondestructive testing (NDT) for monitoring the equipment of overhead power lines (OHL) such as conductors, ground wires, and guy wires is discussed. Magnetic NDT allows effective testing of steel ground wires, guy wires, and steel cores of bimetallic conductors. The results of monitoring the conductors and ground wires of 35 – 220-kV OHLs in Rosseti networks are illustrated. The residual load-carrying capacity (strength) of the tested conductors and wires is estimated based on test data. It is concluded that magnetic detectors are effective in testing ground wires, guy wires, and steel cores of bimetallic conductors.

Calculational model for first-mode eigenfrequency of a semi-guy-wired vertical-axis wind turbine tower

A simple model for accounting for tower mass when estimating the first-mode eigenfrequency of a semi-guy-wired tower has been derived. This extends previous work where an analytical model of the semi-guy-wired tower of a 200-kW vertical-axis wind turbine was developed. The model was primarily used to estimate the eigenfrequencies as a result of adding guy wires to a free-standing tower (thus creating a semi-guy-wired setup). However, a weakness with the model was that the tower mass was accounted for in a rough way that essentially ignored the guy wires, which gave a larger-than-necessary error. In this work, an effective top mass, that takes into account the tower mass and the constraints from the guy wires, is derived to achieve a higher accuracy when estimating the first-mode eigenfrequency. This, together with the earlier models, gives a more complete method to estimate the eigenfrequencies for a semi-guy-wired wind turbine.

Finite element method for the static and dynamic analysis of FRP guyed tower

AbstractA research study has been carried out to provide design guidelines for glass-fiber reinforced polymer (GFRP) guyed tower. Both material testing and theoretical analysis are involved. The tower examined in this study has 81 m in height with a uniform equilateral triangle cross section having sides of 450 mm. The tower supported by seven sets of guy wires oriented at 120°, each set consisting of three guy wires. The tower was assumed to be supported at the base by means of a pinned connection to provide full moment release. The tower was analyzed using the finite element ANSYS software and was designed to satisfy both the ultimate and the serviceability limit state requirements of the CSA-S37-01 Standard. The guyed tower was analyzed in static to evaluate the tower strength failure using several advanced failure theories. Modal analysis and full dynamic analysis using CSA-37-01 Standard were extensively performed to evaluate the vibration performance and to obtain an accurate dynamic response of the full-scale tower. The paper presents the results obtained from material testing and from a finite element, ANSYS models developed for the static and dynamic analysis of the multi-cells 81 m lightweight-guyed towers.Highlights The research = involved the analysis and the design of FRP guyed tower composed of individual cells fabricated from fiberglass matting bonded together to form an equilateral triangle. The layout, the dimensions of the tower and the thickness of the cell walls were determined from a finite element analysis. Fifteen coupons were fabricated and tested based on ASTM standards to evaluate the mechanical properties of the GFRP material. Several non-linear finite element models were developed to meet both the manufacturing constraints and strength requirements. Several non-linear finite element models were carried out for the static and dynamic analysis of an 81 m tower.

Application possibilities of special lightning protection systems of overhead distribution and transmission lines

Reduction of the overhead lines back-flashover rate (BFR) after application of special lightning protection systems is analyzed in this paper. The following lightning protection systems are considered: line arresters, underbuilt wires, additional shield wire and guy wires. Partial or combined efficiencies of mentioned lightning protection systems are analyzed. Overhead distribution (35 kV) and transmission (110 kV and 220 kV) lines BFR are estimated through the semi-statistical calculation procedure as suggested in international technical documents. System equivalent circuits in the EMTP-ATP software are created with carefully chosen models and parameters of elements. Pursuant to the estimated results, conclusions about application possibilities of different lightning protection systems are given.

Техническое диагностирование оттяжек антенно-мачтовых сооружений

Техническое диагностирование оттяжек антенно-мачтовых сооружений

Stability of Large Reinforcing Column Cages during Temporary Construction Conditions

AbstractReinforcing cages for large columns requires shoring during the fabrication and erection stages of construction before concrete is placed to form a permanent load-bearing structure. Many column-reinforcing cage collapses have occurred, resulting in injuries and fatalities because the cages were not properly supported in the temporary condition. Guying systems are commonly used to stabilize large reinforcing cages during construction to avoid such accidents. This paper presents a two-dimensional first-principle stability analysis of reinforcing cages that are either pinned or fixed at the base, and supported by one level of guy wires along the height of the cage. The effect of lowering guy-wire attachment points on the stability of cages is also included because this construction practice is reported to be used in some locales. Critical buckling-load diagrams are determined that account for the relative stiffness of the guy wires with respect to the reinforcing cages and the effect of pretensioning...

A proposal and a theoretical analysis of a novel concept of a tilted-axis wind turbine

A novel wind turbine is proposed with a downwind rotor, tilted upward. An external cable that is attached to the blades' center of force supports each rotor blade, and the tower is supported by guy wires at the top. The nacelle is eliminated and the main axle is replaced by power take off from an annular ribbon, rotating with the rotor; thus most large bending moments are eliminated and replaced by tensile and compressive loads. Further, the proposed wind turbine does not use a gearbox or a direct drive generator. The proposed system is structurally analyzed and compared with a conventional wind turbine. The comparison shows that manufacturing the proposed system may be 2.5 times less expensive than manufacturing a conventional wind turbine of the same power on land. The cost advantage promises to be even bigger offshore.

Finite Element Analysis of Guyed Offshore Monotower Subjected to Extreme Environment in Malaysian Water

This paper presents the finite element structural sensitivity analysis of a cable guyed monotower known as the Tarpon Monopod when subjected to extreme environments in Malaysian waters. A hydrodynamic loading and static platform response analysis is performed in SACS v5.3 to gauge the structural robustness in extreme Malaysian metocean conditions. A Stokes Fifth Order Wave Theory was employed to obtain wave kinematics and dynamics for load computation. The Tarpon Monopod design is reviewed generically. An actual platform located in 60m water depth within Malaysian waters is modelled for analysis. Four different guying cable scenarios are considered which are the fully guyed condition (three guy cables pinned), two guy cables condition (one wire loss), one guy cable condition (two wire loss) and free standing condition (total loss of guy wires) are presented. The environmental load sets are simulated at different headings using 45 degree steps. The results suggest that the structural caisson contributes little to the lateral stiffness of the platform. The Tarpon Monopod has little structural redundancy and its integrity is highly dependent on guy wire condition and environmental load headings.