Compression Connectors Research Articles

Finite Element Analysis of Prefabricated Semi-Rigid Concrete Beam–Column Joint with Steel Connections

This paper introduces a novel type of prefabricated semi-rigid concrete beam–column joint, aiming to examine its load-carrying capacity and seismic performance in comparison with a traditional cast-in-place joint. This study utilized the ABAQUS 2020 software to establish finite element models for both types of joints and conducted finite element analysis under low circumferential reciprocating displacement loads. When comparing the energy dissipation capacity, ductility, ultimate load-carrying capacity, stress mechanism, and damage mode, a comprehensive evaluation of the two types of joints was performed. Furthermore, this study investigated the impacts of various factors such as the axial compression ratio, concrete strength, reinforcement strength, and connector strength on the ultimate load-carrying capacity, ductility, and energy dissipation performance of the joints. Based on the findings, the newly combined joint exhibited a substantial 31.7% increase in its ultimate load-carrying capacity, along with a notable 7.23% enhancement in ductility and an improved energy dissipation capacity when compared with the cast-in-place joint. As a result, it can be concluded that the seismic performance of the new joint surpasses that of cast-in-place joints. Additionally, this study examined the impact of modifying relevant parameters on the seismic performance of the new prefabricated semi-rigid concrete beam–column joint.

Semi-Analytical Methods for the Joint Strength and Sealing Performance in the Failure Process of the Subsea Pipeline Compression Connector

Radial seals are sensitive to axial overload failure and may cause leaks. This paper presents two semi-analytical methods for the joint strength and sealing performance of the subsea pipeline compression connector under axial overload failure. The method for the joint strength consists of two parts: One is the analytical model for the joint strength of the connection and seal under axial tension and compression conditions. The models are based on membrane theory, considering the hardening and bending effects. The other is a two-dimensional, axisymmetric finite element model for the joint strength of the radial metal seal. The semi-analytical method for the overload sealing performance is derived using a finite element model and the Reynolds equation of the laminar flow. The effects of critical parameters on the joint strength and the overload sealing performance are analyzed. The experiments are carried out with specimens and prototypes to evaluate the evolution of the sealing interface and the joint strength. The results show that both the internally turned sealing surface and the deflection of the pipe can improve the joint strength. In addition, the compression-type connector can remain sealed under the maximum axial overload. The proposed methods allow the prediction and identification of the overload joint strength and the sealing condition of the compression-type connector and provide a better understanding of the radial metal seal under the axial overload condition.

A Semi-Analytical Method for the Sealing Performance Prediction of Subsea Pipeline Compression Connector

To predict the sealing performance of the subsea pipeline compression connector, a semi-analytical method is proposed and verified. The leakage condition is obtained as a function of the minimum radial deflection. The semi-analytical method consists of three parts: a macroscopic analytical model for the interference process deduced based on the membrane theory, a mesoscopic two-dimensional finite element analysis of the internally turned sealing surface according to scanning electron microscope observation, and a formulation of the leakage ratio according to the Abbott–Firestone curve. The influences of the geometry parameters are analyzed. The prediction and identification of the leakage condition near the minimum preloaded deflection are investigated. Experimental tests are also carried out to verify the proposed method. The results show that, within five times the pipeline threshold of the thin wall thickness, compression connectors designed by the proposed method can create a reliable seal with a rough internally turned surface, saving 57% of the design time while reducing the machining time and costs.

Analisis Susut Energi Pada Titik Sambung Ring Penyulang Sepat Menggunakan Thermovision Di PT PLN (Persero) Rayon Kota Metro

In electric energy dispatch process, interference were often found especially at medium voltage network. One of major problem from this processis the loss of electricsl energy which called losses. Losses caused be technical and non technical factors.One causes of the factor itself come from poor connecting point. This paper presents losses calculating with the result which caused by poot connecting point. Power loss count by long and cross sectional area at the connecting point. It also infected by the amount of load current flowing at that point. The biggest value of power loss occur at the connecting point which use joint sleeve. Otherwise, the smallest value of power loss occur at the connecting point which use compression connector (CCO).

Performance and Diagnosis of Aluminum Connectors Tested Inside MV Cable Splices

Performance of power cable connectors is usually evaluated under bare conditions as for overhead applications, such as specified in the test standards ANSI C119.4 and IEC 61238-1. Significant differences exist between the requirements of these two standards, in particular, the short-circuit current test that only becomes optional in the recent ANSI 2011 edition. Furthermore, past and recent experience with testing medium-voltage cable splices according to the standard IEEE 404 have revealed the shortcoming of the aluminum connectors tested on aluminum conductors with overheating failure. New mechanical power connectors on the market offering range-taking capability and easy installation promise better connectivity and reproducibility based on the shear-bolt technology. This paper discusses the results as obtained in an accelerated aging test on different types of cable splices with both compression and mechanical connectors. Based on the test results, a simple and effective method is also proposed to identify a degraded connector inside a cable splice.

A New Method for Determining the Connection Resistance of the Compression Connector in Cable Joint

The compression connector of a cable joint is one of the major components causing joint overheating. This paper proposed a new model to determine the connection resistance of the compression connector. It innovatively integrated electrical contacts model analysis (ECMA) with finite element analysis (FEA) in the modeling. The compacted stranded structure of the cable conductor was taken into account in the proposed model. The streamline distortion effect on the connection resistance was also established. To verify the applicability of the proposed model, the connection resistances of five compression connectors with different cross sections were measured. The modeling results and measurement results were in close agreement with each other.

Directions for Solving Bad Workman Practices in Power Distribution Line Connections

Standardization of the process of power line connector installation and proper die selection technique for compression connectors is essential for power system reliability improvements. This paper presents an attempt to identify good workman practices required for making proper power distribution line connections. This will be a guide in the assembly and preventive maintenance of efficient electrical connections for power distribution circuits. Data and experience gained through usage of power line connectors by Ceylon Electricity Board is the basis of this study. Properties of conductor metals and metal oxides illustrate the requirements of standardized methods of making connections. Requirements for the proper selection of connectors; the proper preparation of conductors; and the proper application of fusion, compression, and bolted connectors are identified. Standards available on power line connectors are given. Photographs of bad workman practices are included with explanations. Mathematical formulas are developed for calculating the correct die size for compression connectors. Performance identification of any type of connector installed in a power line is carried out by thermal imaging. Thermal images taken from a few installed connectors are included and a procedure for assessing connector performance is suggested.

Case Study Report

Cutting cable and crimping compression connectors are the two most commonly performed tasks by direct-bury line workers who repair and bury underground cable for electric power utilities. Battery-p...

Investigation of extrusion ratio effect on mechanical behaviour of extruded alloy AA-6101 from the billets homogenised-rapid quenched and as-cast conditions

This article describes the effect of extrusion ratio in direct extrusion process on mechanical behaviours of alloy AA-6101. The alloy is used mainly as feedstock in manufacturing of AAAC type aluminium alloy conductors and extrusions for compression joints and connectors in electrical industry. Extrusion ratio effect was examined by extruding the billets at different billet temperatures. The billet structures have been prepared as homogenised-rapid quenched (HRQ) and unhomogenised-slow cooled (UHSC). Keeping up constant the forward speed of the main ram and the exit temperature of the extrusions, AA-6101 billets were extruded directly by using three different dies with diameters 10, 30 and 50 mm. Mechanical measurements of the specimens were made after T-1 and T-6 treatments. Extrusion ratio effect on tensile strength, elongation and hardness of extrusions from the AA-6101 billets was appreciated on the graphics.

Measurement of handle forces for crimping connectors and cutting cable in the electric power industry

Overhead and underground line work in the electric power industry is physically very strenuous and can expose workers to musculoskeletal disorders (MSDs), particularly in the upper extremity. Crimping compression connectors—such as sleeve connectors and lugs—and cutting cables are two of the most frequent tasks that line workers perform. Line workers at many utilities in the US crimp connectors and cut cable with long-handled manual tools. However, the actual magnitude of the forces applied to the handles of these tools is not known. The objectives of this laboratory study were to measure the forces applied to the handles of a manual press and a manual cutter in order to connect typical wire gauges and cut common cables, respectively. The handles of the manual press and cutter were attached to the drive cylinder and load cell of an Instrom Material Testing System, and peak forces exerted against the handles were measured. Results showed that the outer die of the manual press required about 50% more handle force than crimping connectors with the inner die location. The peak handle forces required to cut aluminum conductor cable as large as 2cm diameter exceeded 500N and were about 200N greater than the peak forces to compress connectors manually. When the peak force data were compared to strength capabilities reported in the literature, less than 1% of the general population was found to have the maximum strength to manually make one crimp on a common overhead connector. Less than 1% and approximately 50% of the female and male general population, respectively, were found to have the maximum strength to manually cut a cable with a 2cm diameter conductor. Handle force data from this study provide a biomechanical framework for explaining how the job demands of overhead and underground line workers could possibly cause MSDs. Relevance to industryElectric power utilities can review their work practices and tools in order to determine whether they can reduce the exposure of their workers to risk factors of MSDs, as well as reduce their cost of health care. Manufacturers of crimping and cutting tools can use the experimental approach in this study to measure the external forces required for their respective tools and then set quantitative force benchmarks to improve the design of their tools.

Compression Connectors for Stranded Aluminum Power Conductors

Twelve different commercial compression connectors for 240 mm/sup 2/ stranded aluminum cable conductors have been examined in order to identify and clarify the correlations between the quality of a connector and its design characteristics, assembly procedures, and other relevant parameters. The quality of the connectors is assessed with basis in resistance measurements during short-circuit tests and thermal cycling as specified by the IEC 61238-1 standard. Visual inspections of cross-sectioned connections, hardness measurements, and other examinations revealed that large mechanical deformations in connector-conductor interfaces significantly improve the quality. Connecting soft (annealed) conductors is considerably more difficult than hard-drawn conductors, but excellent results can be obtained if the work hardening during compression increases the conductor hardness to a level approaching that of hard conductors. The sequence in which the compression indents is made can be decisive for the quality of a connector. Unless the connector barrel or sleeve contains excessive amounts of contacting compound, it is advantageous to set the first indents at the ends of the barrel and the last ones in the middle.

Performance of Compression Connectors on Strand-Filled Conductors

Water-related damages are of major concern to the reliability of underground lines. Several strategies are developed to prevent water entry in extruded cables. Strand-filled cables are one of the available means to prevent water penetration and circulation in underground cable conductors, thus eliminating aluminum conductor corrosion and hydrogen gas buildup as well as reducing water-related treeing. However, published results on the connection performance with strand-filled aluminum conductors were scant and inconclusive. This report summarizes our latest findings on the subject with more conclusive data and some unexpected results.

Design and Testing of 15kV to 35kV Porcelain Terminations Using New Connection Techniques

New techniques for conductor connection in underground cable terminations were investigated in a design of a new distribution class porcelain cable termination. Connections to the conductor were accomplished using set screws, building upon previous designs with additions to assure a conservative design approach. The connector design was tested according to applicable standards for load cycling of connections, and the result appears capable of conservative performance in the operating environment. Use of such screw connections in distribution primary circuits has been very limited. They are not suitable for insulated splices because of the bulk and sharp edges found in this type of connection. Use in terminations has also been limited and compression connectors usage is commonplace. The compression connector is not without its problems as stated earlier and includes the problem of selecting the proper die, maintaining the equipment in proper condition to give full pressure, bringing the equipment from ground to bucket during riser pole installation and in manipulating the large heavy compression head during installation. With these drawbacks in mind a termination design using set screw connectors conservatively designed to reduce field problems and make reliable connections was investigated.