Dielectric Self Research Articles

Examination of Wind Effect on Adss Cables Aging Test

DOI: 10.5152/iujeee.2018.1818 ADSS (All dielectric self supporting) cables are generally installed on high voltage transmission lines and mostly used under different environmental effects, such as temperature, wind, UV radiation, etc. In this study, wind affect on ADSS cables was investigated by using dry band arcing (IEEE 1222 Electrical surface degradation) test method. A wind source was implemented to the test setup to evaluate the performance of PE (Poly-ethylene) cable jacket on ADSS cable under different wind speeds. Test results indicate that life time of the ADSS cable decreases while the wind speed is increasing.

Self-consistent field model for strong electrostatic correlations and inhomogeneous dielectric media.

Electrostatic correlations and variable permittivity of electrolytes are essential for exploring many chemical and physical properties of interfaces in aqueous solutions. We propose a continuum electrostatic model for the treatment of these effects in the framework of the self-consistent field theory. The model incorporates a space- or field-dependent dielectric permittivity and an excluded ion-size effect for the correlation energy. This results in a self-energy modified Poisson-Nernst-Planck or Poisson-Boltzmann equation together with state equations for the self energy and the dielectric function. We show that the ionic size is of significant importance in predicting a finite self energy for an ion in an inhomogeneous medium. Asymptotic approximation is proposed for the solution of a generalized Debye-Hückel equation, which has been shown to capture the ionic correlation and dielectric self energy. Through simulating ionic distribution surrounding a macroion, the modified self-consistent field model is shown to agree with particle-based Monte Carlo simulations. Numerical results for symmetric and asymmetric electrolytes demonstrate that the model is able to predict the charge inversion at high correlation regime in the presence of multivalent interfacial ions which is beyond the mean-field theory and also show strong effect to double layer structure due to the space- or field-dependent dielectric permittivity.

Analysis of frequency characteristics of electrical arcs on the insulating sheath of the ADSS fiber optic cables

The insulating outer-sheath of ADSS (All dielectric self supporting) cables used on high voltage transmission lines are often subjected to various environmental effects. The ageing process of cable sheath can be investigated by using the dry-band arcing test method under laboratory conditions. Dry-band arcing is the most common technique to determine the ageing period of insulating materials. Environmental effects such as rain, humidity, dew and ice produce various amounts of wet regions on the cable surface. Electrical arcs and hence degradations are occurred on the cable surface due to the enhanced electrical field with formation of wet regions. In this study, the ageing process of ADSS cables was investigated by using the dry band arcing test method (IEEE 1222 Electrical surface degradation). Rainfall intensity determines the wet regions on the cable surface which affects the ageing process of the cable. During tests electrical arc signals were investigated by analyzing wet region scope versus amplitude and frequency spectrum variations via the FFT method. It is possible to claim that the proposed FFT analysis clearly identifies the ageing period of the ADSS cable which was subjected to different rainfall intensities by monitoring frequency spectrum of the arc signals.

Experimental Verification of the Proposed IEEE Performance and Testing Standard for ADSS Fiber Optic Cable for Use on Electric Utility Power Lines

All Dielectric Self Supporting (ADSS) fiber-optic cable jackets are subject to dry band arcing associated with wet, conductive pollution, quantified electrically by ohms per meter, in conjunction with the location of the ADSS in relation to conductor placement on high-voltage transmission structures. In order to determine the suitability of a particular ADSS jacket material to resist dry band arc damage in various levels of pollution as well as for incipient voltage levels, an electrical test, employing equivalency to the dry band environment, has been proposed. A set of desirable hypothetical results are briefly discussed. The tests results described herein, for common polyethylene jacketed ADSS, support the nature of the hypothetical data. It is noted that this is not "pass-fail" but a test that establishes performance criteria. It has been submitted to the fiber optics standards working group.

Study on development of dry band on ADSS fiber optic cable

All dielectric self supporting (ADSS) fiber optic cables are suffering from damage caused by dry-band arcing. This paper investigates the formation of the dry band, which is crucial to the arcing. The formation of the dry band is the result of evaporation of water deposit some point on the cable surface. When the dry band is formed the current is interrupted. Then high voltage is applied to the small gap separated by the dry band, and may cause arcing. This paper discusses the drying process of the wet layer on the surface of the cable in detail. The differential equation of the drying rate is formulated and numerical simulation is performed. With this equation, the time-to-arcing and variation of the layer resistance can be estimated. For verification of the results, the time-to-arcing and layer resistance are measured in the laboratory. The numerical results provide guidance for design of an automatic dry-band arcing aging test system. The onset of arcing is investigated based on the results.

Analysis of Electric Field Distribution Around the High-Voltage Overhead Transmission Lines With an ADSS Fiber-Optic Cable

This paper is an analysis of electric-fields distribution around overhead transmission lines (OHTLs) with an all dielectric self supporting (ADSS) fiber-optic cable. The aim of this analysis is to determine electrical interactions on a fully dielectric cable located in the electric field of OHTL. Two characteristic areas were taken into consideration. The first of these-in the middle of the line span, and the second-around the clamps which fit the cable to the transmission line tower. These areas follow from localization of ADSS-type cable in the line span. The latter of this area was taken into detailed analysis for determining the conditions of electric discharge initialization on the cable's surface.

Communications technology guidelines for EMS/SCADA systems

The purpose of this Guideline Technical Paper is to provide a summary of the different communications technologies available for use or application with EMS/SCADA system projects. All of the various communication media are addressed with a brief description along with tables of the advantages and disadvantages of each and recommendations for choosing the most appropriate communication technology. The technologies discussed are: twisted pair metallic cable; coaxial metallic cable; fiber optic cable (either optical power ground wire (OPGW), all dielectric self supporting (ADSS), or wrapped types (WOC)); distribution line carrier (DLC); power line carrier (PLC); satellite (VSAT, LEO, others); leased service; VHF radio (mobile); point-to-point UHF radio; multiple address radio system (MARS) 400/900 MHz UHF radio; trunked mobile UHF radio; spread spectrum UHF radio (monitor frequency for potential interference before installation); and microwave radio (2-40 GHz).

On the measurement of overhead transmission lines conductor self-damping

This work is about a new methodology for determining the overhead transmission line (OHTL) conductor self damping by means of tests on a laboratory span. The method proposed relies on the inverse standing wave ratio (ISWR) method, but introduces a measurement procedure in condition to limit some of the problems connected to the straight-forward application of the method. It has been studied and tested especially in view of its application to the measurement of the self-damping of particular conductors, such as the optical ground wires (OPGW) and the relatively new all dielectric self supporting (ADSS) optical cables, whose self-damping is very low. A comparison with the results obtained by means of other methods for determining the conductor self damping is presented too.

Solutions for Fibre-Optic Cables installed on Overhead Power Transmission Lines-A Review

The criticality of fibre-optic cable design for overhead power transmission line applications presents a challenging task to the cable designers the world over. The cable design must ensure that there are no long term problems with fibres or cable construction, which might otherwise lead to the collapse of fibre-optic communication system. Optical Fibre Ground Wire (OPGW) is designed as a two function aerial conductor viz, a shield wire to take care of fault current and lightning strike, and integrated fibre-optic unit taking on the function of communication. The OPGW has been found to be the best solution when installed as replacement of conventional earthwire on new transmission lines or when there is a need to change the old groundwire of existing line. On existing transmission lines, the preferable option is to install an All Dielectric Self Supporting Fibre Optic Cable (ADSS), being cost-effective. The installed ADSS is independent of power lines and provides an attractive solution in respect of main...