Gas Insulated Busduct Research Articles

The Impact of Functionally Graded Material Insulator in a Three Phase Gas Insulated Busduct under Protrusion Defect

The Impact of Functionally Graded Material Insulator in a Three Phase Gas Insulated Busduct under Protrusion Defect

Electric field intensity minimization in three-phase gas-insulated busduct with metal inserts under delamination

Electric field intensity minimization in three-phase gas-insulated busduct with metal inserts under delamination

Insulation integrity of single phase gas insulated busduct with protrusion and depression defects under particle contamination

The increased demand for electricity, as well as the increasing energy density in urban areas, has necessitated the extension of the high voltage network all the way to the customer. Gas-insulated substations are the best solution to the problem described above and recently, the insulator failures of the Gas Insulated Busduct (GIB) have been observed due to several defects such as protrusion and depression. These defects make a significant impact on the surface of the insulator and hence de-energies the GIB device, resulting in a huge economic loss. In this paper, a Functionally Graded Material (FGM) insulator is designed for a single-phase GIB having protrusion and depression abnormalities for the study of electric stress at the Triple Junction and reduction of stress is done by inserting metal inserts. Simulation is carried with the designed insulator for various voltages and for different gradings of FGM.

Image Charge effect on Metallic Particle Movement in a single phase Gas Insulated Bus Duct with Dielectric Coated Enclosure

Image Charge effect on Metallic Particle Movement in a single phase Gas Insulated Bus Duct with Dielectric Coated Enclosure

Dielectric withstand capability of functionally graded material disc insulator in single phase - gas insulated busduct

Regardless of the environment, electrical substations must be secure and efficient, and they must also be able to recover rapidly from any damage they suffer. Metal inserts at the conductor end of a single-phase gas insulated busduct (GIB) are shown to minimise stress in FGM insulator and to assess stress on a Triple Junction. Functionally graded materials are spatially scattered with several filler materials and doped with varying permittivity values in order to create homogeneous electrical field stress.Various voltages and grades of FGM are used in the simulation, as well as the insulator. The effect of grading on electrical field stress is further decreased by inserting the Metal Insert into the FGM insulator. The suggested insulator's efficiency is demonstrated by the findings gathered and examined.

Study of Electric Field Stress with Metallic Particle Adhering to FGM Spacer in Three Phase GIS

Recently, spacer design is considered as an important factor for the smooth functioning of three phase gas insulated busduct (GIB) to prevent itself from several defects like delamination, void, particle etc. In this paper, a post type spacer with functionally graded material (FGM) has been designed for a three phase GIB with particle and further electric field stress is minimized by inserting metal inserts. FGM post type spacer is spatially distributed with multiple fillers materials to achieve uniform electric field stress using the finite element method. Simulation is carried out with the designed spacer and with a particle as a defect for different FGM gradings and operating voltages. The effect particle with different sizes is minimized with the insertion of the metal insert to the post type FGM spacer and the results obtained are presented and analyzed.

Electric Field Stress in a Three Phase Common Enclosure Gas Insulated Busduct with FGM Post Type Spacer and Reduction with Metal Inserts

The establishment of supporting insulators plays a vital role in the continuous operation of the three-phase Gas Insulated Busduct (GIB), which primarily depends on the distribution of electric field stress on the spacer surface. Shape control is a technique used along the spacer surface to achieve uniform field intensity, but this technique can also lead to very irregular shapes. The Triple Junction (TJ) is the region where the field stress has to be reduced. Over a period, high field stresses along the spacer surface will result in a surface flashover and thus de-energize the complete GIB, leading to enormous losses economically. In this paper, a Functionally Graded Material (FGM) spacer for a three-phase GIB has been designed with more number of gradings and further field stress at TJ is minimized by inserting and reshaping the metal inserts (MI) at the end of the enclosure. By doping them with different permittivity values, functionally graded materials are spatially distributed with multiple filler materials to achieve uniform stress on the electric field. Simulation is carried out with the FGM and epoxy (post type) Spacers for different voltages and FGM gradings. With MI, the stress is minimized and an enhanced uniform field allocation along the surface is obtained.

Particle movement pattern in a 1-φ GIB under abnormal conditions

Power system comprises of various over voltages which are transient in nature namely lightning and switching phenomenon under abnormal conditions which cause flashover in Gas Insulated Bus-duct (GIB) if not protected properly. So, there is a necessity for GIS to have withstanding capability of lightning and switching. Otherwise they may cause shut down of the system. In this work, 1050 kV Lightning Impulse and 750 kV Switching Impulse is superimposed on normal frequency voltage class of 100 kV, 132 kV and 145kV and are given to 1-ΦGIB for finding peak radial movement for Al and Cu particles. The movement patterns for both lightning and switching over voltages are compared. All the simulation results are shown in this paper.

Study of electric field stress on the surface contour and at the triple junction in three phase GIS with FGM spacer under the depression defect

Abstract Now days, the establishment of spacers is in wide usage in three-phase Gas Insulated Busduct (GIB) for providing mechanical support and better insulation to the conductors. The region of the intersection of SF6 gas, enclosure end and the spacer is one of the weakest links in GIB, so the major concentration is done on minimization of electric field stress at this junction by using Functionally Graded Material (FGM) technique. The other incidents of insulation failures are due to several defects like depression, delamination etc. reduces the dielectric strength of the spacers. In this paper, an FGM post type spacer has been designed for a three-phase GIB under depression and further electric field stress at Triple Junction (TJ) is reduced by introducing a metal insert (MI) nearer to the TJ. Several filler materials are used as doping materials for obtaining different permittivity values using FGM technique to achieve uniform electric field stress. Simulation is carried out for the designed spacer at various operating voltages with different types of FGM gradings. The effect of depression with different dimensions and positions is analyzed before and after inserting MI to the FGM post type spacer in three-phase GIB.

Design and analysis of FGM post type spacer in a three phase common enclosure gas insulated busduct under delamination

In the present days, the establishment of supporting insulators plays a vital role in the continuous operation of three-phase gas-insulated busduct (GIB) which mainly depends on the distribution of electric field stress on the surface of the spacer. The triple junction (TJ's) which is one of the regions where the electric field stress has to be minimized. The insulator failures of GIB are observed due to several defects like delamination, protrusion etc. These defects affect the electric field distribution badly over the spacer length, hence de-energies the complete GIB leading to huge loss economically. In this paper, for a three-phase GIB under delamination, a post-type spacer with Functionally Graded Material (FGM) was designed to reduce the high electrical field stress at TJ's by inserting metal inserts at the enclosure end. Functionally graded materials are distributed spatially with several filler materials by doping them with different permittivity values to obtain uniform electric field stress. Simulation is performed and the electrical field stress is calculated by varying the dimensions of delamination for different operating voltages at different sizes and FGM gradations with different permittivity ranges, the results obtained are presented and analysed.

Study of electrostatic field effect in a three-phase gas-insulated busduct with FGM spacer under the effect of protrusion

Recently, the defects in Gas-Insulated Busduct (GIB) affect the electric field distribution badly over the spacer length and de-energies the GIB leading to huge loss economically. In this paper, a post type spacer with Functionally Graded Material (FGM) has been designed for a three-phase GIB under protrusion and further electric field stress is minimized by inserting metal inserts. Functionally graded materials are spatially distributed with several filler materials by doping them with different permittivity values to achieve uniform electric field stress. Simulation is carried out with the designed spacer for different voltages and also for different types of FGM gradings. The protrusion effect on the electric field stress is studied with different sizes and the results obtained are presented and analyzed.

Effect of Metallic Particle Movement at Different Positions of Particle on Spacer in a 1-Ø GIB

Gas Insulated Substation has been more credible than Air Insulated Substation thus increasing its application in the electrical industry. Though being more advantageous there are some areas in the system where there is a need for study. Metallic particle contamination is one of the areas where there are chances for the risk or failure; the particles reduce the dielectric strength of the insulating medium i.e. the SF6 gas. The metallic particles can be formed from the enclosure, conductor or the insulating material during various operations such as assembling, operating, and transporting etc. The particles can exist anywhere on the enclosure, conductor and the spacer. In this paper a single phase Gas Insulated Busduct with conductor diameter of 55mm and outer enclosure of diameter 152 mm with a spacer inclined at an angle of 450 to the enclosure is considered. Movement of aluminum and copper particles are studied which are present on the spacer at a certain distance from the enclosure.

Assessment of SF6 and N2 Gas Mixtures as a Dielectric Medium in a Gas Insulated Busduct

SF6 gas is used as a dielectric medium in Gas Insulated Systems; it has an excellent dielectric strength and high arc quenching property. Despite of having these properties SF6 gas has high GWP, thus it is required to reduce the usage of the gas. In this paper SF6 and N2 gas mixtures were used as an alternate to the SF6 gas. The movement of free moving metallic particles present in a GIB has been analyzed for both the pure SF6 gas and by using various percentages of N2 gas and SF6 gas as an insulating medium

Effect of Coating of Dielectric in a 3-Phase GIB with Particle Movement

The dielectric coating effect on the motion of the Particle inside a Gas Insulated Bus duct (GIB) of three phase using epoxy resin coating of dielectric inside f GIB outer enclosure of inner surface without image charge is presented in this paper. Simulation is performed by considering various parameters like drag, gravitational and the electrostatic forces acting on the particle and a mathematical model was derived. A 2nd order differential equation for the particle motion is solved and restitution coefficient was considered at each impact of particle with the GIB enclosure. At the particle locations, estimation of electric fields instantaneously was made by CSM. The particle motion in the absence of effect of image charge is considered in a 3-phase GIB with dielectric coating. For voltage levels like 220kV, 400kV, 600kV and 800kV class, the movement of radial in nature is found for particles like aluminum and copper inside GIB. Analysis of all the results were done and presented in this paper.

Impact of Lightning Impulse on Electric Field Stress of Spacer in Single Phase Gas Insulated Busduct

During the last two decades, for reliable power supply, GIS have found a broad range of application in power systems because of their high reliability, easy maintenance, small space requirement, etc. Gas insulated sub-stations employs a superior dielectric gas, SF6 at moderate pressure for phase to phase and phase to ground insulation. Several troubles and system outages in GIS have been reported world-wide due to insulation failures which resulted in the intensification of electric field along the spacer surface and especially at the triple point electrode – spacer – gas. Hence, it was required to reduce the rate of insulation failure. In this work, Conventional cone type spacer geometry is taken for which field study has been done. Electric field stresses developed by the cone type spacer on the surface of the spacer and also at the triple junction is determined. It is found that the electric field stress at the surface of the spacer is maintained uniform, the electric field stress at the critical junctions formed by the conductor, solid insulator and SF6 gas is not maintained at minimum value. Metal inserts are considered as a means to reduce the stress at the triple point junction. The impact of Lightning Impulse on the Electric Field Stress along the spacer is carried and the reduction of stress is mitigated with the insertion of Metal Inserts.

Field Stress Control of a Functionally Graded Disk Type Spacer in a Gas Insulated Bus Duct with Metal Inserts

High voltage electric utilities are hindered with certain difficulties like high stress distribution and insulation damage that are needed to be taken care for reliable operation of the system. In a Gas Insulated bus duct, high field stress along the spacer surface especially at the contact point of the conductor, insulator and gas (called triple junction) is a major factor affecting the insulation strength. Research studies of shaping the spacer were found effective in controlling the stress distribution but found to be complicated in real time application. In this paper, functionally graded materials of disc type spacer with different permittivity are proposed for controlled field stress distribution at the spacer surface. Electric field calculations with different gradings from high to low and U shape are done. Properly shaped metal inserts are incorporated to have a uniform stress distribution along the spacer.

A Wideband Spiral UHF Coupler With Tuning Nodules for Partial Discharge Detection

This paper reports on the development and testing of a wideband spiral-shaped coupler for a partial discharge (PD) detection in the UHF spectrum. The coupler design, which is based on the log-periodic spiral slot antenna, has been optimized using finite element simulation. The following parameters have been optimized: feed location, arm termination shape, width of arm root, and termination. The unique feature of the coupler is the inclusion of tuning nodules on the spiral arms, which widen its bandwidth without the need for additional components. Tests in an anechoic chamber have shown a close agreement with the simulation results. The coupler exhibits a wide bandwidth (S11 < −9.55 dB) between 0.5–2.6 GHz and a peak gain of 4.8 dBi (at 1.35 GHz), while using an infinite balun coaxial feed, which allows for an input impedance of 50 Ω. The PD testing in the laboratory has shown that the phase resolved PD patterns acquired with the coupler are very similar to those captured with conventional PD sensors. An application of the coupler as an internal sensor in a gas-insulated busduct is detailed and a bandwidth comparison with other UHD PD sensors is provided.

Electric Field Distribution around Contaminating Wire Particles Inside Gas Insulated Bus Duct

The presence of metallic contaminating particles lowered the dielectric strength of the gas sharply. The determination of the insulation breakdown inside gas insulated bus duct requires the knowledge of the field distribution inside it. Finite Element Method (FEM) has been used throughout this work, for its favorable accuracy, to calculate the electric field distribution inside the bus duct. In this paper, the electrostatic modeling of gas insulated bus duct (GIBD) with particle contamination is studied. The effect of particle length, hemi-spherical radius and ratio (L/r) on the electric field values is presented. The effect of the dielectric coating of the inner surface of enclosure, is presented and discussed. Multi-contaminating fixed particles are considered in this work and the electric field distribution in this case is presented. The effect of particle length and radius of middle fixed particle of multi contaminating particles on the electric field values are also studied. Electric field distribution around disc-spacer with and without an earthed particle contamination is presented and discussed. Finally, the effect of distance between particle and spacer on the electric field values is also studied.

Effect of Coating of Earthed Enclosure and Multi-Contaminating Particles on Breakdown Voltage inside Gas Insulated Bus Duct

Metallic particle contamination is one of the areas of insulation design that are considered critical. This paper demonstrates the control of metallic particles in gas insulated bus duct (GIBD) by using dielectric coating on the inside surface of the outer enclosure of a coaxial electrode system. Several models of GIBD with single and multi-contaminating particles will be studied. In this paper, the Finite Elements Method (FEM) is used to evaluate the electric field distribution on and around single and multi-contaminating wire particles which in contact with dielectric coating of earthed enclosure inside GIBD. The effect of changing the length and the radius of middle particle for multi-contaminating particles on the electric field values are studied. Breakdown Voltage calculations for gas mixtures with single and multi-contaminating wire particles are studied. The effects of gas pressure on the breakdown voltage for various fractional concentrations of SF 6 -gas mixtures with and without particle contamination and also with and without coating of earthed enclosure are studied. The optimum gas mixture which gives higher dielectric strength with lower cost is also determined. The effect of coating thickness of earthed enclosure on the breakdown voltage for various fractional concentrations of SF 6 -gas mixtures is also studied. Finally, the effect of length and hemi-spherical radius of multi-contaminating particles on the breakdown voltage with various SF 6 -gas mixtures and varying gas pressure one time and another time with fixed pressure are studied. DOI: http://dx.doi.org/10.11591/ijece.v4i4.5693

Movement Patterns of Metallic Particles in a Single Phase Compressed Gas Insulated Busduct with Electromagnetic Field Effect

Movement Patterns of Metallic Particles in a Single Phase Compressed Gas Insulated Busduct with Electromagnetic Field Effect