Effect of Aminosilane Coupling Agent-Modified Nano-SiO2 Particles on Thermodynamic Properties of Epoxy Resin Composites

From the perspective of improving the thermodynamic properties of epoxy resin, it has become the focus of research to enhance the operational stability of GIS (Gas Insulated Substation) basin insulators for UHV (Ultra-High Voltage) equipment. In this paper, three aminosilane coupling agents with different chain lengths, (3-Aminopropyl)trimethoxysilane (KH550), Aminoethyl)-γ-aminopropyltrimethoxysilane (KH792) and 3-[2-(2-Aminoethylamino)ethylamino]propyl-trimethoxysilane (TAPS), were used to modify nano-SiO2 and doped into epoxy resin, respectively, using a combination of experimental and molecular dynamics simulations. The experimental results showed that the surface-grafted KH792 model of nano-SiO2 exhibited the most significant improvement in thermal properties compared with the undoped nanoparticle model. The storage modulus increased by 276 MPa and the Tg increased by 61 K. The simulation results also showed that the mechanical properties of the nano-SiO2 surface-grafted KH792 model were about 3 times higher than that of the undoped nanoparticle model, the Tg increased by 36.5 K, and the thermal conductivity increased by 24.5%.

Suppression of very fast transients in 245 kV gas insulated substation

Very Fast Transient Over voltages (VFTOs) generate during operation of the disconnector switches or circuit breakers in a gas insulated substation (GIS). These transient voltages stress the insulation system in GIS and further result in mal-operation of the control circuitry as well as the secondary equipment connected to it. Since the VFTOs affect the reliability of GIS, it is necessary to mitigate them. This paper presents the mitigation of the very fast transient over voltages and the associated very fast transient currents (VFTCs) using the nano-crystalline rings in a 245 kV GIS. The mitigation in the peak amplitude of VFTOs and VFTCs at various locations in the GIS for various switching configurations are analyzed in this paper. The nano-crystalline rings of different geometries and permeabilities are considered to understand the damping effect being offered. The nano-crystalline rings are considered at all the possible switches of 245 kV GIS bays. An equivalent circuit model of the nano-crystalline ring is obtained through an iterative algorithm. The very fast transients have been calculated using Electromagnetic Transients Program software. Further, attenuation in the dominant frequency components of VFTOs and VFTCs at different GIS components is also studied for various switching configurations with nano-crystalline rings.

Distribusi Medan Listrik di Kompartemen Busbar Gas Insulated Switchgear (GIS) Menggunakan Charge Simulation Method

Penelitian ini bertujuan untuk mengilustrasikan distribusi medan listrik di kompartemen busbar tipe gas insulated switchgear (GIS). Gas Insulated Substation (GIS) merupakan rangkaian peralatan gardu induk yang terpasang di dalam sebuah metal enclosure dan diisolasi oleh gas bertekanan yaitu Sulfur Hexafluoride (SF6). Dalam simulasi ini, diasumsikan titik referensi berada di sekitar contact pin busbar, dan titik muatan buatan berada disekitar kompartemen busbar. Simulasi dilakukan dengan menentukan titik referensi dan titik muatan bantuan untuk menghitung nilai muatan yang akan dicari yaitu contact pin. Titik muatan buatan ini terletak disembarang titik disekitar kompartemen busbar GIS dan akan dihitung nilai muatannya melalui metode simulasi muatan (charge simulation method) dengan bantuan komputasi Matlab

Investigating the Effect of Several Model Configurations on the Transient Response of Gas-Insulated Substation during Fault Events Using an Electromagnetic Field Theory Approach

Assessment of very fast transient overvoltage (VFTO) requires good knowledge of the behavior of gas-insulated substation when subjected to very high frequencies. The international standards and guidelines generically present only recommendations regarding the VFTO suppression without a technical and mathematical background. Therefore, to provide an accurate image regarding the critical locations across a gas-insulated substation (GIS) from a transient response point of view, a suitable modeling technique has to be identified and developed for the substation. The paper aimed to provide an accurate assessment of the GIS holistic transient response through an electromagnetic field theory (EMF) approach. This modeling technique has always been a difficult task when it came to gas-insulated substations. However, recent studies have shown that through suitable Computer-aided design models, representing the GIS metallic ensemble, accurate results can be obtained. The paper investigated several simplifications of the computational domain considering different gas-insulated substation configurations in order to identify a suitable modeling approach without any unnecessary computational effort. The analysis was performed by adopting the partial equivalent element circuit (PEEC) approach embedded into XGSLab software package. Obtained results could provide useful hints for grounding grid designers regarding the proper development and implementation of transient ground potential rise (TGPR) mitigation techniques across a gas-insulated substation.