Considering the effects of a RTV coating to improve electrical insulation against lightning

One of the factors that cause power outages on distribution lines is being struck by lightning. Cloud to ground lightning often affects overhead distribution lines and can occur with negative or positive polarities. It can affect the performance of insulators and cause power line failure. Furthermore, outdoor polymer insulators are exposed to extreme weathering and pollution, which can cause chemical changes in the material properties and further leads to material degradation. These can cause a reduction in the insulator withstand capabilities and may lead to flashover. This paper investigates the effects of a RTV (room temperature vulcanisation) coating on a 10 kV polymer insulator in order to improve the electrical insulation performance against a lightning impulse under clean and polluted conditions. The up and down test method was used to evaluate the withstand voltage capabilities of an RTV coated polymer insulator. For reference, the withstand voltage for a basic setting polymer insulator was measured for comparison

Considering the effects of a cross-arm on a contaminated polymer insulator at different angles

This paper considers the effects of a cross-arm on a contaminated polymer insulator at different angles (90°, 60° and 45°) with negative and positive impulses. An experiment was conducted using a 10 kV polymer insulator that was contaminated with 4 % salt (a mixture of distilled water and sodium chloride). From the experiment, the behaviour of the voltage breakdown and leakage current of the contaminated insulator positioned at different angles from the cross-arm was evaluated under different impulse polarities. The results show that the values of the breakdown voltage and leakage current decrease with angle when using the 90° angle as a reference. The reason for this study into the effects of the cross-arm on a contaminated polymer insulator is because in the real case, when the insulators are installed on an angle tower, the forces or tensions due to the weather conditions (especially under strong winds) and from the distribution lines themselves will force the installed insulators to be tilted from its original 90° angle position

Considering the effect of angle on polymer insulator performance under wet condition

This paper reviews a study of the inclination angle of an insulator due to mechanical forces imposed by overhead conductors. The angle theoretically shortens the effective leakage path and flashover distance of the insulator, thus change the electrical performance of the insulator. To take it into consideration, this study had focused on experimental works to investigate effect of insulator inclination to the breakdown voltage and leakage current. Regards to the important of wetness to improve surface conductivity of insulator surface, authors have considered to conduct the test in wet conditions. In addition, standard lightning voltage was applied according to IEC 60060 in both positive and negative impulses. Based on the test, the performance of an insulator under positive and negative impulses was compared accordingly. A significant reduction of breakdown voltage was recorded when the angle decreased. The reduction was recorded as high as 17 %. Meanwhile, the breakdown voltage was much higher under negative impulses compared to positive impulses which showed a difference of 12 % to 14 % and the leakage current increased by 17 % due to the inclination angle. The calculation of U50 with consideration of the reduction factor was suggested and briefly discussed

Evaluation of electromagnetic fields on polluted polymer insulator under lightning impulse current

This paper presents a simulation study of a polluted insulator under a direct lightning impulse current. The pollution condition was considered and divided into two cases which are partial and full pollution. Under those conditions, the electromagnetic profiles of the insulator were evaluated. In the study, six points of measurement recognised as the weak points of the insulator were introduced to be evaluated. Meanwhile the electric field and magnetic field values at the points were related to the common discharge and damage of polymer insulators. It was found that the pollution condition effectively influenced the electric field and magnetic field profile. A significant difference in the electric field value indicated at least 65.15 % in both cases. For the magnetic field, at least a 10.9 % percentage difference was recorded

Effect of RTV coating material on electric field distribution and voltage profiles on polymer insulator under lightning impulse

Lightning has been known as one of major factors that cause power line failure in Malaysia. Presence of contaminants on polymer insulator surface will reduce voltage withstand capabilities in the event of lightning and could lead to insulator failure or worst power line disruptions. This paper presents a study on effects of Room Temperature Vulcanisation (RTV) coating material in order to improve electrical performances of polymer insulator and its effect towards electric field distribution and voltage profile. This study involves both experimental and simulation works. For experimental works, polymer insulator is tested inside fog chamber and voltage breakdown under lightning impulse were evaluated for clean and salt conditions. 3-Dimensional model of polymer insulator were simulated using ANSYS Maxwell and electric field distribution and voltage profile were evaluated. From the study, it shows that RTV coating material helps to improve voltage breakdown level of insulator and reduce concentration of electric field at triple region

Polymer insulator coated by room temperature vulcanization for strengthening voltage withstand capabilities

Non-ceramic type insulator, also known as polymer insulator has become an alternative to most power utilities worldwide due to its advantages. However, polymer insulator has some major drawbacks such as its material properties that are easily degraded and aging that results in unknown long-term reliability. Typical problems encountered by the polymer insulator during its years of service have included tracking and erosion of the shed that could lead to flashover, and chalking that can increase contamination accumulation on the shed or housing, and bonding and electrical failures due to interference between different materials. All these typical problems were due to prolonged exposure to atmospheric pollution, ultra-violet radiation (UV), rain and salt fog. Furthermore, being a tropical country with high lightning intensity, 70% of power outages in Malaysia are caused by lightning. Lightning strikes overhead power lines, causing surge over voltages and that affect performance of polymer insulators and lead to flashover and damage to the insulator or power lines. Under normal circumstances, the damaged polymer insulator will be replaced with a new one but it is labour-intensive and costly. Alternatively, in this research, new method of use, which is applying Room Temperature Vulcanisation (RTV) coating on polymer insulator surfaces in order to increase electrical performance of the insulator and also to restore a damaged insulator without the need to shut down the power lines. Previously, RTV coating method was widely used in outdoor porcelain and glass insulators to enhance electrical performance under pollution condition and increase their life span. Since there are no past measurements available for the polymer insulator, this research offers three different types of insulator configuration settings used in this work, namely, basic uncoated, and RTV types 1 and 2 coated insulators. All the insulators were tested under dry, clean-wet and pollution conditions under alternating and different lightning impulse voltage conditions. From the research, RTV-coated insulator was found to increase polymer insulator withstand capabilities up to 50% under pollution condition and reduce leakage current magnitude. From the study, application of RTV coating was found to be effective for strengthening voltage withstand capabilities under alternating and lightning impulse voltages. RTV coating can be used to improve and protect the surface condition of the polymer insulator. This may help to improve the performance of the polymer insulator and increase its lifespan and power system reliability

Research on low-carbon evaluation of green buildings based on the whole life cycle theory

Abstract Cities are highly dense areas with significant energy consumption and waste generation. Therefore, developing buildings with low energy consumption and reduced pollutant emissions is an important approach for China to achieve its goals of carbon neutrality, peak carbon emissions, and sustainable development. In this context, the concept and practice of green buildings have emerged. This research is based on the whole life cycle assessment method of the whole life cycle theory, integrating relevant indicators for calculating carbon emissions in buildings. It conducts a multidimensional evaluation and analysis of the low-carbon level of green buildings. Quantitative analysis is carried out based on five stages and five dimensions of the entire construction process. A conceptual model for the low-carbon evaluation of green buildings is established, and grey relational analysis and analytic hierarchy process are employed to rank and evaluate projects. The study aims to identify the key factors in the low-carbon evaluation of green buildings and discusses the focus and suggestions for future low-carbon management throughout the whole life cycle of green buildings

Fabrication and Investigation of Graphite-Flake-Composite-Based Non-Invasive Flex Multi-Functional Force, Acceleration, and Thermal Sensor

This work examines the physics of a non-invasive multi-functional elastic thin-film graphite flake–isoprene sulfone composite sensor. The strain design and electrical characterization of the stretching force, acceleration, and temperature were performed. The rub-in technique was used to fabricate graphite flakes and isoprene sulfone into sensors, which were then analyzed for their morphology using methods such as SEM, AFM, X-ray diffraction, and Fourier transform infrared spectroscopy to examine the device’s surface and structure. Sensor impedance was measured from DC to 200 kHz at up to 20 gf, 20 m/s2, and 26–60 °C. Sensor resistance and impedance to stretching force and acceleration at DC and 200 Hz rose 2.4- and 2.6-fold and 2.01- and 2.06-fold, respectively. Temperature-measuring devices demonstrated 2.65- and 2.8-fold decreases in resistance and impedance at DC and 200 kHz, respectively. First, altering the graphite flake composite particle spacing may modify electronic parameters in the suggested multi-functional sensors under stress and acceleration. Second, the temperature impacts particle and isoprene sulfone properties. Due to their fabrication using an inexpensive deposition technique, these devices are environmentally friendly, are simple to build, and may be used in university research in international poverty-line nations. In scientific laboratories, such devices can be used to teach students how various materials respond to varying environmental circumstances. They may also monitor individuals undergoing physiotherapy and vibrating surfaces in a controlled setting to prevent public health risks.The authors are grateful to UCSI Universiti for funding this research