Electrical treeing and partial discharge characteristics of silicone rubber filled with nitride and oxide based nanofillers

This article presents a study on electrical treeing performances with its associated partial discharge (PD) and the influence of filler concentration in silicone rubber (SiR) samples which are filled with silicon dioxide (SiO2) and silicon nitride (Si3N4) as nanofillers for electrical tree growth suppression. There are many researches on electrical treeing in SiR with SiO2 nanofillers but none of the publication have reported on Si3N4 nanofillers for suppression of the electrical tree growth. In this study, the treeing experiments were conducted by applying a fixed AC voltage of 10 kV and 12 kV at power frequency of 50 Hz on unfilled SiR, SiR/SiO2, and SiR/Si3N4 nanocomposites with different filler concentrations by 1, 3, and 5 weight percentage (wt%) and the electrical treeing parameters were observed with its correlated PD patterns. The outcome from this study found that the SiR/Si3N4 nanocomposites were able to withstand the electrical treeing better than the pure SiR or SiR/SiO2 nanocomposites. Furthermore, the increase in filler concentration improved the electrical tree performances of the nanocomposites. This finding suggests the Si3N4 can be used as filler in polymeric insulating materials for electrical tree inhibition. Meanwhile, the PD activity shows increment when the tree progresses thereby indicating correlation in both parameters which can be as key parameter for monitoring unseen electrical treeing in the opaque samples

Extensive 1-year survey of trace elements and compounds in the airborne suspended particulate matter in Cleveland, Ohio

Concentrations of 75 chemical constituents in the airborne particulate matter were measured in Cleveland, Ohio, during 1971 and 1972. Values covering a 1-year period (45 to 50 sampling days) at each of 16 sites are presented for 60 elements. A lesser number of values is given for sulfate, nitrate, fluoride, acidity, 10 polynuclear aromatic hydrocarbon compounds, and the aliphatic hydrocarbon compounds as a group. Methods used included instrumental neutron activation, emission spectroscopy, gas chromatography, combustion techniques, and colorimetry. Uncertainties in the concentrations associated with the sampling procedures, the analysis methods, the use of several analytical facilities, and samples with concentrations below the detection limits are evaluated in detail. The data is discussed in relation to other studies and source origins. The trace constituent concentrations as a function of wind direction are used to suggest a practical method for air pollution source identification

Estuarine Macrophytes at Bakkhali, Cox’s Bazar, Bangladesh with Reference to Mangrove Diversity

The diversity and ecosystem significance of macrophyte communities was studied, with emphasis on the mangrove species in the Bakkhali estuary of Cox’s Bazar, Bangladesh. Macrophytes of the Bakkhali river estuary were mainly mangroves (Avicennia marina Forssk Vierh and A. alba Blume and Acanthus ilicifolius Linnaeus) of inundation Class-IV; i.e., the mangroves are inundated 2-20 times per month (Watson, 1928), a wild rice variety of salt marsh (Porteresia coarctata Tateoka), Congon grass (Imperata cylindrica P. Beauv.), seagrass (Halophila beccarii Ascherson), macro-algae (Ulva intestinalis Linnaeus, Catenella nipae Zanardini and Hypnea sp.) and mangrove associates Suaeda maritima Only two individual plants of mangrove, Sonneratia apetala and Aegialitis rotundifolia, were found growing in the inter-tidal area of this estuary. On the eastern side of the estuary, almost 100% of the intertidal area is covered by the salt marsh plant P. coarctata, with patches of seagrass Halophila beccarii. The western portion of the estuary is covered by mangroves, mixed with patchy salt marsh and seagrass in and sheltered by a sand bar. Salt marsh and seagrass grow in mangrove dominated sites as 2nd pioneer species in the newly accreted land at the mouth of Bakkhali estuary. These estuarine macrophytes are of both economic and ecological significance and the macrophyte community plays a principal role directly or indirectly in supporting the local communities as source of food, cash and energy

Transformer Fault Early Warning System Model Using GSM Network

This paper presents the design and implementation of amobile embedded system using an Arduino microprocessor to monitorand record key operational indicators of a distribution transformer,such as transformer oil level, temperature and vibration of adistribution transformer in a substation. If there is any abnormalityor an emergency situation, the system sends SMS (Short MessageService) messages to designated mobile telephones containinginformation about the abnormality of the mentioned parameters.Providing early warning of the abnormality of the distributiontransformer can be accomplished by shutting down the entire unitwith the aid on-line monitoring system integrates with Global ServiceMobile (GSM) Modem. Furthermore, the design generally consiststand-alone single chip microcontroller, modem and sensor packageslocated on distribution transformer site. In general, the design isdeveloped for the user to easily recognize the distribution transformerthat is suffered by any high vibration and rise in temperatures andlocated in remote or suburban area which is rarely and hard to reachfor manual monitoring. The ultimate objective is to monitor thetransformer oil level and temperature of 24 hours, 7 days a weekcontinuously besides the current and voltage parameter whichincluded in basis monitoring syste

Clarification of the optimum silica nanofiller amount for electrical treeing resistance

This paper aims to clarify the optimum amount of fumed silica (SiO2) nanofiller in resisting the initiation and propagation of electrical treeing in silicone rubber (SiR). Unlike other works, SiR/SiO2 nanocomposites containing seven different weight percentages of SiO2 nanofiller were prepared for this purpose. To achieve the objective, the electrical tree characteristics of the SiR/SiO2 nanocomposites were investigated by comparing the tree initiation voltage, tree breakdown time, tree propagation length and tree growth rate with its equivalent unfilled SiR. Moreover, the structural and morphological analyses were conducted on the SiR/SiO2 nanocomposite samples. The results showed that the SiR, when added with an appropriate amount of SiO2 nanofiller, could result in an improved electrical tree resistance. It implies that the 5 wt% of silica is the optimum amount to achieve the optimal electrical tree resistance such that above 5 wt%, the tree resistance performance has been abruptly reduced, subjected to the agglomeration issue

Analysis of Transmission Lightning Arrester Locations Using Tflash

Tropical countries with extensive lightning activity, such as Malaysia, encounter numerous problems on their electrical transmission and distribution systems. Many overhead lines trip because of back flashover of lightning and shielding failures of the grounding system. To overcome the problem and improve transmission line performance, a detailed lightning study is required to analyse the corresponding lines and determine the best location for transmission line arrester (TLA) installation. We used TFlash to analyse a TLA installation on a 132-kV SSWW-BBST overhead transmission line system located in Selangor, Malaysia. Based on the results, the installation of the TLA at the optimum quantity and at appropriate towers have reduced the number of lines that trip

Analysis of transmission lightning arrester locations using Tflash

Tropical countries with extensive lightning activity, such as Malaysia, encounter numerous problems on their electrical transmission and distribution systems. Many overhead lines trip because of back flashover of lightning and shielding failures of the grounding system. To overcome the problem and improve transmission line performance, a detailed lightning study is required to analyse the corresponding lines and determine the best location for transmission line arrester (TLA) installation. We used TFlash to analyse a TLA installation on a 132-kV SSWW-BBST overhead transmission line system located in Selangor, Malaysia. Based on the results, the installation of the TLA at the optimum quantity and at appropriate towers have reduced the number of lines that trip

Partial Discharge and Breakdown Strength of Plasma Treated Nanosilica/LDPE Nanocomposites

Nanocomposites have been actively studied in recent years as an insulating material due to their excellent in electrical, mechanical and thermal properties. Even though, the addition of nanoparticles into polymer matrices showed better performance in relation to partial discharge (PD) and AC breakdown strength tests. However, the introduction of nanoparticles could lead to the formation of agglomeration of the fillers which may nullify the true capabilities of the composites. Therefore, silane coupling agent was introduced for surface functionalization treatment of the nano filler but among the issues associated are toxicity and complexity. In the present study, atmospheric pressure plasma is proposed to enhance the surface functionalization of the nano filler. This proposed method was used to treat the nanosilica (SiO 2 ) surfaces to enhance the interfacial interaction between the host (LDPE) and nano filler. SiO 2 nano filler was added into the LDPE at weight percentages of 1, 3 and 5%. The phase-resolved PD behaviour and Weibull analysis of AC breakdown strength of untreated and plasma-treated LDPE nanocomposites were measured to evaluate the performance of the samples. As results, the plasma treated LDPE nanocomposites experience apparent increments of the PD resistance and AC breakdown strength as compared to the untreated nanocomposites. It is implied that the plasma treatment of nanosilica has contributed to the enhancement of the filler dispersion and eventually reducing the agglomeration

Evaluation of residential grid-connected photovoltaic system as the potential energy source in Malaysia

Application of solar energy in Malaysia has been started in 1998. This country has a large potential of solar energy due to its location at equatorial region. The current energy consumption and demand in Malaysia is describes in this paper. The potential of solar energy in Malaysia is described together with the suitable photovoltaic construction. It also explains the plans conducted by Malaysia involving solar energy that covers investments and also projects involved such as Malaysia Building Integrated Photovoltaic (MBIPV). Simulation of grid-connected photovoltaic system in this study is performed using HOMER software. Finally, the potential of having a grid-connected PV system in a residential area is analyzed. The positive and negative findings in terms of cost and suitability of the system are explained

Potential of Residential Grid-Connected Photovoltaic System as the Future Energy Source in Malaysia

Malaysia has started the implementation of solarenergy harvesting in 1998. Located at equatorial region, Malaysia hasa large potential for solar energy. This paper examines the currentenergy consumption and demand in Malaysia. The potential of solarenergy harvesting in Malaysia is described together with the suitablephotovoltaic construction. It also explains the plans conducted byMalaysia involving solar energy that covers investments and alsoprojects involved such as Malaysia Building Integrated Photovoltaic(MBIPV). Finally, this paper analyses the potential of having a gridconnectedPV system in a residential area. The positive and negativefindings in terms of cost and suitability of the system are explaine