2020 International SAUPEC/RobMech/PRASA Conference最新文献_第6页

Investigating the Effects of Creepage Discharges on the Breakdown Voltage of Natural Ester Oil Impregnated Pressboard in Power Transformers 蠕电放电对电力变压器天然酯油浸渍板击穿电压影响的研究

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9040954

Bakhekile Ndlovu, Cuthbert Nyamupngedengu

{"title":"Investigating the Effects of Creepage Discharges on the Breakdown Voltage of Natural Ester Oil Impregnated Pressboard in Power Transformers","authors":"Bakhekile Ndlovu, Cuthbert Nyamupngedengu","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9040954","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9040954","url":null,"abstract":"Power transformers are the most expensive and important equipment in the transmission network. It is therefore crucial that they are well protected to avoid damage of equipment and possibly loss of life. The common transformer failure modes are due to dielectric failures. The aim of this project is to subject pressboard to creepage partial discharges and investigate the effects on the AC breakdown voltage. Furthermore, since ester oils are considered to have superior characteristics to mineral oil, the effects of creepage discharges on the respective breakdown voltages are investigated and reported. This is done by using an inclined needle-plane electrode configuration, with an electrode gap of 25 mm. Creepage discharges are generated for various times and the pressboard samples undergo breakdown voltage tests. Ester oil was found to withstand breakdown voltages up to 20 % higher than mineral oil. Generally, a downward trend was observed as the exposure to creepage discharges increased for both oils. The Weibull distribution model reveals that a brand new mineral oil-impregnated pressboard sample can withstand breakdown at the same level as an ester oil-impregnated pressboard sample that has been exposed to creepage discharges for 7 hours. Ester oils can therefore improve the lifetime of pressboard (and thus the transformer itself) regardless of exposure to insulation deterioration through creepage discharges.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128058264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Fused Deposition Modelling for fabrication of a hybrid Vertical Take-off and Landing Unmanned Aerial Vehicle 垂直起降混合动力无人机的熔融沉积建模

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9040964

Matt Harcus, Professor Glen Bright

引用次数: 0

The Effect of Thermal Transient on the Leakage Current of Metal Oxide Arresters 热瞬变对金属氧化物避雷器泄漏电流的影响

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9040952

A. Dlamini, P. Bokoro, W. Doorsamy

{"title":"The Effect of Thermal Transient on the Leakage Current of Metal Oxide Arresters","authors":"A. Dlamini, P. Bokoro, W. Doorsamy","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9040952","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9040952","url":null,"abstract":"The operation of surge arresters depends on the insulating packaging of zinc- oxide (ZnO) utilized in arresters. The leakage current within the arrester increases due to the decay on the insulating property. The decaying of the insulating property will increase leakage current within the arrester. The over-voltage that is generated from surges is clamped by the nonlinear characteristics of the ZnO block and is neutralized to its regular level. In this paper, an experiment has been conducted to monitor the leakage current behaviour at different thermal and ac low voltage stresses. The metal oxide varistors (MOVs) were subjected to thermal degradation under ac field voltage stress. Measured results from the MOV samples exposed to the electrical field and thermal stresses are presented and the leakage current behaviour is analysed. During the time of measurement, it was observed that the leakage current is affected by the applied temperature and voltage. The results obtained illustrate that as soon as the reference temperature approaches higher temperature a high rise in leakage current is generated and self-healing phenomenon is clearly observed during the thermal transient.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125083304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Multiband Multi-rate Narrowband Software Defined Radio waveform using Continuous Phase Modulation 使用连续相位调制的多频带多速率窄带软件定义无线电波形

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041070

引用次数: 0

Improving Unsupervised Acoustic Word Embeddings using Speaker and Gender Information 利用说话者和性别信息改进无监督声学词嵌入

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9040986

L. V. van Staden, H. Kamper

{"title":"Improving Unsupervised Acoustic Word Embeddings using Speaker and Gender Information","authors":"L. V. van Staden, H. Kamper","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9040986","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9040986","url":null,"abstract":"For many languages, there is little or no labelled speech data available for training speech processing models. In zero-resource settings where unlabelled speech audio is the only available resource, speech applications for search, discovery and indexing often need to compare speech segments of different durations. Acoustic word embeddings are fixed dimensional representations of variable length speech sequences, allowing for efficient comparisons. Unsupervised acoustic word embedding models often still retain nuisance factors such as a speaker's identity and gender. Here we investigate how to improve the invariance of unsupervised acoustic embeddings to speaker and gender characteristics. We assume that speaker and gender labels are available for the untranscribed training data. We then consider two different methods for normalising out these factors: speaker and gender conditioning, and adversarial training. We apply both methods to two unsupervised embedding models: a recurrent neural network (RNN) autoencoder and a RNN correspondence autoencoder. In a word discrimination task, we find little benefit by explicitly normalising the embeddings to speaker and gender on English data. But on Xitsonga, substantial improvements are achieved. We speculate that this is due to the higher number of speakers present in the unlabelled Xitsonga training data.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122072025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Distributed Generation Interconnection with Improved Unified Power Quality Conditioner for Power Quality Mitigation 改进统一电能质量调节器的分布式发电互联，缓解电能质量问题

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041125

O. Osaloni, A. K. Saha

{"title":"Distributed Generation Interconnection with Improved Unified Power Quality Conditioner for Power Quality Mitigation","authors":"O. Osaloni, A. K. Saha","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9041125","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9041125","url":null,"abstract":"This paper presents the results of the integrated operation of the Improved Unified Power Quality Conditioner with distributed generation of photovoltaic (I-UPQCPV). The 1-UPQCPV supply power from the PV through the shunt inverter to the load, which result into the high Volt-Amp (VA) loading on the shunt inverter. Hence, the power angle control approach aims at the adequate utilization of series and shunt inverter by proper coordination of imaginary power sharing between the two inverters to reduce VA loading on shunt inverter. In this arrangement, DC-link is connected to the generator with the application of the rectifier. The UPQC consist of series and parallel voltage source inverter (VSI) connected back to back with the same DC-link with DG to mitigate under-voltage, overvoltage and interruption. The execution of the proposed system is tested with nonlinear loads connected system with PV solar generation. The effective operation of the system is confirmed during grid disturbance such as sag/swell and interruption. The execution of this work was performed using Matlab/Simulink. The investigation of this approach indicates that (I-UPQCPV) maintain the load voltage within the permissible limit of ±5 % during disturbance.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131348219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Development of a Cost-effective Solar-Wind-Fuel cell Independent Power Plant for a Remote Base Transceiver Station 一种具有成本效益的用于远程基站收发站的太阳能-风能燃料电池独立发电厂的开发

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041091

Tshilidzi Ramunenyiwa, K. Awodele, Okeolu Samuel Omogoye

{"title":"Development of a Cost-effective Solar-Wind-Fuel cell Independent Power Plant for a Remote Base Transceiver Station","authors":"Tshilidzi Ramunenyiwa, K. Awodele, Okeolu Samuel Omogoye","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9041091","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9041091","url":null,"abstract":"This paper analyses the performance of a hybrid renewable energy system (HRES) by comparing it to a standalone diesel generator when both are used independently to power a Base Transceiver Station (BTS) at Sigonde village in Limpopo, South Africa. The comparison is based on energy output, economics and emission of pollutants. The hybrid optimization of multiple energy resources (HOMER) software was used to simulate and optimize both systems. The objective is to develop a cost-effective HRES that performs better than standalone diesel generator and emits less to zero pollutants. This hybrid power supply system comprises of solar, wind and fuel-cell power sources with a battery back-up pack. Furthermore, the system has zero capacity shortage, zero unmet load and abides by the country's discount rate of 6.75%. The results showed that the best system to power the BTS at Sigonde village is made up of 12.25 kW solar PV capacity, 1 kW wind turbine, 4 kW fuel-cell, 10.5 kWh capacity battery and a 3.75 kW converter. The HRES costs 50% (Net Present Cost and Cost of Energy), emits 80% less pollutions and lastly, has an excess energy of 10079 kWh.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126247953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Harmonic Emission of Non-Linear Loads in Distribution Systems - A Computer Laboratory Case Study 配电系统中非线性负荷的谐波发射-一个计算机实验室案例研究

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041104

Connor L. Collocott, K. Awodele, A. V. Adebayo

引用次数: 3

Application of Active Power Filters for Distribution Network Performance Enhancement 有源电力滤波器在提高配电网性能中的应用

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041032

A. Ojo, K. Awodele, A. Sebitosi, Mdu Mzulwini

{"title":"Application of Active Power Filters for Distribution Network Performance Enhancement","authors":"A. Ojo, K. Awodele, A. Sebitosi, Mdu Mzulwini","doi":"10.1109/SAUPEC/RobMech/PRASA48453.2020.9041032","DOIUrl":"https://doi.org/10.1109/SAUPEC/RobMech/PRASA48453.2020.9041032","url":null,"abstract":"The phenomenal growth in electricity demand due to population growth, industrialization, and the inadequacy of generation, transmission and distribution capacities have affected the quality of power and the overall performance of the entire power system network. In order to minimize the effect and reduce the huge cost of capacity expansion, performance enhancement of the existing transmission and distribution system which can be achieved through load compensation. Load compensation is one of the well-recognized methods for its contribution to the reduction of energy losses, along with other benefits; such as power factor correction, increase of the transfer and operation capacity of distribution networks. The presence of substantial single-phase loads, large industrial loads and the recent increase in the use of power electronic-based devices/equipment in both industrial, commercial and residential sectors due to advancement in technology and the need for energy efficiency measures contribute to the degradation of power quality in the distribution networks. The quality of electricity supply is vital as it affects both the utility and its customers. An effective compensation technique is required to solve these problems and improve the performance of the system. This paper, therefore, presents the mitigation of unbalance, reactive power and harmonic distortion for performance improvement using active power filter.","PeriodicalId":215514,"journal":{"name":"2020 International SAUPEC/RobMech/PRASA Conference","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131128340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The Ollie: A Case Study in Trajectory Optimization with Varied Contacts 奥利:一种不同接触轨迹优化的案例研究

2020 International SAUPEC/RobMech/PRASA Conference Pub Date : 2020-01-01 DOI: 10.1109/SAUPEC/RobMech/PRASA48453.2020.9041027

Nicholas B. Anderson, Stacey Shield, Amir Patel

引用次数: 1