Thesis Project: Power Quality Analysis at Murdoch University eng470: Engineering Honours Thesis
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Un b al an ce Vo ltage Fact o r Time of the Day UBF UBF(sqrt((1-a)/(1+a))*100) Figure 34: Unbalance Voltage Factor Power Quality Analysis at Murdoch University 56 therefore, there may a voltage unbalance. Nevertheless, it definitely must be lower than when facilities at working at the almost optimal condition. In comparison, voltage unbalance according to National Electrical Manufacturers Association (NEMA) is defined as the maximum deviation from the average line voltage referred to the average of the line voltages times 100 [61]. Mathematically, this is given as [62], and it was calculated using equation (24): V av − V L V av ∗ 100 (33) Where: V av = V L1 + V L2 + V L3 3 (34) Power Quality Analysis at Murdoch University 57 Chapter 5: Conclusion and Future Work To summarize, this project has discussed and analysed about power quality analysis at Murdoch University, in particular from 1.330, in substation 12, South Street Building 330, chancellery. From the literature in this project, the most common type of power disturbances was identified to be harmonic distortion, voltage transients, voltage sags, and short power interruptions. In addition, from the literature, it was found that most of the power quality problems originate from the end user’s equipment. Costs that are associated with poor power quality are classified into direct costs and indirect costs. Direct costs include production losses, costs associated with damage to equipment, environmental and financial penalties, costs based on restarting the process, expenditure on salary during down times, resources and unrecoverable downtime. Moreover, costs including human health and safety, financial penalties due to a breach of contracts, utility costs because of a power interruption and loss of quality of semi-finished products. On the other hand, indirect costs include costs of restoring a brand, loss of market share and postponement of income or revenue of the organization. In this project, power data was measured from the electrical system at Murdoch University and saved in the form of spreadsheets. From these spreadsheets, calculations were done and graphs plotted in order to identify the power quality issues experienced at the institution. After identification of the power quality issues, the effect of these issues on parameters such as voltage angle and phase, current angle and phase, temperature of the equipment was determined either by calculation or visually from the plots of these parameters. These results were then compared to the theoretical principles contained in the literature review section. Power Quality Analysis at Murdoch University 58 The results indicate that at the institution the power quality factors experienced are voltage unbalance, current unbalance, distortion in current angle, harmonic distortion, and power factor. Using both the IEC and NEMA methods, the percentage voltage unbalance was found to be lower than the maximum set value of 2 %. As a result, this voltage unbalance would not affect three-phase equipment in the system. However, the current unbalance was found to be extremely high, and this is not safe for the equipment as it can result in heating and thus degradation in windings of motor and transformers and a reduction of their efficiency. The harmonic distortion measured from the institution that ranges between 1.8 and 2.8 % is lower than the 5 % limit, and therefore is also safe for use with equipment. From these results, it is clear that the power received at the institution is of high quality, and hence safe for use with equipment. The major problem is the high current unbalance and the distortions in the current angle. In fact, by using compensating device UPQC consequently should be employed in the institution electrical network in order to decrease current unbalance and distortions of the current angle. The significant goal of this project of performing a power quality analysis at Murdoch University to identify the causes of poor power quality and provide solutions to improve the power quality as well as all the specific objectives that had been set before the commencement of this research have all been achieved. Accordingly, both power consumers and the electric utility will find this project of considerable significance. There will be a decrease in the occurrence of power quality disturbances as through this project these disturbances can be identified monitored, predicted, and mitigated thus power consumers will benefit from less malfunctions of electronic devices. Less malfunctioned devices translate to cost savings for the consumers because of the reduced repair and maintenance costs Power Quality Analysis at Murdoch University 59 required for malfunctioned devices. Since the power quality disturbances can be identified, monitored, predicted, and mitigated through this project. Subsequently, industrial consumers will benefit from lower interruptions of production. This translates to higher quality of products, cost savings since idle time of personnel throughout the interruption would be decreased, and the industry also benefits from less equipment damage. The electric utility may gain considerable knowledge regarding their transmission, distribution network, and sources of power quality disturbances in the electricity grid through this project. Therefore, this project is of great significance to them. 5.1 Future Work Opportunities for the Power Quality Analysis at Murdoch University First of all, in the project presented in this thesis report, data was collected from the electrical network of the institution and used to identify the power quality issues experienced at the institution. Further work that can be conducted involves taking a detailed study of each power quality issue identified and proposing a solution to decrease the power quality issue. After installation of the proposed solution to the network, more tests should be carried out and analysis of the test results done in order to prove the effectiveness of the proposed solution. In addition, another further work that can be performed finds out the individual harmonic order such as even order (2, 4, 6, 8) and odd order (3, 5, 7, 9). By doing this for all the power quality issues identified, then we can conclusively say a problem was identified and a practical and working solution presented to solve the problem. The conclusion will not be based on theoretical information, but on proved and tested information. Power Quality Analysis at Murdoch University 60 Because of the increased adoption of the internet of things and automation in the world currently. An algorithm can be developed that automatically computes and plots the power quality issues from the data it receives from a power quality meter. The automated system then transmits the computed data and plotted graphs to a power quality expert for further action. In this system, the power quality meters will automatically send the data it measures to a computer containing the algorithm. After processing the data, the computer will transmit the processed information to an expert for further action. This algorithm can be designed in such a way that it can be trained to monitor and even predict the occurrence of a power quality issue. Furthermore, the algorithm can be designed to have additional functionalities such as predicting failure of equipment in the network due to a reoccurrence of a power quality issue. Power Quality Analysis at Murdoch University 61 Reference List [1] CEA Technologies Inc. (CEATI), “Power Quality: Energy Efficiency Reference,” CEA Technologies Inc. (CEATI), Ontario, 2007. [2] C. Sankaran, Power Quality, Florida: CRC Press, 2002. [3] "Why is good power quality necessary," MERUS POWER, 13 October 2016. [Online]. Available: http://www.meruspower.fi/why-is-good-power-quality-necessary/. [Accessed 3 January 2018]. [4] A. Baggini, Handbook of Power Quality, West Sussex- England: John Wiley and Sons, 2008. [5] M. M. Canteli, “Power Quality Monitoring,” in Power Quality Mitigation Technologies in a Download 1.28 Mb. Do'stlaringiz bilan baham: 
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