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| dc.contributor.author | ASGEDOM, BEWKET | |
| dc.date.accessioned | 2020-03-16T09:54:13Z | |
| dc.date.available | 2020-03-16T09:54:13Z | |
| dc.date.issued | 2020-03-16 | |
| dc.identifier.uri | http://hdl.handle.net/123456789/10365 | |
| dc.description.abstract | The overall production process of modern Industries of our country is highly supported by various linear and nonlinear loads like micro controllers, microprocessor’s, I/O interfacing devices, sensors and PLC’s. These loads are sensitive to the occurrences of voltage quality problems due to unpredictable faults or disturbances in the transmission as well as distribution sides. The existence of faults or disturbances on the system will results a damage or work stoppage of the sensitive loads and an interruption of the production process of Industries which will result up to a data and economic losses. Therefore, the fastest development of power electronic technology is now playing its own role in protecting the Industries from the consequences of voltage quality problems. In this thesis, the voltage quality problems and its mitigation techniques in Dashen Brewery Share Company has studied. Based on the one-week data’s that are obtained from the Industry, three types of voltage quality problems are identified; on the 1st day of the week, a voltage sag on the three phases due to energization of heavy loads; on the 4th day of the week, a single phase outage on phase 1 due to the broking of the power transmission line; on the 6th day of the week, a voltage swell on the three phases due to single line to ground fault. These problems have resulted a damage and work stoppage of the sensitive loads of the industry. Due to this, the industry has been faced a partial and full shutdown of the production process for hours or even for days until the problem is cleared. This results an economic loss of around 125,901.00 $ annually and a wastage of time to the industry until the problem is cleared. And also, those problems are now reducing the life span and efficiency of electrical devices, particularly for motors. In order to alleviate those voltage quality problems, a DVR based on direct converter is developed in this thesis. The reason that is why DVR is chosen for our mitigation technique is due to its attractiveness, low losses, higher energy capacity and cost effectiveness as compared to the other power custom devices. Based on the collected data’s and load parameters of the industry, the voltage profile of the industry is analyzed with and without of the designed mitigating technique. As the numerical simulation shows, the deigned device restores the voltage of the three phases from 0.521p.u, 0.515p.u and 0.512p.u respectively to 1p.u; the balance voltage swells of the three phases from 1.492p.u, 1.528p.u and 1.499p.u respectively to 1p.u; the unbalanced voltage swells of the three phases from 1.264p.u, 1.8p.u, and 1.527p.u respectively to 1p.u. And also the single phase outage occurred on phase-a is cleared by the designed DVR and it compensates from zero voltage to 1p.u. This shows the effectiveness of the designed method for mitigating the existed voltage quality problems of Dashen Brewery Share Company. | en_US |
| dc.language.iso | en | en_US |
| dc.subject | POWER SYSTEMS ENGINEERING | en_US |
| dc.title | MITIGATION OF VOLTAGE SAG, SWELL AND SINGLE-PHASE OUTAGE USING DYNAMIC VOLTAGE RESTORER (DVR) WITH DIRECT CONVERTER | en_US |
| dc.type | Thesis | en_US |
