Studies on Ethiopian High Voltage Grid Security Enhancement Using UPFC
| dc.contributor.advisor | Getachew, Biru (PhD) | |
| dc.contributor.author | Gezahegn, Shituneh | |
| dc.date.accessioned | 2021-09-08T04:11:28Z | |
| dc.date.accessioned | 2023-11-28T14:26:41Z | |
| dc.date.available | 2021-09-08T04:11:28Z | |
| dc.date.available | 2023-11-28T14:26:41Z | |
| dc.date.issued | 2021-07 | |
| dc.description.abstract | Nowadays, more attention is given for electrical energy transportation system security. Securing electrical energy transportation system in such a way that it can deliver the demanded energy both under normal steady state operation (NSSO) and contingency conditions is very important in a power system. Ethiopian Electric Power (EEP) manages and operates national power system centrally which consists of geographically dispersed generation stations and long-interconnected transportation system. In this study, existing national grid is modeled and the model under study has network elements of 106 buses, 146 transmission or sub-transmission lines, 51 transformers, 17 power plants, 23 lumped shunts and 69 merged loads. The grid is simulated using Power System Analysis Toolbox (PSAT) in MATLAB so that 30 top ranked MVA line flows of transmission lines (TLs) and 11 top ranked installed capacity of power plants (PPs) are selected for further outage case studies. The criticality of the selected contingent elements are ranked by using Overall Composite Severity Index (OCSI). Moreover, feasible locations for the UPFC deployment are identified using OCSI and Individual Severity Indice (ISI). Then, grid model with unified power flow controller (UPFC) is simulated both under normal steady state operation (NSSO) and contingency conditions. After all, the results obtained without and with UPFC deployment is compared in terms of TL loading and bus voltage of NSSO condition and in terms of Line Stability Index (LSI), Real Power Performance Index (PPI), Individual Composite Severity Index (ICSI) and OCSI for all outage case studies. At NSSO condition, 37 bus voltage limit violations (far below acceptable minimum voltage) without UPFC but 27 bus voltage limit violations with UPFC deployment yet appreciably improved. In addition, 400 kV TL from Gilgel Gibe II to Wolyta Sodo , 11_GG-II PP to 7_Wolyta, is overloaded without UPFC deployment hence, its line flow determined is 12.217675 pu apparently where its thermal limit is 12.17 pu but solved after UPFC is deployed i.e., the line flow changed from 12.217675 pu to 3.796130 pu. It is investigated from the simulations of the grid before UPFC deployment that 140 statically instable TLs when evaluated in terms of LSI, 5 overloaded TLs when evaluated in terms of PPI and 27 TLs’ limit violated when evaluated in terms of ICSI. Following the same procedures but with UPFC devices deployed on the grid: 90 TLs are statically stabilized, 41 TLs improved, and 9 TLs negatively impacted when evaluated in terms of LSI; overloading status of 2 TLs solved, and 3 TLs are a little bit negatively impacted when evaluated in terms of PPI and 17 limit violated TLs solved, 1 TL improved, and 9 TLs are negatively impacted when evaluated in terms of ICSI. Finally, the security of grid with UPFC deployed is enhanced for 38 contingency case simulations whereas for 2 contingency cases, it is negatively impacted as evaluated in terms of OCSI. As per the grid security enhancement evaluation carried out by using UPFC, the existing grid security is weak, and implementation of this study is highly recommended. | en_US |
| dc.identifier.uri | http://etd.aau.edu.et/handle/12345678/27829 | |
| dc.language.iso | en_US | en_US |
| dc.publisher | Addis Ababa University | en_US |
| dc.subject | Overall Composite Severity Index (OCSI) | en_US |
| dc.subject | Individual Composite Severity Index (ICSI) | en_US |
| dc.subject | Real Power Performance Index (PPI) | en_US |
| dc.subject | Line Stability Index (LSI) | en_US |
| dc.subject | Individual Severity Index (ISI) | en_US |
| dc.subject | Outage, Contingency | en_US |
| dc.subject | Unified Power Flow Controller (UPFC) | en_US |
| dc.subject | Power System Analysis Toolbox (PSAT) | en_US |
| dc.subject | Security | en_US |
| dc.subject | Grid Model | en_US |
| dc.subject | Contingency Ranking | en_US |
| dc.title | Studies on Ethiopian High Voltage Grid Security Enhancement Using UPFC | en_US |
| dc.type | Thesis | en_US |