Power Systems & Energy Engineering

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/72

Browse

Has files: YesSubject: search.filters.subject.Distributed Generation

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    IMPACT OF DISTRIBUTED GENERATION ON DISTRIBUTION NETWORK PROTECTION SCHEME AND ADAPTIVE PROTECTION COORDINATION USING HARRIS’ HAWKS OPTIMIZATION
    (Hawassa University, 2022-07-26) ABENEZER KASSA USAMO
    The Modern Power System which has grown both in size and complexity, that means requires fast, accurate and reliable Protective schemes for protecting major equipment’s and to maintain system stability and reliability. Distribution networks are evolving into active meshed networks with bidirectional power flow as the penetration of distributed generation (DG) sources is increasing. Interconnecting DG to an existing distribution system provides various benefits to several entities as for example the owner, utility, and the final user. DG provides an enhanced power quality, higher reliability of the distribution system and can peak shaves and fill valleys. Penetration of a DG into an existing distribution system has many impacts on the system, with the power system protection being one of the major issues. This necessitates the use of directional relaying schemes in these emerging active distribution networks. However, conventional directional overcurrent (OC) protection will not be adequate to protect these networks against the stochastic nature of DGs and the changing network architectures. Hence, this study proposes an adaptive directional overcurrent relay algorithm that determines optimal protection settings according to varying fault currents and paths induced by the DGs in active meshed distribution networks. Location and technology of the DG sources are changed to study the effect that these changes may have on the coordination of protective directional over-current relays (DOCR). Results are compared to that of the normal case to investigate the impact of the DG on the short circuit currents flowing through different branches of the network to deduce the effect on protective devices. This study presents an adaptive protection coordination scheme for optimal coordination of DOCRs in interconnected power networks with the impact of DG. The used coordination technique is the Harris Hawks Optimization (HHO), selected due to adaptive & time-varying parameters allows HHO to handle difficulties of search including local optimal solution, multi modality & deceptive optima. Adaptive relaying describes protection schemes that adjust settings and/or logic of operations based on the prevailing conditions of the system. These adjustments can help to avoid relay miss-operation. Adjustments could include, but are not limited to, the logging of data for post-mortem analysis, communication throughout the system, as well changing relay parameters. Several concepts will be discussed, one of which will be implemented to prove the value of the new tools available. The optimal coordination of DOCR is find by with MATLAB code using HHO technique and the adaptive protection scheme model will develop in DIgSILENT/Power Factory. The results validate the ability of the proposed protection scheme to capture the uncertainties of the DGs and determine optimal protection settings, while ensuring minimal operating time
  • No Thumbnail Available
    Item
    ENHANCING THE RELIABILITY OF DISTRIBUTION SYSTEM THROUGH RENEWABLE ENERGY RESOURCES
    (Hawassa University, 2024-04-12) FIRAOL KASAHUN MENGESHA
    The distribution system connects high-voltage transmission networks with end-users. Most of the time, power plants are situated distant from the consumer's location, resulting in large power losses in both the distribution and transmission systems, However, distribution system losses are typically greater than transmission line side losses. The main objective of this study is to reduce power losses and enhance system reliability using Distributed Generation (DG) in the case of the Guder Substation. The Guder Substation has three feeder lines that provide energy for different customers. From these feeders, the Guder town feeder has been chosen since it is frequently interrupted. The chosen feeder has been modeled in ETAP software, and simulation results have been obtained with both ETAP and MATLAB software. The results show that the feeder has a power loss of 611.9843 KW and 323.8237 kVar active and reactive, respectively. Additionally, the study investigates the existing reliability indices of SAIFI, SAIDI, and EENS, which have values of 303.7458 f/cust.yr, 306.4240 hr/cust.yr, and 2368.307 MWhr/yr, respectively. Particle Swarm Optimization algorithm has been suggested to decide the best size and position of DG. After renewable Distributed Generation penetrated the network, the real and reactive power loss reduced from 611.9843 KW and 323.8237 kVar to 302.75 KW and 132.34 kVar, respectively. Additionally, the SAIFI, SAIDI, and EENS system reliability indices were enhanced from 303.7458 f/cust.yr, 306.4240 hr/cust.yr, and 2368.307 MWhr/yr to 27.4968 f/cust.yr, 13.650 hr/cust.yr, and 111.758 MWh/yr, respectively. Finally, reliability indices and line losses before and after Distributed Generations penetrated the network are compared. In general, the simulation results indicate that the suggested method is efficient in maintaining system reliability and minimizing power losses