Electrical Computer Engineering

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Subject: search.filters.subject.Distributed Generation

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    POWER DISTRIBUTION SYSTEM LOSS MINIMIZATION AND VOLTAGE PROFILE IMPROVEMENT USING HARRIS HAWKS OPTIMIZATION TECHNIQUES (CASE STUDY: DEBRE BERHAN POWER DISTRIBUTION SYSTEM
    (Hawassa University, 2021-10-12) SEID AHMED MUHYE
    Growing concerns over environmental impacts, conditions for improvement of the whole distribution network, shortage and expensiveness of fossil fuel, the deficiency in generating capacities, and ever-increasing demand for electricity have set the way towards distributed generation (DG) units in commercial and domestic electrical power systems. The major problems of distribution systems, such as load growth, power outage, overloaded lines, quality of supply, and reliability can be solved by optimally placing distributed gener ation near to the customer side. However, the non-optimal placement and size of DG units may lead to high power losses and bad voltage profiles on the power network. This thesis paper aims to minimize system real and reactive power losses, cost and improve the voltage profile of the system by determining the optimal size and penetration of wind based distributed generation using Harris hawks optimization. The results of base case load flow analysis showed that the case study distribution network feeder has a base case active and reactive power loss of 1629.04KW and 609.513KVAr respectively. The feeder minimum bus voltage and total voltage drop index at the base case is 0.8497V and 0.4407 respectively. The propossed HHO determines the optimal location and size of DG based on minimum loss reduction index, voltage deviation index, and the cost of DG at the same time to use the existing distribution network in an optimal manner. The optimal location of DG is determined to be 33 and 38 with a size of 2.4997MW and 2.4896MW respectively. The active and reactive power loss reduced to 290.097KW and 254KVAr after the DG integration. The method is implemented and tested on the Sheno feeder of the Debre Berhan power distribution system
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    SALP SWARM ALGORITHM BASED OPTIMAL NETWORK RECONFIGURATION WITH DISTRIBUTED GENERATION FOR POWER LOSS MINIMIZATION AND VOLTAGE PROFILE IMPROVEMENT (CASE STUDY: YIRGALEM SUBSTATION)
    (Hawassa University, 2022-04-26) FIKADU ALEMAYEHU
    In a distribution system, power loss and voltage deviation are the main concern for the customers and utility. The distribution system has a lower voltage level and higher amount of flowing current than the transmission system, so that, the percentage real power loss in the distribution system is higher. Therefore, this thesis work presents optimal network reconfiguration with the distributed generation of yirgalem radial distribution network to minimize the power loss, operation cost, and enhance the voltage profile of the distribution system using the Salp Swarm Algorithm (SSA). The resource feasibility of solar and wind power in yirgalem city was analyzed and the outcomes showed that solar power generation is more desirable. For this reason, the solar-type Distributed Generation (DG) is used. The proposed SSA algorithm was compared with Particle Swarm Optimization (PSO) and Whale Optimization Algorithm (WOA) in three various scenarios (only optimal network reconfiguration, only optimal DG size and site, and simultaneous optimal network reconfiguration and DG allocation) for the abosto feeder. After analysis of the three scenarios in MATLAB-R2016a, it can be concluded that the simultaneous network reconfiguration with DG shows a dominant result over only network reconfiguration and only DG allocation. The simulation result of base case backward forward sweep load flow analysis revealed that the abosto feeder has a base case power loss of 401.3KW. The feeder minimum voltage profile at the base case is 0.87pu. After simultaneous optimal network reconfiguration and DG size and site with SSA, the optimal tie switch open is 11, 25, 16, 42, 14 and the optimal location of the solar-type DG is at bus 23 and its size is found to be 895.3KW. Consequently, power loss of the selected abosto feeder is reduced to 101.5KW from the base case. The power loss reduction of the abosto feeder is 74.7% with respect to the base case loss. The voltage profile after optimal network reconfiguration with DG is improved by 11.4%. As per the economic evaluations, the proposed method is cost-effective. Depending on the findings of this thesis, it is concluded that optimal network reconfiguration with DG reduces power loss, operating cost and enhance the voltage profile of the distribution system.
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    STUDY THE IMPACT OF DISTRIBUTED GENERATION ON THE RELIABILITY OF LOCAL DISTRIBUTION SYSTEM (Case study: Motta Distribution Substation)
    (Hawassa University, 2020-10-28) Bimrew Mhari Enyew
    Electric distribution system power quality is a rising concern. Customers require higher quality service due to more sensitive electrical and electronic equipment‟s, and effectiveness of a power distribution system is measured in terms of efficiency, service continuity or reliability, service quality in terms of voltage profile and stability and power distribution system performance. The present Motta distribution substation has encountered frequent power interruptions and power quality problems. The interruptions are caused mainly by Permanent Short circuit (PSC), Transient Earth fault (TEF). There are also planned outages for operation and maintenance purpose. The substation‟s System Average Interruption Frequency Index (SAIFI) and System Average Interruption Duration Index (SAIDI) are 806 and 1,394.145, respectively. The substation is not reliable by the standard of Ethiopian Electric Agency (EEA) which set (SAIFI =20 and SAIDI= 25). This reliability gap calls for searching of effective methods for improving the reliability of the distribution system. This thesis presents impact of DG on reliability assessment at Motta distribution substation of 230/33 transformer two 33 kV radial outgoing feeders distribution and the base case reliability analysis using Monte Carlo and analytical enumeration system and has high loss of money that is 0.438 M$/a and 0.444 M$/a respectively for utility but Monte Carlo analysis is better than that of Analytical Enumeration. The improved reliable power distribution is due to the use of proper size and site of DG at the low voltage profile value bus of the distribution system by using probabilistic Monte Carlo simulation of reliability analysis and that of Enumeration analysis of the system using DIgSILENT power factory software. The NPC of DG is 20,831,473.21$ which optimized using HOMER software at the required size and the reliability of the distribution system is improved after the use of DG that is reducing SAIFI, CAIFI by 97.8%, and SAIDI by 76%, increasing ASAI by 14.38% and reducing ASUI by 76% and reducing the total power loss to 0.32 MW. The cost analysis is done on this thesis by using the Monte Carlo reliability analysis output and the DG total net present cost (TNPC) so the payback period is less than five years that is 4.28 years which means that the project is profitable
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    IMPACT OF DISTRIBUTED GENERATION ON DISTRIBUTION NETWORK PROTECTION SCHEME AND ADAPTIVE PROTECTION COORDINATION USING HARRIS’ HAWKS OPTIMIZATION (CASE STUDY: HAWASSA DISTRIBUTION NETWORK)
    (Hawassa University, 2022-10-16) 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