Development of a Power Flow Model for Optimal Location of Distributed Generators in Electrical Distribution Systems

Distributed generation (DG) is any small scale electrical power generation technology that provides electric power at the load site. An increase in the number of DG units in commercial and domestic electrical power output has brought concerns over improvement of distribution network. Installing these generator units at no optimal places usually result in an increase in system losses and an undesired effect on the system. It is therefore important to develop a power flow model for optimal location of DG in the distribution system. This paper develops a power flow model for distribution system to determine the optimal placement of DG units in distribution network in order to reduce power losses. The feasibility and effectiveness of the developed model are demonstrated on the 33kV distribution network of EKO Electricity Distribution Company Plc (EKEDP) using computer simulations. The result revealed that the system loss is reduced by 1.1952p.u (that is 67% reduction)after introduction of DG which indicates a reduction in power losses with installation of DG at various feeders of the distribution system. The model confirmed that, with integration of DG in distribution network, the power losses are reduced and optimal DG placement is achieved. The analysis of the model will help to reduce the cost of electric power production and increase the capacity and efficiency of the electrical distribution systems. Keywords: Distributed Generation, Distribution System, Power Flow, Power Loss, EKEDP, Optimal location, Power losses

A Genetic Algorithm Approach for Optimal Distribution System Network Reconfiguration

Electrical energy is an essential ingredient for the industrial and all-round development of any country. Power distribution systems are radial in configuration and this makes the networks hard to manage, thus, the need for optimization. This paper presents the optimization of network reconfiguration of distribution system using genetic algorithm to get the optimal switching scheme for network reconfiguration with objective function to reduce power loss and improve active power of the system. Load flow for the network reconfiguration problem was formulated as single objective optimization problem. The optimization model was simulated using MATLAB/SIMULINK and validated on standard IEEE 13-bus and 25-bus distribution test feeders. The result shows that active power increases by 91.1% (1.6469p.u.) while the power loss reduced by 99.4% (1.6372p.u.) for 13-bus system. For 25-bus system, active power increased by 27% (0.9154p.u.) and power loss reduced by 96.2% (4.3074p.u.) after optimization. The results provide solutions to the power distribution system for the optimal switching scheme for network reconfiguration with improvement in active power of the system. Total real power loss was minimized according to the corresponding fitness values of the genetic algorithm solutions. The paper provides technical information that could help in the future expansion and operation planning of the power distribution network. Keywords: Distribution System, Load Flow, Network Reconfiguration, Distribution Test Feeder, Active Power, Power Loss, Genetic Algorithm

Development of A Newton Raphson Symmetrical Component Based Technique for Fault Analysis on Nigerian 330 KV Transmission Lines

Fault analysis is one of the basic problems of power system engineering. It plays a significant role in the power system security for supply of stable and economical operations of power systems. This study carried out fault analysis on Nigerian 330 kV, 28 bus system using Newton-Raphson analysis and symmetrical components method to determine the voltage magnitude and fault magnitude in the system. Newton-Raphson method was used to calculate the short circuit pre-fault voltages and currents on power system. This was used to check the weak buses that are out of acceptable voltage limit of ± 10%. After identifying the buses with problems, a three-phase fault on the power network was then calculated using symmetrical component analysis and was simulated using MATLAB to determine the post-fault voltage magnitudes, angles and fault magnitudes of the power network. The pre-fault result showed that buses 13 (New-Haven), 14 (Onitsha) 19 (Jos), 22 (Kano) and 25 (Markurdi) were the buses that fell out of tolerance range of ± 10% and were termed as weak buses. These buses with low voltage values were examined and post-fault calculations were carried out and the results of voltage magnitude and voltage angle were reduced to zeros.The results of pre-fault current magnitude showed that the selected weak buses namely; Makurdi, New-Haven, Kano, Onitsha and Jos have the current magnitude values of 10.4200 p.u, 9.4350 p.u, 8.4501 p.u, 7.5440 p.u and 5.3320 p.u respectively. The results also showed that Makurdi, had the highest fault magnitudes with a value of  25.1006 p.u followed by New-Haven with value of 23.9455, Kano with value of 22.4917, Jos with value of 21.4686 and Onitsha had the least fault magnitude value of 19.8765 p.u under post-fault condition. More so, it was observed that the voltage on the affected buses was reduced however current magnitudes of these buses when fault occurred were excessively high compared to the pre-fault currents.The result confirmed that symmetrical three phase fault is the most severe kind at the transmission lines. The result also revealed the abnormally high magnitude of current that flows through the Nigerian power network to the point of fault. Therefore, the Nigeria power regulator and policies are required to determine the flow of current regularly during faults occurrences in the power system so as to ensuring improvements in the country power sector. The study therefore recommendations that additional lines should be introduced into the network to assist in the strengthening and reduction of long lines to improve the voltage profile of the network, especially New-Haven, Kano, Onitsha and Markurdi lines. The study will assist the power regulators for selection of circuit breakers and rating of protective switchgears installed in power system to enhance the efficiency of the power supply in Nigeria. Keywords: Fault Analysis, Nigerian Power Network, Newton-Raphson, Symmetrical Components, Three-Phase Fault, Voltage Magnitude, Fault Magnitude. DOI: 10.7176/JNSR/9-16-02 Publication date: August 31st 201

Effect of Non-Optimal Amplitude Frequency Response on Transmission of Power Line Communication Signals

Power line Communication (PLC) systems represent a relatively recent and rapidly evolving technology, aimed at the utilization of the electricity power lines for the transmission of data. This is due to increasing demand of low cost telecommunication, broadband and access to internet services. Power lines are inherently the most attractive medium for home networking due to its universal existence in homes, the abundance of alternating current outlets and the simplicity of the power plug. This work presented the effect of non-optimal amplitude frequency on transmission of power line communication signals by utilizing Orthogonal Frequency Division Multiplexing (OFDM) system. The simulation was carried out using MATLAB/SIMULINK with additive white Gaussian noise (AWGN) in order to obtain correct simulation performance results. Two channels of PLC were considered, the worse channel was taken into account and the channel output signal power was obtained. Bit Error Rate (BER) of Binary Phase Shift Keying (BPSK) in conjunction with multipath channel was used for a comparative performance of the studies.  The results indicated that data transmission in PLC environment needed a signal to be amplified or transmitted at higher powers. The result also showed that non-optimal amplitude frequency response had no effect on transmission of the PLC signal in the frequency bands despite the low noise signal in the system. The result demonstrated that OFDM exhibited better BER performance for providing adequate transmission channel for information over a PLC system.  This approach provided accurate reliability, security and robustness for better management of available energy resources to overcome the limitations of existing Power line communication technology. Keywords: Power Line Communication, Bit Error Rate, Orthogonal Frequency Division Multiplexing, Gaussian Noise, Transmission Line, Binary Phase Shift Keying DOI: 10.7176/JIEA/10-1-03 Publication date: January 31st 202

Analysis of the Effect of Distributed Generation on Loss Reduction in Electrical Distribution Network

Distribution network is said to be the most visual part of the electric production and the most observed by the utilities for investment, maintenance and operation. The system have been operated under stressed conditions due to limited structure and increasing day to day requirement of power consumption, which have a significant economic and social impact on the system. Due to the system high resistance to impendence ratio, large amount of power loss occur in the network. This loss is the most severity factors affecting the power quality delivered to the end users and depend on power network expansion and load complexity. Among the support methods available for power loss minimization in distribution network, strategic allocation of Distributed Generation (DG) in distribution system is widely considered a viable option. DGs are electrical sources connected to the power network located to consumer’s side but very small when compared with the centralized power plant. They can be in form of wind, mini-hydro, photovoltaic and fuel-based system such as fuel cells and micro-turbines. Therefore, in this study, different approaches for power loss minimization in electrical distribution system with the incorporation of DG by various researchers were reviewed. These approaches have become powerful tools to overcome the problem of power loss minimization in distribution system. Keywords: Distribution System, Power Loss. Distributed Generation, Power Consumption, Photovoltaic System, Centralized Power Plant. DOI: 10.7176/JETP/11-6-02 Publication date: November 30th 202

Analysis of Energyauditing in Nigerian Power Systems

Energy is one of the major drivers for the economic development of any country. In order to reduce energy consumptions for sustainable development, continuous energy audit of industrial machines become necessary. Energy audit is one of the most comprehensive methods in achieving energy savings in industry and thus reducing excessive energy consumption. This paper analyzes energy auditing in power system in order to identify the sources of energy waste and assess the effectiveness of the strategies for energy savings using A and T Foods and Beverages PLC as a case study. This was with a view to recommending a policy that would enhance the effectiveness of electrical energy savings in the company. A detailed energy audit is adopted for energy project implementation plan and data from the publication of the International Standard Industrial Classification of All Economic Activities (ISIC) in Nigeria for the period of (2011 -2017)were used for the analysis. The sources of energy in the company comprised of electricity from utility company and use of generating sets (fuel). The result showed that the electrical energy consumption in the companies was mainly from generating set. In addition, the total percentage of electric energy consumed from utility company was 40.95% with an average percentage of 5.85%. The total percentage of fuel consumed by the company was 659.05% with an average value of 94.15%. The results identified areas where the company used and wasted energy, and where actions for energy conservation should be implemented. The study therefore established that energy was not sufficiently utilized, and therefore suggested possible strategies for efficient energy usage for the company. Keywords: Energy Audit, Energy Saving, A and T Food and Beverages PLC, ISIC, Power System, Generating Set, Electric Utility Companies.

ANALYSIS OF POWER SECTOR PERFORMANCE: NIGERIA AS A CASE STUDY

Electric power supply is one of the basic infrastructural, requirements for industrialization, productivity and growth in any economy as well as improvement in the quality of life. The Nigerian electricity industry has undergone long overdue reform and has been deregulated. The new institutions and regulations are to be overseen by an independent regulator. Despite the deregulation and reforms, electricity generation is epileptic. This study analyzes the performance of Nigerian power sector so as to suggest possible means of ensuring improvements of the sector. Specification and estimation techniques were used for a period of eleven years.. Secondary data were sourced from Central Bank of Nigeria (CBN) Statistical Bulletin of 2018 and Nigerian Electricity Regulatory Commission (NERC). The performance of the power generated was evaluated using the overall efficiency and thermal efficiency.The results showed that the average value of the overall efficiency for the ten years period of study was 15.68% while the thermal efficiency had the average value of 15.37%. The result confirmed that deregulation of power sector has no effect on the efficiency of Nigerian power sector when the results were compared with the international best practice standards which are 30% and above for overall efficiency and 45% and above for thermal efficiency. The study therefore suggested possible strategies for efficient power sector improvement. Keywords: Electric Power, Nigerian Electric Industry, Deregulation, Reform, NERC, CBN, Specification Technique

Investigation of Distribution System Stability with Incorporation of Capacitor Switching: A Case Study of Monatan 11 Kv Distribution System

Effectiveness of an electrical distribution system depends on the stability of its voltage profile. Several methods such as Static Compensator (SC), Thyristor Controlled Series Compensation (TCSC) and Series Capacitor have been applied for the stability of the system. However, these methods have been characterized by harmonic variation and low efficiency. Therefore, this research paper applied Shunt Switching Capacitor (SSC) on 11 kV distribution system located at Monatan, Ibadan, Oyo State in order to investigate the stability of the system during outages. Hourly data on bus voltage of the system were collected to determine the average bus voltage and voltage drop of the distribution system for stability evaluation using IEEE statutory limits method. Load Flow Model (LFM) of the distribution system was developed with incorporation of Capacitor Switching Compensation (CSC). This was solved using Kirchoff’s Current Law( KCL) analysis to improve the average bus voltage and voltage drop of the distribution system while simulation was done using MATLAB R2015a. The results of the average bus voltage and voltage drop of the distribution system were 10.5  and 4.2 , respectively. The CSC model improved the average bus voltage and voltage drop by 6 % and 33 % respectively. The research showed that incorporating capacitor switching as a compensation technique enhanced the stability of the distribution systems. The research is useful in the planning and optimization of electrical distribution systems. Keywords: Electrical Distribution System, Voltage, Capacitor Switching Compensation, Load Flow Models, Monatan 11 kV Distribution System, Voltage Drop, MATLAB. DOI: 10.7176/NCS/14-02 Publication date:August 31st 202

IMPACT OF EMBEDDED GENERATION ON POWER DISTRIBUTION SYSTEM VOLTAGE COLLAPSE

ABSTRACT: The term "embedded generation" (EG