Livingstone Ngoo

Multimedia University of Kenya

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Christopher Maina Muriithi

Murang'a University of Technology

George N. Nyakoe

Jomo Kenyatta University of Agriculture and Technology

Michael Juma Saulo

Technical University of Mombasa

Willy Stephen Tounsi Fokui

Pan African University Institute for Basic Sciences, Technology and Innovation

Peterson K. Hinga

Jomo Kenyatta University of Agriculture and Technology

Charles Ndungu

South Eastern Kenya University

Demsew Mitiku Teferra

Pan African University Institute for Basic Sciences, Technology and Innovation

J. N. Nderu

Jomo Kenyatta University of Agriculture and Technology

Geoffrey O. Barini

Jomo Kenyatta University of Agriculture and Technology

S N Njoroge

Jomo Kenyatta University of Agriculture and Technology

Cooperative Institutions

Jomo Kenyatta University of Agriculture and Technology

Pan African University Institute for Basic Sciences, Technology and Innovation

Multimedia University of Kenya

University of Nairobi

Murang'a University of Technology

Technical University of Kenya

Tokushima University

Office of Energy Efficiency and Renewable Energy

Technical University of Mombasa

Tottori University

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Economic and operational effects of introducing Independent Power Producers into the Kenyan power system

AFRICON (2009)

A. O. Akumu Alloyce Godia Oduor Livingstone Ngoo

Some significant occurrences like increase in the electricity demand, degrading catchment areas and unpredictable climatic patterns have a direct impact on the energy sector. To address this scenario, a number of changes have been made in the energy sector by the Kenyan government. These include the unbundling of the power generation from transmission and distribution functions and contracting the independent power producers (IPPs), and cogeneration (collectively referred to as non utility generation - NUG) to supplement the power generation from the state controlled entity - The Kenya Electricity Generating Company (KenGen) so as to meet the national electrical demand. This research study aimed at analyzing the effects of these IPPs on the cost of electrical energy in Kenya and also on the operational flexibility of the Kenyan power system. These studies have been done using the supervisory control and data acquisition (SCADA) system from the Kenya Power and Lighting Company (KPLC). The economic aspect of this study has been done by taking a sample of four large power consumers (Kenya Pipeline Company - KPC, Sameer Africa, British American Tobacco - BAT and East African Portland Cement - E.A Portland) and analyzing their electricity bills while focusing on the fuel cost adjustment (FCA) levy from the year 2003 to 2007, since majority of the IPPs run on a variety of fuels that are quite expensive and these costs are passed on to the customers at a rate proportional to the energy they consume. More so, the cost of the fuels used for power generation is dependent on the fluctuating international prices. This study has shown that the IPPs have improved the operational flexibility of the power system in terms of management of system outages and the loading of various power system equipment, but have also made the cost of electricity to increase exorbitantly to the customers. This study may further assist all the stakeholders in the energy sector to plan, design and control power system operations, while at the same time putting more emphasis on industrial cogeneration.

Cogeneration

Kenya

10.1109/afrcon.2009.5308227

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Citations (2)

Optimal Integration of Electric Vehicle Charging Stations and Compensating Photovoltaic Systems in a Distribution Network Segregated into Communities

Journal of Advanced Engineering and Computation (2022)

Willy Stephen Tounsi Fokui Livingstone Ngoo Michael Juma Saulo

This paper proposes a method of optimally utilizing electric vehicles (EVs) in the distribution network. The method is firstly based on segregating the distribution network into communities and then optimally placing an EV charging station (EVCS) in each community using the backward forward sweep (BFS) technique. The Second phase uses particle swarm optimization (PSO) to size and allocates photovoltaic systems in the network for power loss minimization and voltage improvement. The proposed method is tested on an IEEE 33 node test feeder and simulation results showed the effectiveness of the BFS in finding the best nodes for the placement of EVCS in each community as well as the effectiveness of the PSO in allocating the photovoltaic systems. To validate the effectiveness of the BFS technique, its results obtained are compared with those obtained when the EVCSs are placed on some nodes other than those chosen by the BFS technique.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Minification

10.55579/jaec.202264.380

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Citations (6)

Optimal Sizing of Grid-Tied Solar PV for Transmission Congestion Management in a Deregulated System using LMP Analysis

International Journal of Applied Engineering Research (2019)

Malado Diallo Livingstone Ngoo Michael Juma Saulo Benaissa Bekkouche

In deregulated power system, it is desired to transmit power to every part of the network without any limits resulting from congestion and as a result avoiding inefficiencies in generation dispatch.In order to reduce congestion in the transmission lines, a new approach to manage transmission congestion and improve social welfare is proposed in this research.This approach consists of optimal sizing and placement of grid-tied solar PV system using LMP analysis for congestion management and maximization of social welfare.The LMP and congestion rent (CR) at each node of the system are obtained from the Lagrange multiplier associated with OPF formulation to determine the optimal location of solar power plant.With optimal sizing and placement, a grid-tied solar PV system has the ability to reduce power losses, improve voltage profile and power quality.Since solar power is a random and intermittent energy, the sizing of solar PV system is done by taking into account the power variation of the solar system.The results show that the proposed approach gives better results, reduced congestion in the system while maximizing social welfare is.The proposed methods are implemented on the modified IEEE 30-bus test system.

Congestion management

10.37622/ijaer/14.17.2019.3598-3609

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Citations (4)

Investigating the impact of power system stabilizers in a multi-machine system with an induction motor load

C M Mureithi Livingstone Ngoo George N. Nyakoe

The high reactive power demand by the induction motor load during fault condition due to reduced bus voltages may cause a generator to behave like a voltage source behind the synchronous reactance and its terminal voltage reduces leading to the possibility of a voltage collapse scenario. For reliability of these systems, and in an attempt to reduce system oscillations, Power System Stabilizers (PSS) have used to add damping by controlling the excitation system. Studies on a SMIB and those using static loads have shown that a well-tuned PSS using a Fuzzy Logic Controller (FLPSS) can effectively improve power system dynamic stability. This paper investigates the impact of the FLPSS in maintaining voltage stability in a system with induction motor loads. A large induction motor is introduced as a load in a multi machine system, and the impact of the FLPSS are investigated by introducing a temporary three phase fault. For comparison the FLPSS is compared to other PSS found in literature. Results indicate that the FLPSS may lead the generator to lose its capability to maintain constant voltage and hence lead to the stalling of the induction motor load soon after the fault is cleared.

Reactance

10.1109/afrcon.2011.6071959

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Citations (0)

Fuzzy-Swarm Intelligence-Based Short-Term Load Forecasting Model as a Solution to Power Quality Issues Existing in Microgrid System

Journal of Electrical and Computer Engineering (2022)

Demsew Mitiku Teferra Livingstone Ngoo George N. Nyakoe

Load demand is highly stochastic and uncertain. This is because it was highly influenced by a number of variables like load type, weather conditions, time of day, the seasonality factor, economic constraints, and other randomness effects. The loads are categorized as holiday loads (national and religious), weekdays, and weekend days. The nonlinearity and uncertain characteristics of electrical load in a microgrid are one of the major sources of power quality problems in a microgrid system, and they can be handled using an accurate load forecast model. The fuzzy load prediction model can effectively handle these nonlinearity and uncertainty characteristics to have an accurate load forecast, but the main challenge with this model is its inability to accommodate a large volume of historical load and weather information when the membership function of the input and output fuzzy variables and the number of the fuzzy rules are tremendous. The swarm intelligence load forecast model based on particle swarm optimization algorithms can improve the limitations of the fuzzy system and increase its forecasting performance. The parameters of time, temperature, historical load, and error correction factors are considered as the Fuzzy and Fuzzy-PSO model input variables, while the forecasted industrial load is the only output variable. The Gaussian membership function is considered for both the input and output fuzzy variables. A 3-year historical hourly load data of an Ethiopian industrial system is used to train and validate both prediction models. The mean absolute percentage error (MAPE) is used to evaluate the performance of these prediction models. The Fuzzy-PSO load prediction model shows results that have superior performance to the fuzzy-alone load prediction results.

Microgrid

10.1155/2022/3107495

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Citations (2)

Improving the Voltage Quality and Power Transfer Capability of Transmission System Using FACTS Controller

International Journal of Energy and Power Engineering (2021)

Demsew Mitiku Teferra Livingstone Ngoo

One of the main challenges of the future in the utility sector is constructing the new transmission line corridor. This is due to the fact that land compensation cost associated with the expansion of a new transmission line corridor becomes very expensive and also power transmission efficency is very low. In addition to that, the high carbon emission, which is the major challenge of the world right now, related to the additional conventional energy-based power generation to meet dramatically increased electricity demand and the volatility nature of the existing transmission networks are some of the main drivers to implement FACTS controller in transmission network for flexible, reliable, efficient and stable power transmission. This study accounts modeling of static VAR compensator (SVC), static synchronous compensator (STATCOM), unified power flow controller (UPFC) in a 5-bus transmission system to enhance transmission efficency and the quality of power supplied to the costomer. FACTS devices for improving the transmission line capacity and voltage profile of the power system. The three FACTS controllers are modeled for the standard 5 bus IEEE system based on Newton Raphson algorithm using NEPLAN simulation software in order to investigate their impacts on transmission line capacity and voltage profile improvement. Based on the simulation result, the voltage profile as well as the capacity of the IEEE 5 bus system is improved well by using each of the FACTS controller. From the simulation result we can conclude that the STATCOM and SVC are very efficent in voltge profile improvement whereas the UPFC is well performed for the power transmission capability of the transmission network.

Static VAR compensator

Transmission system

Power transmission

10.11648/j.ijepe.20211001.12

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Citations (8)

Fuzzy Dynamic Load Analysis and Power System Voltage Stability Studies

Livingstone Ngoo

Source

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Citations (0)

Review of HVDC Circuit Breakers Topologies.

IOSR Journal of Electrical and Electronics Engineering (2017)

J. K. Muriuki Christopher Maina Muriithi Livingstone Ngoo George N. Nyakoe

Voltage Source Converter-High Voltage Direct Current (VSC-HVDC) is the most efficient and reliable method for electrical power transmission over long distances.The greatest challenge with VSC-HVDC system is that short-circuit faults damages the converter valves and the transmission network.The fault clearing time for the available DC breakers are not fast enough and reliable to provide adequate protection for DC faults on multi-terminal networks.Hence, the development of fast DC breakers has been ongoing for some time and significant contributions have been made especially on the DC breaker response time and provisions to force artificial current to cross the zero current point.Though with these improvements, the research on fast DC breaker continue to attract a lot of interest.In addition, the integration of large amount of wind power to a conventional power grid demands a fast DC breaker.The need to integrate large amount of wind power has necessitated the development of VSC-HVDC system with multi-terminal systems.This ensures that under the influence of severe short-circuit faults, only the affected converters will be switched off while normal supplies to other converters remain uninterrupted.Currently, there are various types of DC breakers at the market while others are at various stages of development.This paper review and compares the available DC breakers topologies, recent developments made, challenges encountered and recommendations for DC breakers improvement.

10.9790/1676-120302109117

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Citations (6)

Management of Voltage Profile and Power Loss Minimization in a Grid-Connected Microgrid System Using Fuzzy-Based STATCOM Controller

Journal of Electrical and Computer Engineering (2020)

Mezigebu Getinet Yenealem Livingstone Ngoo Dereje Shiferaw Peterson K. Hinga

The expansion of renewable energy is continuing powerfully. Electrical system ought to transmit power with diminished loss, improved power quality, and reliability while pleasing the need of customer’s load demand. Nevertheless, owing to the exhaustion of fossil fuels and their environmental impact, the availability of quality, stable, and reliable power in developing countries is worrying. Integrating a solar-wind based microgrid to the distribution network is the more feasible and best alternative solution to gratify the customer intensifying power demand while seeing the strict environmental regulations of generating power. However, the microgrid system connected in a distribution network has diverse problems and challenges. The problems comprise the development of voltage sag and swell, voltage unbalance, and power losses because of the intermittent nature of PV and wind resources. The objective of this study is to integrate microgrid system with STATCOM (static synchronous compensator) controller to ensure the higher power flow with enhanced voltage profile and reduced power loss. MATLAB/PSAT is used to model microgrid and STATCOM controller connected to the grid. Proportional integral (PI) and fuzzy logic controllers (FLC) are also applied to control the STATCOM. The effectiveness of STATCOM with microgrid integration is tested by connecting to the main distribution system using standard IEEE 30-bus system. Finally, it was observed that STATCOM raises the capacity of the distribution line and contributes to voltage profile improvements and power loss reduction.

Microgrid

Voltage Sag

10.1155/2020/2040139

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Citations (20)

A Fuzzy Controlled Pitch Angle in a Permanent Magnet Synchronous Generator Type Wind Energy Conversion System

2022 IEEE 21st Mediterranean Electrotechnical Conference (MELECON) (2022)

Demsew Mitiku Teferra Livingstone Ngoo George N. Nyakoe

Controlling technique of the pitch angle is an efficient mechanism to control the mechanical torque of the wind turbine system during a strong wind beyond the rated operating wind speed of the turbine. To control the pitch angle, we have to choose generator’s electrical power, rotor speed, wind speed, and the turbine power coefficient as control parameters. In this article, a pitch angle controller based on fuzzy logic is introduced using the PMSG power as a control variable and wind speed as a sensitivity parameter to improve the control performance of the controller. The fuzzy logic controller is designed and its effectiveness is compared to the PI controller and fixed pitch angle control mechanisms. The simulation result shows that the fuzzy logic pitch angle controller has superior performance at various operation conditions when it was compared to the PI and fixed angle pitch control mechanisms.

Pitch angle

Pitch control

10.1109/melecon53508.2022.9843136

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Citations (3)