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Author: search.filters.author.Davidson, Innocent EwaenStart date: 2022

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Now showing 1 - 7 of 7
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    Power transformer differential protection for three Eskom feeders
    (IEEE, 2022-08-22) Ngema, Philani N.; Davidson, Innocent Ewaen; Buraimoh, Elutinji
    Differential protection's purpose is to offer phase fault protection that is both quicker and more discriminative than that provided by basic overcurrent relays. Transformer differential protection is the primary protection against earth faults and phase-to-phase faults. CTs on the HV side are counterbalanced by CTs on the LV side. There are a variety of distinct connections, but there are a few key considerations that apply to every design. This sort of protection continually monitors and compares the current flowing between CTs (in this example, HV and MV CTs) inside a protected zone. The following are the primary requirements of this protection, Highest sensitivity, Load stability over the whole tap range, Stability in through-fault circumstances, Stability for magnetizing inrush with associated DC offset decay, when a zone fault is identified, simultaneously opens both HV and MV breakers.
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    Speed performance enhancement and analysis of a three-phase induction motor driving a pump load using vector control technique
    (IEEE, 2022-08-22) Umoette, Anyanime Tim; Okoro, Ogbonnaya I.; Davidson, Innocent Ewaen
    Speed control of an induction motor driving a pump load using vector control technique with proportional integral derivative controller, fuzzy logic controller and hybrid of proportional integral derivative fuzzy logic controllers is presented in this paper. The induction motor drive was designed and simulated with these controllers using MATLAB/Simulink software package. The performance of the induction motor using proportional integral derivative(PID) controller, fuzzy logic controller (FLC) and hybrid controller (FLC-PID) on this load was studied and compared .steady state error of PID, FLC, and FLCPID are 0.5rad/sec, 0.5rad/sec, and 0,1rad/sec respectively, while the undershoot are also respectively 20%, 6% and 4%.FLC-PID further gives arise and settling time of 0.1sec and 0.05sec respectively. From the results obtained, the hybrid controller provides a far more superior performance in enhancing the speed performance of the induction motor.
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    A load flow analysis of the southern African power pool interconnections using high voltage AC, high voltage DC, and flexible AC transmission system
    (IEEE, 2022-08-22) Ndlela, Nomihla W.; Davidson, Innocent Ewaen
    Globally, the importance of power interconnections is growing due to the possibility of power exchange, Thus, the effective solution of bulk power transmission over large distances is achievable with High Voltage Alternating Current (HVAC) which has losses along the transmission line. High Voltage Direct Current (HVDC) uses converters to transform AC power into DC, resulting in superior active and reactive power compensation and reduced losses. The Flexible AC Transmission System (FACTS) combines shunt and series convectors for improved voltage control and power stability, and it enables the transmission of large amounts of electricity over long distances with lower losses than a conventional system. This study implements a load flow model between three substations with bulk power coupled by long-distance transmission lines to compare and conclude which technology is best for transferring bulk power over long distances to offer secure and sustainable electricity.
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    Reliability and security analysis of the southern Africa power pool regional grid
    (IEEE, 2022-08-22) Ndlela, Nomihla W.; Davidson, Innocent Ewaen
    Over the last decade, Southern Africa has experienced power outages. This is due to insufficient electrical power supply systems, as well as load development in areas that were not sufficiently planned for. The Southern African countries can have a reliable, sustainable, and efficient electrical power grid with the use of power interconnections to exchange power. The primary difficulty with the present grid is to generate electricity using the old electrical infrastructure while also serving loads inside national borders. Most Southern Africa interconnections were implemented in 1995, after the formation of the Southern African Power Pool (SAPP). It was discovered that when electricity interconnection grows larger, the network system becomes more complex. Additionally, power connectors may encounter issues with frequency and voltage control. Numerous Southern African countries are unable to fulfill peak demand within their borders due to population n growth and aging infrastructure, resulting in electrical shortages. This article discusses the results on how to improve grid reliability by controlling voltages with a static var compensator. The remainder of the study discusses an efficient technique for optimizing the current SAPP power network through the use of High Voltage Direct Current Line Commutated Converter (HVDC-LCC) links and as a component of the Flexible AC Transmission System (FACTS)
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    Performance evaluation of percentage differential relays on power transformer and reliability assesment in HVDC grid protection scheme
    (IEEE, 2022-08-22) Ngema, Philani; Davidson, Innocent Ewaen; Buraimoh, Elutunji
    Percentage differential relays remain the most sensitive protection tool applied as backup protection on power transformers, busbar, and generators. Relays sometimes do mis-operate with the current transformer being affected by external fault leading to saturation, and the subsidence current present after clearing external faults. The cause of misoperation of percentage differential relays cannot be ignored that it entirely depends on magnitudes more than directionality for tripping decisions. This paper covers evaluating differential element performance, analysis of transformer inrush current, internal faults, external faults, and overexcitation conditions. The accurate computing of current transformers is also included. This protection only applies to 10MVA and above on transformers; however, it is not limited to transformers, but also transmission lines, busbars, and generators. The balance of the paper is on reliability assessment based on the HVDC grid protection scheme operation
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    Enhancement of solar PV output error under variable irradiation and temperature using an improved regulation strategy
    (IEEE, 2022-08-22) Akinyemi, Ayodeji Stephen; Kabeya, Musasa; Davidson, Innocent Ewaen
    A Photo-Voltaic Solar System (PVSS) is being operated in Steve Biko campus, Durban University of Technology. The energy generated by the PVSS is time varying, based on the quantity of sunlight and the temperature at which the photovoltaic (PV) cell functions. Consequently, in all situations, it is critical to obtain the full power from the PV array. The monitoring control strategy of Maximum Power Generated (MPG) from the PVSS connected to a Boost Inverter (BI) is presented in this research paper by employing an Improved Incremental Conductance and Integral Regulator (IIC & IR). The outcomes of the simulation indicate that full power can be obtained from the PV array while ensuring a consistent generated voltage under various operating scenarios.
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    Modelling of solar PV under varying condition with an improved incremental conductance and integral regulator
    (MDPI AG, 2022-04-01) Stephen, Akinyemi Ayodeji; Musasa, Kabeya; Davidson, Innocent Ewaen
    The introduction of solar photovoltaic (PV) systems would provide electricity accessibility to rural areas that are far from or have no access to the grid system. Various countries are planning to reduce their emissions from fossil fuel, due to its negative effects, by substituting with renewable energy resources. The use of solar PV systems is expanding globally because of growing energy demands and depleting fossil fuel reserves. Grid integration of the solar system is expected to increase further in the near future. However, the power output of solar PV systems is inherently intermittent, and depends on the irradiance and the temperature operation of the solar cell, resulting in a wide range of defects. Hence, it is vital to extract peak power from the solar panel in all conditions to provide constant power to the load. This paper presents a tracking control method of the peak output power of a solar PV system connected to a DC-DC boost converter using an improved incremental conductance and integral regulator (IC + IR). The research was carried out because the solar PV output is dependent on environmental parameters, such as solar insolation and temperature. Therefore, it is pertinent to forecast the peak power point in outdoor conditions and to operate at that point, so that solar PV can produce the highest output each time it is used. A peak power point strategy that maximizes the output of a solar PV array is proposed. This method establishes the maximum output operation point under the effects of the solar insolation and the module temperature. An automatic converter restoration scheme with block/de-block signal control is proposed to protect the converters from the higher phase current, total capacitor voltage deviation, grid disturbance, and fault current. The proposed scheme also tracks the peak power point (PPP) of the solar array with stable output voltage under varying operating conditions. It reduces the error signal and ripples at the PPP during instantaneous and incremental conductance to zero. In addition, it controls the solar PV system under constantly changing climatic conditions, and thus improves the system efficiency.