Performance evaluation of 2.4kVA grid-tie inverter

This paper is focused on experimenting the overall performance of a 2.4kVA direct solar power supply system. The overall aim is to implement a solar power supply system without a battery back-up in order to minimize cost. The objectives include measuring the performance of grid-tie inverter, determine its period of operation under load conditions, to make the use of batteries optional in solar power supply system and minimize initial cost of installation. Various tests (variable load, fixed load and no-load) were carried out for the purpose of analysis. A dual trace digital storage oscilloscope was used to monitor the output waveform of the inverter to observe possible harmonic distortion on the waveform. The inverter takes its input power directly from the solar modules (panels) through the maximum power point tracker (MPPT) charge controller. Each category of test was conducted for at least three days of different weather conditions, to determine how variation in the sun’s intensity (irradiance) affects the operation of the inverter and its output power. Test results show that the inverter performs its function during the day apart from the early hours in the morning and later in the evening of each day, and the loads were powered successfully during the period of test. The output waveform as observed from the oscilloscope is not purely sinusoidal; it is rather a modified sine wave.

Impact of faults on bus stability on an island 330kV mesh network on the Nigerian grid

This study carried out an assessment on the impact of faults on bus stability along the Benin-IkejaWest-Aiyede-Oshogbo-Benin (BIAOB) 330kV island network. The sensitivity of BIAOB as a ring network on the Nigerian grid aroused the interest behind its choice for this study. The network parameters were collated from the National Control Centre, Oshogbo and the network was modeled on the MATLAB 2015 environment using the obtained data. A high reactive power flow was observed in all the buses while the lowest voltage profile was observed on the Line-Line-Line-Ground (L-L-L-G) simulated in bus 1. This is an indication that symmetrical faults have the greatest impact on the network. Further results showed that the BIAOB network has a better voltage profile when compared with other radial network from existing literature. The paper concluded by recommending the closure of more radial network on the grid in order to improve its performance.

Design and implementation of a prototype active infrared sensor controlled automatic sliding door for mitigation of coronavirus disease 2019 (COVID-19)

The door is an essential part of any structure that provides access and security of lives and properties. The manual operation of a door could be cumbersome and laborious when the traffic volume is high. Also, it has been observed that doors could serve as a medium of spreading the deadly coronavirus disease 2019 (COVID-19) infection. Therefore, a prototype automatic sliding door that plays a crucial role in curbing the spread of this infectious diseases has been designed and implemented in this paper. The design of the prototype sliding door is in two parts namely; the structural part and the automation part. The structural design of the door was achieved using the Microsoft Visio 2016 while the design of the automation system was achieved using express printed circuit board. The implementation of the structural part was achieved using 1 inch particle board while the implementation of the automation system was based on the components like the active infrared sensor, resistors (10 kΩ), capacitor (1000 µF), transistors (TIP41 Q8, BC548 Q7), LED indicators, press button switch, pulley system, drive belt, stepper motor (IP65), and ATMEGA 8 microcontroller. The result of the tests carried out on the door showed that the prototype automatic sliding door was characterized by average opening time, closing time, delay time, and optimal sensing range of 3.10 s, 3.05 s, 5.72 s, and 23.5 cm, respectively. It can therefore be concluded from this work that the prototype automatic sliding door is effective in overriding the manual operation of the door.

Reliability optimization on power systems network using genetic algorithm

In this study, reliability optimization of a non-linear transmission network using Genetic Algorithm (GA) based optimization approach is presented and proposed. A GA based algorithm was developed for Koko, Guinness, Nekpenekpen, Ikpoba-Dam, Switch station, Etete and GRA 33kV tertiary transmission feeders within Benin Metropolis, Nigeria and was used to determine the optimal performance of the feeders’ reliability and availability through the minimization of downtime and the Mean Time between Failure (MTBF) by the appropriate selection of the objective functions and constraints. The equality and inequality constraints for each feeder on the network were defined, thereafter, codes were written on the Matlab 2016a environment to optimize the selected parameters. The results from the study showed a reduction in downtime of 5.63%, 26.87%, 34.20%, 5.42% 8.37%, 5.18% and 10.97% and an increment increased in MTBF by 4.95%, 19.87%, 4.58%, 3.85%, 4.88%, 5.77% and 13.56% for Guinness, Etete, Nekpenekpen, GRA, Switch station and Ikpoba-Dam feeders respectively. The obtained results, therefore, yielded an average corresponding improvement on the network’s reliability and availability by 1.85% and 2.83% respectively. Conclusively, the desired result reached in this paper validates the robustness of the GA tool in reliability studies. However, conscious effort must be geared concerning the ways and manners the system is operated in order to achieve desired results.

Development of an RFID-based security door system

This paper describes the development of a two-factor radio frequency identification (RFID)-based security door authentication scheme that can provide efficient control facilities to restrict the entry of an unauthorised door user. The developed system consists of the RFID unit, a microcontroller programmed to control the operation of the door using a synchronous motor. The multiplexers that comprise integrated circuits combined with the liquid crystal display was utilized for displaying the status of the card user while the alarm system informs the public of an intruder. The experimental results are presented and discussed.

Response characteristics of a negative temperature coefficient thermistor

This article focuses on the thermistor as a device that is widely used for temperature measurement and control in most electrical and electronic devices and appliances. The research is based on the type of thermistor used in photocopiers with particular reference to Minolta Bizhub (model-210) photocopier. The resistance and temperature were recorded by the application of conventional heat to deduce the response curves of resistance versus temperature and resistance/time. Results obtained from the characteristics show that the thermistor employed in the photocopier is a negative temperature coefficient (NTC) device. Also, there was a time variation in the response of the thermistor resistance to temperature changes, which indicates that the thermistor under test functions as a temperature control device. The shape of resistance versus temperature curve appeared to be similar to that of a typical NTC thermistor characteristics.

Analysis of radio frequency spectrum usage using cognitive radio

This paper presents the analysis of radio frequency (RF) spectrum usage using cognitive radio. The aim was to determine the unused spectrum frequency bands for efficiently utilization. A program was written to reuse a range of vacant frequency with different model element working together to produce a spectrum sensing in MATLAB/Simulink environment. The developed Simulink model was interfaced with a register transfer level - software defined radio, which measures the estimated noise power of the received signal over a given time and bandwidth. The threshold estimation performed generates a 1\0 output for decision and prediction. It was observed that some spectrum, identified as vacant frequency, were underutilized in FM station in Benin City. The result showed that when cognitive radio displays “1” output, which is decision H1, the channel is occupied and cannot be used by the cognitive radio for communication. Conversely, when “0” output (decision H0) is displayed, the channel is unoccupied. There is a gradual decrease in the probability of detection (Pd), when the probability of false alarm (Pfa) is increased from 1% to 5%. In the presence of higher Pfa, the Pd of the receiver maintains a high stability. Hence, the analysis finds the spectrum hole and identifies how it can be reused

Analysis of energy revenue and electrical power losses in distribution line

This study presents the analysis of energy revenue and electrical power losses in distribution network, aimed to determine the energy losses on power distribution system. The 11kV power transmission line at Ujokuen community feeding to Benson Idahosa University was investigated. The following data were obtained as follow: energy delivered, energy billing, total cash amount, billed collected and correspond percentage. From the research work various technical power losses associated with power distribution network were determined and their effect on energy delivered and energy billing and corresponding difference under the area of investigation. It was observed that energy delivered is not constant or linear for the year 2013. The comparison of energy delivered and energy billed for various years were determined. It was observed that there is decreased in energy delivered and energy billed from 2013 to 2015 and the system witnessed a slightly increase of energy delivered and energy billed from 2016 to 2018. The energy level differentials are due to copper losses, energy theft and core loss.