Unavailability of K-out-of-N: G Systems with non-identical Components Based on Markov Model

The process industry has always been faced with the challenging tasks of determining the overall unavailability of safety instrumented systems (SISs). The unavailability of the safety instrumented system is quantified by considering the average probability of failure on demand. To mitigate these challenges, the IEC 61508 has established analytical formulas for estimating the average probability of failure on demand for K-out-of-N (KooN) architectures. However, these formulas are limited to the system with identical components and this limitation has not been addressed in many researches. Hence, this paper proposes an unavailability model based on Markov Model for different redundant system architectures with non-identical components and generalised formulas are established for non-identical k-out-of-n and n-out-of-n configurations. Furthermore, the proposed model incorporates undetected failure rate and evaluates its impact on the unavailability quantification of SIS. The accuracy of the proposed model is verified with the existing unavailability methods and it is shown that the proposed approach provides a sufficiently robust result for all system architectures. &nbsp

MODEL IDENTIFICATION AND LEVEL CONTROL OF COUPLED TANKS SYSTEM

The Couple Tank (CT) system remains as a benchmark to investigate and test new emerging control schemes in the process industry since its dynamic emulates many factual system in the field of process control. In this paper, we examine the performance evaluation of two control algorithms, proportional derivative controller (PD) and proportional-integral-derivative controller (PID). The dynamics of the CT system is experimentally derived by system identification method and validated with a mathematical model that depicts the dynamic behaviour of the coupled tank system. Furthermore, the control schemes are expanded on the model obtained through system identification method. The simulation results showed that the PD controller did not meet all the specified control objectives. To improve the response an integral controller was incorporated to the PD controller and the response was compared to that of the PID controller and uncompensated system. The results revealed that the PID controller satisfied all the control goals. However, the PD controller was more satisfactory in terms of time response criteria

MODEL IDENTIFICATION AND LEVEL CONTROL OF COUPLED TANKS SYSTEM

The Couple Tank (CT) system remains as a benchmark to investigate and test new emerging control schemes in the process industry since its dynamic emulates many factual system in the field of process control. In this paper, we examine the performance evaluation of two control algorithms, proportional derivative controller (PD) and proportional-integral-derivative controller (PID). The dynamics of the CT system is experimentally derived by system identification method and validated with a mathematical model that depicts the dynamic behaviour of the coupled tank system. Furthermore, the control schemes are expanded on the model obtained through system identification method. The simulation results showed that the PD controller did not meet all the specified control objectives. To improve the response an integral controller was incorporated to the PD controller and the response was compared to that of the PID controller and uncompensated system. The results revealed that the PID controller satisfied all the control goals. However, the PD controller was more satisfactory in terms of time response criteria

DESIGN ANALYSIS OF A LOW-COST PARABOLIC ANTENNA FOR DEVELOPING NATION

This paper is aimed at designing a locally fabricated fiberglass parabolic antenna as a replacement for a metallic fabricated parabolic antenna. They are coated with a thin film of aluminum dust to enhance reflectivity since electromagnetic radiations do not travel deep in a conductor. This reduces the thick mass of metal usually used for constructing metallic parabolic antenna leading to a reduced cost of production. It incorporates a Low Noise Block (LNB) Converter comprising of amplifiers and frequency down converter. Metallic parabolic antenna contributes more to signal loss by reflecting radio waves. The Parabolic antenna is designed to receive microwave signals in the K-band with the down converter converting it to very high frequency (VHF) and ultra-high frequency (UHF) employing the super-heterodyning principle. The study shows the design and installation of a low-cost parabolic antenna in the rural community in Nigeria. The designed parabolic antenna is used to receive a signal with the center frequency of 11.3GHz and signal strength of 60%. The economic viability is that fiber-glass Parabolic antenna can replace the metallic fabricated ones

Development of a Hybridized Model for Determining the Degree of Polymerization of Power Transformers

Power transformers have been described as an important equipment of electrical switchyard in which its failure results in long hours of outage. Some of the existing models for determining the Degree of Polymerization (DP) of power transformers were based on singular parameter which is not sufficient for the assessment of power transformers’ lifespan. This research paper therefore developed a hybridized model for determining the degree of polymerization of power transformers. The study employed the use 2-Furaldehyde (2FAL) content values of 0.5 ppm to 10ppm in determining the DP value and simulation was carried out using MATLAB. The result was compared with existing DP model for effectiveness of the Hybridized DP model. The developed model yielded a DP range of 247 ≤ DP ≤ 1184 based on a constant hotspot temperature of 1100C and the values of activation energy and pre-exponential factors used. The results from this research presented a better method of determining the Degree of Polymerization of power transformer compared to the existing method. Therefore, the Hybridized DP model developed is more sufficient for the evaluation of lifespan of power transformers. Keywords: Power Transformers, Electrical Switchyard, Lifespan, Degree of Polymerization, Statistical Tools, Power Failure, Outages. DOI: 10.7176/ISDE/12-6-04 Publication date:October 31st 2022

DESIGN ANALYSIS OF A LOW-COST PARABOLIC ANTENNA FOR DEVELOPING NATION

This paper is aimed at designing a locally fabricated fiberglass parabolic antenna as a replacement for a metallic fabricated parabolic antenna. They are coated with a thin film of aluminum dust to enhance reflectivity since electromagnetic radiations do not travel deep in a conductor. This reduces the thick mass of metal usually used for constructing metallic parabolic antenna leading to a reduced cost of production. It incorporates a Low Noise Block (LNB) Converter comprising of amplifiers and frequency down converter. Metallic parabolic antenna contributes more to signal loss by reflecting radio waves. The Parabolic antenna is designed to receive microwave signals in the K-band with the down converter converting it to very high frequency (VHF) and ultra-high frequency (UHF) employing the super-heterodyning principle. The study shows the design and installation of a low-cost parabolic antenna in the rural community in Nigeria. The designed parabolic antenna is used to receive a signal with the center frequency of 11.3GHz and signal strength of 60%. The economic viability is that fiber-glass Parabolic antenna can replace the metallic fabricated ones

MODEL IDENTIFICATION AND LEVEL CONTROL OF COUPLED TANKS SYSTEM

The Couple Tank (CT) system remains as a benchmark to investigate and test new emerging control schemes in the process industry since its dynamic emulates many factual system in the field of process control. In this paper, we examine the performance evaluation of two control algorithms, proportional derivative controller (PD) and proportional-integral-derivative controller (PID). The dynamics of the CT system is experimentally derived by system identification method and validated with a mathematical model that depicts the dynamic behaviour of the coupled tank system. Furthermore, the control schemes are expanded on the model obtained through system identification method. The simulation results showed that the PD controller did not meet all the specified control objectives. To improve the response an integral controller was incorporated to the PD controller and the response was compared to that of the PID controller and uncompensated system. The results revealed that the PID controller satisfied all the control goals. However, the PD controller was more satisfactory in terms of time response criteria