A Review of Fault Diagnosing Methods in Power Transmission Systems

Transient stability is important in power systems. Disturbances like faults need to be segregated to restore transient stability. A comprehensive review of fault diagnosing methods in the power transmission system is presented in this paper. Typically, voltage and current samples are deployed for analysis. Three tasks/topics; fault detection, classification, and location are presented separately to convey a more logical and comprehensive understanding of the concepts. Feature extractions, transformations with dimensionality reduction methods are discussed. Fault classification and location techniques largely use artificial intelligence (AI) and signal processing methods. After the discussion of overall methods and concepts, advancements and future aspects are discussed. Generalized strengths and weaknesses of different AI and machine learning-based algorithms are assessed. A comparison of different fault detection, classification, and location methods is also presented considering features, inputs, complexity, system used and results. This paper may serve as a guideline for the researchers to understand different methods and techniques in this field

Non-uniform Haar Wavelet Method for Solving Singularly Perturbed Differential Difference Equations of Neuronal Variability

A non-uniform Haar wavelet method is proposed on specially designed non-uniform grid for the numerical treatment of singularly perturbed differential-difference equations arising in neuronal variability.We convert the delay and shift terms using Taylor series up to second order and then the problem with delay and shift is converted into a new problem without the delay and shift terms. Then it is solved by using non-uniform Haar wavelet. Two test examples have been demonstrated to show the accuracy of the non-uniform Haar wavelet method. The performance of the present method yield more accurate results on increasing the resolution level and converges fast in comparison to uniform Haar wavelet

Anterior Cervical Discectomy and Fusion: Operative Technique and Post-Operative Complications – An Experience in a Tertiary Care Hospital

Background and Objective: The most common spinal procedure in our set up to address various disorders of the cervical spine like prolapsed intervertebral disc, trauma, and degenerative disc disease is an anterior cervical discectomy and fusion (ACDF). As there is no technique without complication, this procedure is also related with certain important complications. We evaluated post-operative complications of ACDF in our institution.Material and Methods: The preoperative data of 148 patients who were operated in last 3 years for ACDF isincluded in the study. Patients with previous neck surgery are excluded.Results: The most commonly performed surgical interventions is single level ACDF (65%). Dysphagia is mostsignificant (16%) complication. After which neurological deterioration (9%) with equal incidence of RecurrentLaryngeal Nerve Palsy and wound infection that is 8% each.Conclusion: The most common post-operative complications are dysphagia and worsening of preexistingneurology and multilevel ACDF is identified as the most common risk factor. Early recognition of complicationsand management may help to reduce mortality and morbidity

Close accord on partial discharge diagnosis during voltage harmonics in electric motors fed by variable frequency drives

Partial discharge (PD) diagnostics test is a reliable solution for estimating insulation health conditions in power system components. During laboratory PD diagnostics, the effect of harmonic components in the voltage waveform generated by variable frequency drives (VFD) fed electric motors (EMs) is often overlooked. As VFD-fed EMs operate at low speeds, the harmonic concentration in the voltage increases. It has been found that PD activity in VFD-fed EM is significantly affected by the addition of harmonic components in the voltage, thus making it necessary to consider their impact when performing true PD diagnostics. This paper investigates the influence of voltage harmonic distortion produced in VFD-fed EM on PD severity and the subsequent insulation degradation. Eight VFD-fed EM are used to study the PD behaviour under different levels of harmonic pollution. The PD characteristics, such as inception voltage, pulse repetition rate, accumulated apparent charge, average discharge current, discharge power, and quadratic rate, are determined. Using probability distribution functions, PD activity and severity at various voltage harmonic levels are estimated. The proposed technique can be used to plan the maintenance activities that ensure the reliability for industrial applications dealing with the voltage harmonic distortion

Close Accord on Partial Discharge Diagnosis During Voltage Harmonics in Electric Motors Fed by Variable Frequency Drives

Partial discharge (PD) diagnostics test is reliable for estimating insulation health conditions in power system components. During laboratory PD diagnostics, the effect of harmonic components in the voltage waveform generated by variable frequency drives (VFD) fed electric motors (EMs) is often overlooked. However, these harmonic components can cause significant distortion in the applied voltage waveform. As VFD-fed EMs operate at low speeds, the harmonic concentration in the voltage increases. It has been found that PD activity in VFD-fed EM is significantly affected by the addition of harmonic components in the voltage, thus making it necessary to consider their impact when performing true PD diagnostics. This paper investigates the influence of voltage harmonic distortion produced in VFD-fed EM on PD severity and the subsequent insulation degradation. Eight VFD-fed EM are used to study PD behavior under different levels of harmonic pollution. The PD characteristics, such as inception voltage, pulse repetition rate, accumulated apparent charge, average discharge current, discharge power, and quadratic rate, are determined. With the help of probability distribution functions, the chance of PD activity and its severity at various voltage harmonic levels are estimated. The proposed technique can be used to plan maintenance activities that ensure reliability for industrial applications dealing with voltage harmonic distortion

2-Benzoyl-2H-1,4-benzothia­zin-3(4H)-one

In the title compound, C15H11NO2S, the dihedral angle between the aromatic rings is 80.35 (7)°. The heterocyclic six-membered ring is not planar: the puckering parameters of this ring are Q = 0.5308 (15) Å, θ = 63.11 (18) and ϕ = 23.5 (2)°. The mol­ecules are linked into inversion dimers with R 2 2(8) ring motifs by pairs of N—H⋯O hydrogen bonds. The dimers are inter­linked into polymeric sheets extending parallel to the bc plane by C—H⋯O hydrogen bonds, generating R 2 1(7) ring motifs. π–π inter­actions occur between the benzoyl phenyl rings with centroid–centroid separations of 3.9187 (15) Å

Solution of partially singularly perturbed system of initial and boundary value problems using non-uniform Haar Wavelet

An efficient non-uniform Haar wavelet method is proposed for the numerical solution of system of first order linear partially singularly perturbed initial value problem on piecewise uniform Shishkin mesh and ρ-mesh. Further, we apply same technique for solving system of second order linear partially singularly perturbed boundary value problems on piecewise uniform Shishkin mesh and q-mesh. Our method produces better results in comparison to uniform Haar wavelet, classical finite difference operator method and parameter uniform methods. We demonstrated two test problems to support the theory, accuracy and efficiency of the non-uniform Haar Wavelet method.Publisher's Versio

The externality cost of environmental (dis)amenities in the urban housing market: an emerging evidence from Pakistan

Rising urbanization on abiotic environmental conditions in housing units is one of the most severe difficulties that city municipality authorities face, all over the world. Waste production has increased as a result of households failing to implement waste management strategies that ensure sustainability. Thus, property values in the housing market have regularly deteriorated as a result of environmental (dis)amenities. The study examines the impact of a waste dump site on proximate property values in Pakistan’s twin cities. Using a systematic random sampling technique, questionnaires were distributed to 849 households. 35 dump sites were chosen from 100 metres to 500 metres. The dump sites were chosen based on their size and proximity to residential homes in the study area. The empirical results show that the distance between a residential property and a waste dump site significantly impacts rental values. Moreover, rents exhibit a negative relationship with increasing distance from the dump sites. Based on applied findings, more proactive enforcement of sanitary laws and regulations, such as removing all irregular dump sites from residential areas, is recommended

Assessing Household’s Municipal Waste Segregation Intentions in Metropolitan Cities of Pakistan: A Structural Equation Modeling Approach

There is a growing concern about inappropriate waste disposal and its negative impact on human health and the environment. The objective of this study is to understand household waste segregation intention considering psychological, institutional, and situational factors simultaneously. Insights into the motivations of household waste segregation drivers may assist in a better knowledge of how to pursue the most efficient and effective initiatives. For this purpose, data from a representative sample comprising 849 households is obtained from the twin cities of Islamabad and Rawalpindi (Pakistan). The empirical analysis employs a Structural Equation Modeling (SEM) approach, showing that policy instruments have significant direct and indirect impacts on households’ segregation intentions. The results highlight that government policy instruments strengthen personal and perceived norms for waste segregation intentions, resulting in an external intervention that would encourage intrinsic motivation. Therefore, policy actions become the main entry point for initiating waste segregation behavior. Public policy must continue to emphasize waste segregation since it may help resource recovery. This is imperative because the environment is a shared resource, and its conservation increases social welfare