Neutral Ground Research Articles

Spectroscopic signatures of the S0, S1, and D0 states of indan: An experimental and theoretical investigation

The electronic and vibrational spectra of indan were explored through the utilization of Fourier transform infrared (FT-IR) spectrum, one-color resonant two-photon ionization (1C-R2PI) spectrum, and two-color resonant two-photon ionization (2C-R2PI) slow electron velocity-map imaging (SEVI) techniques in combination with quantum chemical calculations. Experimental spectra are found to be in good overall accordance with the theoretical calculations. The vibrational modes of the S0 neutral ground state, S1 first electronic excited state, and D0 cationic ground state were assigned with the assistance of density functional theory (DFT) calculations. The S1 ← S0 electronic transition energy was determined to be 36909 ± 5 cm−1 from the one-color resonant two-photon ionization spectrum. Moreover, the adiabatic ionization energy was deduced as 68419 ± 6 cm−1 based on the SEVI spectra.

Three‐phase four‐wire power flow solution for multi‐grounded distribution networks with non‐bolted grounding

AbstractThis study proposes a direct three‐phase four‐wire power flow method to accurately analyse the neutral line and multiple grounding characteristics. In particular, the proposed grounding impedance building‐based solution method was used to analyse the neutral grounding impedance in power flow studies based on the slack bus grounding impedance. The accuracy of the proposed method was verified using a neutral‐to‐earth voltage test system. IEEE 13‐bus and 123‐bus test systems were used to compare the advantages and disadvantages of the proposed method. Compared to the current injection full Newton and forward–backward sweep methods, the proposed method achieves a significant reduction in iteration numbers of up to 76.92% and 77.78%, respectively. For different grounding scenarios, stable convergence characteristics were exhibited by the proposed method after six to seven iterations.

Vibrational assignments and energy analyses of 3,4-difluorophenylacetylene using resonance-enhanced multiphoton ionization and slow electron velocity-map imaging techniques

Here, we report spectroscopic investigations of 3,4-difluorophenylacetylene applying two-color resonant two-photon ionization (2C-R2PI) and slow electron velocity-map imaging (SEVI) techniques. With the assistance of density functional theory (DFT) calculations, vibrational modes of the S0 neutral ground state, S1 first electronic excited state, and D0 cationic ground state were assigned. The adiabatic excitation energy of the S1 ← S0 electronic transition was determined to be 35639 ± 5 cm−1 from the resonance-enhanced multiphoton ionization (REMPI) spectroscopy. Additionally, the adiabatic ionization potential was found to be 72398 ± 5 cm−1 based on the SEVI spectra.

Molecular Association and Reactivity of the Pyridine Dimer Cation.

A recent experimental report has identified the formation of the C-N hemibonded pyridine dimer cation following vacuum ultraviolet near-threshold photoionization [J. Phys. Chem. Lett., 2021, 12, 4936-4943]. Herein, the dynamics and consequent reactivity of the pyridine dimer cation were investigated employing Born-Oppenheimer molecular dynamics (BOMD) simulations. An antiparallel π-stacked pyridine dimer in the neutral ground state is transformed into a noncovalently interacting C-H···N hydrogen-bonded structure which can lead to proton transfer in the cationic state. Additionally, C-N- and N-N-bonded adducts were formed in the cationic state. Further, metastable C-H···H-C-bonded cationic species was observed, which rearranged to an N-N bonded adduct. In contrast to the experimental observation, migration of the proton to the α position was not observed in the C-N bonded adduct owing to a high barrier of about 2 eV. The observed trends in the molecular association, proton transfer, and the formation of C-N and N-N bonded adducts are a consequence of the roaming dynamics of one pyridine moiety over the other in the cationic state.

An investigation on NGR failure in Indian smart cities while replacing the existing overhead lines by underground cables

Abstract Nowadays, Indian power distribution companies (PDCs) are implementing smart distribution networks. Older cities are becoming smarter as per the recent government’s policy. Existing overhead distribution lines are being replaced by underground cables as an essential criterion of a smart city. One of the main problems arising in this process is the overheating of the neutral grounding resistor (NGR) in 11 kV distribution systems, even in normal conditions. NGRs, placed inside the substations, are overloading the air conditioning and exhaust systems of the substation. Sometimes failure of the NGR occurs due to overheating. In this paper, a comprehensive investigation has been carried out to reach the roots of this problem. It is observed that long underground cables have a higher ground capacitance than overhead distribution lines. Due to the higher cable capacitance, the third harmonic current circulates through neutral, which overheats the NGR even in normal conditions. The situation becomes worse when the substation runs on diesel generators (DGs) in an isolated state under main grid failure, as a higher amount of third-harmonic current circulates depending on the type of winding and pitch factor of the DGs. Different solutions are proposed, and their advantages and disadvantages are analyzed. Finally, the rating of the NGR is modified, and louvers-cooling fan arrangement is preferred for the running substation.

KENDALI BERBASIS WEB PADA ANOMALI NEUTRAL GROUND RESISTOR (NGR)

A real-time monitoring and control system for Neutral Grounding Resistor (NGR) has been developed utilizing Internet of Things (IoT) technology. The system employs the PZEM-004T sensor for measuring current and voltage, and the NodeMCU ESP8266 for data processing and communication. Measurement data is displayed in real-time on an LCD screen and a website, with early warning alerts provided through a buzzer/alarm if abnormal conditions are detected. This system addresses the limitations of traditional monitoring methods, which are typically visual and periodic, by enabling continuous monitoring. Integration with a circuit breaker adds an additional layer of protection by disconnecting the power supply when necessary. Testing results demonstrate the effectiveness of the device in measuring voltages ranging from 5V to 220V and current, with a reliance on internet connectivity to ensure measurement accuracy. This system offers an efficient and proactive solution for maintaining the safety and reliability of electrical equipment at substations

Singing songs for a secular society? The elusive politics of cultural activism in contemporary Bangladesh

Abstract In Bangladesh, many secularists pursue their political goals through cultural activism. While committed to achieving a secular, progressive, and non-communal society, they often refrain from explicitly articulating their politics due to the sensitivity of their goals. Instead, cultural performances allow them to instantiate and embody a secular ethos with transformative potential, expressed through distinct cultural genres that become recognized as secular aesthetics. While activists consider culture to be a morally superior and ‘purer’ way to promote their political aims than party politics, which they perceive as ‘dirty’ and corrupt, cultural traditions are hardly neutral ground from which to enact secular aspirations. This article explores the ethical struggles that emerge from this position to illuminate what it means to act politically while trying to avoid politics, and why people might choose comparatively elusive forms of political engagement despite their strong commitment to a cause. Attending to less tangible forms of politics encourages us to rethink the role of political messages and visibility in social movements by highlighting the significant role, as well as contradictory implications, of aesthetics, embodiment, and gestures in political action. Conversely, the elusive politics of cultural activism underlines the need to go beyond analysing national discourses to understand the contested nature of secularism in Bangladesh.

Ground fault protection algorithm of active distribution network based on energy extremum direction

AbstractAfter large‐scale distributed power sources are connected to the distribution network, the fault current undergoes noticeable changes, affecting the accuracy of traditional single‐phase grounding fault algorithms. Therefore, the objective of this paper is to address the impact of distributed power integration on the grounding algorithms of distribution networks. The main contribution is: by establishing an electrical system structure and model for distribution network grounding faults that include distributed generation (DG), theoretically deriving and calculating the transient zero‐sequence current frequency changes at the moment of fault, analysing the directional characteristics of zero‐sequence currents under DG connection conditions, designing a local grounding fault judgment algorithm based on energy extremum direction, and providing a fault judgment and isolation process for grounding fault monitoring devices. The results show: through simulation and experimentation, the algorithm was tested, and the method can reliably judge grounding faults under various transition resistances, different numbers and capacities of connected distributed power sources, and different grounding switch‐on angles. The applicability of the algorithm covers both methods of neutral grounding through an arc suppression coil and ungrounded neutrals, adapting to scenarios with or without DG connections.

Home-Field Advantage in Soccer: UEFA Champions League and Europa League Evaluation on the 2021-2022 Season

Competition analysis in football is an important method to evaluate the success and failure of teams. Home advantage is considered as an important factor in achieving success in competitions. The aim of this study is to examine the effect of home advantage on technical criteria in the UEFA Champions League and UEFA Europa League, which are organised at club level, played in the 2021-2022 season. In the data collection phase, descriptive survey method was used. Within the scope of the research, a total of 262 football matches, excluding the final matches played at neutral grounds and total of 744 goals scored in these matches were analysed in terms of home and away teams in the UEFA Champions League and Europa League. The goals scored were categorised as the goal minutes intervals, the goal scoring areas (Inside the Penalty Area: IPA; Outside the Penalty Area: OPA), the ways goals were scored (Head Kick; Foot Kick), the number of touches on the ball before the goal (1 Touch: 1T; 2 Touches: 2T; 3 Touches: 3T; 4 Touches + >4T), the direction of attack before the goal and the goals scored from set-pieces (Corner Kick; Penalty Kick and Free Kick) for the home and away teams. The images of the analysed goals were accessed on the UEFA official website with open access permission. Frequency (f) and percentage (%) were calculated for the evaluation of the data obtained, and since the data did not show normal distribution according to the Shapiro-Wilk test results, Kruskal-Wallis test was applied to look at the difference between the groups and the significance level was accepted as p

Adaptable Ground Fault Relay Protection for Neutral Grounding Resistor in Transformers and Generator: A Study in Indonesian Context

Adaptable Ground Fault Relay Protection for Neutral Grounding Resistor in Transformers and Generator: A Study in Indonesian Context

Photoionization of aziridine: Nonadiabatic dynamics of the first six low-lying electronic states of the aziridine radical cation.

In this article, the theoretical photoionization spectroscopy of the aziridine (C2H5N) molecule is investigated. To start with, we have optimized the geometry of this molecule at the neutral electronic ground state at the density functional theory/augmented correlation-consistent polarized valence triple zeta level of theory using the G09 program. The electronic structure calculations were restricted to the first six low-lying electronic states in order to account for the experimental photoelectron spectrum of the C2H5N molecule. The first six low-lying electronic states (X̃2A', Ã2A', B̃2A″, C̃2A″, D̃2A', and Ẽ2A') of the potential energy surfaces (PESs) are calculated by both equation of motion-ionization potential-coupled cluster singles and doubles and multi-configuration quasi-degenerate perturbation theory abinitio quantum chemistry methods along the dimensionless normal displacement coordinates in which multiple conical intersections were established among the considered electronic states. A (6 × 6) model vibronic Hamiltonian is constructed on a diabatic electronic basis, using the symmetry selection rules and Taylor series expansion. The Cs symmetry point group of the aziridine molecule leads to electronic states symmetry of either A' or A″, and these states are close in energy, due to which the same symmetry electronic states avoid each other. To get a smooth diabatic PES, a fourfold diabatization scheme is used, which is implemented in the General Atomic and Molecular Electronic Structure Systems suite of programs. All the parameters used in the diabatic vibronic coupling model Hamiltonian are calculated in terms of the normal modes of vibrational coordinates. Finally, the vibronic model Hamiltonian constructed for the coupled six electronic states is used to solve both time-independent and time-dependent Schrödinger equations using the multi-configuration time-dependent Hartree program module to obtain the dynamical observables. The theoretical vibronic band structure is found to be in good accord with the available experimental results.

Универсальная централизованная защита от однофазных замыканий на землю в кабельных сетях напряжением 6–10 кВ

Selective protection against single phase earth faults in distribution 6–10 kV cable networks can be performed both with the use of individual (per connection) and centralized devices covering all connections of the protected object. The advantages of centralized devices are reduction of specific (per connection) costs of protection, simplification of its operation and design. Well-known technical solutions in terms of centralized protection devices against this type of damage do not always provide versatility (the possibility to use neutral cables of 6–10 kV in various grounding modes) and high technical perfection (selectivity and stability of operation). Thus, it is relevant to develop a universal centralized protection against single-phase earth faults, ensuring high technical perfection for all types of earth faults in 6–10 kV cable networks with different neutral grounding modes. The authors have used a comprehensive simulation model "cable network – protection device" to study the selectivity and stability of the developed principles of implementation and algorithms for centralized protection against earth faults. The model is designed in SimPowerSystems and Simulink software. The configuration and parameters of the cable network model have been selected considering the key features of 6–10 kV distribution cable networks of industrial and urban power supply systems. A universal centralized protection against all types of earth faults in 6–10 kV cable networks with various neutral grounding modes has been developed. The results of functional tests on the simulation model have confirmed the effectiveness of the developed algorithms of the developed centralized protection for all types of earth faults both in uncompensated and compensated cable networks of 6–10 kV. The proposed technical solution implements a multifunctional multiparametric centralized protection against earth faults. It has such properties as versatility, selectivity, and high stability of operation for all types of earth faults, recognition of types of single-phase earth faults, continuity of action in stable and most dangerous arc intermittent earth faults.

Study on phase selection control characteristics of fast vacuum circuit breakers suitable for new power systems

Abstract With a high proportion of new energy access to the power system, the user side of the randomness and volatility of distributed photovoltaic large-capacity access to the 10 kV medium-voltage distribution grid operation results in more frequent fluctuations in the system voltage and more frequent switching of reactive compensation of the shunt capacitor bank on the 10 kV side of the conventional substation. Conventional reactive compensation switching circuit breakers adopt a spring mechanism whose mechanical stability is insufficient and the selection of the relevant fit capacitor bank accuracy is not enough. The 12 kV fast vacuum circuit breaker of small mechanical dispersion for selection related to the combination was proposed. First of all, based on the neutral grounded and ungrounded system of the capacitor bank, the strategy of capacitor bank phase selection closing was developed. For the action characteristics of the phase selection of the 12 kV fast vacuum circuit breaker, the variation laws of mechanical dispersion and the influence factors such as ambient temperature, capacitance voltage, capacitance degradation, mechanical wear, and conductive rod deformation were obtained by simulation and experiment. The results showed that the ambient temperature and capacitance voltage had a great influence on the switching time of the fast circuit breaker, while other factors had a small influence. Again, the pre-breakdown characteristics of the 12 kV fast vacuum circuit breaker were obtained by experiments. The results showed that the influence of contact opening distance and pre-breakdown voltage was a linear relationship, and the pre-breakdown slope was 30 kV/mm. According to the pre-breakdown closing characteristic curve, the pre-breakdown time of the fast circuit breaker was 0.45 ms at most. The feedforward compensation mechanism based on a neural network was proposed to compensate for the action characteristics of the fast circuit breaker and aimed to improve the phase selection accuracy. Finally, two rounds of capacitive current switching tests of 12 kV fast vacuum circuit breakers with C2 level were carried out in a third-party test station. The accuracy of phase closing is within the ±0.5 ms closing window, effectively preventing the occurrence of closing inrush current.

Trust and distrust in public governance settings: Conceptualising and testing the link in regulatory relations

ABSTRACT The relationship between trust and distrust in public governance is still an open question. In the literature, three different perspectives on how trust and distrust are related are intensively debated: (1) trust and distrust as two ends of the same conceptual continuum; (2) trust and distrust as opposites, but with neutral ground in between; and (3) trust and distrust as related, yet distinct concepts. Employing a new measure for distrust and by using perceptual data on trust and distrust in regulatory agencies from multiple types of stakeholders in nine countries and three sectors, this article shows that high trust and high distrust can co-exist at the same time, and that trust and distrust are negatively correlated only to a limited extent. Moreover, while trustworthiness correlates strongly with trust, trustworthiness does not or only weakly correlate with distrust in a negative way. These findings are robust even when controlling for respondents' characteristics, different types of stakeholders, sectors and countries. This suggests that in public governance settings trust and distrust should be considered as distinct concepts, and the article calls for more research into the distinctiveness of the measurement, causes and effects of distrust, compared to trust.

Geopolitics of decolonization: Carnegie Endowment’s diplomatic training program 1960–73

This paper considers the case of the Carnegie Endowment for International Peace’s ‘Programs in Diplomacy’, which from 1960 to 73 provided international, bilingual training for the diplomats of ‘newer states’ – former colonies that gained independence after 1945. Drawing on archival research in three continents, we can see that the spaces and practices of diplomatic training through these programmes were inherently geopolitical: they would shape social and professional norms and networks, in turn shaping state-building and international life. As a result, the pedagogies, curricula, and spaces of these courses must be understood through the prism of contemporary (geo)political tensions: the ideological confrontations of decolonization and the Cold War. Organizers sought ‘neutral ground’ for the programmes, in terms of both their locations and their content. Beginning in Geneva and New York, the programmes shifted quickly towards universities in the Global South and articulated Third World ideals such as African unity. Despite consistent attempts to frame the programmes as technical and non-ideological, their discursive and material geographies reveal an approach to ‘learning the international’ that privileged Western liberal norms and practices, particularly through a pedagogy of socialization.

A novel high‐impedance neutral grounding method for medium‐ or large‐size hydroelectric generators

AbstractAs the capacity of medium or large hydroelectric generators increases, conventional grounding methods face challenges in effectively limiting single‐phase to earth fault current and neutral displacement voltage within acceptable range. Excessive fault current and neutral displacement voltage pose threats to the stability and safety of power generation and transmission systems. Inherent design deficiencies in conventional grounding methods lead to failures in meeting fault current and voltage requirements. To address this, this paper proposes a novel grounding method utilizing high impedance to restrict excessive fault current and neutral displacement voltage. The method minimizes both fault current and neutral displacement voltage by optimally selecting device parameters through minimal iterative trials. Additionally, a novel indicator is introduced to evaluate the effectiveness of grounding method by monitoring changes in neutral displacement voltage. The method is tested through theoretical calculation and field experiments, successfully implemented in large‐size hydroelectric generator.

Current spectral norm and phase variation based fault region identification for active distribution network

The paper presents a fault region identification method for the active distribution network (ADN) with limited PMU. First, PMU configuration and region division strategies are proposed based on the network topology. Next, the difference in three-phase current variations between the normal and fault regions of the ADN is analyzed. A multi-dimensional state monitoring matrix is built using the measured current data. The spectral norm ratio coefficient is constructed based on the 2-norm to lower the complexity of the multi-dimensional state monitoring matrix and quantify the difference in state changes before and after the fault occurs in each region. Then, the fault region is identified by combining each region’s spectral norm ratio coefficient and the change of the current phase. Finally, an IEEE 33-node simulation model is created to simulate faults under different working conditions. According to the simulation results, the suggested approach is less impacted by fault type, neutral point grounding mode, and transition resistance. Furthermore, even if the communication does not match the rigorous synchronization requirements, the proposed method can still complete the fault identification of the distribution network correctly and has high robustness.

Extended N-centered ensemble density functional theory of double electronic excitations.

A recent work (arXiv:2401.04685) has merged N-centered ensembles of neutral and charged electronic ground states with ensembles of neutral ground and excited states, thus providing a general and in-principle exact (so-called extended N-centered) ensemble density functional theory of neutral and charged electronic excitations. This formalism made it possible to revisit the concept of density-functional derivative discontinuity, in the particular case of single excitations from the highest occupied Kohn-Sham (KS) molecular orbital, without invoking the usual "asymptotic behavior of the density" argument. In this work, we address a broader class of excitations, with a particular focus on double excitations. An exact implementation of the theory is presented for the two-electron Hubbard dimer model. A thorough comparison of the true physical ground- and excited-state electronic structures with that of the fictitious ensemble density-functional KS system is also presented. Depending on the choice of the density-functional ensemble as well as the asymmetry of the dimer and the correlation strength, an inversion of states can be observed. In some other cases, the strong mixture of KS states within the true physical system makes the assignment "single excitation" or "double excitation" irrelevant.

High-Resolution Photoelectron Imaging of Cryogenically Cooled BiB2- and BiB3- Bismuth-Boron Clusters.

We report a high-resolution photoelectron imaging study of cryogenically cooled BiB2- and BiB3- clusters. Vibrational features are completely resolved for the ground-state detachment transitions, providing critical information about the structures of the anionic clusters and their corresponding neutrals. The electron affinities of BiB2 and BiB3 are accurately measured to be 2.174(1) and 2.121(1) eV, respectively. The B-B and Bi-B stretching frequencies are measured to be 1262 and 476 cm-1, respectively, in the ground state of BiB2. Three vibrational frequencies are measured for the ground state of BiB3: 1194 cm-1 (B-B stretching), 782 cm-1 (B-B stretching), and 339 cm-1 (Bi-B stretching). Both BiB2- and BiB3- and their neutral ground states are found to have planar C2v structures in which the Bi atom bridges two B atoms. BiB2- is found to have a triplet spin state (3B2), consistent with its complicated photoelectron spectra, whereas BiB3- is a doublet (2B1) and neutral BiB3 is closed shell (1A1). Both BiB2 and BiB3 consist of peripheral localized Bi-B and B-B σ bonds and delocalized π and σ bonds.

Impact of Cavity on Molecular Ionization Spectra.

Ionization phenomena have been widely studied for decades. With the advent of cavity technology, the question arises how quantum light affects molecular ionization. As the ionization spectrum is recorded from the neutral ground state, it is usually possible to choose cavities which exert negligible effect on the neutral ground state, but have significant impact on the ion and the ionization spectrum. Particularly interesting are cases where the ion exhibits conical intersections between close-lying electronic states, which gives rise to substantial nonadiabatic effects. Assuming single-molecule strong coupling, we demonstrate that vibrational modes irrelevant in the absence of a cavity play a decisive role when the molecule is in the cavity. Here, dynamical symmetry breaking is responsible for the ion-cavity coupling and high symmetry enables control of the coupling via molecular orientation relative to the cavity field polarization. Significant impact on the spectrum by the cavity is found and shown to even substantially increase for less symmetric molecules.