Neutral Ground Research Articles

Down with This Sort of Thing: Seth Heringer and the End of the Historical-Critical Method

Down with This Sort of Thing: Seth Heringer and the End of the Historical-Critical Method

Single phase line‐broken fault detection and location based on differential voltage in radial distribution network

Single phase line-broken (SPLB) fault is one kind of high impedance fault (HIF). When a SPLB fault occurs, there are four scenarios: SPLB fault with neither side conductors grounded (SPLB-NSCG), with source side conductor grounded only (SPLB-SSCG), with load side conductor grounded only (SPLB-LSCG), with both side conductors grounded (SPLB-BSCG). Traditional HIF detection methods using current or voltage characteristics have low sensitivity to SPLB fault. In this paper, voltage characteristics are analysed firstly in the cases of the first three scenarios of SPLB fault, respectively. Theoretical analysis finds that the voltage at both the sides of the disconnection point is significantly different. A high sensitive SPLB fault detection method based on differential voltage is proposed for radial distribution network with different data synchronization ability. Finally, SPLB fault location methods based on centralized intelligent mode feeder automation (FA) and intelligent distributed mode FA are proposed. Simulations based on PSCAD verify that the proposed SPLB fault detection method is feasible, highly sensitive and immune to the neutral grounded mode, fault scenarios and fault resistance.

Analysis of a Grounding System In 20 Kv Distribution Transformer Line in PLTD Gayo Lues

The main purpose of grounding is to create a low-impedance path to the earth's surface for electric waves and transient voltages. An effective grounding system will minimize these effects. The grounding system plays a very important role in the protection system. The grounding system is used as a fault current discharge path to the ground. According to its function, grounding is divided into 2, namely grounding the neutral point of the power system and grounding equipment. The neutral grounding of the power system serves as a safety system or network, while the grounding of the equipment functions as a safety against touch voltage. Measurement of the type of grounding electrode on a 20 kV distribution transformer at PT. PLN Rema Gayo Lues Area uses 2 rod electrodes with a grounding resistance value of 2 Ohms.

On the correlation between the TiN thin film properties and the energy flux of neutral sputtered atoms in direct current magnetron discharge

In this study, the energy flux of sputtered atoms on a substrate was correlated to the properties of titanium nitride (TiN) films deposited using direct current magnetron sputtering (dcMS) under mixed Ar and N2 atmospheres. The neutral titanium sputtered atoms velocity distribution functions (AVDFs) were measured by tunable diode-laser induced fluorescence (TD-LIF), and the flux of particles and their energy were derived. Mass spectrometry was used to characterize the energy-resolved flux of the ions. It was found that the neutral sputtered atoms flux and deposition rate were in good agreement, indicating that the flux of the neutral titanium ground state represents the number of deposited atoms. Moreover, TiN films were deposited at different gas pressures and at various Ar/N2 gas mixtures close to the conditions where stoichiometric TiN was formed, without bias voltage and heating of the substrates. The energy flux of the sputtered neutral Ti into the substrate was calculated from TD-LIF measurements. At a relatively low magnetron discharge pressure of 0.4 Pa, we demonstrated that the energy of sputtered neutral Ti impinging on the substrate is higher than the energy flux of ionized particles corresponding mainly to Ar+. Thus, the influence of the energy flux of the sputtered atoms on the texture and microstructure of the films is revealed. The (200) texture was obtained at 0.4 Pa when the energy flux of the sputtered atoms was higher than the ion energy flux. At 1.3 Pa where the sputtered atoms energy flux is one order lower compared to 0.4 Pa the (111) texture was obtained. The high-energy flux of the ground state of Ti sputtered atoms seems to allow stress removal in the films.

Ensuring Electrical Safety in 20 kV Electrical Networks with Low-Resistance Neutral Grounding

Ensuring Electrical Safety in 20 kV Electrical Networks with Low-Resistance Neutral Grounding

A Method for Measuring Capacitive Current in Arc Suppression Coil Grounding System

With the rapid development of the national economy, the system cabling rate continues to improve, the system capacitive current continues to increase, and the arc suppression coil grounding method is more and more widely used. Among them, the pre adjustable turn adjustable arc suppression coil accounts for the highest proportion. How to accurately, quickly and real-time measure and calculate the capacitive current of the system is the foundation to realize the automatic tracking and compensation of the arc suppression coil, It is also the key to reliably extinguish the arc and reduce the influence range of the fault when the single-phase grounding fault occurs in the system. Based on the analysis of the variation law of the capacitive current in the distribution network neutral grounding system through the arc suppression coil, this paper proposes a new method for measuring the capacitive current based on the resonance point curve fitting, which is suitable for the pre adjustable turn adjustable arc suppression coil grounding system, and verifies its reliability and accuracy through simulation.

Условия полной компенсации токов однофазного замыкания на землю в кабельных сетях напряжением 610 кВ с заземлением нейтрали через дугогасящий реактор

To improve the reliability of power supply of consumers, a significant part of 6–10 kV cable networks (in Russia about 20 %) operate with resonant neutral grounding via arc suppression coil (ASC) (single-phase earth fault capacitive current compensation). This neutral grounding mode provides suppression of arcing earth faults accompanied by dangerous overvoltage and reduction of current at the point of fault by compensating the capacitive component of the elementary frequency. Field experience of operation of 6–10 kV compensated cable networks has shown that the reason of the decrease of the efficiency of the neutral grounding mode is an increase of the residual current at the point of fault. It happens due to the active component of the elementary frequency and higher harmonic components that are not compensated via ASC up to the values when long time arc duration and transition of the earth fault to the short circuit become possible. The existing solutions of the problem of full compensation of the current of a single-phase earth fault are not sufficiently developed and substantiated. Thus, the solution of the problem to increase the efficiency of grounding the neutral of the network via ASC can be achieved by developing and implementing methods and devices of the full compensation of the earth fault current, including the active component of the elementary frequency and higher harmonic components. To achieve the terms and conditions of full compensation of the current components of a single-phase earth fault, the classical theory of electrical circuits has been used. To verify the validity of the results obtained, simulation modeling in the Matlab software package has been carried out. For an electrical network with neutral grounding via ASC, the authors have obtained a general mathematical description of the terms and conditions of full current compensation at the point of earth fault, including higher harmonic components and transient components. The authors have defined the requirements for accuracy to determine the moment of a single-phase earth fault and the voltage value of the damaged phase when insulation fault occurs. Possible options of algorithms to compensate higher harmonics in the current of stable earth fault are proposed. The obtained general mathematical description of the terms and conditions of full current compensation at the point of a single-phase earth fault in 6–10 kV compensated cable networks allows us to substantiate existing methods and develop new ones to compensate both the total current at the point of fault and its components.

Demonstration of Neutral Grounding Mode of New 10kV Distribution System in Nuclear Power Station

Different grounding methods are used at the neutral point of distribution system, which have a direct impact on the reliability, continuity, insulation level of equipment, relay protection and action characteristics of automatic devices. It is a comprehensive technical and economic problem to choose the appropriate neutral grounding mode of distribution system. Taking the newly added 10kV power distribution system of a nuclear power plant as an example, this paper briefly analyzes the methods and principles of neutral grounding demonstration of distribution network, and provides a referential solution for subsequent similar projects.

Charge Delocalization and Vibronic Couplings in Quadrupolar Squaraine Dyes.

Squaraines are prototypical quadrupolar charge-transfer chromophores that have recently attracted much attention as building blocks for solution-processed photovoltaics, fluorescent probes with large two-photon absorption cross sections, and aggregates with large circular dichroism. Their optical properties are often rationalized in terms of phenomenological essential state models, considering the coupling of two zwitterionic excited states to a neutral ground state. As a result, optical transitions to the lowest S1 excited state are one-photon allowed, whereas the next higher S2 state can only be accessed by two-photon transitions. A further implication of these models is a substantial reduction of vibronic coupling to the ubiquitous high-frequency vinyl-stretching modes of organic materials. Here, we combine time-resolved vibrational spectroscopy, two-dimensional electronic spectroscopy, and quantum-chemical simulations to test and rationalize these predictions for nonaggregated molecules. We find small Huang-Rhys factors below 0.01 for the high-frequency, 1500 cm-1 modes in particular, as well as a noticeable reduction for those of lower frequency modes in general for the electronic S0 → S1 transition. The two-photon allowed state S2 is well separated energetically from S1 and has weak vibronic signatures as well. Thus, the resulting pronounced concentration of the oscillator strength in a narrow region relevant to the lowest electronic transition makes squaraines and their aggregates exceptionally interesting for strong and ultrastrong coupling of excitons to localized light modes in external resonators with chiral properties that can largely be controlled by the molecular architecture.

Single-Phase Grounding Fault Identification Based on Transition Conductance Tracking Method

The instability of single-phase grounding faults makes it difficult to track the fault development process accurately. In this paper, a transition conductance tracking method for single-phase grounding fault identification is established to perceive the health state of the distribution network. To solve the situation that the insulation parameters of the neutral ungrounded system are difficult to obtain, a phase-shift method is proposed to measure the insulation parameters accurately. Based on the measurement results of insulation parameters, a transition conductance tracking model is constructed to monitor the changes of transition conductance in real time. Since the transition conductance varies steadily, it can be used as an important parameter to evaluate the development of a single-phase grounding fault. The innovative tracking method is verified by the simulation model, and the error analysis shows that the tracking error of transition conductance is less than 9%. The simulation results demonstrate that the proposed method can track the development of grounding faults effectively and give a quick warning to the operator. The fault identification theory adopted in this paper is not limited by the neutral grounding mode and especially can be applied to situations where the neutral point parameters are not adjusted.

New Orleans Coffee in The Awakening: The Legacy of Rose Nicaud

New Orleans Coffee in <i>The Awakening</i>: The Legacy of Rose Nicaud

Research on Neutral Grounding Mode of Interconnecting Transformer in Renewable Energy Plant

With the increasing number of renewable energy plants connected to the power system, the gap grounding mode is often adopted by the high-voltage side neutral point of the interconnecting transformer of the renewable energy plants in order to improve the performance of the zero sequence protection. In practical engineering applications, the low-voltage side of the interconnecting transformer is connected with the renewable energy source (RES). It is necessary to analyze and evaluate the possible overvoltage at the high-voltage side neutral point when the power grid fails, as well as the damage brought to the stable operation of power grid. According to the operation characteristics of RES, the calculation method of neutral point overvoltage is proposed and the influence of different types of RES on neutral point overvoltage is analyzed when a single-phase grounding fault or a single-phase break-line fault (incomplete phase operation state) occurs in the power grid. Then the suggestions to prevent neutral overvoltage are proposed. The correctness of correlation analysis is verified by digital simulation and the conclusion can provide an important reference for the reasonable choice of the neutral grounding mode of the interconnecting transformer in renewable energy plant.

Regarding the Ruins: Dehousing and the Places Where Nothing Remains

This paper seeks to reframe the way we think about the rise of “dehousing” (Hulchanski et al., 2009, p. 3) in Toronto. Outsourced private security and militaristic, colonial policing by the state (Kanji &amp; Withers, 2021) displace people from warm air vents, tiny homes, tarps, tents, and other secluded places of refuge. Rather than see empty public space or fenced off parks as neutral ground amidst a housing crisis, I propose that these sites constitute a “ruin.” How might the ruins bear witness to the violence of dehousing? I frame my analysis through Crane’s premise (2021) that Nothing must be seen as a Something. She reveals how photography can help us in the documentation of Nothing (Crane, 2021). With the help of photographs, this paper attempts to animate the pedagogical witness of the places where Nothing remains. Rather than being conceived as a natural result of some “generic human tendency” (Crane, 2021, p. 121), ruins can be understood as part of presently existing unjust systems that must be changed. The “ruins of dehousing” turn us toward histories of colonial displacement, our relationship to public space, and our obligation to become conscious of Nothing.

A Novel Neutral Point-Based Active EMI Filter for Common Mode Noise Attenuation

This paper proposed a new configuration of neutral point based common mode (CM) active EMI filter (NP-CM-AEF). It is achieved by setting the reference of filtering system to the neutral point of equipment under test (EUT). Therefore, CM noise could be sensed across neutral point and ground. Meanwhile, compensation signal could be built by op-amp and re-injected to cancel the initial CM noise. The main advantage of the proposed NP-CM-AEF lies in that no more noise separation such as bulky passive CM transformer is needed to get pure CM noise. The whole filter becomes smaller, lighter and more compact compared with traditional CM AEF. Working principle is analyzed in details and hardware experimental tests are also performed. It shows that the proposed NP-CM-AEF has a good attenuation to CM noise and total size is pretty tiny.

Study of Iran–Saudi Arabia Sports Relations

Political tensions and conflicts have been accompanying modern sports for a long time. The objective of this study was to determine the political reasons for not hosting football matches between Iranian and Saudi football teams. To address the research objective, a mixed-method approach was used. First, in the qualitative part, the political reasons for not hosting the matches identified through the content analysis and interviews were reviewed and evaluated by Delphi Group (25 people) in the second and third stages. Secondly, in the qualitative section of the study, the questionnaire was also used to rank the reasons. The research findings showed that tensions between Tehran and Riyadh increased after the Saudi Embassy attack in Tehran and Mashhad (January 2016) and the execution of Sheikh Nimr, a Shia sheikh opposed to the Saudi government. Saudi Arabia has requested that the Asian Champions League matches against Iranian opponents be held on neutral grounds in order to ensure the safety of its players. It is therefore recommended that sports managers and politicians in Iran reduce the political tensions between the two countries. In addition, they need to strive toward creating peace, friendship, and security between the two countries.

A Hybrid Flexible Neutral Grounding Mode for Large Generators

Single-phase ground faults frequently occur at the generator stator windings. To realize reliable arc suppression, a dual-frequency active arc-suppression strategy has been widely considered. However, the existing method needs an inverter with large capacity, which is large in volume and high in cost, causing limited engineering application prospects. To reduce the capacity, a novel hybrid flexible neutral grounding method for large generators is proposed in this paper. It combines the dual-frequency active arc-suppression strategy with the arc-suppression coil-grounding mode. Thus, most of the fundamental components in the fault current are compensated by the arc-suppression coil, and the rest are compensated by the active arc-suppression device. The capacity of the inverter can be greatly reduced under the premise of reliably realizing arc suppression. To identify transient and permanent ground faults after arc suppression, the phase-angle relation between the third-harmonic voltage and current variation at the generator neutral point is used to form the fault-type identification criterion. The third-harmonic quantities can avoid the blind area at the neutral point caused by fundamental quantities. Simulation and experimental test results verify the effectiveness of the proposed method.

An Innovative Shielding Strategy for Stray Loss Reduction of Neutral Grounding Reactor

Leakage fluxes formed by power equipment are one of the serious concerns of the electricity industry. Stray losses, which are a consequence of leakage fluxes, can lead to thermal stresses in metallic parts and dramatically reduce the life of the equipment. To alleviate this obstacle, this article aims to deploy a new approach to mitigate the stray losses in structural parts. This method is based on electric and magnetic shielding to deviate or bypass the stray fluxes and abstain from hot spots. Computation of stray losses inside the shields and other metallic structures is conducted using 3-D finite element analysis (FEA). To determine the dimensions of shields, various contingency simulations are implemented. A 0.51 MVAr, air-core, oil-immersed neutral grounding reactor (NGR) is considered as a case study to verify the effectiveness of the presented method. The performance of the suggested shield arrangement has been experimentally investigated, and the obtained results present an indication of a best-suited design with respect to performance and size.

Electron-impact ionization cross sections of small molecules containing Fe and Cr ∗ ∗ This work is dedicated to Enrico Clementi who pioneered the interdisciplinary use of quantum chemistry and computational modelling.

We present the electron-impact ionization cross sections (EICSs) of iron and chromium hydrides, nitrides, and oxides. The motivation of this work stems from the fact that chemical sputtering from a steel surface exposed to a hot plasma can create these molecules which in turn influence the composition and energy balance of the plasma. The latter influence is quantified by the EICS which we derive by using two semi-empirical methods which can be employed in the relevant energy range of 10–1000 eV. They are important molecular properties for plasma- and materials science. We discuss the foundations of the methods and present the cross sections of the high- and low-spin states of the species in their neutral ground states and of their cations.

Study on Dynamic Characteristics of Single-Phase Grounding Fault of 1000 MW Hydro Generator under Different Grounding Modes

The continuous operation of 1000 MW large hydro generators in China is of great value to the implementation of “double carbon strategy” and power grid safety. However, with the continuous increase of single unit capacity of the hydro generator, the problems of unit fault grounding current and neutral point voltage drift become more and more prominent, and the traditional analysis methods cannot accurately obtain the fault dynamic data. Therefore, starting from the neutral point grounding mode of the large hydro generator, taking a 1000 MW hydro generator as the research object, this paper establishes the single-phase grounding fault model under the condition of three-phase parameter asymmetry of stator winding and analyzes the dynamic characteristics of fault current, transient overvoltage, and neutral point voltage drift under different grounding modes by using transient analysis method; the influence of frequency offset on neutral voltage drift and the dynamic characteristics of single-phase grounding fault of the large hydro generator under different grounding modes are also obtained. Finally, according to the analysis results, the selection and optimization method of neutral grounding parameters are proposed, which provides a reference for the selection of neutral grounding mode and the research of protection strategy of the large hydro generator.

Drastic effects of an inert Pt wire on the redox behavior of the Belousov-Zhabotinsky reaction.

This research investigated responses of the Belousov-Zhabotinsky (BZ) reaction to the presence of a chemically inert Pt wire in solution. Experiments showed that connecting the Pt wire to a neutral ground caused a spontaneous drastic shift in the redox potential and might even induce complex behavior. Characterizations using an unstirred ferriin solution demonstrated the formation of a red colored propagating front at the grounded Pt wire, suggesting the reduction of ferriin to ferroin. Measurements with different combinations of electrodes in both stirred and reaction-diffusion media further confirmed the reduction of BZ metal catalysts at the Pt wire and the accompanying oxidation reaction at the reference electrode. The observed drastic change in redox potential and oscillation waveform can be understood based on the passive reduction reaction at the indicator electrode that is connected to the reference electrode through a potential meter. The obtained influence can be further manipulated by adding a resistor between the Pt wire and the neutral ground, making this convenient perturbation method attractive for the study of redox chemical reaction dynamics.