Explore the vast range of titles available.

Electrical grounding is an indispensable part of the power system network. The grounding system is mainly affected by grounding resistance and the nature of the soil. High ground resistance produces the phenomenon of soil ionization, surface arching, and back flashover. A conventional grounding system requires the deep digging of electrodes, thus creating maintenance difficulties. This research work focuses on the safe operation of an electric power system from external and internal impulses arising due to lightning strikes or short circuits. The study proposes an application of mineral samples as grounding materials, and bentonite is used as backfilling material in portable grounding systems. A detailed experimental analysis was conducted under controlled conditions to evaluate the performance of selected materials in high-resistance soil. The problem of a deeply driven electrode is addressed by designing the portable grounding system. The study results demonstrate that the proposed portable grounding system could be installed in troubled environments such as forests, deserts, and rocky terrains. To measure the breakdown voltages of the proposed samples, X-ray Diffraction (XRD) analysis and other laboratory tests were conducted. The electric field intensities are extracted through Finite Element Analysis (FEA). The experimental and simulation findings show the expected performance of mineral samples under various operating conditions. The findings of this study can guide the practitioners for safe and efficient operations of portable electrical grounding systems.

In the resonant grounding system, the accurate judgment of arc-extinction time has guiding significance for the line selection of grounding fault, the evaluation of the arc suppression effect, and the extraction and utilization of transient information after arc extinction. Aiming at the single-phase grounding fault of resonant grounding system, this paper analyzes the frequence change characteristics before and after arc extinction. It is found that the frequence of zero-sequence electrical quantity before arc extinction is power frequence, and it changes after arc extinction. It is used to construct single-frequence methods and dual-frequence methods for judging arc-extinction time. As a tool for dynamic frequence measurement, SOGI-FLL is utilized to realize the engineering application of the method for judging arc-extinction time. The method’s accuracy is proved by Matlab/Simulink simulation and field test.

A grounding system is crucial for safeguarding electrical systems, ensuring they function effectively under both normal and fault conditions. This research investigates the effectiveness of enhancement materials, specifically wood ash and sodium chloride (NaCl), compared to conventional bentonite using fall-of-potrnial method. The study evaluates the suitability, advantages, and limitations of these materials. Experiments involved filling holes with 10 kg of bentonite, wood ash, and various mixtures of wood ash and NaCl (7 kg wood ash + 3 kg NaCl, 8 kg wood ash + 2 kg NaCl, 9 kg wood ash + 1 kg NaCl), using a reference hole without enhancement material. Copper earth rods was employed over 12 weeks. Results showed that the 7 kg wood ash + 3 kg NaCl mixture performed similarly to 10 kg of bentonite, achieving a 62% and 62.7% reduction in ground resistance, respectively. This indicates that a carefully mixed combination of NaCl and wood ash can be a viable alternative to bentonite. The data indicates that resistance generally decreases with higher rainfall and is lower for systems using NaCl mixtures, particularly the one with the highest NaCl content.

The true-type test platform is widely used to evaluate whether relay protection devices are effective and accurate in handling simulated single-phase ground faults. However, since the system scale needs to be increased or decreased by switching capacitors connected in parallel on the feeder line, uncontrolled switching of capacitors may cause the magnetic latching relay to burn out. This article studies the transient process of switching and analyzes the reasons for relay burnout. Switching capacitors at non-current zero-crossing points will produce a large inrush overvoltage, which will burn the relay. To solve this problem, a switching control strategy based on delay compensation is proposed to ensure no inrush overvoltage during the switching process, improve the service life of the magnetic latching relay, and improve the safety of the power capacitor.

This paper presents a method to detect the different types of defects in cross connected cable sheath in a flat 500kV three leaf high voltage cable system with sheath current as input data. Three different defects are analyzed: the loss of electrical continuity of grounding, the short circuit between metal sheath of cable joint segment and the immersion of junction box. The model of cable system is simulated by theoretical analysis and ATP software. The results obtained by these two methods have achieved good consistency.

A BC-phase short-circuit grounding fault occurred on the 35kV Xiaai line at the 110kV Xiajiaka substation in a specific power grid. This fault caused an incorrect operation of the differential instantaneous protection of the 110kV Xiajiaka #1 transformer. Theoretical analysis suggests that this maloperation may have been caused by the simultaneous action of the line protection during the fault, which led to the saturation of the protection CT on the medium-voltage side of the transformer. To thoroughly investigate the cause of the incident, a detailed electromagnetic transient simulation model was developed using PSCAD. The simulation results revealed that the maloperation of the #1 transformer differential protection was primarily due to two factors: the differing voltage states at the time of the two fault occurrences and the remanence in the CT. The overlap of the line protection action with the fault triggered the saturation of the medium-voltage side CT, leading to the maloperation of the differential protection. These simulation results, based on a realistic grid fault scenario, are crucial for analyzing similar incidents and enhancing the safe and reliable operation of power grids.

The substation grounding grid has been in the open air for a long time, and it is prone to problems such as fracture and desoldering, which leads to a decrease in grounding capacity and becomes a threatening factor affecting the normal operation of the substation. Based on the principle of state response, this paper demonstrates the feasibility of using impulse current to evaluate the defects of the grounding grid, constructs an impulse impedance test system, and conducts defect detection tests on 8 m×8 m (2 m equal intervals) and 28 m×25 m (unequal interval) grounding grids in the laboratory. It analyzes the measured impulse impedance and amplitude-frequency response curves. After testing the grounding grid of a substation of a power grid company, the test results show that the test system based on the principle of state response is effective. The response voltage waveform and amplitude-frequency response curve when detecting the conductor fracture of the grounding grid are different from the waveform curve when there is no defect. It can be applied to the defect evaluation of the grounding grid and has a certain reference value for practical engineering applications.

In recent years, single-stage boost inverters with common ground have shaped the inverter markets due to the many benefits associated with these types of inverters, including their high efficiency, single control scheme, and integrated boost converter. A new boost-type inverter that utilizes a common ground and has fewer switches is proposed in this article. It uses two DC-link capacitors connected in parallel and discharged independently while being charged simultaneously. The voltage for the positive and negative half cycles is supplied by the capacitors located at the top and bottom of the circuit, respectively. In addition, a comparison is made between the proposed circuit and the boost inverter already in use in the literature. Using PLECS as the computing software, the efficiencies are determined depending on the various percentages of output power. To validate performance, present experimental data, and attain the best possible efficiency of 97%, a 400 W prototype model is constructed. In addition to that, the breakdown of the costs is shown.

The grounding device is indispensable and vital to transmission lines, and its corrosion is a problem that cannot be ignored. The corrosion of grounding materials could both shorten its lifespan and cause growth in the earth resistance of the grounding grid, reducing the scattering capacity of the earthing electrode. When the lightning strikes the transmission line or transmission tower, the lightning current cannot be discharged to the ground promptly, which endangers the safety of construction and maintenance personnel around the tower and damages the auxiliary equipment of nearby substations. This paper investigates the severe corrosion issue of flat ground steal in a 220 kV transmission tower with experimental methods including macro and microstructure detection, chemical component assay, erosion form, energy distribution, zinc-plating-coat thickness measurement, sediment physicochemical nature assessment, as well as additional experimental ways to investigate causes of corrosion. As the findings suggested, the incorrect choice of anti-corrosion methods for ground flat steel, together with the highly alkaline and salty service environment, may be the prime cause of its corrosion fracture. Based on the experimental results, it is suggested that cold zinc plating ground flat steel should be avoided utilized for electrical system infrastructure and that the imposed monitoring of earthing flat steel for transmission towers is needed within the Yellow River rinse region.

Neuropixels are silicon-based electrophysiology-recording probes with high channel count and recording-site density. These probes offer a turnkey platform for measuring neural activity with single-cell resolution and at a scale that is beyond the capabilities of current clinically approved devices. Our team demonstrated the first-in-human use of these probes during resection surgery for epilepsy or tumors and deep brain stimulation electrode placement in patients with Parkinson’s disease. Here, we provide a better understanding of the capabilities and challenges of using Neuropixels as a research tool to study human neurophysiology, with the hope that this information may inform future efforts toward regulatory approval of Neuropixels probes as research devices. In perioperative procedures, the major concerns are the initial sterility of the device, maintaining a sterile field during surgery, having multiple referencing and grounding schemes available to de-noise recordings (if necessary), protecting the silicon probe from accidental contact before insertion and obtaining high-quality action potential and local field potential recordings. The research team ensures that the device is fully operational while coordinating with the surgical team to remove sources of electrical noise that could otherwise substantially affect the signals recorded by the sensitive hardware. Prior preparation using the equipment and training in human clinical research and working in operating rooms maximize effective communication within and between the teams, ensuring high recording quality and minimizing the time added to the surgery. The perioperative procedure requires ~4 h, and the entire protocol requires multiple weeks. Key points This Protocol describes the structural reinforcement of Neuropixels 1.0-S, ensuring their correct insertion into the human cortex; the extensive perioperative procedures required to maintain sterile conditions; and coordination with the surgical team. Neuropixels 1.0-S enables the recording of spiking activity from up to hundreds of cortical neurons, a feat currently not possible with single-neuron resolution devices such as microwire bundles, laminar microelectrode arrays, microelectrode contacts and the Utah array. This Protocol documents the extensive preparation required to adopt Neuropixels probes for use in patients for recording spiking activity from up to hundreds of cortical neurons and associating it with local field potentials.