Negative-sequence Network
Negative-sequence Network - Related Videos
01:24
Sequence Networks of Rotating Machines
0 Views •
2024
A Y-connected synchronous generator, grounded through a neutral impedance, is designed to produce balanced internal phase voltages with only positive-sequence components. The generator's sequence networks include a source voltage that is exclusively in the positive-sequence network. The sequence components of line-to-ground voltages at the generator terminals illustrate this configuration. Zero-sequence current induces a voltage drop across the generator's neutral impedance and other...
08:19
Generating Transposon Insertion Libraries in Gram-Negative Bacteria for High-Throughput Sequencing
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We describe a method to generate saturating transposon mutant libraries in Gram-negative bacteria and subsequent preparation of DNA amplicon libraries for high-throughput sequencing. As an example, we focus on the ESKAPE pathogen, Acinetobacter baumannii, but this protocol is amenable to a wide range of Gram-negative organisms.
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Protein Networks
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An organism can have thousands of different proteins, and these proteins must cooperate to ensure the health of an organism. Proteins bind to other proteins and form complexes to carry out their functions. Many proteins interact with multiple other proteins creating a complex network of protein interactions. These interactions can be represented through maps depicting protein-protein interaction networks, represented as nodes and edges. Nodes are circles that are representative of a protein,...
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Fluorescence-Activated Nuclei Negative Sorting of Neurons Combined with Single Nuclei RNA Sequencing to Study the Hippocampal Neurogenic Niche
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Presented here is a method to sequence single nuclei isolated from the mouse dentate gyrus that excludes most neurons through fluorescence-activated nuclei (FAN)-sorting. This approach generates high-quality expression profiles and facilitates the study of most other cell types represented in the niche, including scarce populations such as neural stem cells.
01:23
Negative Regulator Molecules
0 Views •
2019
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria. Three of the best-understood negative regulators are p53, p21, and retinoblastoma protein (Rb). The regulatory roles of each of these proteins were discovered after faulty copies were found in cells with uncontrolled replication (i.e., cancer). These...
FAQs
The reverse phase order creates a magnetic field that rotates opposite to the normal positive-sequence field. In rotating machines, this opposing field can contribute to overheating and torque disturbances, making the negative-sequence component more than a mathematical description. Including it in analysis helps engineers assess how unbalanced conditions may affect machine behavior and equipment safety.
Negative-sequence impedance determines how the component travels through each modeled element. Engineers represent generators, transformers, lines, and loads with their respective negative-sequence impedances, then use those paths to evaluate resulting component currents and voltages. Differences among element impedances influence the calculated network response, supporting more realistic fault and equipment-impact assessments.
Unlike the positive sequence, which follows the normal phase order, the negative sequence has the opposite order and produces a reverse-rotating field in rotating machines. This distinction matters because an unbalanced system can contain sequence components with different physical effects. Separating the two sequences lets engineers examine the adverse contribution without treating all three-phase behavior as balanced.
The negative-sequence network is connected with other sequence networks when the fault produces an asymmetrical three-phase condition. Line-to-line and double-line-to-ground faults are examples that require this combined representation. The resulting interconnected model describes how the sequence components participate in the fault, allowing engineers to evaluate fault currents and related protection behavior.
Engineers first represent the relevant generators, transformers, lines, and loads with negative-sequence impedances. They then connect this network to the other sequence networks required by the asymmetrical fault under study. Analysis of the connected model provides the negative-sequence contribution and supports evaluation of fault currents, machine effects, and relay operation.
The analysis can indicate how negative-sequence components propagate through the modeled power system and how they contribute to fault conditions. Its results help predict fault currents, overheating, torque disturbances, and relay operation. These outcomes give engineers information for assessing equipment response and determining whether protection behavior is consistent with reliable system operation.
Protection engineers use the analysis to evaluate relay operation under asymmetrical faults, while equipment designers use it to consider the effects of reverse-rotating fields and unbalanced currents. The same results support safer equipment design and more reliable power-system operation by linking sequence-network behavior with overheating, torque disturbances, and fault-current expectations.