Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 53 for “"GIC"”.
-
Power transformer magnetization under GIC/GMD
Geomagnetically induced currents (GIC) could saturate a transformer core. Two significant effects are the abnormal stray flux in transformers and extremely large harmonic contents in excitation currents, which can lead to serious equipment damage and power system misoperation. Such incidents have …
-
Synchronous generator and excitation system response to GIC
… The resultant Geomagnetically Induced Currents (GIC) lead to periodic part wave saturation of transformers, harmonic pollution, increased non-active power demand and potential voltage collapse. While most power system studies have focussed on the transformer's response to GIC, there has been very …
-
Ensemble estimation and analysis of network parameters: strengthening the GIC modelling chain
… of Network Parameters - Strengthening the GIC Modelling Chain - Abstract Large grounded conducting networks on Earth's surface have long been known to be affected by solar activity and geomagnetic storms. Geomagnetically induced currents (GICs) in these quasiantennas are just one of the …
-
Geomagnetically induced currents (GIC) in large power systems including transformer time response
Geomagnetically induced currents (GIC) are the result of changing geomagnetic fields which are a consequence of a geomagnetic disturbance (GMD). The flow of GIC through transmission lines and transformers across the power network could have severe consequences, if the magnitudes of the GIC are high …
-
Effects of GIC Neutral Blocking Devices (NBDs) on transmission lines protection performance and potential for resonance
Geomagnetic Induced Current (GIC) is a quasi-DC current that may have adverse effects on power system reliability. Several GIC blocking device (NBDs) designs are available, but the majority is capacitive. Concerns have arisen about the effects of NBDs on distance-protection relays. To investigate …
-
Duality derived topological model of single phase four limb transformers for GIC and DC bias studies
Geomagnetic disturbances brought about by solar activity cause geo-electric fields in the Earth that drive geomagnetically induced currents through the earthed neutrals of transformers and through power transmission networks. The flow of these currents causes the magnetic cores of transformers to …
-
Development of a finite element matrix (fem)three-phase three-limb transformer model for Geomagnetically Induced Currents (GIC) experiments
Geomagnetically Induced Currents (GIC) have been a growing concern within power system operators and researchers as they have been widely reported to lead to power system related issues and material damage to system components like power transformers. In power transformers, GIC impacts are …
-
Impact of Geomagnetically Induced Currents on Power Transformers
… the impact of Geomagnetically Induced Current (GIC) on power transformers in electrical power systems. A simulator to calculate the flows of GIC in an electrical power network, based on an assumed or measured induced geoelectric potential is proposed. This simulator includes all needed mapping …
-
Design of Low-Frequency acGIC Voltage Stability Laboratory Protocol
Geomagnetically Induced Currents (GICs) are formed as a direct consequence of space weather phenomena and have detrimental effects on power systems. GICs enter the power system through transformers' grounded neutrals, causing an array of problems ranging from transformer overheating to voltage …
-
Three-phase five limb transformer responses to geomagnetically induced currents
Geomagnetically induced currents (GIC) are quasi-DC currents that result from space weather events arising from the sun. The sun ejects hot plasma in a concept termed ‘coronal mass ejections' which is directed towards the earth. This plasma interferes with the magnetic field of the magnetosphere …
-
Transformer Thermal Assessment under Geomagnetically Induced Current Conditions
… such as Geomagnetically Induced Current (GIC). To fulfill this goal, it is necessary to perform several tasks in different fields, such as geometry and material modeling, electromagnetic studies, and investigation into computational fluid dynamic (CFD) analysis of transformers. First, the …
-
Magnetic properties of transition metal dichloride - graphite intercalation compounds
… dichloridegraphite intercalation compounds (GIC's) have been studied by neutron scattering and static magnetization measurements. Because of the large spatial anisotropy introduced by intercalation, the compounds studied represent good approximations to magnetic systems in two dimensions. …
-
Geomagnetically induced current sensitivity to assumed substation grounding resistances in the power system
… currents called geomagnetically induced current (GIC). Protection against GMD therefore necessitates the accurate estimation of GICs. GICs estimation is challenging because it depends on substation grounding resistances, which 1) depend more on the local soil and earth conditions than the …
-
Optimal Mitigation of Geomagnetically Induced Current Effects in Power Systems Considering Transformer Thermal Limits
… give rise to geomagnetically induced currents (GIC) which have adverse effects on the national power grid and potentially damage transformers on the grid. GIC flowing along transmission lines and through the transformers in power systems can be attributed to problems ranging from overheating of …
-
Fluid and gas models in FLRW and almost FLRW universes
… thereof, leading to Gauge Invariant Covariant (GIC) perturbations of these fluid models. It is well known that kinetic theory provides a physically sound and consistent description of the matter and radiation in the universe, so a perturbative theory of gas models using kinetic theory would be …
-
Geomagnetically induced currents and their effect on power systems
… magnetic field. Geomagnetically induced current (GIC) then enters the power grid and causes unusual real and reactive power flows, voltage fluctuations, frequency shifts, undesired relay operations, high third-harmonic currents and telemetry and supervisory alarm failures. A storm on the order of …
-
Study of Power Transformer Abnormalities and IT Applications in Power Systems
… failures. Geomagnetically induced current (GIC) is another possible cause of transformer abnormality. A simplified method based on the equivalent magnetizing curve for transformers with different core design was developed and validated to estimate harmonic currents and MVar drawn by power …
-
Operational modelling of geomagnetic fields and geomagnetically induced currents
Geomagnetically induced currents (GICs) have long been known to affect power systems adversely. Modelling these GICs usually involves consideration of a chain of coupled systems. The scope of the modelling chain spans multiple disciplines, from solar physics through to geophysics and power …
-
Saturation Effects in 3p3L Power Transformers due to Geomagnetically Induced Currents
Geomagnetically induced currents (GIC's) caused by solar storms or other sources of dc excitation can impact the normal operation of power transformers in transmission networks. The impact is caused by the dc current introduced into the windings of a transformer energised with ac, which leads to a …
-
Evaluation of Shear Bond Strength of Two Resin-Modified Glass-Ionomer Cements
… of resin-modified glass-ionomer cement (Rm-GIC) to an exising powder-liquid formulation. The study will test the hypothesis that the new paste-paste formulation of Rm-GIC (Fuji-Cem ™, GC Corp, Tokyo, Japan) has the same bond strength as an existing popular powder-liquid formulation of Rm-GIC …
Page 1 of 3