Temperature State of the Electrical Insulation Layer of a Superconducting DC Cable with Double-Sided Cooling

2021 ◽  
pp. 71-85
Author(s):  
V.S. Zarubin ◽  
G.N. Kuvyrkin ◽  
I.Yu. Savelyeva
Keyword(s):  
Mathematical Model ◽  
Electrical Resistivity ◽  
Liquid Nitrogen ◽  
High Voltage ◽  
Electrical Insulation ◽  
Insulation Layer ◽  
Electrical Potentials ◽  
Annular Channels ◽  
Temperature State ◽  
Integral Relations

For the reliable operation of a high-voltage DC cable with high-temperature superconducting current-carrying conductors with a sufficiently high difference in electrical potentials, it is necessary to maintain a fixed temperature state not only of the conductors but also of other cable elements, including the electrical insulation layer. In this layer, despite the high electrical resistivity of its material, which can be polymer dielectrics, Joule heat is released. The purpose of this study was to build a mathematical model that describes the temperature state of an electrical insulation layer made in the form of a long hollow circular cylinder, on the surfaces of which a constant potential difference of the electric field is set. Within the study, we consider an alternative design of a cable with central and external annular channels for cooling liquid nitrogen. Using a mathematical model, we obtained integral relations that connect the parameters of the temperature state of this layer, the conditions of heat transfer on its surfaces, and the temperature-dependent coefficient of thermal conductivity and electrical resistivity of an electrical insulating material with a given difference in electrical potentials. A quantitative analysis of integral relations is carried out as applied to the layer of electrical insulation of the superconducting cable. The results of the analysis make it possible to assess the possibilities of using specific electrical insulating materials in cooled high-voltage DC cables under design, including superconducting cables cooled with liquid nitrogen

In-situ electrical-resistivity measurements in the high-voltage electron microscope

1978 ◽  
Vol 36 (1) ◽  
pp. 68-69
Author(s):  
W. E. King
Keyword(s):  
Electrical Resistivity ◽  
Electron Microscope ◽  
High Voltage ◽  
Resistivity Measurements ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Wide Range ◽  
Helium Gas

A side-entry type, helium-temperature specimen stage that has the capability of in-situ electrical-resistivity measurements has been designed and developed for use in the AEI-EM7 1200-kV electron microscope at Argonne National Laboratory. The electrical-resistivity measurements complement the high-voltage electron microscope (HVEM) to yield a unique opportunity to investigate defect production in metals by electron irradiation over a wide range of defect concentrations.A flow cryostat that uses helium gas as a coolant is employed to attain and maintain any specified temperature between 10 and 300 K. The helium gas coolant eliminates the vibrations that arise from boiling liquid helium and the temperature instabilities due to alternating heat-transfer mechanisms in the two-phase temperature regime (4.215 K). Figure 1 shows a schematic view of the liquid/gaseous helium transfer system. A liquid-gas mixture can be used for fast cooldown. The cold tip of the transfer tube is inserted coincident with the tilt axis of the specimen stage, and the end of the coolant flow tube is positioned without contact within the heat exchanger of the copper specimen block (Fig. 2).

scholarly journals A Review of Techniques for RSS-Based Radiometric Partial Discharge Localization

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 909
Author(s):  
David W. Upton ◽  
Keyur K. Mistry ◽  
Peter J. Mather ◽  
Zaharias D. Zaharis ◽  
Robert C. Atkinson ◽  
...  
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Partial Discharge ◽  
Specific Area ◽  
Electrical Insulation ◽  
Acoustic Detection ◽  
Advantages And Disadvantages ◽  
Initial Stage ◽  
Catastrophic Failures ◽  
Radiometric Detection

The lifespan assessment and maintenance planning of high-voltage power systems requires condition monitoring of all the operational equipment in a specific area. Electrical insulation of electrical apparatuses is prone to failure due to high electrical stresses, and thus it is a critical aspect that needs to be monitored. The ageing process of the electrical insulation in high voltage equipment may accelerate due to the occurrence of partial discharge (PD) that may in turn lead to catastrophic failures if the related defects are left untreated at an initial stage. Therefore, there is a requirement to monitor the PD levels so that an unexpected breakdown of high-voltage equipment is avoided. There are several ways of detecting PD, such as acoustic detection, optical detection, chemical detection, and radiometric detection. This paper focuses on reviewing techniques based on radiometric detection of PD, and more specifically, using received signal strength (RSS) for the localization of faults. This paper explores the advantages and disadvantages of radiometric techniques and presents an overview of a radiometric PD detection technique that uses a transistor reset integrator (TRI)-based wireless sensor network (WSN).

Inhibiting Effect of Nonlinear Shielding Layer on Electrical Tree Propagation inside Insulation Layer of High-Voltage Cable

2014 ◽  
Vol 989-994 ◽  
pp. 1273-1277
Author(s):  
Chang Ming Li ◽  
Bao Zhong Han ◽  
Long Zhao ◽  
Chun Peng Yin
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
High Voltage ◽  
Electric Field Distribution ◽  
Uniform Electric Field ◽  
Insulation Layer ◽  
Breakdown Time ◽  
Electrical Tree ◽  
Traditional Structure ◽  
Initiation And Propagation

Nonlinear insulated materials can uniform electric field distribution in non-uniform electric field. In order to inhibit the electric tree initiation and propagation inside high-voltage cross-linked polyethylene (XLPE) insulated cable, a kind of 220kV high-voltage XLPE insulated cable with new structure is designed by embedding nonlinear shielding layer into XLPE insulation layer of high-voltage cable with traditional structure in this study. Experimental and simulation results indicate that the nonlinear shielding layer can effectively inhibit electrical tree propagation inside the XLPE specimens, and obviously extend the breakdown time caused by electric tree propagation. When the electrical tree propagates into the nonlinear shielding layer sandwiched between insulation layers of cable, the electric field distribution near the tip of electrical tree is obviously improved. These findings prove the feasibility and the effectivity of inhibiting electrical tree propagation inside high-voltage cable by adding nonlinear shielding layer into the insulation layer.

STUDY OF THE DEPENDENCE OF HIGH Tc ON VARIOUS SINTERING TEMPERATURES FOR Bi-Pb-Sr-Ca-Cu-O SUPERCONDUCTORS

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1635-1638
Author(s):  
S.M. M.R. NAQVI ◽  
A.A. QIDWAI ◽  
S.M. ZIA-UL-HAQUE ◽  
FIROZ AHMAD ◽  
S.D.H. RIZVI ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Liquid Nitrogen ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Resistivity Measurements ◽  
Zero Resistance

Bi1.7-Pb0.3-Sr2-Ca2-Cu3-Ox superconducting samples were prepared at 855°C, 862 C, 870 C, and 882 C sintering temperatures respectively. All samples were sintered for 120 hours. The samples were then quenched in liquid nitrogen. The electrical resistivity measurements showed that the samples sintered at 870° C had the best Tc. For these samples the Tc onset was around 120 K and the zero resistance was obtained at 108 K. X-ray diffraction studies showed that the samples were multiphased.

Sign in / Sign up

Export Citation Format

Share Document