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Related Research On High Voltage Corona Rings:
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ABSTRACT: The three-dimensional finite element method is used to calculate the electric field of insulator strings for ±800 kV UHV DC transmission lines. After the comparison of electric field distribution and voltage distribution with different ring diameter, tube diameter and shielding depth, the dimension and position of grading ring is recommended. The ball-gap method is used to measure the voltage distribution of insulator strings for ±800 kV UHV DC transmission lines. Test results are consistent with calculation results. Findings of this paper are important for the grading ring configuration of ±800 kV UHV DC transmission lines.
KEY WORDS: electric field; finite element method; grading ring; insulator strings; optimization; UHV transmission lines.
ABSTRACT: In order to serve reasonable arrangement forms of grading rings for the tension composite insulator string of ±800 kV DC power transmission, and with the domain decomposition method to decompose the whole 3D electric field into several limited parts, this paper adopts the finite element method to calculate the electric field distribution around tension string with two composite insulators in parallel. A 3D model of ±800 kV DC power transmission consisting of tower configuration, bundled conductors and tension insulator string is established based on ANSOFT software, and the influence of the ring radius, ring tube radius and the ring position of the grading ring on the string’s electric field distribution is researched, resulting in an optimum scheme for the grading ring structure. The calculation results of the finite element method show that with the designed grading ring in installation, the electric field intensity around the sheath, metal fitting and the grading ring are controlled satisfactorily.
KEY WORDS: UHVDC power transmission; tension insulator string; composite insulator; arrangement form; grading ring; electric field intensity
Abstract: With mass application of shielding ring basin-type insulator and constant miniaturization of equipment size, utilization of gas insulated metal-enclosed switchgear partial discharge ultra-high frequency sensor is greatly restricted and PD UHF detection is becoming difficult day by day. Aiming at above problems, regarding basin-type insulator grading ring as UHF aerial, relationship between loop aerial and factors such as PD apparent discharge magnitude, sensor position and grounding mode was tested. Meanwhile, frequency response characteristics of various UHF sensors were compared and analyzed. It was considered that GIS basin-type insulator grading ring was provided with good UHF receiving characteristic and was applicable for GIS PD test as UHF aerial.
Abstract: SF6 gas insulated metal enclosed switchgear widely applies shrinkage fit Corona Ring, match dimension of this type of Corona Ring and conductor is interference fit, by utilizing thermal expansion property of the material, expand match dimension of the Corona Ring via heating so that the dimension of Corona Ring and conductor coordinates into clearance fit. After the assembly, Corona Ring is cooled off and shrink to the dimension before expansion, connection between conductor and Corona Ring is tighter. Proper heating temperature is the guarantee of assembly clearance. Currently applied heating temperature causes undersize assembly clearance, which leads to the problem of incomplete installation of Corona Ring, causing high rate of rework and scrapping. This article defines appropriate heating temperature by researching and testing heating temperature of aluminum Corona Ring for shrinkage fit of SF6 switchgear, solves the problem during manufacture and installation.
Key words: Corona Ring, heating temperature, expansion, dimension fit
Abstract: High voltage capacitive voltage transformer grading ring plays a key role in improving electric field distribution and reducing maximum electric field strength. The study conducted grading ring optimization design by testing 500kV capacitive voltage transformer, maximum electric field strength of the equipment setting and asymmetric coefficient are selected as objective function; grading ring dimension and location as optimization variables. Optimization design is performed applying simulated annealing optimization strategy to come up with optimal dimension and installation location.
Key words: Capacitive voltage transformer; Optimization design; Simulated annealing method; Grading ring