Dual-Temperature Evaluation of a High-Temperature Insulation System for Liquid-Immersed Transformer

Zhang, Xiaojing; Ren, Lu; Yu, Haichuan; Yang, Xu; Lei, Qi; Li, Xin; Han, Baojia

doi:10.3390/en11081957

Cited by 12 publications

(8 citation statements)

References 18 publications

(20 reference statements)

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“…Thermal properties are improved by reducing the thermal conductivity of the unit's liquid and solid dielectrics. The two most common types of solid dielectrics (paper insulation) for liquid immersed transformers are TUK and variations of Dupont's Nomex (910 or 410), which are documented as having at least 10 • C better thermal performance than the former [46][47][48][49].…”

Section: New Unit Design Changes-normal Operationsmentioning

confidence: 99%

Demand Side Management Effects on Substation Transformer Capacity Limits

2019

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In high penetrations, demand side management (DMS) applications augment a substation power transformer’s load profile, which can ultimately affect the unit’s capacity limits. Energy storage (ES) applications reduce the evening peaking demand, while time-of-use rates incentivize end-users to charge electric vehicles overnight. The daily load profile is further augmented by high penetrations of photovoltaic (PV) systems, which reduce the midday demand. The resulting load profile exhibits a more flattened characteristic when compared to the historical cyclic profile. Although the initial impact of PV and ES applications may reduce a unit’s peak demand, long-term system planning and emergency conditions may require operation near or above the nameplate rating. Researchers have already determined that a flattened load profile excessively ages a unit’s dielectrics more rapidly. The focus of this research was to identify an approach for establishing new transformer capacity limits for units serving flattened load profiles with a high harmonic content. The analysis utilizes IEEE standards C57.91 and C57.110 to develop an aging model of a 50 MVA SPX Waukesha transformer. The results establish a guideline for determining transformer capacity limits for normal operation, long-term emergency operation, and short-term emergency operation when serving systems with high penetrations of DSM applications.

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Section: New Unit Design Changes-normal Operationsmentioning

confidence: 99%

Demand Side Management Effects on Substation Transformer Capacity Limits

2019

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“…Based on the study, it was reported that the intensity of the discharge processes, comparing the same voltage levels, was mostly higher when streamers developed in ester liquids. Zhang et al [9] studied the performance of new alternative insulating oil/paper systems based on ester/Nomex, respectively, for high temperature applications, based on a typical loading curve on the China Southern Power Grid. Authors evaluated the physiochemical and mechanical properties along with the thermal index of the oil paper insulation system and reported that the considered new oil/paper insulation system is a promising one for high thermal applications compared to mineral oil/kraft paper insulation systems.…”

Section: A Review Of the Special Issuementioning

confidence: 99%

Engineering Dielectric Liquid Applications

Fofana

Rao

2018

Energies

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“…The moisture due to aging mechanism leads to reduced dielectric strength and increased viscosity especially for the aged oil. Hence, the electrical properties deteriorate; the breakdown voltage and the resistivity decrease, and the dielectric dissipation factor increase as reported by several researchers [13][14][15][16][17]. The degree of polymerization (DP) and tensile strength (TS) of paper are reduced and these precipitate the deterioration of the solid insulation.…”

Section: Introductionmentioning

confidence: 97%

The Correlation of Transformer Oil Electrical Properties with Water Content Using a Regression Approach

Abdi

Harid

Safiddine³

et al. 2021

Energies

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An experimental investigation is conducted to measure and correlate the impact of the water content on the electrical characteristics of the mineral oil for transformers, particularly the breakdown voltage, the resistivity, and the dielectric dissipation factor. Regression method is carried out to compare the results obtained through laboratory experiments with those predicted using an analytical model. A treatment to reduce water content in oil involving filtration, degassing and dehydration using a SESCO mobile station was applied to the new, regenerated, and used oil samples in service. The breakdown voltage, the resistivity, and the dielectric dissipation factor of the samples were measured. Regression analysis using an exponential model was applied to examine the samples electrical properties. The results show that, after treatment, the breakdown voltage and resistivity increase as the water content decreases, unlike the dielectric dissipation factor which exhibits a decreasing trend. This trend is found to be similar for the three oil samples: new, regenerated, and used. The results of the regression analysis give close agreement with the experimental results for all the samples and all studied characteristics. The model shows strong correlation with high coefficients (>90%).

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Dual-Temperature Evaluation of a High-Temperature Insulation System for Liquid-Immersed Transformer

Cited by 12 publications

References 18 publications

Demand Side Management Effects on Substation Transformer Capacity Limits

Demand Side Management Effects on Substation Transformer Capacity Limits

Engineering Dielectric Liquid Applications

The Correlation of Transformer Oil Electrical Properties with Water Content Using a Regression Approach

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