A5019725786- Power Transformer Diagnostics and Insulation
- High voltage insulation and dielectric phenomena
- Metallurgical Processes and Thermodynamics
- Nanofluid Flow and Heat Transfer
- Heat Transfer Mechanisms
- Power Quality and Harmonics
- Thermal Analysis in Power Transmission
- Fire dynamics and safety research
- Radiative Heat Transfer Studies
- Magnetic Properties and Applications
- Advanced Cellulose Research Studies
- Elevator Systems and Control
- Magneto-Optical Properties and Applications
- Lightning and Electromagnetic Phenomena
- Vacuum and Plasma Arcs
- Fire Detection and Safety Systems
- Fluid Dynamics and Vibration Analysis
- Vibration and Dynamic Analysis
- Advanced Fiber Optic Sensors
- Fluid Dynamics and Thin Films
- Heat Transfer and Optimization
- Solar Thermal and Photovoltaic Systems
- Corrosion Behavior and Inhibition
- Semiconductor Lasers and Optical Devices
- Heat Transfer and Boiling Studies
BGT Materials (United Kingdom)
2019-2024
University of Manchester
2016-2019
Mineral oil is traditionally used in liquid immersed transformers to act as a coolant, an information carrier, and electrical insulator. Emerging alternative transformer liquids provide advantages, such improved fire safety better biodegradability, which operators would like utilize. In this paper, experimental study conducted compare the thermal performance of mineral hydrocarbon oil, gas-to-liquid synthetic ester coolants zig-zag disc type winding model. Comparisons are made under directed...
The thermal design of a power transformer determines its lifetime and loading capability, so correct modelling liquid flow temperature distributions in the winding is vital importance. Existing standards widely used simple calculation models can seriously under/overestimate hotspot temperatures under certain circumstances. In this paper, physical model representing disc-type forced directed cooling mode are investigated experimentally using Particle Image Velocimetry (PIV) measurement system...
The liquid flow and temperature distributions in oil natural (ON) cooled power transformer windings are of great importance for thermal design, rating life estimation ON transformers. In this paper, both experimental numerical investigations a disc-type winding model conducted. influences representative operating conditions on studied using Particle Image Velocimetry (PIV) measuring systems. Reverse flows consequential localised overheating at the top part passes recorded experiments. 2D 3D...
Retro-filling transformers with ester fluids have been increasingly practiced. Transformers may be retrofilled at different service years. In this paper, the ageing behaviour of cellulose insulation years (with conditions paper insulation) are studied. Since temperature rise after retrofill due to high viscosity liquids, a increase 10 °C and 20 in cellulose-liquid systems is considered. The degree polymerization (DP) moisture both liquid measured before retrofilling. measurements used for...
Oil-flow distribution in the winding has a direct impact on cooling performance. In addition, static pressure drop over determines oil split among windings connected hydraulically parallel. this paper, experimental verifications are provided to support computational fluid dynamics (CFD) simulations for disc-type oil-forced and directed (OD) modes. models measured using particle image velocimetry system differential instrument, respectively. Dimensional analysis is adopted analyze...
Ageing of paper insulation within oil immersed power transformers is the determining factor for transformer expected life. A thermal diagram as shown in IEC 60076-2:2011 standard specified a hot spot method to estimate temperature based on heat run test data. The split into Q factor, which depends loss distribution winding, and an S flow winding cooling ducts. In this paper, experiment conducted disc type model study under fixed geometries subjected wide range inlet rates uniform or...
Since being introduced 40 years ago, synthetic esters have become established as an alternative option to mineral oil in locations where enhanced fire protection measures are required. In this paper, repeatability of point and flash measurement investigated for unused ester mixtures after a retrofilling scenario. This study found the contamination can reduce mixture. It was that there across over from K classification O occurs at 3.5% ester. also noted is more sensitive comparison point. To...
Oil immersed power transformers have complex structures for which electrical, mechanical and thermal considerations to be taken into account during design. To produce a reliable transformer, the profile in terms of temperature windings is interest because ageing transformer its constituents mainly affected by operating temperature. The not uniform within winding uneven loss distribution flow coolant structure. Hot Spot Temperature (HST) defined as hottest strongly affects oil paper...
Particle image velocimetry is used to not only measure oil flow velocity but also reveal reversal and recirculation phenomena within radial cooling ducts of disc type transformer windings.
The lifetime and reliability of power transformers are primarily dependent on the hot-spot temperature in windings, as is most important factor determining insulation degradation rate. Key to removing heat from transformer radiator which must be carefully designed keep temperatures within limits under all operating conditions whilst minimizing size, weight cost. This paper compares analytical method used predict performance with computational fluid dynamics (CFD) models terms dissipation. It...
Bubble formation in transformers could result severe consequences leading to power outages and huge financial losses. There is an increased risk of bubble the future due increasing load demand much higher loading fluctuations. The process transformer insulation has been studied for decades water content paper addressed as most influential impact parameter. However, results from common insulating material combination Kraft mineral oil vary widely a meaningful comparison other parameters or...
The assessment presented indicates ongoing operation of transformers filled with synthetic ester after many years in service.
Synthetic esters have been used in transformers since the 1970s. They are known for being fire-safe, environmentally friendly dielectric liquids and can extend transformer's life. In addition, they high oxidation stability a low pour point, maintenance requirements like mineral oil hence, simplifying their adoption. Although experience has grown use of synthetic ester liquid, there is still need to understand performance liquid in-service transformers. This paper features data from 10 $11...
In this paper, an introduction is presented in terms of key benefits and in-service practices for condition assessment transformers filled with synthetic esters contrast mineral oil. The results a survey 12 ester are discussed.
In this article, the author discusses reproducibility of fire and flash point measurements unused liquids. The results are also presented following laboratory-based aging studies, either under sealed or partially open conditions.
Particle image velocimetry is used to not only measure oil flow velocity but also reveal reversal
One of the most convenient methods to estimate condition transformer solid insulation is measure byproducts in oil which generate from degradation. Furanic compounds and carbon oxides have been commonly measured by-products. However, alcohol based by-products such as methanol ethanol emerged new ageing indicators. The measurement may be used a complementary gain more confidence assessment insulation. In this paper applicability indicator for retrofilled transformers investigated....
The insulation lifetime of power transformers is primarily dependent on the hot-spot temperature (HST) transformers, as HST most important factor determining degradation rate. To control a liquid-immersed transformer, an insulating liquid used to transfer heat generated from active part surrounding ambient environment through radiators. Therefore, understanding thermal performance radiators for transformer design. In this paper, analytical method was proposed determine total dissipation and...
The increasing fire safety and environmental concerns have significantly increased the retrofilling of large number indoor distribution transformers. However, effects winding geometric parameters on hot spot temperature retrofilled transformer not been explored thoroughly. In this paper, a parametric sweep analysis is performed to investigate layered transformer. investigation carried out using same geometry filled with mineral oil natural ester liquid. Firstly, temperatures are determined...