Properties Of Mineral Insulating Oils In Service
Properties of Mineral Insulating Oils in ServiceP. Wiklund1 and B. Pahlavanpour21-PhD, Nynas Co., Nynashamn, SwedenAbstract:The infrastructure of the electricity grid and super grid system in the hitherto industrialized world was to a large extentbuilt up in the decades following World War II with a peak in investments around 1960-1980. This means that theflotilla of power transformers is now starting to reach projected lifetime of around 40 years. During the last couple ofdecades there has also been an ongoing deregulation and privatization of electricity generation and distribution. Thishas led to higher utilization of existing equipment to deliver an ever increasing demand of power. The demand forplanned asset management, investments, reliability and availability of power delivery, has also increased. To ensure thataging equipment is working satisfactory and will do so for yet some time, interest in aging behavior of powerequipment has increased. Yet there is precious little basic information openly available on how the insulating materialsin transformers behave over longer periods of time. Such information is valuable both from the perspective oftransformer maintenance/asset management, and as background information to make informed choices on which type ofinsulating liquid to employ in new equipment.Journal of Iranian Association of Electrical and Electronics Engineers - Vol.7- No.2- Fall & Winter 2010Downloaded from jiaeee.com at 17:48 0330 on Sunday March 14th 20212- PhD, Nynas Co., Nynashamn, Swedenbruce.pahlavanpour@nynas.comAcceptance date: Mar. 5, 2011Corresponding author: B. PahlavanpourCorresponding Author’s Address: Nynas AB SE-149 82 Nynashamn, Sweden1389 ﭘﺎﺋﻴﺰ و زﻣﺴﺘﺎن - ﺷﻤﺎره دوم - ﺳﺎل ﻫﻔﺘﻢ - ﻣﺠﻠﻪ اﻧﺠﻤﻦ ﻣﻬﻨﺪﺳﻴﻦ ﺑﺮق و اﻟﻜﺘﺮوﻧﻴﻚ اﻳﺮان 65
In this study there is a total of 145 separate samplesfrom separate transformers (all samples appearedaround the same time for analysis), of which 114 areinhibited and 31 uninhibited. The inhibited oil samplescame from transformers in the Nordic region, whereasthe uninhibited samples come mainly form the MiddleEast. The transformers span a range of ages from onlya few years up to 45 years.The samples were analyzed for acidity, interfacialtension, dielectric loss (DDF) and peroxide content.The inhibited samples were also analyzed for inhibitorcontent.All of these parameters except peroxide content arestandard measurements, but little information exists onhow they relate to each other statistically. The peroxidemeasurements were performed according to a methodwe have developed. It should tell us more about theoxidation behavior and the efficiency of oxidationinhibitors.2. Monitoring and Maintenance ofInsulating Oils in ServiceThe insulating oil in a power transformer only accountfor about 5% of the initial cost of the complete system,but it is a very vital part both for the monitoring of thefunction of the transformer and the ultimate life timeunder which the investment cost should be regainedwith interest. A high quality insulating oil shouldideally not contribute to premature ageing of the nonreplaceable parts such as winding and solid insulation.Through DGA the oil also serves as an informationcarrier about what is going on inside the transformerconsequently DGA is used for transformer conditionmonitoring routinely (1).However, it is vital to ensure that aging of the oil is notexcessive and that it performs as it should (2). For thisreason there are guides to follow to check theperformance of the oil such as IEC 60422 and IEEEC57.106.3. IEC 60422 Oil Maintenance GuideIEC 60422 is a guide for the supervision andmaintenance of mineral insulating oil in electricalequipment. This standard is used worldwide and iscurrently under revision. The purpose of the revision ofthis standard is to bring it in line with current66methodology, best practice and compliance withrequirements and regulations affecting safety andenvironmental issues.Oxidation of the oil will occur in all equipment whereit is in contact with air. In such equipment, oxidationof the oil will occur gradually and naturally over manyyears.Oxidation is accelerated as operating temperatures ofthe oil increase. Oxidation can also be accelerated bythe presence of catalysts such as metals or metalliccompounds. The cumulative effects of the oil andwindings, and the oxidation of the oil increasecumulatively, leading to possible breakdown.Early warning of the onset of oil oxidation is providedby monitoring of the color and appearance of the oil,regular testing for acidity levels in the oil, monitoringmoisture levels in the oil and visual inspection duringmaintenance for signs of sludgy deposits on internalsurfaces of equipment.The tests for in-service oil are divided into threegroups. Group 1Minimum tests require to monitor theoil and to ensure that it is suitable for continuedservice.Group 2These are additional tests which maybe used to obtain further specific informationabout the quality of the oil and may be used toassist in the evaluation of the oil for continued use.Group 3These tests are used mainly todetermine the suitability of the oil for the type ofequipment in use and to ensure compliance withenvironmental and operational considerations.Individual tests for each group are listed in Table 1. Itshould be noted if test results for Group 1 are notexceeding recommended action limits, usually nofurther tests are considered necessary until the nextregular period for inspection.Although a large number of tests can be applied tomineral insulating oil in electrical equipment, the testslisted in Table 1 are considered sufficient to evaluatethe condition of the oil in service and to establishwhether the condition of the oil is adequate forcontinued operation. Corrective actions, based on theresults are then suggested.1389 ﭘﺎﺋﻴﺰ و زﻣﺴﺘﺎن - ﺷﻤﺎره دوم - ﺳﺎل ﻫﻔﺘﻢ - ﻣﺠﻠﻪ اﻧﺠﻤﻦ ﻣﻬﻨﺪﺳﻴﻦ ﺑﺮق و اﻟﻜﺘﺮوﻧﻴﻚ اﻳﺮان Journal of Iranian Association of Electrical and Electronics Engineers - Vol.7- No.2- Fall & Winter 2010Downloaded from jiaeee.com at 17:48 0330 on Sunday March 14th 20211. Introduction
Table. 1. Tests for Mineral Insulating OilsISO 2049IEC 60156IEC 60814Acidity (neutralization value)Dielectric dissipation factor (DDF) and or resistivityInhibitor contentPassivator contentGroup 2 (Complementary tests)Sediment and sludgeInterfacial tensionParticles (particle count)Group 3 (Special investigative tests)Oxidation stabilityFlash pointCompatibilityPour pointDensityViscosityPolychlorinated biphenyls (PCBs)Potentially corrosive sulfurCorrosive sulfurCorrosive sulfurDBDSIEC 62021IEC 60247IEC 60666IEC 60666, Annex BIEC 61125 method CISO 6295IEC 60970IEC 61125ISO 2719IEC 61125ISO 3016ISO 3675ISO 3104IEC 61619IEC 62535ASTM D1275BDIN 51353IEC 626974. Classification of Oils in ServiceJournal of Iranian Association of Electrical and Electronics Engineers - Vol.7- No.2- Fall & Winter 2010Downloaded from jiaeee.com at 17:48 0330 on Sunday March 14th 2021Group 1 (Routine tests)Colour and appearanceBreakdown voltageWater contentTo assist in the assessment of the condition andsubsequent actions, oils in service may be classified asgood, fair or poor based on the evaluation of significantproperties and their ability to be restored to thecharacteristics desired.Good Oil in normal condition, continue normalsamplingFairOil deterioration detectable, more frequentsampling recommendedPoorOil deterioration abnormal, immediate actionadvisable5. Aging of Mineral OilsEven if there are different types of wear and tear on aninsulating oil, the main force of aging is of courseoxidation. For oxidation to take place there has to besomething to oxidize (oil), oxygen, and heat to providethe activation energy.The details of the oxidation process will not be coveredhere, which can be found in earlier contribution toTechCon (3), but a brief outline is neverthelessnecessary for the continued discussion.Fig. 1. Principle for Oil OxidationWhen a hydrocarbon molecule (oil molecule)encounters the combination of heat and oxygen (air), itcan form a peroxide (Figure 1). Peroxides areinherently unstable and therefore rather reactive. Theycan easily form alcohols or aldehydes or ketones.These are polar types of molecules that will change theproperties of the oil medium in which all this happens.For instance this will affect interfacial tension andthereby the solubility of water in the oil. Water is also aby-product of several of the reactions that underliethese phenomena.Aldehydes and ketones can react again with oxygen toform acids directly, or be oxidized and loose carbondioxide to form acids. Carbon dioxide is in fact themost oxidized form of carbon and the absolute end of1389 ﭘﺎﺋﻴﺰ و زﻣﺴﺘﺎن - ﺷﻤﺎره دوم - ﺳﺎل ﻫﻔﺘﻢ - ﻣﺠﻠﻪ اﻧﺠﻤﻦ ﻣﻬﻨﺪﺳﻴﻦ ﺑﺮق و اﻟﻜﺘﺮوﻧﻴﻚ اﻳﺮان 67
from this and similar sets of data. If assets managersknow what signs to look for and what development toexpect, at least on a statistical level, it should be veryhelpful to secure power delivery to a minimum cost.Other types of correlations may also be interesting,especially to enable maintenance decisions on lesscomplete data, a situation that is all too common.Once the values for age, IFT, acidity, peroxideconcentration, DFF and inhibitor content had beengathered, the data was divided into two categoriesdepending on whether the oil was inhibited (containingDBPC) or uninhibited.The data was then analyzed for linear correlations. Thisdoes not of course give the whole truth, but even aweak linear correlation between sets of data mayindicate that there are other types of interestingcorrelations. Finally the different data sets were plottedagainst each other to enable elucidations of such morecomplex correlations. The results were then comparedto the limits set in IEC 60422 (voltage classes above172 kV).Oxidation inhibitors (natural or synthetic) moderate orstop the reactions of peroxides to give the liquid aprotection against the oxidative reactions.Of these different products one can measure peroxides,the effect of formation of polar compounds on IFT,acidity and also in principle carbon dioxide by DGA.6. Study of Field SamplesThe weakness of this approach is that it cannot tell youanything about the development over time in the sametransformer as it gives only statistical correlations.The data for this study was mined from the database ofanalyses within Nynas IOM, which is our insulating oilmanagement service in Europe with laboratories inSweden, UK, Norway and Poland. In this case theperoxide content of the oil samples were also analysedusing a GCMS-based method developed in NynasResearch department (4).For maintenance and reinvestment strategies, thedevelopment of the different oil parameters over timeis perhaps the most interesting insight to be elucidated7. Inhibited Versus Uninhibited OilsBefore going into details of correlations of the differentmeasurable parameters, a broad comparison of theproperties of the set of oil samples should beconsidered (Table 3).Table. 2. Comparison of Inhibited and Uninhibited Oils (c.d. complete data)Inhibitedmedianaverageextremeoldest c.d.Uninhibitedmedianaverageextremeoldest c.dAge(years)IFT(mN/m)Acidity(mg 410.472.180.32Even if the data is a bit skewed because of the muchhigher number of inhibited oils it is clear that most ofthe numbers are indicating that inhibited oils remainmuch more pristine during the service life of thetransformer. It is very indicative to look at the oldestcomplete data (oldest c.d.) where the IFT of theuninhibited sample has gone down to alarming levels,whereas the inhibited sample of almost the same age isstill in very good shape.68Also take note of the fact that peroxide concentrationsin the uninhibited oils are at least an order ofmagnitude higher than in the inhibited samples. Thisindicates that destructive oxidation processes are goingon to a much larger extent in the uninhibited samples.It also explains why the extreme values are muchworse for the uninhibited oils as the processes ofoxidation will give these results.1389 ﭘﺎﺋﻴﺰ و زﻣﺴﺘﺎن - ﺷﻤﺎره دوم - ﺳﺎل ﻫﻔﺘﻢ - ﻣﺠﻠﻪ اﻧﺠﻤﻦ ﻣﻬﻨﺪﺳﻴﻦ ﺑﺮق و اﻟﻜﺘﺮوﻧﻴﻚ اﻳﺮان Journal of Iranian Association of Electrical and Electronics Engineers - Vol.7- No.2- Fall & Winter 2010Downloaded from jiaeee.com at 17:48 0330 on Sunday March 14th 2021the process. However, both aldehydes and acids canreact with eachother to form complex compounds thatare not soluble in oil, i.e. sludge.This is in essence the oxidative reactions in a mineraloil-based insulating liquid, although in a verysimplified form. What is lacking in this simple pictureis the positive feedback loop of the reactions ofperoxides; peroxides react and form even moreperoxides in the same process as other oxidationproducts are formed. This comes about by chainreactions of radicals of peroxides. Ester-type of liquidsfollows the same general pattern, but the details differ.
8. Inhibited OilsIn this study there are 113 samples from separatetransformers. For 78 of these the age of the transformer(and the oil) was known. A total of 103 transformersare known to be of the free-breathing type with silicadrying of the ingoing air. Inhibitor content, acidity andperoxide content was measured for all samples. 73samples had been analyzed for IFT (interfacialtension), and 61 for DDF (dielectric dissipation factor,i.e. dielectric 18-0.441.00-0.17-0.391.000.071.00The greatest correlation (Table 3) is found between IFTand inhibitor content. This actually shows that theinhibitor really works. As long as there is enoughinhibitor left there will be very little oxidation andtherefore very few polar compounds that affect IFT areformed.Age correlates best to DDF, and second best to acidity.The most likely explanation is that it is chieflyionisable compounds li
Breakdown voltage IEC 60156 Water content IEC 60814 Acidity (neutralization value) IEC 62021 Dielectric dissipation factor (DDF) and or resistivity IEC 60247 Inhibitor content IEC 60666 Passivator content IEC 60666, Annex B Group 2 (Complementary tests) Sediment and sludge IEC 61125 method C Interfacial tension ISO 6295
Insulating Gloves and Sleeves must have a color coded label to meet appropriate ASTM Specifications. ASTM Specification Reference D120 Rubber Insulating Gloves D178 Rubber Insulating Matting D1048 Rubber Insulating Blankets D1049 Rubber Insulating Covers D1050 Rubber Insulating Line Hose D1051 Rubber Insulating Sleeves F478 In-Service Care of .
63 shell australia lubricants product data guide 2013 industry industry industry hydraulic fluids shell tellus and shell irus compressor oils shell corena turbine oils shell turbo oils bearing and circulating oils shell morlina electrical insulating oils shell diala gas engine oils shell mysella oil industrial gear oils shell
1.1 Production and Production Areas 3 1.1.1 Overview of the essential oils market and its composition 6 1.1.2 Identification of Products 6 2. HARVESTING OF ESSENTIAL OILS 7 2.1 Harvesting 7 2.2 Essential Oils Marketing Activities 7 3. EXPORTS VOLUMES 8 4. IMPORTS VOLUMES 19 5. USES OF ESSENTIAL OILS 25 6. QUALITY & MAINTANANCE OF ESSENTIAL OILS .
IEC 60156, Insulating liquids – Determination of the breakdown voltage at power frequency – Test method IEC 60247, Measurement of relative permittivity, dielectric dissipation factor and d.c. resistivity of insulating liquids IEC 60422, Supervision and maintenance guide for mineral insulating oils in electrical equipment
- insulating according to EN 60903:2003 - tested in according to IEC 61482-1-2, class 2 (APC 2) - Cuff length 410 mm - incl. undergloves Description Material number insulating protective glove, latex, EN 60903, class 0, size 8 7421008 insulating protective glove,
BS EN 826:2013 EN 826:2013 (E) 4 EN 1609, Thermal insulating products for building applications — Determination of short-term water absorption by partial immersion EN 12085, Thermal insulating products for building applications — Determination of linear dimensions of test specimens EN 12086, Thermal insulating products for building applications — Determination of water vapour
Rubber Insulating Blankets Inflated Rubber Insulating Glove for Visual Inspection Dielectric Testing of Rubber Insulating Gloves 2 The Voltgard Test Lab at Saf-T-Gard is a NAIL4PET-accredited test lab NAIL incorporates the only Laboratory Accreditation for the electrical equipment test labs program in .
Today, a modern cutting fluid is sub . new formulation category for long term corrosion protec . Compressor Oils 32-34 Refrigeration Oils 35-38 Environmentally Friendly Industrial Oils 39-41 Cylinder Oils, Tacky Oils,
