RU2004580C1 - Insulating oil - Google Patents

Abstract

Electrical insulating oil contains,% (С-С) 0.5 - 10.0, phenopod type oxidation inhibitor 0.1 - 0.4: petroleum oil up to 100 1 table, 1 silt

Description

The invention relates to compositions of oils intended for use as a heat sink and an insulating medium in oil filled equipment: transformers, capacitors, cables, etc.

Transformer oils must have a long service life of 25 years or more, provide reliable electrical insulation of live parts, not form precipitation and have good compatibility with other structural materials. Therefore, one of the main requirements for transformer oils is their high antioxidant stability, allowing to provide the required oil life. At present, the antioxidant stability method described by the International Electrotechnical Commission in publ. Is used to predict the life of ionol-inhibited transformer oils. 474. The stability criterion is the length of the induction period during which the additive inhibits the oxidation of the oil. The IEC considers the induction period to be 120 hours the most acceptable lower level of stability of transformer oils, which corresponds to 25-30 years of reliable operation of the oil.

Electrical insulating oils used in cables, capacitors, and other sealed devices are less in contact with air, however, the electric field strength in these devices is several times higher than in transformers. Due to the high electric field strength, the performance of the oils in these devices is determined by their resistance to ionized gas molecules. The stability of oils to the effects of ionized molecules to the effects of ionized molecules is called the term gas resistance in the art. To evaluate this characteristic, the International Electrotechnical Commission has developed a method (publication 628) in which 5 ml of oil is exposed to a medium of hydrogen in a field of variable voltage of about 40 kV / cm. This method simulates the conditions that may arise in electrical equipment if a gas bubble enters the electric field. If under these conditions, due to the reactions occurring at the gas-oil interface, the volume of the gas bubble begins to increase, an emergency can occur in the equipment leading to electrical breakdown. Thus, with increased electric field strength, the second important factor, in addition to stability against oxidation, determines the term

electrical services, is the resistance of the oil to ionized gas. Testing according to IEC 628 in a hydrogen medium allows one to conditionally divide oils into 2 classes: gas-absorbing and gas-generating.

“Experts in the electrical industry believe that for some devices with increased electric field strength to the greatest extent

oils with a high stability against oxidation and also gas absorption properties in a gas resistance test are suitable.

It is known that the susceptibility of petroleum insulating oils to ionol, and therefore their antioxidant stability, and gas resistance, is largely dependent on the content of aromatic hydrocarbons in them. Moreover

the susceptibility of oils to antioxidant additives decreases with increasing content of aromatic hydrocarbons, while gas resistance increases, The drawing shows the test results of various

varieties of petroleum insulating oils obtained by various types of currently used technologies: T-750 and T-1500 - acid-base purification, HA and AGC - hydrocatalytic processes, TV - a combination of selective purification and hydrocatalytic processing.

1- experimental arctic oil AGK,

2- commercial oil hydrocracking GK s - experimental oil GB

4- Shell Oil Dayal Dh Shell company

5- commercial oil T-1500

6- Shell Dayal Fx Shell Oil

7- commodity oil T-750

With a total aromatic hydrocarbon content of less than 20% oil, gas is released when tested according to IEC 628,

whereas oils with a high content of aromatic hydrocarbons absorb gas. The induction oxidation period of the getter oils is less than 80 hours. and therefore the indicator they are significantly

inferior to the best samples of electrical insulating oils,

Thus, upon receipt of oils by technologies developed by industry, their gas-emitting character is

inevitable consequence of high stability against oxidation.

An electrical insulating oil is known containing 20-70% of the oil fraction and 30-80% of a mixture of alkyl aromatic hydrocarbons (mono- and / or polyalkylbenzenes and di- and / or polyarylalkanes), as well as containing an antioxidant, a depressant and compounds with the group.

It is known electrical insulating oil, consisting of a mixture of 10-70% naphthenic oil, 3-30% transformer oil and a mixture of alkyl aromatic hydrocarbons or fractions isolated from them containing mono and / or polyalkylbenzenes and / or di and / or polyarylalkanes and containing antioxidant.

Transformer oil is known which is obtained by mixing the oil fraction with alkylbenzenes and alkylnaphthalenes (an alkyl chain of normal structure Cd-Cbb), followed by purification with sulfuric acid and activated clays.

Transformer oil containing petroleum oil and arylphenylethane derivatives is known.

The closest in technical essence to the claimed is an insulating oil, including as additives in petroleum or synthetic oils to improve their resistance to corona discharge of 0.5-40% diarylalkanes or alkylnaphthalenes containing in alkyl chains 2 double bonds.

The proposed insulating oil differs from the known one in that in order to improve its resistance to the effects of an ionized gas medium in an electric field, it contains 0.5-10% alkylnaphthalene, in which the alkyl group has no double bonds and the number of carbon atoms in it is from 1 to 4.

The above compositions of oils either contain a large amount, above 20% of aromatic hydrocarbons, or include additives of aromatic hydrocarbons, which reduce the gas evolution of the oil in the electric field only in significant concentrations.

An increase in the aromatic hydrocarbon content in the oils may adversely affect the antioxidant properties of the inhibited oils. The presence of double bonds in the alkyl groups of the added additives can also lead to a decrease in antioxidant stability.

The proposed composition of electrical insulating oil along with high stability against oxidation, achieved through the use of highly refined

antioxidant-inhibited bases. It simultaneously has gas absorption properties in an electric field.

The authors observed the effect of oil simultaneously exhibiting simultaneously high antioxidant stability and gas absorption properties due to the introduction of aromatic hydrocarbons namely alkylnaphthalene with 0 carbon atoms in the alkyl chain 1-4. At the same time, the amount of aromatic hydrocarbon additive added to give the oil the required gas absorption properties does not have a noticeable 5 negative effect on the antioxidant stability of the oil.

The following components can be used to prepare the oil of the proposed composition:

0 alkylnaphthalenes with the number of carbon atoms in the alkyl group from 1 to 4, which does not contain C-C double bonds. In the examples given, methylnaphthalene-2 is technical according to TU 14-267-11-88 and 5 is tert-butylnaphthalene;

phenolic type oxidation inhibitor. In the given example, 2,6-ditretbutyl-4-methylphenol according to GOST 10894-76;

deeply refined petroleum oil with 0 low content of aromatic hydrocarbons. In the above examples, the oil obtained by hydrocracking a vacuum gas oil fr. 376-500 ° C on a zeolite-containing alumina-nickel-molybdenum catalysis-5 torrep 23030400 ° Sidefaraffin on a zeolite-containing selective hydrocracking catalyst at 40 at and 320 ° C.

An oxidation inhibitor and alkylnaphthalene are added directly to the oil, either directly or in the form of a concentrate.

In this way, samples of electrical insulating oil of the following compositions were prepared 1 wt.%:

Example 2,6-Di-tert-but-5 tyl-4-methylphenol 0.1

Methylnaphthalene-20.5

Hydrocracking OilUp to 100

PRI me R 2. 2,6-Di-tert-butyl-4-methylphenol 0, 4

0 tert-butylnaphthalene 10.0

Hydrocracking OilUp to 100

Oil resistance tests

carried out according to the International method

Electrotechnical Commission (publ. 628,

5 method A) under the following conditions: 10 kV,

80 ° C, H2 atmosphere.

The antioxidant stability of the oils was also evaluated by the method of the International Electrotechnical Commission (publ. 474) under the following conditions: 120 ° C, the catalyst was copper wire, the flow rate was Oa - 1 (56), GDR patent N 217238, cl. With YUM 1/16,

l / h. 1985.

The test results are given in Patent GDR No. 217536, cl. C 10 M 1/04,

table. 1985.

The obtained test results go-5 Japan Patent No. 45-19662, cl. 62C 41,

He said that the oil that meets the pre-1970.

the invention, possesses Japan Patent No. 55-3762, cl. H 01 V

increased resistance to impact 3/22, 1980,

electric floor and ionized gas of Japan Order No. 60-18588, cl. From 10 m

eovoy environment and at the same time high an-10 105/06, 1985. thiooxidative stability.

Claims (1)

The claims, c / Onaphthalene in the following ratio ELECTRIC INSULATION OIL, components, wt%: containing oil, inhibitor Alkyl (C1 - C4) naphthalene 0.5-10.0 phenol type oxidation and alkylnaphtha-phenolline oxidation inhibitor, characterized in that as the scarlet type 01-04 Kilnaphthalene oil contains alkyl (C1 -20 Neft oil Up to 100 Induction oxidation period for netol GOK VW, h