Transformer oil GK
Content
Technical specifications
The composition and properties of transformer oil grade GK are determined by the standards of GOST 982-80. These rules mean:
- High electrical insulation performance, including at elevated temperatures.
- The presence of antioxidant additives (ionol), excluding corrosion under high voltage.
- Absence of water-soluble alkalis and mechanical impurities.
- Stability of viscosity indicators in a certain temperature range.
- Minimum content of free acid ions.
The standard physico-chemical norms for the described product are:
- Density, kg / m3, at room temperature — 890±5.
- Kinematic viscosity, mm2/ s, at a temperature of 50 °C, not less - 9 ... 10.
- Kinematic viscosity, mm2/s at the minimum recommended application temperature -30 °C, no more than 1200.
- Relative acid residue in terms of KOH, not more than 0,01.
- Flash point ºC, not less than 135.
- Thickening temperature, °С, not less than -40.
- The limiting oxidation coefficient after the expiration of the warranty period for the use of the product, not more than 0,015.
The breakdown voltage for GK grade oil is 2 kV, which fully complies with the technical requirements of GOST 6581-75.
What are the differences between GK and VG transformer oils?
Mineral oil VG is intended for use in electrical installations - capacitor banks, ballasts and relays, which are designed for operating voltages up to 1,15 kV. This is due to the presence of inhibitory additives in the composition of the oil, which reduce the intensity of corrosion processes, but at the same time lower the dielectric properties.
Transformer oil GK is considered semi-synthetic, since it contains an increased percentage of anti-corrosion, dielectric and inhibitory additives. This was done in order to use the more accessible sour oils from West Siberian deposits in the production of the final product. Thus, it is possible to maintain stable temperature values in the closed volumes of powerful transformers. However, at the same time, the corrosion resistance of steel parts of devices in a bath with HA oil decreases.
Technical recommendations suggest using GK oil until replacement for a period of not more than a year. Product quality control is carried out according to visual characteristics - transparency, the presence of mechanical sediment - and the presence of excess acid ions. For GK oil, this rate is 0,015 (above this indicator, the allowable breakdown voltage drops to 750 V). In VG oil, due to the absence of free ions, there is practically no deterioration in performance over time.
Application features and reviews
The quality of GK transformer oil depends on its manufacturer. The minimum percentage of sulfur compounds is typical for products manufactured at JSC Ufaneftekhim, the Kstovo enterprise Nefteorgsintez and the Omsk refinery. Other manufacturers add an increased amount of gas-resistant additives to the final product, which increases the allowable temperature, but reduces the dielectric performance. Such transformer oils as a whole also comply with the requirements of GOST 982-80, but are not recommended for high electric field strengths.
Price per liter
With bulk purchases, the price of one barrel of oil (200 liters) will cost from 14000 to 16000 rubles. The retail price of GK oil per liter (when packed in 20 l canisters) is from 140 ... 150 rubles.
