GlobeCore has designed TOR-7, a multipurpose tester that can be used by both electrical lab and transformer maintenance company personnel. TOR-7 measures four key parameters of transformer oil: volumetric gas content, moisture content, solids contamination level, and content of hydrogen as a key gas in chromatographic analysis to determine possible defects occurring in a transformer.
General view of TOR-7 tester
The principle of the tester’s operation is based on recording a change in gas pressure inside a cylinder under vacuum when it is filled with a portion of oil. Knowing the volumes of the cylinder and of the oil filled, the pressure inside the cylinder before and after filling makes it possible to determine the volumetric gas content.
The moisture content and temperature of oil, the hydrogen content, and the amount of solids in oil are calculated and visually displayed through the use of sensors and a controller board.
If necessary, the measurement results can be printed out with the use of an integrated mini-printer.
Table 1 – Specifications of TOR-7 tester
| No. | Parameter | Value |
| Moisture measurement specifications | ||
| 1 | Operating range, aw (active water (aw)) | 0…1 |
| 2 | Precision at 20 °C | ±0.02 aw (0…0.9 aw) ±0.03 aw (0.9…1 aw) |
| 3 | Temperature measurement | Yes |
| 4 | Operating medium temperature, °С | 0…55 |
| Hydrogen measurement specifications | ||
| 6 | Measurement range, ppm | 25–5,000 |
| 7 | Precision | 20% of indication, or 25 ppm |
| 8 | Repeatability | 10% of indication, or 15 ppm |
| 9 | Response time | <60 min (90% step change) |
| 10 | Сross-sensitivity | Less than 2% cross-sensitivity to other gases (CO, CO2, hydrocarbons) |
| 11 | Operating medium temperature, °С | 0…55 |
| Solids contamination measurement specifications | ||
| 6 | Measurement range, ppm | 25–5000 |
| 7 | Precision | 20% of indication, or 25 ppm |
| 8 | Repeatability | 10% of indication, or 15 ppm |
| 9 | Response time | <60 min (90% step change) |
| 10 | Cross-sensitivity | Less than 2% cross-sensitivity to other gases (CO, CO2, hydrocarbons) |
| 11 | Operating medium temperature, °С | 0…55 |
| Purity or contamination levels | ||
| 12 | Permissible viscosity range, mm²/s | 1 to 1,000 |
| 13 | Measured variables | ISO 99 (ISO 4406:1999)SAE (SAE AS 4059), orISO 87 (ISO 4406:1987)NAS (NAS 1638) |
| 14 | Measurement range | Measurement from ISO 9/8/7 (MIN) to ISO 25/24/23 (MAX)Calibrated within the ISO range from 13/11/10 to 23/21/18 |
| 15 | Precision | +/- 1/2 of ISO class in the calibrated range |
| 16 | Operating medium temperature, °С | 0 … +85 |
Summary
Thus, TOR-7 provides the most appropriate set of data for rapid diagnostic evaluation of transformer oil: volumetric gas content, moisture content, solids content, and hydrogen content. The obtained information allows saving time and money on lab analyses, as well as making quick decisions as part of transformer maintenance program (further use, more complete analysis, or purification of oil). Prompt decision-making contributes to preventing the occurrence of defects in due course through timely oil treatment and enhancing the reliability of transformers operation.
About authors:
Stanislav Mykytenko, Founder and Director of GlobeCore
Oleg Kryvokhyzha, Founder and Director of GlobeCore
Contact: media@globecore.com
