OTD - Oil Tan Delta test set
The OTD tests the electrical insulation of the oil in high voltage transformers and switchgear.
The OTD tests the electrical insulation of the oil in high voltage transformers and switchgear.
Key Benefits
- Able to check calibration regularly
- Everything you need in a compact unit
- Excellent productivity
- Meets requirements of international standards
Description
The OTD Oil Tan Delta is a laboratory instrument designed to measure the tan delta, resistivity, and relative permittivity of insulating liquids. These tests give a wider picture of the overall quality of the insulating oil and will indicate if there is any contamination. Megger has developed features of the OTD to ensure that productivity levels within laboratories are maximised.
The microprocessor-controlled inductive heater means that there is uniformity of temperature throughout the cell, in compliance with IEC 60247, and for cooling a fan effectively speeds up the cell cooling time. The instrument has a temperature measuring range of 10 to 110 ºC, with an accuracy of ± 1 ºC. It can be set to preheat before testing takes place. The automated oil drain facility negates the need to move the oil vessel.
This test set has been designed with your safety in mind so that during a test, you can terminate at any time by pressing any button on the keyboard and this will remove the high voltage immediately and abort the test. The design of the cell components also maximises the oil fill rate but minimise turbulence in oil flow and eliminate trapping of air. What's more, with only 32 cell components, it is easy to assemble and disassemble.
The OTD comes with a calibration checker so you can carry out a quick measurement to validate the tan delta, resistivity, and permittivity results. An on-site service with an approved service centre for calibration also gives you the opportunity to adjust measurements where necessary and minimise downtime. Furthermore, the OTD comes with PowerDB Lite, Megger's asset and data management software, at no extra cost, giving you an excellent tool for downloading and printing results. Additionally, it is easy to use with fast tabular navigation and quick text input via a telephone-style keypad.
The OTD test sets are supplied with standard test sequences pre-installed to support the following international test standards:
IEC 60247:2004
IEC 61620:1998
ASTM D924-08
ASTM D1169:2002
BS 5737:1979
JIS C2101:1999
VDE 0380-2:2005_01
IS 6262:1971
IS 6103:1971
As well as these standards, the OTD supports up to 6 customer configurable test sequences.
Specifications
Frequently Asked Questions
What does OTD measure?
OTD measures the leakage current through an oil, which serves as a measure of contamination or deterioration. Specifically, it reveals the presence of moisture, resin, varnishes, or other products of oil oxidation, as well as foreign contaminants such as motor oil or fuel oil. However, the test is not specific in its detection; rather, it acts as a screening test.
Is this test supported by international standards?
Yes. Tan Delta or Dielectric Dissipation Factor is an internationally recognised test and OTD is compliant with IEC, 60247; ASTM D924 & 1169;, JIS C2101; IS 6262 & 6103; & VDE 0380-2.
Why do I need an OTD?
OTD detects the slight mismatch in the sinusoidal waveforms between voltage and current (Tan Delta). Some of this energy is lost as heat and this loss are proportional to the load the transformer is subjected to. The higher the load, the greater the loss, and the more heating this causes for the unit in question. Smaller units with inadequate cooling can become dangerously overheated, and in extreme cases, this can cause an explosion, which some operators have unfortunately experienced with CTs and VTs—clearly a scenario to be avoided.
