IEC 61620:1998 pdf download – Insulating liquids – Determination of the dielectric dissipation factorby measurement of the conductance and capacitance – Test method

IEC 61620:1998 pdf download – Insulating liquids – Determination of the dielectric dissipation factorby measurement of the conductance and capacitance – Test method.
IEC 61620 describes a method for the simultaneous measurement of conductance G and capacitance C enabling the calculation of the dielectric dissipation factor tan 8 of insulating liquids. The proposed method applies both to unused insulating liquids and insulating liquids in service in transformers and in other electrical equipment.
The standard Is no substitute for IEC 60247: rather It complements it insofar as it is particularly suited to highly insulating liquids and it recommends a method of measurement for these liquids. This method allows values of the dielectric dissipation factor as low as 10 at power frequency to be determined with certainty. Moreover, the range of measurements of tan 8 lies between 10-8 and 1 and can be extended up to 200 in particular conditions.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All normative documents are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards.
IEC 60247:1978. Measurement Of relative permithvity. dielectric dissipation factor and d.c. resistivity of insulating liquids
IEC 60475:1974, Method of sampling liquid dielectrics
ISO 5725-1:1994, Accuracy (trueness and precision) of measuremenf methods and results — Part 1: General principles and defintlons
ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods arid results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method
ISO 5725-3:1994. Accuracy (trueness and precision) of measurement methods and results — Part 3: intermediate measures of the precision of a standard measurement method
ISO 5725-4:1994, Accuracy (trueness and plecision) of measurement methods and results — Part 4: Basic methods for the determination of the trueness of a standard measurement method
The distance between the outer and the inner electrode is typically 4 mm. the minimum distance should not be lower than 1 mm. The material recommended for the electrodes is stainless steel. As an example, the diameter of the Inner electrode Is 43 mm. that of the outer electrode is 51 mm; the height of the electrodes is 60 mm: the diameter of the stainless steel vessel is 85 mm.
This type of test cell was designed tO minimise the effects of contamination from the surfaces in contact with the liquid: although the surface in contact is large. the raho z — electrode surtaces / liquid volume is rather small (x • 2,6 cm”) due to the large volume of liquid (v — 200 cm3).
NOTE — lis recommended to reslrict th use ol a giren c.lI 10 a paslicular lyp. 01 liquid
5.2 HeatIng device
The heating device shall be adequate to maintain the temperature of the measurement cell within ti C of the prescribed value, It may consist of a forced draught air oven or an oil-filled thermostatically controlled bath fitted with a shelf to support the cell.
The heating device shall provide screened electrical connections to the cell.