7/23/2019 IEEEC57-1991

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IEEE C57.106-1991 Suggested Limits

for Mineral Insulating Oil

Table 1 Table 2 Table 3 Table 4

NEW OIL SUGGESTED LIMITS   New Oil Received in

 New Equipment

Processed New Oil,

Before

Filling

Apparatus Voltage Class

 New Oil

from

Vendor <69kV 69-230kV   ≥345kV

 New Oil in

Equipment,

After Filling

and Standing,

BeforeEnergizing

Properties ASTM Units   LIMIT VALUESColor D1500 max   0.5 1.0 1.0 0.5 1.0

Visual Examination D1524 Clear &Bright

Clear &Bright

Clear &Bright

  UnspecifiedClear &Bright

Interfacial Tension D971 mN/mm min   40 35 35 40 35 Neutralization Number D974   g KOH/g   max   0.03   Unspecified   0.03   Uns pec ifi ed Unsp ec ifie d

Dielectric Breakdown Voltage

(DBV)   D877 kV min   30 30 30 30 30DBV, 0.04” gap D1816 kV min   Unspecified   20 30 30 30DBV, 0.08” gap D1816 kV min   Unspecified   40 48 60 48

Water Content D1533B ppm max   35 25 20 10 20Power Factor, 25oC D924 % min   0.05 0.15 0.10 0.05 0.10Power Factor, 100oC D924 % min   0.3 1.50 1.00 0.30   Unspecified

Table 5 Table 6SERVICE-AGED OIL

SUGGESTED LIMITS  Limits for Continued Use of 

Service-Aged OilLimits for Oil to be

Reconditioned or Reclaimed

Classification/Group*I

Apparatus Voltage Class   ≤69kV 69-288kV >345kV   II IIIProperties ASTM Units   LIMIT VALUES

Interfacial Tension D971 mN/mm min   24 26 30 24 16

 Neutralization Number D974   g KOH/g   max   0.2 0.2 0.1 0.2 0.5Dielectric Breakdown Voltage(DBV)

  D877 kV min   26 26 26   U ns peci fi ed U ns peci fi ed

DBV, 0.04” gap D1816 kV min   23 26 26   U ns peci fi ed U ns peci fi ed

DBV, 0.08” gap D1816 kV min   34 45 45   U ns peci fi ed U ns peci fi ed

Water Content D1533B ppm max   35 25 20   U ns peci fi ed U ns peci fi ed

* IEEE C57.106-1991 Classification of Service-Aged Insulating Oil

Group I Oils that are in satisfactory condition for continued use

Group II Oils that required only reconditioning for further service

Group III Oil in poor condition. Such oil should be reclaimed or disposed of depending on economic considerationsGroup IV Oils in such poor that it is technically advisable to dispose of them