Howard Medium Power Substation - Manual (Page 6)

Document 2.4.06, Revision 4
June 2013 Medium Power Substation Transformers
vapor Pressure (Micrometers of Mercury)
De
w P
oint T
em
perature (°C)
+20
+10
0
-10
-20
-30
-40
-50
-70
-60
10 100 1,000 10,000
6
TABlE A: Conversion of dew point in degrees centigrade to vapor pressure in micrometers of mercury
Insulation T
em
perature (°C)
vapor Pressure (Micrometers of Mercury)
10 100 1,000 10,000
TABlE B: Moisture equilibrium chart showing acceptable and unacceptable moisture limits.
+80
+70
+60
+50
+30
+20
+10
0
+40
Acceptable range is above the curve
Unacceptable range is below the curve `
`