Influence of moisture on the insulation characteristics of nitrogen

Figures & data

Table 1. Comparison of main characteristic of N₂ and SF₆.

Physical and chemical characters	N2	SF6
Molecular weight	28.02	146.07
Liquefaction temperature	−198	−51
Toxicology	–	–
Gas density	1.16	6.05
GWP	0	23,900
ODP	0	0

Figure 1. Schematic diagram of the test rig.

Table 2. Non-uniform coefficient for electric field at different gap distance.

Sphere-Plate electrode
Gap distance (mm)	Inhomogeneity factor
5	1.067
10	1.137
15	1.208
20	1.282
25	1.357
30	1.434
40	1.591

Table 3. Moisture content of N₂.

No.	Calculated value (μL/L)	Measurements (μL/L)
I	0	23
II	500	532
III	1000	1042
IV	1500	1553
V	2000	2057

Figure 2. H₂O saturated steam pressure curve [15].

Figure 3. Breakdown characteristics of N₂ in the condition of different moisture content under lightning impulse (Li−).

Figure 4. Breakdown characteristics of N₂ in the condition of different moisture content under lightning impulse (Li+).

Figure 5. Breakdown voltage of N₂ with different moisture content.

Martin C. Water phase diagram. Available from: http://www1.lsbu.ac.uk/water/phase.html.

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