The electrical characteristics of creeping discharges and single creep
ing streamers in transformer oil first are compared with those of stre
amers developing in the liquid bulk. The distribution of electric pote
ntial along the channel of a single negative creeping streamer is dete
rmined using a capacitive probe technique. Then the distribution of th
e space charge associated with each streamer channel is discussed and
the electric field around the channels is estimated. A strong correlat
ion between the mean potential gradient and the capacitance of the str
eamer channels is found. The different results and considerations tend
to support the hypothesis of the same basic physical mechanism for bo
th creeping discharges and streamers developing in the bulk.