In order to investigate the conductance characteristics of HTV silicone rubber materials for composite insulators

experimental research is done on composite insulator in field and artificial accelerated ageing test.The conductance current of the samples are measured by the conduction current measuring device

and the conductance characteristics of the samples are summarized.Preliminary study found that if the HTV silicone rubber material is in the low field strength test phase（about 0

5

kV/mm）

the test of the conductance current I and the field

strength E satisfy Ohm’s Law;if the material is in a higher field strength test phase（about 5

3

0 kV/mm）

conduction current characteristics of materials is in space charge limiting current（SCLC）region

the traps inside the material began to capture the carrier to form space charge;if the material is in the high field strength test phase（about 30

4

0 kV/mm）

the conductance characteristics of the samples entered the trap filled space charge limited current

and the sample may have the potential of breakdown.The electrical degradation threshold has a certain corresponding relationship with the trap level and trap carrier density

after the artificial corona accelerated aging test

the conduct current value is increased and the electrical degradation threshold are significantly decreased.In addition

the electrical degradation threshold react the difficulty of the space charge formation of the material and partly to reflect the aging state of HTV materials

further research is needed.