Insulation material for a DC electrical component
An insulation material for a DC electrical component. The insulation material includes a thermoset or thermoplastic matrix and a functional filler component. The functional filler component has a non-linear DC conductivity depending on an applied electrical field strength. At least in a temperature range of 0° C. to 120° C., the functional filler component has a bandgap in the range of 2 to 5 eV, and optionally in the range of 2 to 4 eV. Furthermore, a method for producing an insulation material, a use of an insulation material for a high voltage DC electrical component, a DC electrical component comprising the insulation material and the use of a DC electrical component comprising the insulation material in a high voltage DC gas insulated device are suggested.
1. An insulation material for a direct current (DC) electrical component, the insulation material comprising:
a thermoset or thermoplastic matrix;
a functional filler component combined with the thermoset or thermoplastic matrix and comprising any one of the group consisting of silica with antimony-doped tin oxide, titanium oxide with antimony doped tin oxide, and n-type tin oxide; and
a bulk filler component,
wherein the functional filler component has a non-linear DC conductivity depending on an applied electrical field strength,
wherein at least in a temperature range of 0° C. to 120° C., the functional filler component has a bandgap in the range of 2 to 5 eV,
wherein a DC conductivity of the insulation material measured after the application of a constant and homogeneous electric field of a field strength under normal DC operation for a time duration equal or longer than 10 5 seconds, is within the range of 10 −18 siemens per meter (S/m) to 10 −10 S/m for 303 to 378 K, or a DC conductivity is dependent on the electric field strength applied to the insulation material at a temperature of the insulation material of any one temperature within the range between 303 and 378 K, for the electric field strength being in a range between a minimum electric field strength of 1 kV/mm and a maximum electric field strength of 10 kV/mm, such that the DC conductivity at the maximum electric field strength is less than 10 5 times the DC conductivity at the minimum electric field strength.
2. The insulation material according to claim 1 , wherein the total amount of the functional filler component within the insulation material is within the range of 30 to 80 wt.-%.
3. The insulation material according to claim 1 , wherein the amount of the bulk filler component in the insulation material is within the range of up to 50 wt.-%.
4. The insulation material according to claim 3 wherein the bulk filler component is alumina.
5. The insulation material according to claim 1 , wherein an average particle size of the functional filler component is within the range of 0.1 to 30 μm.
6. The insulation material according to claim 1 , wherein a DC conductivity is dependent on the temperature of the insulation material at any one field strength within the range between 0 kV/mm and 10 kV/mm, such that the DC conductivity at the maximum temperature is less than 10 4 times the DC conductivity at the minimum temperature.
7. A DC electrical component for high voltage DC power transmission or distribution, the DC electrical component comprising a conductor surrounded at least partially by an insulation layer of an insulation material according to claim 1 .
8. The insulation material according claim 1 , wherein the total amount of the functional filler component within the insulation material is within the range of 55 to 75 wt.-%.
9. The insulation material according to claim 1 , wherein a DC conductivity is dependent on the temperature of the insulation material at any one field strength within the range between 0 kV/mm and 10 kV/mm, such that the DC conductivity at the maximum temperature is less than 10 4 times the DC conductivity at the minimum temperature.
10. A method for producing an insulation material comprising the steps of:
combining a functional filler component having a non-linear resistive behavior depending on an applied electrical field strength and/or a non-linear capacitive behavior depending on an applied electrical field strength and having, at least in a temperature range of 0° C. to 120° C., a bandgap in the range of 2 to 5 eV, optionally in the range of 2 to 4 eV; and comprising any one of the group consisting of silica with antimony-doped tin oxide, titanium oxide with antimony doped tin oxide, and n-type tin oxide, a bulk filler component, and a thermoset or thermoplastic matrix compounding the ingredients according to the type of matrix, and processing the compounded ingredients according to the type of matrix,
wherein a DC conductivity of the insulation material measured after the application of a constant and homogeneous electric field of a field strength under normal DC operation for a time duration equal or longer than 10 5 seconds, is within the range of 10 −18 siemens per meter (S/m) to 10 −10 S/m for 303 to 378 K, or a DC conductivity is dependent on the electric field strength applied to the insulation material at a temperature of the insulation material of any one temperature within the range between 303 and 378 K, for the electric field strength being in a range between a minimum electric field strength of 1 kV/mm and a maximum electric field strength of 10 kV/mm, such that the DC conductivity at the maximum electric field strength is less than 10 5 times the DC conductivity at the minimum electric field strength.