Bushing and a method for monitoring of the bushing

1 . A high-voltage DC bushing arrangement, comprising:

a high-voltage DC bushing with a test or voltage tap;

a monitoring device configured to inject an electrical pulse signal, being at least one of a voltage pulse or a current pulse signal, via said tap and to detect and process a corresponding response signal; and

said monitoring device having a pulse generator configured to generate said electrical pulse signal and an induction element connected in parallel with said pulse generator.

2 . The high-voltage DC bushing arrangement according to claim 1 , wherein said electrical pulse signal has a predetermined frequency distribution.

3 . The high-voltage DC bushing arrangement according to claim 1 , wherein said electrical pulse signal comprises frequencies in a range between 30 Hz and 100 KHz.

4 . The high-voltage DC bushing arrangement according to claim 1 , wherein said inductance element has an induction value Lg chosen to render an impedance of a parallel circuit formed by said inductance element and a parallel capacitance of said bushing substantially maximal for a signal frequency of said electrical pulse signal.

5 . The high-voltage DC bushing arrangement according to claim 1 , wherein said bushing further comprises:

an inner conductor;

an insulating body disposed to surround said inner conductor along a longitudinal direction thereof;

insulating layers configured from a synthetic material or paper that is impregnated with a resin; and

electrically conductive control inserts for the control, wherein said control inserts being spaced apart from one another by respective said insulating layers.

6 . The high-voltage DC bushing arrangement according to claim 5 , wherein said tap is connected with one of said control inserts.

7 . A method for operating a bushing arrangement, the method comprising the following steps:

providing a high-voltage DC bushing arrangement according to claim 1 ;

injecting a voltage and/or current pulse signal via the test or voltage tap of the high-voltage DC bushing;

detecting and processing a corresponding response signal;

comparing the response signal with a predetermined calibrated reference signal; and

providing a bushing status information based on said comparison.

8 . The method according to claim 7 , which comprises frequency analyzing the response signal.

9 . The method according to claim 7 , which comprises extracting resulting pulse frequency components from the response signal using a Fourier analysis, and deriving a related impedance for each frequency component.

10 . A high-voltage DC transformer, comprising a high-voltage DC bushing arrangement according to claim 1 .

11 . A converter arrangement, comprising a converter with a first converter component located within a valve hall and a second converter component located outside said valve hall, and wherein said first and second converter components are electrically connected via at least one high-voltage DC bushing arrangement according to claim 1 .

12 . A high-voltage DC bushing arrangement, comprising:

a high-voltage DC bushing with a test or voltage tap; and

a monitoring device configured to inject an electrical pulse signal, being at least one of a voltage pulse or a current pulse signal, via said tap and to detect and process a corresponding response signal;

said monitoring device having a pulse generator configured to generate said electrical pulse signal and an induction element connected in parallel with said pulse generator;

said inductance element having an induction value Lg chosen to render an impedance of a parallel circuit formed by said inductance element and a parallel capacitance of said bushing substantially maximal for a signal frequency of said electrical pulse signal.