Method and device for reducing leakage currents
View Patent ↗A method for reducing leakage currents in a protective conductor of an electricity network including a neutral conductor and a phase conductor in addition to the protective conductor. A differential current is determined depending on a phase conductor current in the phase conductor and a neutral conductor current in the neutral conductor. A compensation current is fed into the phase conductor and/or into the neutral conductor. The compensation current compensates for a leakage current caused by the differential current. Also described is a device for carrying out such a method.
1. A method for reducing leakage currents in a protective conductor (PE) of an electricity network comprising a neutral conductor (N) and a phase conductor (Lx) in addition to the protective conductor (PE), the method comprising:
determining a differential current depending on a phase conductor current in the phase conductor (Lx) and a neutral conductor current in the neutral conductor (N);
determining a frequency spectrum of the determined differential current;
generating the compensation current based on the determined frequency spectrum and a predefined phase shift; and
feeding the compensation current into the phase conductor (Lx) and/or into the neutral conductor (N), said compensation current compensating for a leakage current caused by the differential current.
2. The method as claimed in claim 1 , wherein the differential current is determined by a differential current converter.
3. The method as claimed in claim 1 , further comprising converting the determined differential current into a digital differential current using an analog-to-digital converter.
4. The method as claimed in claim 1 , further comprising generating the compensation current depending on the determined differential current and a predefined phase shift.
5. The method as claimed in claim 1 , further comprising feeding in the compensation current via a capacitive coupling.
6. The method as claimed in claim 1 , further comprising feeding in the compensation current via an inductive coupling.
7. The method as claimed in claim 1 , further comprising feeding in the compensation current via a galvanic coupling.
8. The method as claimed in claim 1 , wherein the compensation current is generated to have a frequency spectrum based on the determined a frequency spectrum of the determined differential current.
9. A device for reducing leakage currents in a protective conductor (PE) of an electricity network comprising a neutral conductor (N) and a phase conductor (Lx) in addition to the protective conductor (PE), the device comprising:
a determining unit for:
determining a differential current depending on a phase conductor current in the phase conductor (Lx) and a neutral conductor current in the neutral conductor (N),
determining a frequency spectrum of the determined differential current, and
generating the compensation current based on the determined frequency spectrum and a predefined phase shift; and
an infeed unit for feeding a compensation current into the phase conductor (Lx) and/or into the neutral conductor (N), said compensation current compensating for a leakage current caused by the differential current.
10. A charging device for charging an electrical energy storage element with the electricity network and the device as claimed in claim 9 .
11. The charging device as claimed in claim 10 , wherein the charging device is a galvanically non-isolated charging device.
12. The device as claimed in claim 9 , wherein the determining unit generates the compensation current to have a frequency spectrum based on the determined a frequency spectrum of the determined differential current.