Locating a ground fault in a DC system

Patent metadata

Field	Value
Publication number	US-12007452-B2
Application number	US-202017439110-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Mar 18, 2019
Publication date	Jun 11, 2024
Grant date	Jun 11, 2024

Abstract

A method is for locating a ground fault in a DC system to which a plurality of load zones can be connected. The method includes specifying a time window and, after the ground fault is detected, assigning the ground fault to a load zone which was connected to the DC system within the time window before the detection of the ground fault.

First claim

The invention claimed is:

1. A method for locating a ground fault in a DC system to which a plurality of load zones are connectable, the method comprising:
defining a time window; and
assigning, after detection of the ground fault, the ground fault to a load zone connected to the DC system, within the time window defined before detection of the ground fault, wherein
upon the plurality of load zones being connected to the DC system within the time window defined before the detection of the ground fault, the ground fault is assigned to one of the plurality of load zones connected to the DC system relatively latest within the time window.

2. The method of claim 1 , further comprising:
disconnecting, from the DC system, the load zone of the plurality of load zones to which the ground fault is assigned.

3. The method of claim 2 , further comprising:
checking, after disconnection of the load zone from the DC system, to ascertain whether the ground fault is still present, and
upon the checking indicating that the ground fault is still present in the DC system after disconnection of the load zone from the DC system, canceling the assigning of the ground fault to the load zone and reconnecting the load zone to the DC system.

4. The method of claim 1 , further comprising:
storing, by an evaluation unit, a detection time of the detection of the ground fault, the time window and, for each instance of connecting a load zone, a connecting time of the connecting and a connecting assignment of the connecting time to the load zone connected, and wherein
the ground fault is assigned to the load zone based upon stored data.

5. The method of claim 4 , wherein the evaluation unit is a control unit configured to control the connecting of the load zone.

6. The method of claim 4 , wherein the evaluation unit is a ground fault monitoring unit configured to detect the ground fault.

7. The method of claim 4 , further comprising:
reporting, by a control unit, the connecting time and the corresponding connecting assignment to the evaluation unit to control the connecting of the load zone.

8. The method of claim 4 , wherein the ground fault is detected by a ground fault monitoring unit and reported to the evaluation unit.

9. The method of claim 1 , wherein the DC system has, for each of the plurality of load zones, a respective connecting unit assigned to a respective load zone of the plurality of load zones, the respective load zone being connectable to the DC system by the respective connecting unit, and each respective connecting unit being configured to store the time window and determine, for each instance of connecting the respective load zone, whether the connecting was effected within the time window before the detection of the ground fault.

10. The method of claim 9 , wherein the ground fault is detected by a ground fault monitoring unit and reported to each respective connecting unit.

11. The method of claim 9 , wherein each respective connecting unit is configured to detect the ground fault.

12. The method of claim 1 , wherein, after the ground fault has been detected, the ground fault cannot be assigned to a load zone of the plurality of load zones because no load zone was connected to the DC system within the time window before the detection of the ground fault, wherein a faulty load zone is determined by a procedure in which firstly all the plurality of load zones are disconnected from the DC system and then each respective load zones of the plurality of load zones are connected to the DC system at mutually different connecting times for a connected duration that is relatively longer than the time window and does not overlap the connected duration of another load zone of the plurality of load zones, and for each instance of connecting a respective load zone, a check is made to ascertain whether the ground fault occurs within the time window after the connecting.

13. A DC system comprising:
an evaluation unit, the evaluation unit configured to
store data of a detection time for detection of a ground fault,
define a time window and, for each respective instance of connecting a load zone of a plurality of load zones, a respective connecting time of the connecting the load zone and a respective connecting assignment of the respective connecting time to the load zone connected, and
assign, after detection of the ground fault, the ground fault to the respective load zone based upon the stored data.

14. The DC system of claim 13 , wherein
the plurality of load zones are connectable via respective connecting units;
the DC system further includes a ground fault monitoring unit; and
the ground fault monitoring unit is configured to report a detected ground fault to the evaluation unit.

15. A DC system, comprising:
main electrical lines;
a ground fault monitoring unit connected to the main electrical lines;
a plurality of connectable load zones; and
for each respective load zone of the plurality of connectable load zones, a respective connecting unit assigned to each respective connectable load zone, each respective connectable load zone being connectable to the DC system by each respective connecting unit and each respective connecting unit being configured to
store a definable time window, and
determine, for each instance of connecting the respective connectable load zone, whether the connecting was affected within the definable time window before reporting of a ground fault by the ground fault monitoring unit.

16. A method for locating a ground fault in a DC system to which a plurality of load zones are connectable, the method comprising:
defining a time window; and
assigning, after detection of the ground fault, the ground fault to a load zone connected to the DC system, within the time window defined before detection of the ground fault; and
storing, by an evaluation unit, a detection time of the detection of the ground fault, the time window and, for each instance of connecting a load zone, a connecting time of the connecting and a connecting assignment of the connecting time to the load zone connected, wherein
the ground fault is assigned to the load zone based upon stored data.

17. The method of claim 16 , wherein the evaluation unit is a control unit configured to control the connecting of the load zone.

18. The method of claim 16 , wherein the evaluation unit is a ground fault monitoring unit configured to detect the ground fault.

19. The method of claim 16 , further comprising:
reporting, by a control unit, the connecting time and the corresponding connecting assignment to the evaluation unit to control the connecting of the load zone.

20. The method of claim 16 , wherein the ground fault is detected by a ground fault monitoring unit and reported to the evaluation unit.

Assignees

• Siemens Ag

Inventors

• Schierling Hubert
• Weis Benno

Classifications

• H02J13/13

  characterised by the transmission of data to equipment in the power network · CPC title

• H02H7/268

  for DC systems · CPC title

• H02H3/16

  responsive to fault current to earth, frame or mass (with balanced or differential arrangement H02H3/26 {; monitoring earth connection H02H5/105}) · CPC title

• H02H3/042

  combined with means for locating the fault (locating faults in cables G01R31/08) · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title