Transformer isolation response using direct current link

Patent metadata

Field	Value
Publication number	US-11031773-B2
Application number	US-201916366280-A
Country	US
Kind code	B2
Filing date	Mar 27, 2019
Priority date	Mar 27, 2019
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

Unique systems, methods, techniques and apparatuses of a distribution system are disclosed. One exemplary embodiment is an alternating current (AC) distribution system including a first substation including a first transformer and a protective device; a first distribution network portion coupled to the first transformer; a second substation; a second distribution network portion; a DC interconnection system coupled between the first distribution network portion and the second distribution network portion; and a control system. The control system is structured to detect a fault in the first transformer or the transmission network, isolate the first distribution network from the fault, determine a set point of the DC interconnection system, and operate the DC interconnection system using the set point so as to transfer a portion of the MVAC from the second distribution network portion to the first distribution network portion.

First claim

What is claimed is:

1. An alternating current (AC) distribution system comprising:
a first substation including a first transformer and a protective device, the first transformer being coupled to a transmission network;
a first distribution network portion coupled to the first transformer;
a second substation including a second transformer;
a second distribution network portion coupled to the second transformer structured to receive medium voltage alternating current (MVAC) from the second transformer;
a DC interconnection system coupled between the first distribution network portion and the second distribution network portion; and
a control system structured to detect a fault in the first transformer or the transmission network, isolate the first distribution network portion from the fault using the protective device, determine a set point of the DC interconnection system after isolating the first distribution network portion, and operate the DC interconnection system using the set point so as to transfer a portion of the MVAC from the second distribution network portion to the first distribution network portion.

2. The AC distribution system of claim 1 , further comprising a second DC interconnection system, wherein the DC interconnection system is coupled to the second DC interconnection system by way of a DC distribution network.

3. The AC distribution system of claim 1 , wherein the control system comprises a substation controller of the first substation and a converter controller of the DC interconnection system, and wherein the converter controller is structured to determine the set point of the DC interconnection system after the substation controller isolates the first distribution network portion using the protective device.

4. The AC distribution system of claim 3 , wherein the converter controller is structured to operate the DC interconnection system to attempt to prevent a total power interruption of the first distribution network portion.

5. The AC distribution system of claim 4 , wherein the control system is structured to determine a second set point after the converter controller determines the set point, and transmit the second set point to the converter controller, wherein the converter controller is structured to operate the DC interconnection system using the second set point instead of the set point.

6. The AC distribution system of claim 1 , wherein the control system is structured to close a tie switch in response to isolating the fault, determine the second transformer is overloaded, and determine the set point in response to determining the second transformer is overloaded.

7. The AC distribution system of claim 1 , wherein the control system is structured to determine that operating the DC interconnection system using the set point did not successfully restore the first distribution network portion, shed a plurality of non-critical loads in response, transfer MVAC from a third distribution network portion, and reconnect the plurality of shed non-critical loads.

8. A method for fault response in an alternating current (AC) distribution system, the method comprising:
detecting a fault in a first transformer of a first substation or a transmission network coupled to the first substation;
isolating a first distribution network portion from the fault using a protective device of the first substation;
determining a set point of a DC interconnection system coupled between the first distribution network portion and a second distribution network portion after isolating the first distribution network portion;
receiving medium voltage alternating current (MVAC) at the DC interconnection system by way of a second transformer of a second substation and the second distribution network portion; and
operating the DC interconnection system using the set point so as to transfer the MVAC from the second distribution network portion to the first distribution network portion.

9. The method of claim 8 , comprising operating a second DC interconnection system so as to transfer power from the second DC interconnection system to the DC interconnection system by way of a DC distribution network.

10. The method of claim 8 , comprising determining the set point of the DC interconnection system after isolating the first distribution network portion using the protective device.

11. The method of claim 10 , comprising operating the DC interconnection system in order to avoid a total power interruption of the first distribution network portion.

12. The method of claim 11 , comprising determining a second set point after determining the set point and operating the DC interconnection system using the second set point instead of the set point.

13. The method of claim 8 , comprising closing a tie switch in response to isolating the fault, determining the second transformer is overloaded after closing the tie switch, and determining the set point in response to determining the second transformer is overloaded.

14. The method of claim 8 , comprising determining that operating the DC interconnection system using the set point did not successfully restore the first distribution network portion, shedding a plurality of non-critical loads in response to the determining, transferring the MVAC from a third distribution network portion, and reconnecting the plurality of shed non-critical loads.

15. A control system comprising:
a substation controller of a first substation; and
a converter controller of a DC interconnection system coupled between a first distribution network portion and a second distribution network portion and in communication with the substation controller,
wherein the substation controller is structured to detect a fault in a first transformer of the first substation or a transmission network coupled to the first substation and to isolate a first distribution network from the fault using a protective device of the first substation, and
wherein the converter controller is structured to operate the DC interconnection system using a set point after isolating the first distribution network and to transfer medium voltage alternating current (MVAC) from the second distribution network portion to the first distribution network portion.

16. The control system of claim 15 , comprising a second DC interconnection system, wherein the DC interconnection system is coupled to the second DC interconnection system by way of a DC distribution network.

17. The control system of claim 15 , wherein the converter controller is structured to operate the DC interconnection system to attempt to prevent a total power interruption of the first distribution network portion.

18. The control system of claim 17 , wherein the control system is structured to determine a second set point after determining the set point and transmit the second set point to the converter controller, and wherein the converter controller is structured to operate the DC interconnection system using the second set point instead of the set point.

19. The control system of claim 15 , wherein the control system is structured to close a tie switch in response to isolating the fault, determine a second transformer is overloaded, and determine the set point in response to determining the second transformer is overloaded.

20. The control system of claim 15 , wherein the control system is structured to determine that operating the DC interconnection system using the set point did not successfully restore the first distribution network portion, shed a plurality of non-critic

Assignees

• Abb Schweiz Ag
• Abb Power Grids Switzerland Ag

Inventors

• Pan Jiuping
• Yuan Chunming
• Yang Xiaobo
• Majumder Ritwik
• Berggren Bertil
• Dijkhuizen Frans

Classifications

• H02J4/25

  for transfer of electric power between AC and DC networks, e.g. for supplying the DC section within a load from an AC mains system · CPC title

• H02J3/001

  Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies · CPC title

• H02J3/06

  Controlling the transfer of power between connected networks; Controlling load sharing between connected networks · CPC title

• H02H7/04

  for transformers · CPC title

• H02H7/262

  involving transmissions of switching or blocking orders · CPC title