Protection apparatus

Patent metadata

Field	Value
Publication number	US-10998715-B2
Application number	US-201716329379-A
Country	US
Kind code	B2
Filing date	Aug 10, 2017
Priority date	Aug 31, 2016
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

There is provided a protection apparatus for protecting an electrical network. The protection apparatus comprises: at least one protection device configured to protect the electrical network from a fault in response to a or a respective protection criterion being met; and a controller configured to: receive real-time information on a change in topological structure of the electrical network; perform an online determination of the real-time impedance or admittance matrix of the electrical network based on the change in topological structure of the electrical network; and adapt the or each protection criterion based on the real-time impedance or admittance matrix.

First claim

What we claim is:

1. A protection apparatus for protecting an electrical network, the protection apparatus comprising:
at least one protection device configured to protect the electrical network from a fault in response to a or a respective protection criterion being met; and a controller configured to:
receive real-time information on a change in topological structure of the electrical network;
perform an online determined real-time impedance or admittance matrix of the electrical network based on the change in topological structure of the electrical network; and
send this real-time impedance or admittance matrix to the or each protection device, and the or each protection device is configured to adapt the or each protection criterion based on the real-time impedance or admittance matrix.

2. The protection apparatus according to claim 1 , wherein the change in topological structure of the electrical network includes at least one of:
a connection of at least one electrical source into the electrical network; a disconnection of at least one electrical source from the electrical network; a connection of at least one electrical load into the electrical network; a disconnection of at least one electrical load from the electrical network; a connection of at least one previously open electrical link of the electrical network; a disconnection of at least one previously closed electrical link of the electrical network; an increase or decrease in power of at least one connected electrical load or at least one connected electrical source of the electrical network.

3. The protection apparatus according to claim 1 , wherein the controller is configured to calculate the real-time impedance or admittance matrix by adding or subtracting a branch of impedance or admittance into an original reference impedance or admittance matrix based on the real-time measured voltages and currents, and on the information of a change in topological structure of electric network.

4. The protection apparatus according to claim 3 , wherein the protection device is configured to adapt the or each protection criterion by determining an equivalent source voltage and/or an equivalent impedance or admittance seen by the or each protection device based on the real-time impedance or admittance matrix, which is from the controller, and on measured voltage and current of a part of the electrical network corresponding to the or each protection device, and by determining the or each protection criterion based on the determined equivalent source voltage and/or equivalent impedance or admittance.

5. The protection apparatus according to claim 3 , wherein the equivalent source voltage and the equivalent impedance or admittance are respectively the Thevenin's equivalent source voltage and the Thevenin's equivalent impedance or admittance.

6. The protection apparatus according to claim 3 , wherein the controller is configured to receive information on the topological structure of the electrical network and to perform a determination of the reference impedance or admittance matrix prior to the change in topological structure of the electrical network.

7. The protection apparatus according to claim 6 , wherein the determination of the reference impedance or admittance matrix is an offline determination of the reference impedance or admittance matrix.

8. The protection apparatus according to claim 6 , wherein the reference impedance or admittance matrix omits some or all the electrical sources of the electrical network and/or some or all the electrical loads of the electrical network.

9. The protection apparatus according to claim 1 , wherein the controller is configured to determine a branch impedance or admittance value of at least one component of the electrical network and to combine the or each equivalent impedance or admittance value into the reference impedance or admittance matrix by addition or subtraction so as to determine the real-time impedance or admittance matrix.

10. The protection apparatus according to claim 9 , wherein the or each branch impedance or admittance value is selected from a group including:
an equivalent load impedance or admittance of an electrical load of the electrical network;
an equivalent source impedance or admittance of an electrical source of the electrical network;
an equivalent impedance or admittance of an electrical link of the electrical network.

11. The protection apparatus according to claim 1 , wherein the controller communicate with the or each protection device wherein the controller is configured to: receive real-time information about a part of the electrical network corresponding to the or each protection device; and perform the online determination of the real-time impedance or admittance matrix based on the received real-time information from the or each protection device.

12. The protection apparatus according to claim 11 , wherein the controller is configured to transmit the real-time impedance or admittance matrix to the or each protection device, and the or each protection device is configured to adapt the or each protection criterion based on the real-time impedance or admittance matrix.

13. The protection apparatus according to claim 1 , wherein the or each protection device is or includes an overcurrent relay, and the or each protection criterion is or includes a fault level of a circuit interruption device associated with the overcurrent relay and/or a setting value of the overcurrent relay, or wherein the or each protection device is or includes a distance protection relay, and the or each protection criterion is or includes a reach setting value of the distance protection relay.

14. A method of operating a protection apparatus for protecting an electrical network, the protection apparatus comprising at least one protection device configured to protect the electrical network from a fault in response to a or a respective protection criterion being met; and a controller configured to: receive real-time information on a change in topological structure of the electrical network; perform an on-line determined real-time impedance or admittance matrix;
the method comprising:
receiving the real time information on a change in topological of the electrical network, and the measuring of voltages and currents of all the branches;
performing a determination of the real-time impedance or admittance matrix based on the information of topological structure change and the measuring of voltages and currents; and
transmitting the determined impedance or admittance matrix to the or each protection device, and the or each protection device is configured to adapt the or each protection criterion based on the real-time impedance or admittance matrix.

Assignees

• General Electric Technology Gmbh

Inventors

• Ha Hengxu
• Lian Yang

Classifications

• H02H3/08

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• H02H7/261 Primary

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title

• H02H3/40

  responsive to ratio of voltage and current · CPC title

• H02H3/006

  Calibration or setting of parameters · CPC title