CONTROL DEVICE FOR DISTRIBUTED GENERATORS

• US 20140088778A1
• Filed: 06/28/2013
• Published: 03/27/2014
• Est. Priority Date: 09/27/2012
• Status: Active Grant

• Current Assignee: LSIS Co. Ltd. (LS Corporation)
• Original Assignee: LSIS Co. Ltd. (LS Corporation)
• Inventors: Nguyen, Khanh-Loc
• Granted Patent: US 9,671,842 B2
• Time in Patent Office: Days
• US Class Current: 700/295
• CPC Class Codes: G06F 1/26 Power supply means, e.g. regulation thereof for memories G11C
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/466 Scheduling the operation of the generators, e.g. connecting or disconnecting generators to meet a given demand
• CPC Class Codes: H02J 3/48 Controlling the sharing of the in-phase component
• CPC Class Codes: Y02P 80/14 District level solutions, i.e. local energy networks

Abstract

A control device for distributed generators connected to a power main grid includes: a load power measuring unit measuring power consumption of loads connected to the plurality of distributed generators; a distributed generator power measuring unit measuring powers outputted from the plurality of distributed generators; a power flow reference value determining unit determining a power flow reference value of a power line connected to the main grid based on the power consumption and the distributed generator output power; and a mode control unit changing the operation mode of at least one of the plurality of distributed generators such that the flow power of the power line connected to the main grid maintains the reference value.

Claims

1. A control device for distributed generators connected to a power main grid, the control device comprising:

a load power measuring unit measuring power consumption of loads connected to the plurality of distributed generators;

a distributed generator power measuring unit measuring powers outputted from the plurality of distributed generators;

a power flow reference value determining unit determining a power flow reference value of a power line connected to the main grid based on the power consumption and the distributed generator output power; and

a mode control unit changing the operation mode of at least one of the plurality of distributed generators such that the flow power of the power line connected to the main grid maintains the reference value.

2. The control device of claim 1, wherein the power flow reference value determining unit determines, as the power flow reference value, a value obtained by subtracting a total sum of the output powers of the distributed generators from a total sum of the power consumption.

3. The control device of claim 1, wherein the plurality of distributed generators operate in a first mode in which the flow of the power line is constantly maintained, or in a second mode in which the output powers of the distributed generators are constantly maintained.

4. The control device of claim 3, wherein the mode control unit changes the operation mode of at least one of the distributed generators operating in the second mode to the first mode when the flow power of the power line connected to the main grid exceeds the reference value.

5. The control device of claim 3, wherein the mode control unit sequentially changes the operation mode of at least one of the distributed generators operating in the second mode to the first mode until the flow power of the power line connected to the main grid is not more than the reference value.

6. The control device of claim 3, wherein the mode control unit maintains the first distributed generator, which is first connected to the main grid connection power line, at the first mode.

7. The control device of claim 3, wherein, when the flow power of the main grid connection power line exceeds the reference value, the mode control unit sequentially changes the operation mode of the plurality of distributed generators to the first mode according to the sequence of the plurality of distributed generators connected to the main grid connection power line to maintain the flow power of the main grid connection power line at the reference value.

8. The control device of claim 1, wherein, when the determined reference value exceeds the maximum value, the power flow reference value determining unit changes the reference value to the maximum value.

9. The control device of claim 8, wherein the maximum value is determined by a coefficient of a droop characteristic graph when the first distributed generator which is first connected to the main grid connection power line operates in the first mode.

10. The control device of claim 3, wherein the mode control unit changes the operation mode of at least one of the distributed generators other than the first distributed generator to the first mode when it is determined that the total sum of the power consumption of the loads exceeds the total sum of the outputs of the distributed generators.

11. The control device of claim 10, wherein the mode control unit sequentially changes the operation mode of the plurality of distributed generators to the first mode according to the sequence of the plurality of distributed generators connected to the main grid connection power line until the total sum of the power consumption of the loads is not more than the total sum of the outputs of the distributed generators.

18. The control method of claim 3, wherein the changing of the operation mode comprises, when the flow power of the main grid connection power line exceeds the reference value, sequentially changing the operation mode of the plurality of distributed generators to the first mode according to the sequence of the plurality of distributed generators connected to the main grid connection power line to maintain the flow power of the main grid connection power line at the reference value.

12. A control method for distributed generators connected to a power main grid, the control method comprising:

measuring power consumption of loads connected to the plurality of distributed generators;

measuring powers outputted from the plurality of distributed generators;

determining a flow power reference value of the power line connected to the main grid based on the power consumption and the powers outputted from the plurality of distributed generators; and

changing the operation mode of at least one of the plurality of distributed generators such that the flow power of the power line connected to the main grid maintains the reference value.

13. The control method of claim 12, wherein the determining of the power flow reference value of the power line comprises determining, as the power flow reference value, a value obtained by subtracting a total sum of the output powers of the distributed generators from a total sum of the power consumption.

14. The control method of claim 12, wherein the operation mode comprises either a first mode in which the flow of the power line connected to the main grid is constantly maintained, or a second mode in which the output powers of the distributed generators are constantly maintained.

15. The control method of claim 14, wherein the changing of the operation mode comprises changing the operation mode of at least one of the distributed generators operating in the second mode to the first mode when the flow power of the power line connected to the main grid exceeds the reference value.

16. The control method of claim 14, wherein

the changing of the operation mode comprises

sequentially changing the operation mode of at least one of the distributed generators operating in the second mode to the first mode until the flow power of the power line connected to the main grid is not more than the reference value.

17. The control method of claim 14, wherein the changing of the operation mode comprises maintaining the first distributed generator, which is first connected to the main grid connection line, at the first mode.

19. The control method of claim 12, wherein the determining of the power flow reference value of the power line comprises changing the reference value to the maximum value when the determined reference value exceeds the maximum value.

20. The control method of claim 19, wherein the maximum value is determined by a coefficient of a droop characteristic graph when the first distributed generator which is first connected to the main grid connection power line operates in the first mode.