Distributed power generation

• US 9,118,196 B2
• Filed: 04/29/2010
• Issued: 08/25/2015
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Trainer, David R, Roscoe, Andrew J, Knight, Richard C
• Primary Examiner(s): Amaya, Carlos
• Application Number:
  US13/318,390
• Publication Number:
  US 20120104847A1
• Time in Patent Office: 1,944 Days
• Field of Search: 307/23, 307/24, 307/30, 307/64
• US Class Current: 1/1
• CPC Class Codes: H02J 3/00 Circuit arrangements for ac mains or ac distribution networks
• CPC Class Codes: H02J 3/38 Arrangements for parallely feeding a single network by two or more generators, converters or transformers
• CPC Class Codes: H02J 4/00 Circuit arrangements for mains or distribution networks not specified as ac or dc
• CPC Class Codes: H02J 9/002 in which a reserve is maintained in an energy source by disconnecting non-critical loads, e.g. maintaining a reserve of charge in a vehicle battery for starting an engine

Abstract

Distributed power generation systems generally include a number of power sources and electrical power loads interconnected by a distribution network. Electrical switches and fuses are provided such that local groups of power sources and power loads can be established. Should there be a degradation in the distribution network in terms of a set of criteria such as electrical frequency, current or voltage then the switch or fuse may be thrown to establish each local group as an island. By monitoring divergence from a set of criteria a method and controller may be utilised whereby the distribution network as a whole is considered and configured to establish virtual islands which operate prior to the establishment whether inadvertently or deliberately of actual islands within the distribution network. In such circumstances the transition from normal operation for the distribution network to islanded operation for the distribution network is less severe.

Claims

1. A method of operating a distributed power generation system comprising a plurality of electrical power sources and a plurality of electrical loads, interconnected by a main distribution network, one or more switches for forming one or more local group distribution networks, each local distribution network comprising at least one electrical power source and at least one electrical load, the method comprising:

(i) monitoring the main distribution network by comparing the electrical power flow with a set of criteria, the criteria being indicative of an impending disconnection of the local distribution network from the main distribution network,

(ii) determining if the electrical power flow on the main distribution network diverges from the set of criteria,

(iii) maintaining the switch between at least one of the local group distribution networks and the main distribution network closed,

(iv) preemptively configuring the at least one of the local group distribution networks in preparation of the local group distribution network being disconnected from the main distribution network whereby the electrical power from the or each electrical power source within the at least one of the local group distribution networks substantially matches the electrical power requirements of the electrical loads in the at least one of the local group distribution networks if the electrical power flow in the main distribution network diverges from the set of criteria, and

(v) shedding electrical loads within the at least one of the local group distribution networks.

2. A method as claimed in claim 1 comprising identifying priority electrical loads within the at least one of the local group distribution network and ensuring the priority electrical loads are preferentially incorporated within the local group distribution network in preference to lesser priority electrical loads.

3. A method as claimed in claim 1 comprising controlling the power output of the electrical power sources within the at least one of the local group distribution networks.

4. A method as claimed in claim 1 comprising reducing power exchange between the at least one of the local group distribution networks and the main distribution network.

5. A method as claimed in claim 4 comprising reducing power exchange between the at least one of the local group distribution networks and the main distribution network to zero.

6. A method as claimed in claim 1 comprising initiating operation of at least one emergency electrical generator.

7. A method as claimed in claim 1 comprising determining if the electrical power flow on the main distribution network diverges from the set of criteria repeatedly with a set time period between each determination.

8. A method as claimed in claim 7 wherein the time period is more than once a second.

9. A method as claimed in claim 1 wherein the set of criteria comprises at least one of voltage, current, frequency, fluctuation, imbalance, flicker or harmonics of the electrical power flow.

10. A distributed power generation system comprising a plurality of electrical power sources and a plurality of electrical loads interconnected by a main distribution network, one or more switches for forming one or more local group distribution networks, each local group distribution network comprising at least one electrical power source and at least one electrical load, the distributed power generation system comprising at least one controller arranged to:

(i) monitor the main distribution network by comparing the electrical power flow with a set of criteria, the set of criteria being indicative of an impending disconnection of the local distribution network from the main distribution network;

(ii) determine if the electrical power flow on the main distribution network diverges from the set of criteria,

(iii) maintain the switch between the at least one of the local group distribution networks and the main distribution network closed,

(iv) preemptively configure the at least one of the local group distribution networks in preparation of the local group distribution network being disconnected from the main distribution network whereby the electrical power from the or each electrical power source with the at least one of the local group distribution networks substantially matches the electrical power requirements of the electrical loads in the at least one of the local group distribution networks if the electrical power flow in the main distribution network diverges from the criteria, and

(v) operate switches to shed electrical loads within the at least one of the local group distribution networks.

11. A distributed power generation system as claimed in claim 10 wherein the controller is arranged to control the power output of the electrical power sources within the at least one of the local group distribution networks.

12. A distributed power generation system as claimed in claim 10 wherein the controller is arranged to reduce the power exchange between the at least one of the local group distribution networks and the main distribution network.

13. A distributed power generation system as claimed in claim 10 wherein the controller is arranged to initiate operation of the at least one emergency electrical generator.

14. A distributed power generation system as claimed in claim 10 wherein the controller is arranged to determine if the electrical power flow on the main distribution network diverges from the set of criteria repeatedly with a set time period between each determination.

15. A distributed power generation system as claimed in claim 10 wherein the set of criteria comprises at least one of voltage, current, frequency, fluctuation, imbalance, flicker or harmonics of the electrical power flow.