Distributed power generation system, control means and method for controlling the power generation of the system

1. An apparatus ( 120 ) for controlling the power generation of a distributed power generation system ( 100 ) including a plurality of small power plants ( 110 ), characterized in that the apparatus comprises

a first communication interface unit ( 301 ) configured to receive, from each of the small power plants ( 110 ) via a first communication interconnection ( 311 ), measured values of the instantaneous power generated by the small power plants ( 110 ) in the distributed power generation system ( 100 ), and to transmit, through said first communication interconnection ( 311 ) to each of the small power plants ( 110 ), information relating to the individual power control of the small power plants ( 110 ),

a second communication interface unit ( 302 ) configured to receive, from a production control center ( 160 ) via a second communication interconnection ( 312 ), power values to be provided by the distributed power generation system for said power supply system, said power values being specified by said production control system as a function of the instantaneous load of the power supply system managed by said production control system, and

a central data processing unit ( 330 ) configured to determine the aggregate instantaneous power of the distributed power generation system ( 100 ) on the basis of the measured power values received from the small power plants ( 110 ), to determine the difference between the power specified by the production control center ( 160 ) for the distributed power generation system ( 100 ) and the aggregate instantaneous power of the distributed power generation system ( 100 ), and to generate power control information for each of said small power plants as a function of said power difference, according to a predetermined method.

2. The apparatus according to claim 1 , characterized in that the apparatus further comprises a display unit ( 340 ) for monitoring the operation of the distributed power generation system ( 100 ), and an input device ( 350 ) for a partially or entirely manual control of said distributed power generation system.

3. The apparatus according to claim 2 , characterized in that the central data processing unit ( 330 ) is arranged in a server park ( 120 a ), while the display unit ( 340 ) and the input device ( 350 ) are arranged in a dispatcher station ( 120 b ) locating remotely from said server park ( 120 a ), wherein a communication interconnection ( 314 ) between the server park ( 120 a ) and the dispatcher station ( 120 b ) is provided by the internet.

4. The apparatus according to claim 1 , characterized in that the first communication interconnections ( 311 ) are Internet connections.

5. The apparatus according to claim 1 , characterized in that the first and second interface units ( 301 , 302 ) are integrated into a single communication unit ( 300 ).

6. A distributed power generation system ( 100 ) including a plurality of small power plants ( 110 ), each of said small power plants comprising one or more power generation units ( 200 ), at least one power measurement unit ( 210 ), a power plant control unit ( 220 ), a communication network interface unit ( 230 ) and a switching unit ( 250 ) for coupling to a power distribution network ( 150 ), characterized in that the system further comprises

a central control apparatus ( 120 ) according to claim 1 , and

a communication network ( 400 ) for providing communication interconnections ( 311 ) between said control apparatus ( 120 ) and each of the small power plants ( 110 ).

7. The system according to claim 6 , characterized in that the communication network ( 400 ) is the Internet.

8. A method for controlling the power generation of a distributed power generation system including a plurality of small power plants, wherein said distributed power generation system produces power for a power supply system managed by a production control center, characterized in that the method comprises the steps of

receiving measurement data relating to instantaneous power generated by the small power plants for the distributed power generation system (S 600 ), and determining from said measurement data an aggregate instantaneous power of the distributed power generation system (S 610 ),

from said production control center, receiving, at predetermined intervals, a plurality of control reference signal values specifying the power to be produced by the distributed power generation system for said power supply system as a function of the instantaneous load in the power supply system managed by said production control center (S 620 ),

determining a difference between the power specified by said production control center for the distributed power generation system and the aggregate instantaneous power of the distributed power generation system (S 630 ), and

individually controlling the power of each small power plant within a predetermined time limit so that

if the power specified for the distributed power generation system is greater than the aggregate instantaneous power of the distributed power generation system, then instructing at least one small power plant selected from the small power plants having free capacity to increase its power (S 640 ),

if the power specified for the distributed power generation system is equal to the aggregate instantaneous power of the distributed power generation system, then keeping the aggregate power of the distributed power generation system unchanged (S 650 ), and

if the power specified for the distributed power generation system is smaller than the aggregate instantaneous power of the distributed power generation system, then instructing at least one small power plant selected from said plurality of small power plants to decrease its power (S 660 ).

9. The method according to claim 8 , characterized in that step S 640 further comprises increasing the power of each one of those small power plants that have free capacity.

10. The method according to claim 8 , characterized in that step S 640 further comprises increasing the power of the at least one selected small power plant at the highest possible power changing rate.

11. The method according to claim 8 , characterized in that step S 660 further comprises decreasing the power of each of the small power plants.

12. The method according to claim 8 , characterized in that step S 660 further comprises decreasing the power of the at least one selected small power plant at the highest possible power changing rate.

13. The method according to claim 8 , characterized in that in step S 660 , the control reference signal values are received from the production control center at intervals of at most 1 minute, preferably at intervals of at most 1 second, and the time limit of the generation of the power control instructions is at most 1 second, preferably at most 0.5 second, more preferably at most 0.1 second.

14. The method according to claim 8 , characterized in that when the power of the distributed power generation system has reached the power specified by the production control center for it or has approximated the specified power with a predetermined error, the method further comprises a step of modifying the power of at least two small power plants in a predetermined manner for optimizing the combined energetic efficiency of the small power plants, while keeping the aggregate power of distributed power generation system at the same level.

15. The method according to claim 14 , characterized in that the individual powers of the selected small power plants are modified towards such power values that have the same relative deviation from the scheduled power values of the respective small power plants.