ELECTRIC POWER GRID CONTROL SYSTEM AND METHOD FOR ELECTRIC POWER CONTROL

• US 20130184894A1
• Filed: 11/08/2011
• Published: 07/18/2013
• Est. Priority Date: 11/08/2010
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Sakuma, Hisato, Kudo, Koji, Yano, Hitoshi
• Granted Patent: US 9,612,584 B2
• Time in Patent Office: Days
• US Class Current: 700/298
• CPC Class Codes: G05B 13/02 electric
• CPC Class Codes: H02J 3/12 for adjusting voltage in ac networks by changing a characteristic of the network load
• CPC Class Codes: H02J 3/16 by adjustment of reactive power
• CPC Class Codes: H02J 3/381 Dispersed generators
• CPC Class Codes: H02J 3/46 Controlling of the sharing of output between the generators, converters, or transformers
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

An electric power grid control system is provided with: distributed generators connected to an electric power grid; and voltage measurement units that measure voltage at connection points of the distributed generators to the electric power grid. When voltage at a connection point to the electric power grid deviates from a predetermined acceptable range, a centralized control device equally allocates a voltage adjustment amount for returning the voltage to the acceptable range to all distributed generators belonging to a predetermined group that was set in advance. Distribution processing devices cause the distributed generators to adjust voltage at the connection points in accordance with the voltage adjustment amount allocated from the centralized control device.

Claims

1. An electric power grid control system comprising:

distributed generators that are connected to an electric power grid;

voltage measurement units that measure voltage of connection points of said distributed generators to said electric power grid;

a centralized control device that, when voltage at a said connection point deviates from a predetermined acceptable range, equally allocates a voltage adjustment amount for returning the voltage to said acceptable range to all said distributed generators within a predetermined group that has been set in advance; and

distribution processing devices that cause said distributed generators to adjust voltage at said connection points in accordance with said voltage adjustment amount that was allocated from said centralized control device.

2. The electric power grid control system according to claim 1, wherein said distribution processing devices adjust voltage at said connection points by means of active power or reactive power that is caused to flow back to said electric power grid from said distributed generators.

3. The electric power grid control system according to claim 2, further comprising controllable load in which the amount of electric power consumption can be controlled;

wherein;

said distribution processing devices adjust voltage at said connection points by advanced-phase reactive power that is caused to flow back to said electric power grid from said distributed generators, the amount being the amount of power generated by said distributed generators, or the amount of electric power consumed by said controllable load.

4. The electric power grid control system according to claim 1, wherein said distribution processing devices make the ratio between the voltage adjustment amount by said reactive power and the voltage adjustment amount by said active power 1/(dV/dP):

1/(dV/dQ), where V is the voltage at said connection points, P is said active power amount, and Q is said reactive power amount.

5. The electric power grid control system according to claim 1, wherein:

said group is formed of consumers that are connected to the same pole transformer and that are provided with said distributed generators, said voltage measurement units, and said distribution processing devices; and

said centralized control device allocates said voltage adjustment amount to all said distributed generators within a group that contains a distributed generator having a connection point at which said voltage has deviated from said acceptable range.

6. An electric power grid control method of an electric power grid control system that is equipped with distributed generators that are connected to an electric power grid and voltage measurement units that measure voltage of connection points of said distributed generators to said electric power grid, said control method comprising steps of:

when voltage at a said connection point deviates from a predetermined acceptable range, equally allocating a voltage adjustment amount for returning the voltage to said acceptable range to all of said distributed generators that belong to a predetermined group that is set in advance; and

causing said distributed generators to adjust voltage at said connection points in accordance with said voltage adjustment amount that was allocated.

7. The electric power grid control method according to claim 6, wherein voltage at said connection points is adjusted by means of reactive power that is caused to flow back to said electric power grid from said distributed generators or active power.

8. The electric power grid control method according to claim 7, wherein:

controllable load in which the amount of electric power consumption can be controlled is equipped in said electric power grid control system; and

voltage at said connection points is adjusted by advanced-phase reactive power that is caused to flow back to said electric power grid from said distributed generators, the amount being the amount of power generated by said distributed generators, or the amount of electric power consumed by said controllable load.

9. The electric power grid control method according to claim 6, wherein the ratio of the voltage adjustment amount realized by said reactive power to the voltage adjustment amount realized by said active power is 1/(dV/dP):

1/(dV/dQ), where V is the voltage at said connection points, P is said active power amount, and Q is said reactive power amount.

10. The electric power grid control method according to claim 6, wherein:

said group is formed of consumers that are connected to the same pole transformer and that are provided with said distributed generators, said voltage measurement units, and said distribution processing devices; and

said voltage adjustment amount is equally allocated to all said distributed generators within a group that contains a distributed generator having a connection point at which said voltage has deviated from said acceptable range.