Apparatus and method for adjusting a voltage in a power distribution system

• US 9,575,482 B2
• Filed: 09/30/2011
• Issued: 02/21/2017
• Est. Priority Date: 09/27/2011
• Status: Active Grant

• Current Assignee: Korea Electric Power Corporation (Government of South Korea)
• Original Assignee: Korea Electric Power Corporation (Government of South Korea)
• Inventors: Namkoong, Won, Ha, Bok-Nam, Lee, Sung-Woo, Seo, In-Yong, Jang, Moon-Jong, Seo, Dong-Wan, Kim, Sang-Ok
• Primary Examiner(s): Rampuria, Satish
• Application Number:
  US14/347,419
• Publication Number:
  US 20140244061A1
• Time in Patent Office: 1,971 Days
• Field of Search: 700286-296
• US Class Current: 1/1
• CPC Class Codes: G05B 19/02 electric
• CPC Class Codes: H02J 3/144 Demand-response operation of the power transmission or distribution network
• CPC Class Codes: H02J 3/32 using batteries with converting means
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

The present invention relates to an apparatus and method for performing adjustment to optimize the voltage for each distribution network in a power distribution system. The apparatus for adjusting a voltage in the power distribution system adjusts the voltage by switching a switch that lies on a path in the power distribution system. The apparatus determines a switch that is to become a switching target from among switches lying on the path, obtains a voltage optimization value of the determined switching target switch, selects a switch having the minimum voltage optimization value by changing the switching target switch to another switch in order to obtain the voltage optimization value, and adjusts the voltage through switching of the selected switch.

Claims

1. A voltage control apparatus for controlling voltage through switching of a switch present on a path in a power distribution system, the apparatus comprising:

a processor including;

a voltage optimization unit configured to determine switching-target switches from among switches present on the path, and to calculate a voltage optimization value of the determined switching-target switches; and

a switch selection unit configured to select a switch corresponding to a location at which a voltage optimization value is minimum while moving locations of the switching-target switches, and to control voltage of the selected switch through switching of the selected switch,

wherein the voltage optimization unit comprises;

a voltage distribution value calculation unit configured to calculate a voltage distribution value of a transformer and a voltage distribution value of a power distribution line corresponding to the switching-target switches;

a normalization unit configured to normalize the voltage distribution value of the transformer and the voltage distribution value of the power distribution line; and

an optimization unit configured to calculate a voltage optimization value by applying target coefficients to each of the normalized values.

2. The voltage control apparatus of claim 1, wherein the switching of the switch is performed at a switch present on the path between points of two power distribution lines.

3. The voltage control apparatus of claim 1, wherein the voltage distribution value calculation unit calculates the voltage distribution value of the transformer using a target operation value of each substation, an operating voltage value of the substation, and a total number of transformers.

4. The voltage control apparatus of claim 1, wherein the voltage distribution value calculation unit calculates the voltage distribution value of the power distribution line using a target operating voltage value of the power distribution line, a voltage value between switches on the power distribution line, and a number of switch sections on the power distribution line.

5. The voltage control apparatus of claim 1, wherein the optimization unit applies a target coefficient corresponding to voltage optimization of a substation and a target coefficient corresponding to voltage optimization of the power distribution line to each of the normalized values.

6. The voltage control apparatus of claim 1, wherein the switch selection unit selects the specific switch from among the switching-target switches, compares an amount of circulation current with an allowable value when the specific switch is closed, and selects a switch corresponding to a location at which the voltage optimization value is minimum based on results of the comparison.

7. The voltage control apparatus of claim 6, wherein if the amount of circulation current is larger than the allowable value, the switch selection unit selects another switch other than the specific switch from among the switching-target switches, and compares an amount of circulation current with the allowable value again when the other switch is closed.

8. The voltage control apparatus of claim 6, wherein if the amount of circulation current is equal to or lower than the allowable value, the switch selection unit selects a switch corresponding to a location at which the voltage optimization value is minimum while moving locations of the switching-target switches.

9. The voltage control apparatus of claim 1, further comprising a check unit configured to check whether or not voltage optimization values of all the switches on the path have been calculated, and to check whether or not a voltage optimization value of the selected switch is lower than the voltage optimization value obtained by the voltage optimization unit.

10. The voltage control apparatus of claim 1, further comprising a tap selection unit configured to select a tap that allows a bank-based voltage optimization value to be minimum while switching between taps of a tap switching device when a load is applied.

11. The voltage control apparatus of claim 10, wherein the tap selection unit calculates the hank-based voltage optimization value using a target operating voltage value of the power distribution line, a voltage value between switches of the power distribution line within the bank, and a number of switch sections within the bank.

12. A method of controlling voltage in a power distribution system, the method comprising:

determining switching-target switches from among switches present on a path in the power distribution system;

calculating voltage optimization values of the determined switching-target switches;

selecting a switch corresponding to a location at which the voltage optimization value is minimum while moving locations of the switching-target switches; and

controlling voltage of the selected switch through switching of the selected switch,

wherein calculating the voltage optimization values comprises;

calculating a voltage distribution value of a transformer and a voltage distribution value of a power distribution line corresponding to the switching-target switches;

normalizing the voltage distribution value of the transformer and the voltage distribution value of the power distribution line; and

calculating each of the voltage optimization values by applying target coefficients to each of the normalized values.

13. The voltage control method of claim 12, wherein the voltage distribution value of the transformer is calculated using a target operation value of each substation, an operating voltage value of the substation, and a total number of transformers.

14. The voltage control method of claim 12, wherein the voltage distribution value of the power distribution line is calculated using a target operating voltage value of the power distribution line, a voltage value between switches on the power distribution line, and a number of switch sections on the power distribution line.

15. The voltage control method of claim 12, wherein controlling of the voltage comprises:

selecting a tap that allows a bank-based voltage optimization value to be minimum while switching between taps of a tap switching device when a load is applied; and

controlling the voltage via the tap.

16. The voltage control method of claim 12, wherein selecting the switch comprises selecting a specific switch from among the switching-target switches, comparing an amount of circulation current with an allowable value when the specific switch is closed, and selecting a switch corresponding to a location at which the voltage optimization value is minimum based on results of the comparison.