Load leveling system of power system

• US 9,478,986 B2
• Filed: 08/17/2012
• Issued: 10/25/2016
• Est. Priority Date: 08/23/2011
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Tohoku Electric Power Company Incorporated
• Original Assignee: Hitachi, Ltd., Tohoku Electric Power Company Incorporated
• Inventors: Takahashi, Hirotaka, Tomita, Yasushi, Oda, Takashi, Isozaki, Eri, Onishi, Tsukasa, Horikoshi, Kazuhiro, Matsuda, Katsuhiro
• Primary Examiner(s): Ali, Mohammad
• Assistant Examiner(s): Kabir, Saad M
• Application Number:
  US13/588,080
• Publication Number:
  US 20130054040A1
• Time in Patent Office: 1,530 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H02J 2310/58 The condition being electrical
• CPC Class Codes: H02J 3/003 Load forecast, e.g. methods or systems for forecasting future load demand
• CPC Class Codes: H02J 3/144 Demand-response operation of the power transmission or distribution network
• 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

A load leveling system and a method for a power system are capable of attaining load leveling in a distribution substation unit. The load leveling system is for a power system with a controller having a major customer and lower transforming apparatus, and with a customer connected to the lower transforming apparatus via a low-voltage line. The system also has a communication unit between the customer and its own system, and control use time zones of devices within the customer, as well as an electric demand prediction unit, and a first load leveling processing unit. By employing such a system, it becomes possible to provide a load leveling system for a power system that is capable of realizing load leveling of both a distribution substation unit and a pole transformer unit.

Claims

1. A load leveling system of a power system comprising:

a lower transforming apparatus;

an upper transforming apparatus;

a high-voltage line;

a low-voltage line;

a communication unit;

a load leveling device;

an electric demand prediction unit configured to divide a future electric demand into an adjustable demand and a non-adjustable demand and calculate the adjustable and non-adjustable demands in each time zone at least in the lower transforming apparatus and the upper transforming apparatus;

a first load leveling processing unit configured to set an electric demand target within a maximum electric demand, shift a demand larger than the electric demand target to other time zones, and distribute the demand larger than the electric demand target to the lower transforming apparatus for at least one customer in accordance with an electric demand of the upper transforming apparatus from the electric demand prediction unit;

a second load leveling processing unit configured to correct an electric demand of the lower transforming apparatus from the electric demand prediction unit with the electric demand distributed by the first load leveling processing unit, reduce a maximum electric demand after correction by a predetermined amount to set a new target, and repeat a correction while confirming that the electric demand of the upper transforming apparatus in the time zone at a time of shifting the reduced demand to a minimum demand time zone is not larger than the electric demand target; and

an output unit configured to distribute an electric demand in each time zone determined by the second load leveling processing unit to each device within at least one other customer and control a use time zone of the devices within the at least one other customer through a communication unit;

wherein a major customer of the power system and the lower transforming apparatus are connected to the upper transforming apparatus via the high-voltage line, and the at least one other customer of the power system is connected to the lower transforming apparatus via the low-voltage line;

wherein the communication unit is arranged for communication between the major customer and the at least one other customer; and

wherein the load leveling device operates to predict, for each of said time zones, at least electric demands of the upper transforming apparatus and the lower transforming apparatus based on past data for electric demand of a day of conditions nearest to those of a prediction day and further added specific conditions, and output change request information of an operation time of devices within the at least one other customer, according to the prediction made by the load leveling device, so as to reduce a maximum value of electric demands of both the upper transforming apparatus and the lower transforming apparatus for each of the upper and lower transforming apparatuses respectively corresponding to either one of said adjustable demand or said non-adjustable demand.

2. The load leveling system of a power system according to claim 1, wherein the electric demand target is set to a maximum value of a non-adjustable demand.

3. The load leveling system of a power system according to claim 1, wherein a minimum demand time zone for shifting a reduced demand in the second load leveling processing unit is set as a time zone other than the time zone set as an electric demand target in the first load leveling processing unit.

4. The load leveling system of a power system according to claim 2, wherein a minimum demand time zone for shifting a reduced demand in the second load leveling processing unit is set as a time zone other than the time zone set as an electric demand target in the first load leveling processing unit.