# US 2012/0239601 A1 · Restoration Switching Analysis with Genetic Algorithm

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- Number: US 2012/0239601 A1
- Document ID: US20120239601A1
- Status: Published application
- Kind: A1
- Application number: 13/510,301
- Filed: 2010-12-03
- Published: 2012-09-20
- Earliest claimed: 2009-12-04
- Assignees: ABB Research Ltd.
- Inventors: Zhenyuan Wang; Wenping Li
- Web page: https://patentgrep.com/patent/US20120239601A1

## CPC

- G06N 3/126: Evolutionary algorithms, e.g. genetic algorithms or genetic programming
- H02J 13/1323: {using optical fibres}
- H02J 13/333: the equipment forming part of substations
- H02J 3/0073: by providing alternative feeding paths when the main path fails
- H02J 2103/30: Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks
- Y02E 60/00: Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y04S 10/52: Outage or fault management, e.g. fault detection or location
- Y04S 40/124: using wired telecommunication networks or data transmission busses
- Y04S 40/20: Information technology specific aspects, e.g. CAD, simulation, modelling, system security
- G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y04S: SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS

## Abstract

A method for generating switching plans to restore power to out-of-service areas after fault isolation through back feeding. A chromosome architecture is defined to create chromosomes representing candidate post-restoration systems. The chromosomes are evaluated are repeatedly genetically altered until an acceptable solution is identified. The solution identifies a plurality of switching operations that back feed power to the out-of-service areas in the most optimal manner.

## Claims

### Claim 1

A method for determining back-feed paths to one or more out-of-service load areas in a network after fault isolation, the method comprising:
i. defining a chromosome architecture for creating a plurality of unique chromosomes, each said chromosome being a string of characters, each said character representing one of a list of actions for a normally open switch in said network, said list of actions including (1) remaining open, (2) closing, or (3) swapping with a normally closed switch selected from a group of corresponding normally closed switchs;
ii. initializing a chromosome list;
iii. using said chromosome architecture, creating initial chromosomes for a first chromosome population, for each said initial chromosome, if valid and not in said chromosome list, adding said initial chromosome to said initial chromosome population; for each said initial chromosome created, adding to said initial chromosome to said chromosome list;
v. generating fitness function values for each chromosome in said initial chromosome population;
vi. sorting said chromosomes by fitness function value, said chromosome having the lowest fitness function value being the best candidate chromosome;
vii. determining if the fitness function value of said best candidate chromosome is below a threshold fitness value, and if so, outputting a network configuration corresponding to said best candidate chromosome;
viii. if said fitness function value of said best candidate chromosome is not below said threshold fitness value, using genetic manipulation to create new chromosomes for a new chromosome population, during said creation of said new chromosome population, rejecting any new chromosomes already in said chromosome list and adding said new chromosomes in said new population to said chromosome list;
ix. generating fitness function values for each chromosome in said new population; and
x. repeating steps vi-ix until the fitness function value of said best candidate chromosome is below said threshold fitness value or until a predetermined number of new populations are created, whereupon a network configuration corresponding to said best candidate chromosome is output.

### Claim 2 (depends on 1)

The method of claim 1 wherein said fitness function comprises:
fit(idv)=wSwSwOpnr(idv)+wIvioIvionr(idv)+wPPnr(idv)
where idv is an index of an individual network topology corresponding to a chromosome (hereinafter candidate network); Ivionr is a normalized number of back-path current violations in the candidate network; SwOpnr is the normalized switching operations for the candidate network; Pnr is the normalized total unserved load for the candidate network; and wIvio, wSw, wp are user definable weighting factors.

### Claim 3 (depends on 2)

The method according to claim 2 wherein weighting value wp is increased by a factor larger than 1 for each new generation of chromosomes.

### Claim 4 (depends on 2)

The method of claim 2 wherein:
SwOpnr(idv)=NoSwitchOperations(idv)/NoTieSwitchesbase
Pnr(idv)=(TotalWeightedLoadbase−TotalWeightedLoad(idv)/TotalWeightedLoadbase
where base represents said network in a post-isolation configuration and (idv) represents the candidate network; NoTieSwitchesbase is the total number of normally open tie switches in said network; NoSwitchOperations is the number of switch operations, excluding isolation switching operations, needed for a transition from said post-isolation configuration to said candidate network; Total WeightedLoadbase is a weighted total load of said network; Total WeightedLoad(idv) is a weighted total load of the candidate network.

### Claim 5 (depends on 4)

The method of claim 4 wherein:
TotalWeightedLoad=ΣLoadinOOSAreas+PenaltyFactor*ΣLoadinBackFeedingAreas
where LoadinOOSAreas is the load in the out-of-service areas of said network and LoadinBackFeedingAreas is the remaining load in the non-isolated or faulted portions of said network; the PaneltyFactor being greater than 1.

### Claim 6 (depends on 2)

The method of claim 2 wherein:
Ivionr=Ivio(idv)/Iviomax
where Ivio(idv) is the number of current violations for a candidate network and Iviomax is the largest number of current violations for any chromosome in a generation.

### Claim 7 (depends on 1)

The method of claim 1 wherein said step of creating initial chromosomes includes, for each said normally open tie switch, randomly selecting one of said list of actions.

### Claim 8 (depends on 1)

The method of claim 1 wherein, for each said normally open tie switch, said corresponding normally closed switch includes normally closed switches upstream of said normally open tie switch and, if said normally open tie switch bounds one of said out-of-service areas, said corresponding normally closed switch also includes normally closed switches in that out-of-service area.

### Claim 9 (depends on 1)

The method of claim 1 wherein said characters are ASCII characters.

### Claim 10 (depends on 4)

The method of claim 4 wherein the initial population size and the new population size equals 4*N+1, where N=NoTieSwitchesbase/2 and where N is an integer.

### Claim 11 (depends on 1)

The method of claim 1 wherein said step of using genetic manipulation to create new chromosomes for a new chromosome population further comprises:
directly copying a plurality of chromosomes from said initial population to the new population; and
performing crossovers and mutations on said plurality of chromosomes from said initial population to the new population.

### Claim 12 (depends on 1)

The method of claim 1 wherein said step of using genetic manipulation to create new chromosomes of a new chromosome population further comprises:
adding the top N chromosomes from the previous generation to the new generation unchanged;
crossing-over the best candidate chromosome with the next N chromosomes to generate N new chromosomes;
mutating the next N chromosomes after the top N to create N new chromosomes in the new generation; and
if additional new chromosomes are required to fill said new generation, for each said normally open tie switch, randomly selecting one of said list of actions.