Real power loss minimization in radial distribution system by reconfiguration using queen bee

Network reconfiguration is the process of changing the topology of distribution systems by altering the open/closed status of switches.

Open switches are normally called as tie switches. Closed switches are called as sectionalizing switches.

During normal operating condition, networks are reconfigured for: 1. To minimize the system real power losses in the network .

During abnormal operating condition, networks are reconfigured for1.To supply continuous power to the load even under faulty condition.2. To relieve over loads in the feeders.

F = min (PT,Loss)------------(1)

where ,PT,Loss - total real power loss of the system.

In every optimization algorithm two conditions has to be checked for reconfiguration of Radial distribution system

Radiality All the load in the system has to be supplied

Read the input data of the given network Apply distribution load flow procedure to

the network Apply AI technique for reconfiguration

procedure Find the optimal configuration and display

the results

33 BUS RADIAL DISTRIBUTION TEST SYSTEM

33 buses

32 branches

3 laterals

5 tie-lines

10

Line No

Sending Bus

Receiving Bus

Resistance(Ohm)

Reactance(Ohm)

PL (KW)

QL (KVAr)

1 1 2 0.0922 0.0477 100 60

2 2 3 0.4930 0.2511 90 40

3 3 4 0.3660 0.1864 120 80

4 4 5 0.3811 0.1941 60 30

5 5 6 0.8190 0.7070 60 20

6 6 7 0.1872 0.6188 200 100

7 7 8 1.7114 1.2351 200 100

8 8 9 1.0300 0.7400 60 20

9 9 10 1.0400 0.7400 60 20

10 10 11 0.1966 0.0650 45 30

11 11 12 0.3744 0.1238 60 35

INPUT DATA FOR 33-BUS SYSTEMINPUT DATA FOR 33-BUS SYSTEM

Line No Sending Bus

Receiving Bus

Resistance(Ohm)

Reactance(Ohm)

PL (KW)

QL (KVAr)

12 12 13 1.4680 1.1550 60 35

13 13 14 0.5416 0.7129 120 80

14 14 15 0.5910 0.5260 60 10

15 15 16 0.7463 05450 60 20

16 16 17 1.2890 1.7210 60 20

17 17 18 0.7320 0.5740 90 40

18 2 19 0.1640 0.1565 90 40

19 19 20 1.5042 1.3554 90 40

20 20 21 0.4095 0.4784 90 40

21 21 22 0.7089 0.9373 90 40

22 3 23 0.4512 0.3083 90 50

Line No Sending Bus

Receiving Bus

Resistance(Ohm)

Reactance(Ohm)

PL

(KW)QL

(KVAr)

23 23 24 0.8980 0.7091 420 200

24 24 25 0.8960 0.7011 420 200

25 6 26 0.2030 0.1034 60 25

26 26 27 0.2842 0.1447 60 25

27 27 28 1.0590 0.9337 60 20

28 28 29 0.8042 0.7006 120 70

29 29 30 0.5075 0.2585 200 600

30 30 31 0.9744 0.9630 150 70

31 31 32 0.3105 0.3619 210 100

32 32 33 0.3410 0.5302 60 40

RESULTS FOR BASE CASE LOAD FLOWRESULTS FOR BASE CASE LOAD FLOW

Bus No. Voltage Real power(KW) Reactive power(KVAR)

1 1.00334 3917.91 2458.882 0.999673 3905.67 2452.553 0.984357 3392.61 2205.024 0.977662 2342.89 1697.635 0.968257 2204.06 1608.046 0.94823 2105.85 1528.097 0.947799 1093.12 528.1318 0.941539 888.345 419.8369 0.934628 684.217 316.8710 0.928186 620.701 294.37711 0.927081 560.154 274.196

Bus No. Voltage Real power(KW) Reactive power(KVAR)

120.925168 514.283 243.908

130.918582 451.649 206.835

140.916507 390.93 170.888

150.91505 270.578 90.5747

160.913568 210.3 80.372

170.911711 150.052 60.041

180.911059 90 40

190.995094 360.979 160.928

200.991394 270.145 120.176

210.990724 180.044 80.0579

220.990143 90 40

Bus No. Voltage Real power(KW) Reactive power(KVAR)

230.971975 936.531 455.148

240.964742 841.308 401.023

250.961132 420 200

260.944033 948.222 972.35

270.940576 884.888 945.651

280.928216 813.569 910.671

290.919284 745.729 883.839

300.914319 621.823 811.848

310.910099 420.226 210.269

320.909226 270.013 140.021

330.908992 60 40

TOTAL REAL POWER LOSS: 199.1 kw

Generation of bees Identification of Queen bee Mating flight or Reproduction Piping

It is the process of generating bees or solution set. Here, the bees are generated by simple heuristic rules.

In general, fitness function F(X) is derived from the objective function.

The fitness function is defined as

F(X) = f(x) for Max problem F(X) = 1/f(x) for Min problem , if f(x) ≠ 0 F(X) = 1/(1+ f(x)) for Min problem ,if f(x) = 0

where ,f(x) – objective function of the problem

Among the generated bees, queen bee is selected as one which has the best fitness.

The queen bee makes a mating flight for the reproduction of next generation bees.

Drones: All the bees except Queen Bee All drones may not fly fast to reach a queen,

hence incorporating a probability of recombination associated with each drone ( ).

Recombination probability is indicated as . If , no recombination takes and hence no

offspring.

If , the drones combines with queen bee producing two virgin queen bees. This is similar to the crossover operator in standard GA.

Here, two point cross over is used. In a two point cross over, two random sites are chosen . If the cross site 1 is three and cross site 2 is six, then the strings between three and six are exchanged.

cs1 cs2 Parent-1 Parent-2 Strings before mating cs1 cs2 Child-1 Child-2

1 0 1 1 1 1 1 1

1000100 1

1 0 1 1 1001

01

0 1 0 1 1 1 0 1

Strings after mating

In a hive, all the virgin queen bees will fight each other, and the fittest alone survives.

All the virgin queens together with mother queen bee are once again evaluated and new queen bee is identified; all other bees are made drones

3

cba

Queen

65421

d e f g h i j

Virgin Bees + Mother

New Queen Bee + Drones

Stop

Start

No

Yes

Generate n bees randomly

Identify the queen bee using Eq (1)

Mating of queen bee with drones based on a probability approach and generation of virgin queen

bees

Piping and Identification of new queen bee using Eq(1)

Formation of drones of

population size (n-1)

Is termination criterion reached?

Select queen bee as the optimum solution

1. Read the bus data and line data for the distribution test system.

2. Generate queen bee by heuristic algorithm.3. Run the load flow and calculate the fitness for the

population. 4. Mating Flight:Perform Mating Flight or Reproduction

(which is similar to cross over operation in standard GA) by taking two chromosomes(always one is Queen bee and the other is drone taken on by one) at a time from the population. Generate a random number for the crossover point. Here the two point cross over is used

5. Once the crossover is over,check the radiality for the off -springs. If the distribution network has no closed loops and all the loads were connected, the network is radial.

6. Sort the population and off springs.7. Piping:Choose the best individuals of population size

according to their fitness. In that,choose the best one as queen bee for the next iteration.

8. With this new population, repeat the steps 4 to 7 until maximum iteration is reached.

9. The switch status and voltage at each bus of the minimum loss configuration are displayed.

10. Stop the process.

SWITCHES 1 2 3 4 5 6 7 8 9 10

11

12

13

14

15

16

17

18

19

SWITCHING STATUS

1 1 1 1 1 1 0 1 1 1 0 1 1 1 1 1 1 1 1

SWITCHING STATUS AFTER FINAL RECONFIGURATION

SWITCHES

20

21

23

24 25

26

27

28

29

30

31

32

33

34

35

36

37

SWITCHING STATUS

1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0