DOI : 10.17577/IJERTV1IS5073
- Open Access
- Total Downloads : 1840
- Authors : T. Suresh Kumar, V. Sankar
- Paper ID : IJERTV1IS5073
- Volume & Issue : Volume 01, Issue 05 (July 2012)
- Published (First Online): 02-08-2012
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Reliability Analysis of Composite Power System using FACTS Controllers – Combination of TCSC & UPFC
T. Suresh Kumar$ and V. Sankar@
$Member IEEE, Associate Professor, EEE Dept., Vishnu Institute of Technology, Bhimavaram, India,
@ Senior Member IEEE, Professor, EE Dept., JNTUACE, Anantapur, India,
Abstract
FACTS technologies can have major positive impacts on power system reliability performance and the actual benefits obtained can be assessed using suitable models and practice. Emerging techniques for composite power system reliability evaluation mainly focus on conventional generation and transmission facilities. In this paper, the impact of FACTS controllers on Composite Power System Reliability on IEEE 24 Bus Reliability Test System (RTS) is examined by incorporating the controller devices. A novel approach of composite power system has been presented by incorporating FACTS controllers in the RTS system in all the transmission lines for determining the system reliability. In this paper, an attempt is made to study the impact of Thyristor Controlled Series Capacitor (TCSC) & Unified Power Flow Controller (UPFC) combination on composite power system by using state space enumeration techniques. In order to improve system performance the impact of the combination of TCSC & UPFC has been considered. Investigation results show a significant improvement in the Load point, system indices, probability of failure & Expected Energy Not Supplied (EENS) in all transmission lines & generation capacity.
-
Introduction
Flexible AC Transmission System (FACTS) technology is the ultimate tool for getting the most out of existing equipment via faster control action and new capabilities. The most striking feature is the ability to directly control transmission line flows by structurally changing parameters of the fast switching.
Unified Power Flow Controllers (UPFC) and Thyristor Controlled Series Capacitor (TCSC) [1-3] are the most versatile FACTS [2] devices that has emerged for the control and optimization of power flow in electrical power transmission systems [4-5]. They offer major potential advantages for static and dynamic operation [6-8] of transmission lines.
In this paper, the impact of the combination of UPFC & TCSC on composite electric power system reliability is examined. Load point & system indices [9- 11] performances are presented to examine the impact of the combination on the IEEE 24 Bus RTS.
-
Reliability Analysis of UPFC & TCSC
The Single diagram of IEEE 24 Bus Reliability Test System (RTS) is shown in Fig. 1.
Fig 1: Single Line diagram of IEEE 24 Bus Reliability Test System
Average load at the buses is 235.87MW. Depending on the with stand capacity, repair rate and failure rate, it is feasible to have the combination of 3 module UPFC & 3 module TCSC in all the transmission line except in 1 to 2, 1 to 4, 1 to 5, 2 to 2, 2 to 4, 2 to 5, 3 to 2, 3 to 4 and 3 to 5 lines. In these lines the maximum power transmitted is only 97 MW throughout the year. Based on the above criteria, only 1 module TCSC & 1 module
UPFC are incorporated in the above 9 transmission line with 20 % increase in their individual capacities.
Stage 1: 3 Modules TCSC 3 * 40MW 120MW 3 Modules UPFC 3 * 40MW 120MW
Total 240MW Stage 2: with 20% increase in the individual
capacity of TCSC & UPFC (for 1 to 2, 1 to 4, 1 to 5, 2
to 2, 2 to 4, 2 to 5, 3 to 2, 3 to 4 and 3 to 5 transmission lines only)
1 Module TCSC 1 * 48MW 48MW
1 Module UPFC 1 * 48MW 48MW
Total 96MW Stage 1 and Stage 2 are incorporated in the 24 Bus
System independent of the load demand. The reliability analysis is carried out by incorporating Stage 1 and 2 simultaneously in the system. Availability and unavailability of the two stages are calculated by State Space representation.
2.1 RLD using State Space representation
Stage 1
The Reliability Logic Diagram (RLD) of IEEE 24 Bus RTS for the combination of TCSC & UPFC with 3 modules each using state space representation is shown in Fig. 2.
Fig. 2: RLD for Combination of TCSC & UPFC (Stage 1) using State Space Representation
Results
From the above, the Limiting State Probabilities [5] can be obtained.
Consider the data:
Failure rate ( ) = 0.7 f/yr
Repair Rate ( ) = 150 hrs of each component, Individual LSPs are:
P1 = 0.97642 P2 = 0.012402 P3 = 0.00025
P4 =1.3548*10-3 P5 = 2.709*10-4 P6 = 5.4194*10-5 P7 = 3.847*10-7 P8 =4.6684*10-8 P9 = 6.7134*10-9 P10 = 0.008524 P11 = 0.008524 P12=8.3216*10-12 PUP=P1 + P10 + P11 = 0.97642 + 0.008524 + 0.008524
= 0.985666
PDOWN = 1 PUP = 0.014334
Stage 2
The state space representation for stage 2 of combination of TCSC and UPFC is shown in Fig. 3. In Fig. 3, the blocks 1 to 7 represent transition states. The upper transition rates are of UPFC and lower transitional rates are of TCSC. Here, 4 states are considered because the remaining states will represent the failed states as they cannot withstand rated capacity. Stage 2: (for 1 to 2, 1 to 4, 1 to 5, 2 to 2, 2 to 4, 2 to 5,
3 to 2, 3 to 4 and 3 to 5 transmission lines only)
Fig. 3: RLD for Combination of TCSC & UPFC (Stage 2) using State Space Representation
Results
Considering the data of and as given above Individual LSPs are:
P1 = 0.979347 P2 = 0.005871 P3 = 0.001405
P4 = 0.000932 P5 = 0.005989 P6 = 0.005989
P7 = 0.000467
PUP=P1 +P5 + P6 = 0.979347 + 0.003946 + 0.003946
= 0.991325
PDOWN = 1 PUP = 0.008675
In Table 1, the results of availability and unavailability of IEEE 24 bus RTS for stage 1 & stage 2 are presented.
Table 1: Availability & Unavailability of different Stages
Stage
Modules
Availability
Unavailability
TCSC
UPFC
1
3
3
0.985666
0.014334
2
1
1
0.9991325
0.008675
From Table 1, it can be observed that as the no. of stages increase, the availability will decrease although it satisfies the required performance
-
System Indices
System Indices like BPSD, BPII & BPECI [1-3, 5] are calculated for IEEE 24 bus RTS system by incorporating the combination of FACTS devices.
Bulk Power Supply average curtailment / disturbance (BPSD),
locations, the system indices are gradually reduced when compared with other components.
System Indices (BPSD, BPII and BPECI) are further calculated [4] at each bus as shown in Tables 3 to 5. The graphical forms of the Tables 3 to 5 are shown in Figs. 4 to 6.
Bus No.
BPSD
Original
TCSC
UPFC
UPFC & TCSC
1
817.22
784.56
780.19
732.128
2
817.22
784.56
780.19
732.128
3
817.22
784.56
777.18
729.118
4
817.22
784.56
780.09
732.028
tr>
5
817.22
784.56
780.19
732.128
6
817.22
784.56
780.19
732.128
7
816.45
783.79
779.42
731.358
8
817.22
784.56
780.19
732.128
9
817.22
784.56
778.24
730.178
10
817.22
784.56
780.19
732.128
11
817.22
784.56
780.19
732.128
12
817.22
784.56
780.01
731.948
13
817.22
783.91
779.54
731.478
14
817.22
784.56
780.19
732.128
15
817.22
784.56
780.19
732.128
16
817.22
784.56
780.19
732.128
17
817.22
784.56
779.12
731.058
18
817.22
784.56
780.19
732.128
19
817.22
784.56
780.19
732.128
20
817.22
784.56
780.19
732.128
21
817.22
784.56
780.19
732.128
22
817.22
784.56
780.19
732.128
23
817.22
784.56
776.92
728.858
24
817.22
784.56
780.19
732.128
Table 3: BPSD at each Bus with different FACTS
BPSD =
k j x,y
L kjFj
Fj
(1)
j x,y
= 2688.33* 0.98912
3.632
732.18 MW/disturbance
Bulk Power Interruption Index (BPII),
Lkj Fj
= k j x , y
Ls
(2)
= 5939.609* 0.98912
3405
1.7254MW / MW-yr
Bulk Power Energy Curtailment Index (BPECI),
= K j x,y LKj DKj Fj * 60 Ls
(3)
= 60* 4313.9695* 0.986451* 25.47 =1909.94
3405
MWh/MW-yr
The system indices for IEEE 24 Bus RTS are presented in Table 2.
System Indices
Original
TCSC
UPFC
TCSC
& UPFC
BPSD
817.22
784.56
780.19
732.128
BPII
2.620
2.0156
1.9987
1.7254
BPECI
2211.640
1987.41
1924.65
1909.94
Table 2: System Indices with different FACTS Components
From Table 2, it can be observed that the system indices viz. BPSD, BPII & BPECI are reducing when using FACTS controllers in the system (IEEE 24 bus). It can be noted that when the combination of TCSC & UPFC [1] is incorporated in the system at different
Fig. 4: BPSD at each Bus with different FACTS Components
From Table 3, it can be observed that, Bulk Power Supply Disturbance is decreasing when the
combination of TCSC & UPFC is incorporated into the system rather than the system when incorporated by TCSC, UPFC independently. From the graphical form in Fig. 4 it can be clearly seen that there is a reduction in BPSD.
Table 4: BPII at each Bus with different FACTS
Bus No.
BPII
Original
TCSC
UPFC
UPFC & TCSC
1
2.62
2.0156
1.9987
1.7254
2
2.62
2.0156
1.9987
1.7254
3
2.62
2.0001
1.9832
1.7099
4
2.62
2.0156
1.9987
1.7254
5
2.62
2.0156
1.9987
1.7254
6
2.62
2.0156
1.9987
1.7254
7
2.611
2.0066
1.9734
1.7001
8
2.62
2.0156
1.9987
1.7254
9
2.62
2.0156
1.9987
1.7254
10
2.62
2.0156
1.9987
1.7254
11
2.62
2.0156
1.9987
1.7254
12
2.62
2.0156
1.9987
1.7254
13
2.62
2.0072
1.9903
1.717
14
2.62
2.0002
1.9833
1.717
15
2.62
2.0072
1.9903
1.717
16
2.62
2.0156
1.9987
1.7254
17
2.62
2.0156
1.9987
1.7254
18
2.62
2.0156
1.9987
1.7254
19
2.62
2.0156
1.9987
1.7254
20
2.62
2.0156
1.9987
1.7254
21
2.62
2.0156
1.9987
1.7254
22
2.62
2.0156
1.9987
1.7254
23
2.62
2.0156
1.9753
1.702
24
2.62
2.0156
1.9987
1.7254
Fig. 5: BPII of IEEE 24 Bus at each Bus with different FACTS Components
From Table 4, it can be observed that, Bulk Power Interruption Index is decreasing when the combination of TCSC & UPFC is incorporated into the system
rather than the system when incorporated by TCSC, UPFC independently. Once the Interruption Index is decreasing obviously the system performance increases. The graphical form in Fig. 5 shows clearly the reduction in BPII.
Table 5: BPECI at each Bus with different FACTS
Bus No.
BPECI
Original
TCSC
UPFC
UPFC & TCSC
1
2211.64
1987.41
1922.78
1908.07
2
2211.64
1987.41
1924.65
1909.94
3
2211.04
1985.67
1922.91
1908.2
4
2211.64
1987.41
1923.91
1909.2
5
2211.64
1987.41
1924.65
1909.94
6
2211.64
1986.22
1923.46
1908.75
7
2205.82
1979.24
1916.48
1901.77
8
2211.64
1987.41
1924.65
1909.94
9
2211.64
1987.41
1918.44
1903.73
10
2211.64
1987.41
1924.65
1909.94
11
2211.39
1987.16
1924.4
1909.69
12
2211.64
1985.91
1923.15
1908.44
13
2211.64
1987.41
1924.65
1909.94
14
2207.87
1983.64
1920.88
1906.17
15
2211.64
1987.41
1924.65
1909.94
16
2211.64
1987.41
1924.65
1909.94
17
2211.64
1987.41
1924.65
1909.94
18
2211.64
1986.22
1923.46
1908.75
19
2211.64
1986.22
1923.46
1908.75
20
2211.64
1986.22
1923.46
1908.75
21
2210.32
1986.22
1910.11
1895.4
22
2211.64
1986.22
1923.46
1908.75
23
2211.64
1986.22
1912.33
1897.62
24
2211.64
1986.22
1923.46
1908.75
Fig. 6: BPECI of IEEE 24 Bus at each Bus with different FACTS Components
From Table 5, it can be observed that, Bulk Power Energy Curtailment Index is decreasing when the combination of TCSC & UPFC is incorporated into the system rather than the system when incorporated by
TCSC, UPFC independently. Once the Curtailment Index decreases obviously the system performance increases. The graphical form in Fig. 6 shows clearly the reduction in BPECI.
-
Probability of Failure & EENS
Probability of Failure = QK
Pj * Pkj
j
(4)
Where Pj = Probability of existence of outage j
Pkj = Probability of the load at bus K exceeding the maximum load that can be supplied at that bus during the outage j.
Fig. 7: Probability of Failure at different bus
EENS=
Lkj * Pj *8760(MWh)
j
(5)
From Table 6, it can be observed that, Probability of
Further, Probability of Failure & EENS of the system is also calculated at each bus which is presented in Tables 6 & 7 and graphically in Figs. 7 & 8 respectively.
Bus No.
Probability of Failure
Original
TCSC
UPFC
UPFC & TCSC
1
0.0752745
0.0751432
0.0749987
0.0741948
2
0.0752745
0.0751432
0.0749987
0.0741948
3
0.0752745
0.0751338
0.0749587
0.0741348
4
0.0752746
0.0751432
0.0747987
0.0741948
5
0.0752746
0.0751534
0.0749987
0.0741958
6
0.0752749
0.0751432
0.0749987
0.0741548
7
0.0752211
0.0750012
0.0747641
0.0740012
8
0.0752745
0.0751432
0.0749957
0.0741948
9
0.0752745
0.0751232
0.0747987
0.0741978
10
0.0752745
0.0751402
0.0749987
0.0741248
11
0.0752745
0.0751432
0.0749977
0.0741948
12
0.0752745
0.0751132
0.0747985
0.0741948
13
0.0752745
0.0751432
0.0749987
0.0741941
14
0.0752746
0.0751302
0.0748947
0.0741949
15
0.0752745
0.0751432
0.0749981
0.0741748
16
0.0752745
0.0751487
0.0749987
0.0741948
17
0.0752745
0.0751432
0.0748967
0.0741942
18
0.0752745
0.0751432
0.0749987
0.0741448
19
0.0752745
0.0751439
0.0749981
0.0741944
20
0.0752745
0.0751432
0.0749984
0.0741947
21
0.0752745
0.0751431
0.0748987
0.0741748
22
0.0752746
0.0751402
0.0749967
0.0741949
23
0.0752746
0.0751412
0.0749787
0.0740949
24
0.0752745
0.0751432
0.0749987
0.0741948
Table 6: Probability of Failure at different Buses
Failure is decreasing when the combination of TCSC & UPFC is incorporated into the system rather than the system when incorporated by TCSC, UPFC independently. Decrease in Probability of Failure indicates increase in the availability of the system, which leads to increase in system performance. The graphical form in Fig. 7 shows clearly the decrement of Probability of Failure at each and every bus.
Table 7: EENS at different Buses
Bus No.
EENS
Original
TCSC
UPFC
UPFC & TCSC
1
3981.03
3802.9
3583.68
3382.41
2
3575.56
3387.43
3168.21
2966.94
3
6635.01
6456.88
6237.66
6036.39
4
2727.83
2549.7
2330.48
2129.21
5
2617.23
2439.1
2219.88
2018.61
6
5013.68
4835.55
4616.33
4415.06
7
4605.1
4426.97
4207.75
4006.48
8
6303.26
6125.13
5905.91
5704.64
9
6450.7
6272.57
6053.35
5852.08
10
7187.92
7009.79
6790.57
6589.3
11
6781.65
6603.52
6384.3
6183.03
12
3198.47
3020.34
2801.12
2599.85
13
9768.18
9590.05
9370.83
9169.56
14
7151.29
6973.16
6753.94
6552.67
15
4684.9
4506.77
4287.55
4086.28
16
3686.14
3508.01
3288.79
3087.52
17
4368.59
4190.46
3971.24
3769.97
18
4274.7
4096.57
3877.35
3676.08
19
6671.88
6493.75
6274.53
6073.26
20
4718.24
4540.11
4320.89
4119.62
21
5719.24
5541.11
5321.89
5120.62
22
3687.19
3509.06
3289.84
3088.57
23
6781.92
6603.79
6384.57
6183.3
24
7014.67
6836.54
6617.32
6416.05
Fig. 8: EENS at different bus
From Table 7, it can be observed that, Expected Energy not supplied is decreasing when the combination of TCSC & UPFC is incorporated into the system rather than the system when incorporated by TCSC, UPFC independently. Decrease in EENS indicates increase in the availability of the system, which leads to increase in system performance. From the graphical form in Fig. 8 it can be seen clearly the decrement of EENS at each and every bus.
-
Conclusions
In this paper, the reliability analysis of IEEE 24 Bus RTS when using the combination of TCSC & UPFC is presented. Depending upon the generation & transmission line capacity, the combination of TCSC & UPFC is divided into 2 stages. Stage 1, consist 3 Modules each of TCSC & UPFC, where as Stage 2, consists 1 module of TCSC & UPFC each. Reliability analysis of the two stages is determined by using state space representation. System Indices, Probability of Failure & EENS are also calculated.
In IEEE 24 bus RTS system stage 1 & 2 are incorporated simultaneously depending on the transmission line capacity connected between different buses. System Indices, Probability of Failure & EENS are calculated for all the combinations of FACTS controllers of the system and found the combination of TCSC & UPFC is found to be best suitable for the system rather than other combinations.
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International Journal of Engineering Research & Technology (IJERT)
ISSN: 2278-0181
Vol. 1 Issue 5, July – 2012