NCKU - AMAT Collaboration Research
FCL System Study
by National Cheng-Kung University, Taiwan
Prof. Dr. Hong-Tzer Yang, Dr. Chorng-Ping Chang+
Monika Tang, and Angel Tsai
Department of Electrical Engineering,
National Cheng-Kung University
+Applied Materials
01
Problems of FCL Placement
02
FCLs Application Researches
03
Case Studies for Systems in
Taiwan
04
Conclusions
OUTLINE
2
PART ONE
PROBLEMS OF FCL PLACEMENT
•
•
Backgrounds of FCL Placement
Issues to be Considered
FCL Placement Problems
1 Motivation of Research
• OptimalFCLplacementsolves
over-capacityfaultcurrent
issueswithminnumberofFCLs
• Acost-saving andeffectiveFCL
placementschemeisthus
needed
2
Existing Problems
• Existingmethodsareboth
ineffective incostand
performance
• Importantfactorsareignored,
likeimpacts offaultcurrent
onneighborhood andvoltage
deviation
4
Backgrounds of FCL Placement
Restrain
Fault
Currents
Impacts of
FCL
Placement
Influences on
Protective
Schemes
Decrease
Voltage
Deviation
5
Backgrounds of FCL Placement
Examples of FCL Placement
May have the
same effect with
less number of
FCLs
6
Issues on FCL Placement
Transient Fault
Simulations
• Transient Fault
Current Calculation
• Voltage Deviation
due to Fault
• Transient Power
Quality
Potential
Locations to be
Considered
• Sources of Fault
Current
• Over-capacity Fault
Areas
• Affected Power
Facilities
Optimization
Method Needed
• Optimal Location
Search
• FCL Parameter
Optimization
• Sensitivity Analysis
7
Researches for FCL Placement
• Tools for Fault Current Simulations
– DigSILENT
– P/SSE (mainly for steady-state analysis)
– MATLAB
• Screening of Potential Locations
– Sensitivity Factors Considered
• Max Fault Current (MFC)
• Max Contribution Current (MCC)
• Generator Connected Number (GCN)
– Scheme for Screening
• Priority based on Sensitivity Indices
• Fuzzy Logic Decision System
• Export Evaluation System
8
Researches for FCL Placement
Hierarchical Fuzzy
Logic System
Optimization
Method for FCL
Placement
Hashing-Integrated
Genetic Algorithm
Particle Swarm
Optimization
9
Researches for FCL Placement
System Structure for FCL Placement
•
PowerFlowAnalysis
•
FaultCaseCalculations
•
FCL Placement System Data Collection
•
HIGAOptimization
Determination
Sensitivity
FCL Parameter Screening
Tuning
OptimalLocation
•
PSOOptimization
CandidateSorting
10
PART TWO
FCL APPLICATION RESEARCHES
•
•
Placement of FCLs in Power Systems
Over-current Protective Scheme for FCLs
Screening of Potential Locations
• Hierarchical Fuzzy Logic Decision (HFLD) Sorting
MFC
MCC
Sensitivity
Factors
GCN
The proposed HFLD sorting approach
12
Proposed Optimization Approach
• HIGA for Optimization
− A Solution in GA (Chromosome)
1
Fixed bits of a solution considered for
candidate buses
2
Representation of FCL shunt reactance
for each bus
3
Value 0 for a bus means no FCL to
be installed
Bus 1
Chromosome Structure
Bus 2
Bus 3
Bus 4
0 0 0 0 1 1 0 0 0 1 0 1 1 1 1 1
13
Proposed Optimization Approach
• HIGA for Optimization
− Hash Table Design
Enhance
Optimization
Efficiency
the
Hash Table Structure
14
Proposed Optimization Approach
• HIGA for Optimization
– Fitness Function
min J  N
Subject to
SC, max
I SC

I
j  1BM
j
j
where
N
Number of FCLs installed
BM
Bus number
Fault current
ISCj
15
Proposed Optimization Approach
• PSO for Shunt Reactance Optimization
– Fitness Function
N FCL
N FCL
i 1
i 1
min I     Z i , FCL     V
Subject to
Z
min
i , FCL
 Z
i , FCL
 Z
max
i , FCL
i  1 N
FCL
SC, max
I SC

I
j  1BM
j
j
where
Zi,FCL Shunt reactor’s value of ith FCL
V Voltage variation at fault state
,  Impact/weight factors
N FCL Number of buses with FCL installed
16
Over-current Protective Scheme for FCLs
• Motivation
– Influences of FCLs
and DGs on system
protection, especially
the overcurrent relays
– Parameters tuning
due to the FCLs
installed
*DG: Distributed Generator
17
Over-current Relay Tuning for FCLs
• Objective function of GA method
N M 
K 
2 

min   T p,ij  R p,ij   Rb,ijk  Tmb,ijk 

i 1 j 1
k 1



R p ,ij  Tp ,ij  Tp ,ij  FI max


Rb ,ijk  Tb ,ijk  Tb ,ijk  FI max
Tmb ,ijk 
Tp ,ij  FI p ,ij
Tb,ijk  FI b ,ijk

N
total number fault locations
M
total number of primary relays
K
total number of backup relays
R p ,ij
primary constraint factor
Rb ,ijk
backup constraint factor
Tp,ij
operating time of primary relay
Tb ,ijk
operating time of backup relay
FI p,ij
fault index of primary relay
FI b,ijk
fault index of backup relay
18
PART THREE
CASE STUDIES FOR SYSTEMS IN TAIWAN
•
•
Studied System 1
Studied System 2
System 1: Simulation of FCL Placement
• Simplified System without FCL
– Fault on each bus
3-phase to ground fault
161 kV
33 kV
21.827 kA
32.733 kA
34.75 kA
25.261 kA
17.049 kA
32.555
kA
11.5 kV
IC of CB:
40 kA
30 kA
25kA
20kA
15 kA
20
System 1: Simulation of FCL Placement
• Simplified System with FCL
– Fault on each bus
3-phase to ground fault
161 kV
33 kV
21.988
kA
11.5 kV
FCL
22.462
kA 14.491
kA
18.725
kA
7.432 kA
21.728
kA
IC of CB:
40 kA
30 kA
25kA
20kA
15 kA
21
System 1: Simulation of FCL Placement
• Fault Location Analysis
Fault Location
without FCL (kA, rms)
with FCL on Bus 3 (kA, rms)
Bus1
21.827
14.491
Bus 2
25.261
18.725
Bus 3
17.049
7.432
Bus4
32.555
21.728
Bus5
32.773
21.988
Bus6
34.75
22.462
22
System 1: Benefits of FCL Installed in System 1 – Case 1
• Cost Comparison
According to the Test Cases
•
•
Condition
CB type
Without FCL
24KV 1250A,
60KA
Originally, 6 CBs with
capacity 60 kA at 11.5kV
After FCL is installed, all
CBs replaced with 25 kA
With FCL
Difference
24KV 1250A,
25KA
Cost
$95,000* 6 =
570,000
$78,333* 6 =
469,998
$100,002
23
System 1: Power Loss Reduction due to FCL – Case 2
• Power Loss due to Resistance of Reactor
24
System 1: Power Loss Reduction due to FCL – Case 2
• Cost of Power Loss
– Based on simulation results
• Load current ∅ 1.191kA (by simulation)
•
3
3 1.191
0.0256
108.94kW
• Cost of power loss 2,656,020TWD/ year
88,534 USD/ year
25
System 2: The System Topology
• Normally-Opened Switches between 2 Areas, due to Limitation
of Fault Current Capacity
Cogen
IPP
Bus 9211
26
System 2: Fault Current Analysis of FCLs – Option 1
FCL Locations – 4 x FCL on
most fault current contributing
feeders
Additional Fault Locations
Analyzed: Secondary of # 1,
#2, #3, #4 T.T transformers
and Bus # 9211, 9200, 9210
27
System 2: Fault Current Analysis of FCLs
• Prospective Currents – Buses and Feeders (CB Capacity: 50kA)
fault location
total fault
current
#1 T.T feeder
#2 T.T feeder
#3 T.T feeder
#4 T.T feeder
9211
64.4575
11.0975
11.0975
9.66
9.66
dot 1
64.4575
53.3623
11.0952
9.6554
9.6554
dot 2
64.4575
11.0952
53.3623
9.6554
9.6554
dot 3
64.4575
11.0952
11.0952
54.8021
9.6554
dot 4
64.4575
11.0952
11.0952
9.6554
54.8021
9210
29.3595
4.14345
4.14345
9.89345
9.89345
9200
35.926
9.3909
9.3909
3.34995
3.34995
28
System 2: Fault Current Analysis of FCLs – Option 1
The
components
connected
to the Bus
9211
desired
4 x FCL
normal state
operation
#1 & #2
(#1 T.T and #2
(#1 T.T & #2
(6Ohm)
T.T not in
T.T in service
#3 & #4
service)
state)
(10Ohm)
Total
43.792
64.4575
47.748
#3
9.89
9.66
5.267(45.5%)
#4
9.89
9.66
5.267(45.5%)
Line7
3.2775
3.1395
3.1395
Line8
3.2775
3.1395
3.1395
TR2202
2.8635
2.8635
2.8635
TR2203
2.8635
2.8635
2.8635
TR2204
8.8665
8.073
8.073
TR2205
2.8635
2.8635
2.8635
#1 T.T
0
11.0975
7.13(35.7%)
#2 T.T
0
11.0975
7.13(35.7%)
4 x FCL
#1 & #2
(7Ohm)
#3 & #4
(9Ohm)
47.426
5.543
5.543
3.1395
3.1395
2.8635
2.8635
8.073
2.8635
6.693
6.693
4 x FCL
#1 & #2
(9Ohm)
#3 & #4
(7Ohm)
47.242
6.187
6.187
3.1395
3.1395
2.8635
2.8635
8.073
2.8635
5.957
5.957
4 x FCL
#1 & #2
(8Ohm)
#3 & #4
(8Ohm)
47.265
5.842(39.5%)
5.842(39.5%)
3.1395
3.1395
2.8635
2.8635
8.073
2.8635
6.302(43.2%)
6.302(43.2%)
4 x FCL
#1 & #2
(10Ohm)
#3 & #4
(6Ohm)
47.357
6.555
6.555
3.1395
3.1395
2.8635
2.8635
8.073
2.8635
5.6465
5.6465
Total IFAULT = 65kA when #1 T.T and #2 T.T in service
Total IFAULT needs to be limited to 47.5kA on 161kV bus
30
System 2: Fault Current Analysis of FCLs – Option 1
• FCL units placed in the system
− Fault currents are limited under 47.5 kA
Fault Location
Total Fault Current
FCL1
FCL2
FCL3
FCL4
9211
47.3915
6.35145
6.35145
5.88225
5.88225
#1 T.T Sec
24.955
10.3684
0.4209
1.53985
1.53985
#2 T.T Sec
24.955
0.4209
10.3684
1.53985
1.53985
#3 T.T Sec
23.851
1.7089
1.7089
10.33045
0.2645
#4 T.T Sec
23.851
1.7089
1.7089
0.2645
10.33045
9210
25.6335
1.3478
1.3478
5.46365
5.46365
9200
32.6025
5.3245
5.3245
1.02235
1.02235
31
System 2: Fault Current Analysis of FCLs – Option 2
• Bus 9211 Topology
− Double bus bar
CB
31
System 2: Fault Current Analysis of FCLs – Option 2
• Bus 9211 Topology
− with FCLs (split bus 9211)
Terminal 1 Terminal 2
Transformer #1 #2
FCL
FCL
CB
32
System 2: Fault Current Analysis of FCLs – Option 2
• Prospective Fault Currents
1
Without FCLs Installed
Fault Total fault
“Bus tie”
location current
9211-2 64.4575 35.9375
Fault Total fault
“Bus tie”
location current
9211-1 64.4575 28.4855
#1 T.T
#2 T.T
Terminal 1 Terminal 2
11.0975
11.0975
3.1395
3.1395
TR2202
TR2203
TR2205
TR2204
#3 T.T
#4 T.T
2.8635
2.8635
2.8635
8.073
9.66
9.66
33
System 2: Fault Current Analysis of FCLs – Option 2
• Prospective Fault Currents
1
With FCLs Installed
• Asymmetrical fault currents are limited under 47.5 kA (within 5% margin)
Fault location
9211‐2
Total fault FCL unit
current
40.779
12.167
Fault location
9211‐1
Total fault FCL unit
TR2202
TR2203
current
47.2535
11.167
2.8635
2.8635
#1 T.T
11.684
#2 T.T
11.684
Terminal 1 Terminal 2
3.1395
TR2205
2.8635
3.1395
TR2204
8.073
#3 T.T
10.189
#4 T.T
10.189
34
PART FOUR
CONCLUSION
Conclusion
01
02
03
FCL placement
optimization approach is
Due to FCLs and DGs
useful in cost reduction
Installed, systematic
Appropriate FCL installations
and performance
approaches for updates
are helpful to solve over-
insurance for system
on associated protective
current issues in system
planning, especially for
scheme are essential for
expansion and reduce
large power systems
power systems nowadays
system power loss and
and future smart grids
voltage deviation to upgrade
overall system performance
36
THANK YOU FOR YOUR
ATTENTION