M. Khederzadeh Power & Water University of Technology (PWUT) Tehran, IRAN.
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Transcript of M. Khederzadeh Power & Water University of Technology (PWUT) Tehran, IRAN.
Frankfurt (Germany), 6-9 June 2011
M. Khederzadeh
Power & Water University of Technology (PWUT)
Tehran, IRAN.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Distributed Energy Resources (DER) Impacts on the Performance of Special
Protection Schemes (SPS)
Frankfurt (Germany), 6-9 June 2011
Presence of DG increases the uncertainty of load and generation balance during extreme contingencies.
In order to compensate for this uncertainty, many SPSs are designed with pessimistic assumptions and consequently overreact.
For example, too much load could be shed in a specific network situation or disturbance.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Motivation of Research
Frankfurt (Germany), 6-9 June 2011
Introduction DER Impact on Performance of SPS SPS and Uncertainties of DERs Simulation Results Remedial Actions Conclusion
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Presentation Outline
Frankfurt (Germany), 6-9 June 2011
Power System protection can be divided as: 1. Equipment protection
2. System protection(SPS=System Protection Scheme)
SPS are protections which operate on selected rare contingencies usually outside the design range of the system and equipments.
SPS operates upon the detection of extreme contingencies.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Introduction
Frankfurt (Germany), 6-9 June 2011
Renewable energy resources have an uncertain generation nature.
If real-time data of the DERs are not available to the SPS; its reaction is not optimized.
Impact of the DERs uncertainty on the SPS operation depends on its complexity.
Real time SPSs have a more optimized reaction because they are based on the knowledge of the actual network conditions.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
DER Impact on SPS Performance
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Sample Network
9 MW Wind Farm(6 x 1.5 MW)
Phasors
pow ergui
Trip
Trip Time
WindTurbine
Protection
Wind (m/s)
Trip
mA
B
C
mA
B
C
Wind (m/s)
Trip
Wind TurbineDoubly-Fed Induction Generator
(Phasor Type)1
Wind Speed(m/s)
A
B
C
Plant2 MVA
?
More info
A B C
Load500 kW
ABCN
a
b
c
GroundingTransformer
X0=4.7 Ohms
[Trip_WT]
pitch
wr
Vdc
wind
[Trip_WT]
A
B
C
A
B
C
Fault
A
B
C
a
b
c
CB2
A
B
C
a
b
c
CB1
A
B
C
a
b
c
B575(575 V)
A
B
C
a
b
c
B25(25 kV)
A
B
C
a
b
c
B120(120 kV)
A
B
C
A
B
C
30 km line 2
3.3ohms
A
B
C
A
B
C
2500 MVAX0/X1=3
A
B
C
a
b
c
25 kV/ 575 V6*2 MVA
A
B
C
A
B
C
20 km line 1
A
B
C
a
b
c
120 kV/25 kV47 MVA
N
A
B
C
120 kV
A
B
C
A
B
C
10 km line 1
<Vdc (V)>
<wr (pu)><Pitch_angle (deg)>
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Sample Network Transmission Lines
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Sample Network Wind Generation
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Wind turbine output power versus turbine speed for different wind speeds
0.6 0.7 0.8 0.9 1 1.1 1.2 1.3
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
5 m/sA
B
C12 m/s
D
16.2 m/s
Turbine speed (pu of generator synchronous speed)
Turb
ine
outp
ut p
ower
(pu
of n
omin
al m
echa
nica
l pow
er)
Turbine Power Characteristics (Pitch angle beta = 0 deg)
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Generated P and Q of the wind farm for 8m/s and 14m/s wind speed
0 10 20 30 40 50 60 70 80 90 1000
2
4
6
8
10
12
Time (s)
P (
MW
)
Generated P(MW)
0 10 20 30 40 50 60 70 80 90 100-4
-2
0
2
4
6
8
Time (s)
Q (
Mva
r)
Generated Q(Mvar)
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
P and Q for wind speed 8m/s. Line1 is disconnected at t=35s. SPS correctly reacts to mitigate Line 2 overloading.
0 5 10 15 20 25 30 35 40 45 50-5
0
5
10
15
Time (s)
P (M
W)
Generated P(MW)
0 5 10 15 20 25 30 35 40 45 50-5
0
5
10
Time (s)
Q (M
var)
Generated Q(Mvar)
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
P and Q for wind speed 10m/s. Line1 is disconnected at t=35s. SPS overreacts at
t=40s to mitigate Line 2 overloading.
0 5 10 15 20 25 30 35 40 45 50
-2
2
6
10
Time (s)
P (M
W)
Generated P(MW)
0 5 10 15 20 25 30 35 40 45 50-5
-1
3
7
10
Time (s)
Q (M
var)
Generated Q(Mvar)
Frankfurt (Germany), 6-9 June 2011
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
SPS performance for different wind farm generation in response to a disturbance
Frankfurt (Germany), 6-9 June 2011
Development of a communication infrastructure in order to have enough data of DERs applicable in the SPS decision taking, i.e., transformation of conventional SPS into smart SPS.
Another solution could be implementation of pre-prepared wind/sunshine patterns into the SPS reaction plan.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Remedial Actions
Frankfurt (Germany), 6-9 June 2011
The impact of DERs on the conventionally designed SPS is investigated.
It is shown that the uncertainty embedded in the nature of renewable resources such as wind and sunshine can influence the performance of SPS.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Conclusion
Frankfurt (Germany), 6-9 June 2011
Generally, it is assumed that the DERs are operating at their rated power output, so if real-time data from these sources are not available, then the SPS action to shed generation/load to alleviate overloading of transmission lines is overated.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Conclusion…
Frankfurt (Germany), 6-9 June 2011
In order to improve the knowledge on system security, a statistical approach can be defined to allow engineers to study the behavior of power systems taking into account many uncertainties that influence the results.
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Conclusion…
Frankfurt (Germany), 6-9 June 2011
Questions
M.Khederzadeh – IRAN – RIF S3 – Paper 0066
Thank you for your attention!