lvrt induced frequency stability in offshore wind power ......2019/12/09 · ofwf dc chopper option...
TRANSCRIPT
LVRT Induced Frequency Stability in Offshore Wind Power System
M. M. Kabsha, Zakir H. Rather IIT Bombay, India
2nd International Conference on: Large-Scale Grid Integration of Renewable Energy in India 4-6 Sept 2019
Outline
• Introduction • OWF LVRT Requirements • OWF Modelling • OWF LVRT Capability • Results and Discussion • Conclusion
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 2
Statistics of Global Wind Power Installation
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 3
24 31 39 48 59 74 94 121
159 198
238
293 319
370
433
488
540 591
0
100
200
300
400
500
600
700 Global Cummulative Installed Wind Capacity 2001-2018
GW
Global Wind Energy Council (GWEC), “GWEC Report 2018,” 2019.
1 2
3 4
5 7
8
12 14
19
23
0
5
10
15
20
25
30
2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018
Global Cummulative Installed Offshore Wind Capacity 2008-2018
GW
OWF LVRT Requirements
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 4
TenneT TSO GmbH, “Requirements for Offshore Grid Connections in the Grid of TenneT TSO GmbH,” 2012.
0 150 700 1.500 3.000 Time in ms
0
0.7
0.45
0.9
1
FRT: Fault Ride Through
STI: Short Term Interruption
FRT without separation
STI is allowed
Tripping is allowed
M
axim
um L
-L v
olta
ge U
/ UN
24
3
Time when a fault occurs
FRT without separationPossibly STI
1
2
3
4
1Voltage drop / rise (%)
ΔU/Un
Reqiured additional reactive current (%)ΔI/In
Support of the voltage by voltage control
5 %-50
100 %
-100%
-5 %ΔU = U-Uo, ΔI=I-Io
Tennet TSO GmbH, “Grid Code - High and extra high voltage,” November, 2015
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 5
OWF Modelling
Full Converter based WTG and WF
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 6
Grid Side Converter
Machine Side Converter
DC_Link
ACOffshore
Vdc
Vdcref
PMSG
SN
Qg
Qgref
Qgrid
Qref
Pgrid
Pref
Vdc
Vg
Qgrid
Pgrid
PIPI
i*d MSC i*
q MSC i*d GSC i*
q GSC
PIPIfmeas
MPPTω
Vmeas
Kf
Vref
Kvfref
Pred
Qgrid
Pgrid
Offshore Wind Farm
PMSG
SN
PMSG
SN
PMSG
SN
MSC GSC
MSC GSC
MSC GSC
WTG
M. Pöller and S. Achilles, “Aggregated Wind Park Models for Analyzing Power System Dynamics,” in 4th International Workshop on Large-scale Integration of Wind Power and Transmission Networks for Offshore Wind Farms, 2003, pp. 1–10
HVDC Converter Control
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 7
Receiving End Converter
Sending End Converter
DC CablesFilterFilter
Vdc
Vdcref
Vac
Vacref
PI
i*d SEC
PI
i*q SEC
𝟐𝟐𝟐𝟐𝒔𝒔
θ*
0
Fref
i*d REC i*
q REC
ACOffshore
ACOnshore
Qoff
Poff
Qon
Pon
Vref Vmeas
Kf
Kv
Vdc Vdcref
KLVRT
S. Dennetière et al., “The CIGRE B4 DC Grid Test System,” CIGRE Electra Mag., 2013
Test System
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 8
Modified IEEE 39 bus
Wind Farm no
Generator Replaced
No of WT Total MW
1 G 4 469 703.5
2 G10 186 279
3 G 7 416 624
4 G 3 482 723
5 G 9 617 925.5
G10
G8
G6
G1
G2
G5 G4
G3
G7
G9
30 25
37
26 28
38
29
1 3
18 17 24
35
2221
23
363334
19
4
5
6
7
8
14
15
16
12
11
10
31
32
9
20
2
WF 2
WF 1
WF 4
WF 3
WF 5
4847
40
39
49
41
42
44 43 46
45
REC SECAC
Offshore GSC MSCPMSG
SN≡
ACOnshore
P. Demetriou, M. Asprou, J. Quiros-Tortos, and E. Kyriakides, “Dynamic IEEE Test Systems for Transient Analysis,” IEEE Syst. J., vol. 11, no. 4, pp. 1–10, 2015.
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 9
OWF LVRT Capability
Capability to satisfy LVRT
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 10
Onshore Converter
Offshore Converter
DC Cables PCC
Offshore AC Voltage Regulation
Kf
foff*
foff
Offshore Frequency RegulationVDC
VDCoff*
KV
VAC,off*
VAC,off
VDC VDCoff
*
OFWF
DC Chopper
Option 2
Option 1
Option 3
Option 1
Option 1
Conventional LVRT Strategy
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 11
*0 0off off v dcoff dcV V K V V = − −
*0 0off off v dcoff dcf f K V V = + −
( )*
1
0 0
LVRT ref meas
qREC
flt K V V
Iflt
= −= =
( )*red ref meas vP V V K= −
( )*red ref meas fP f f K= −
ref MPPT redP P P= −
(2)
(2)’
(1)
(1)’ (3)
(4)
Grid Side Converter
Machine Side Converter
DC_Link
ACOffshore
Vdc
Vdcref
PMSG
SN
Qg
Qgref
Qgrid
Qref
Pgrid
PMPPT
Vdc
Vg
Qgrid
Pgrid
PIPI
i*d MSC i*
q MSC i*d GSC i*
q GSC
PIPIfmeas
MPPTω
Vmeas
Kf
Vref
Kvfref
Pred
Qgrid
Pgrid
Receiving End Converter
Sending End Converter
DC CablesFilterFilter
Vdc
Vdcref
Vac
Vacref
PI
i*d SEC
PI
i*q SEC
𝟐𝟐𝟐𝟐𝒔𝒔
θ*
0
Fref
i*d REC i*
q REC
ACOffshore
ACOnshore
Qoff
Poff
Qon
Pon
Vref Vmeas
Kf
Kv
Vdc Vdcref
KLVRT
Active Power Recovery
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 12
(With Ramp Rate) (Without Ramp Rate)
Fault Clearance Time
Ramp Time
Ramp Rate
0
0.75
0.25
1
PCC
Vol
tage
(p.u
)
V (p.u)
0.5
0
0.75
0.25
1
Act
ive
Pow
er (p
.u)
P (p.u)
0.5
0 150 1,500 3,000Time in ms 5,150
Fault Clearance Time
0 150 1,500 3,000Time in ms 5,150
Fault Clearance Time
0 150 1,500 3,000Time in ms 5,150
Fault Clearance Time
0 150 1,500 3,000Time inm s
0
0.75
0.25
1PC
C V
olta
ge (p
.u)
Time when a fault occurs
5,150
V (p.u)
0.5
0
0.75
0.25
1
Act
ive
Pow
er (p
.u)
P (p.u)
0.5
Modified Conventional LVRT Strategy
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 13
Receiving End Converter
Sending End Converter
DC CablesFilterFilter
Vdc
Vdcref
Vac
Vacref
KLVRTPI
i*d SEC
PI
i*q SEC
𝟐𝟐𝟐𝟐𝒔𝒔
θ*
0
Fref
i*d REC i*
q REC
ACOffshore
ACOnshore
Qoff
Poff
Qon
Pon
Vref Vmeas
Kf
Kv
Vdc Vdcref
Equations (1) to (5)idref
FaultDetection
( )
*
*
11 0
0 1
d REC dref rampupramp
d REC dref
flt and i i and tRS
flt or i i
= < < =
= =
( ) * *lim , ,
ramp rampREC RECramp down d up dramp
dref dd
REC REC
dV dVR i R ii - idi dt dtdt t V V
− − =
∆
1
0
rampd ramp
refd
dref ramp
i Si
i S
== =
(1)
(2)
(3)
*
1
0
dmax
d RECrefd
i flti
i flt
== =
(4)
(5) ( )
*
1
0 0
LVRT ref onshore
q REC
K V V flt
iflt
− == =
(6)
( ) ( )22 *max 0.95
0.95
q REC onshore
dmax
max onshore
i i V
ii V
− <= ≥
(With APR Ramp Rate)
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 14
Results and Discussion
Results and Discussion
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 15
Test Case I 3-ɸ Fault with 70 % voltage dip for 500 milliseconds,
and wind generation (penetration level of 33%)
Ramp Rate
f Nadir (Hz)
RoCoF (Hz/s)
τ Nadir (p.u)
RoCoT (p.u/s)
𝜔𝜔turbine (p.u)
0.2 p.u /s 49.43 -0.88 0.46 0.27 1.075
0.5 p.u /s 49.69 -0.55 0.58 0.41 1.0378
1 p.u /s 49.87 -0.38 0.63 0.39 1.0275
2 p.u /s 49.92 -0.27 0.644 0.38 1.0235
0 1 2 3 4 5 6 70
0.3
0.6
0.9
1.2
Bus
16
Vol
tage
(p.u
)
Ramp Rate 0.2 pu/s
Ramp Rate 0.5 pu/s
Ramp Rate 1 pu/s
Ramp Rate 2 pu/s
0 1 2 3 4 5 6 7500
1000
1500
2000
2500
PR
EC
Tot
al(M
W)
0 1 2 3 4 5 6 7500
1000
1500
2000
2500
PSE
C T
otal
(MW
)
(b)
(c)
(a)
0 1 2 3 4 5 6 749.2
49.4
49.6
49.8
50
50.2
FO
nsho
re(H
z)
0 1 2 3 4 5 6 7-1.5
-1
-0.5
0
0.5
RoC
oFO
nsho
re (H
z/s)
0 1 2 3 4 5 6 7
time (s)
-500
0
500
1000
1500
QR
EC T
otal
(MW
)(f)
(e)
(d)
0 1 2 3 4 5 6 70.9
1
1.1
1.2
VD
C O
WF1
(pu)
0 1 2 3 4 5 6 70.9
0.95
1
VA
C O
WF1
(pu)
0 1 2 3 4 5 6 7200
400
600
800
PG
SC O
WF
1(M
W)
(g)
(h)
(i)
0 1 2 3 4 5 6 70
0.5
1
1.5
WT
OW
F1 (p
u)
0 1 2 3 4 5 6 7
-1
-0.5
0
0.5
RoC
oTW
T (p
.u/s)
0 1 2 3 4 5 6 7
time (s)
1
1.1
1.2
WT
OW
F1(p
u)
(k)
(j)
(l)
Results and Discussion
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 16
Ramp Rate
f Nadir (Hz)
RoCoF
(Hz/s)
τ Nadir (p.u)
RoCoT (p.u/s)
𝜔𝜔turbine (p.u)
0.2 p.u /s 48.9 -1.85 0.33 0.243 1.1
0.5 p.u /s 49.4 -1.7 0.465 0.49 1.05
1 p.u /s 49.7 -1.48 0.57 0.45 1.03
2 p.u /s 49.9 -1.17 0.67 0.35 1.022
0 1 2 3 4 5 6 70
0.3
0.6
0.9
1.2
Bus 1
6 V
olta
ge (p
.u)
Ramp Rate 0.2 pu /s
Ramp Rate 0.5 pu /s
Ramp Rate 1 pu /s
Ramp Rate 2 pu /s
0 1 2 3 4 5 6 7
1000
2000
3000
PR
EC T
otal
(MW
)
0 1 2 3 4 5 6 7
1000
2000
3000
PSE
C T
otal
(MW
)
(b)
(c)
(a)
0 1 2 3 4 5 6 748.5
49
49.5
50
50.5
FO
nsho
re(H
z)
0 1 2 3 4 5 6 7-2
0
2
RoC
oFO
nsho
re (H
z/s)
0 1 2 3 4 5 6 7
time (s)
-500
0
500
1000
1500
QR
EC T
otal
(MW
)(f)
(d)
(e)
0 1 2 3 4 5 6 70
0.5
1
1.5
WT
OW
F1 (p
u)
0 1 2 3 4 5 6 7-1.5
-1
-0.5
0
0.5
RoC
oTW
T (p
.u/s)
0 1 2 3 4 5 6 7
time (s)
1
1.1
1.2
WT
OW
F1(p
u)
(k)
(j)
(l)
0 1 2 3 4 5 6 70.9
1
1.1
1.2
VD
C O
WF1
(pu)
0 1 2 3 4 5 6 70.9
0.95
1
VA
C O
WF1
(pu)
0 1 2 3 4 5 6 70
200
400
600
800
PG
SC O
WF
1(M
W)
(g)
(h)
(i)
Test Case II 3-ɸ Fault with 100 % voltage dip for 150 milliseconds,
and wind generation (penetration level of 46%)
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 17
Test Case I (70 % voltage dip for 500 milliseconds)
(penetration level of 33%)
Ramp Rate
f Nadir (Hz)
RoCoF (Hz/s)
τ Nadir (p.u)
RoCoT (p.u/s)
𝜔𝜔turbine (p.u)
0.2 p.u /s 49.43 -0.88 0.46 0.27 1.075
0.5 p.u /s 49.69 -0.55 0.58 0.41 1.0378
1 p.u /s 49.87 -0.38 0.63 0.39 1.0275
2 p.u /s 49.92 -0.27 0.644 0.38 1.0235
Ramp Rate
f Nadir (Hz)
RoCoF (Hz/s)
τ Nadir (p.u)
RoCoT (p.u/s)
𝜔𝜔turbine (p.u)
0.2 p.u /s 48.9 -1.85 0.33 0.243 1.1
0.5 p.u /s 49.4 -1.7 0.465 0.49 1.05
1 p.u /s 49.7 -1.48 0.57 0.45 1.03
2 p.u /s 49.9 -1.17 0.67 0.35 1.022
Test Case II (100 % voltage dip for 150 milliseconds)
(penetration level of 48%)
Conclusion
• The results suggest that the VDIF is significantly improved by increasing APR ramp rates.
• With increasing the APR ramp rate the RoCoT is increased, however the WTG rotational speed decreased.
• The WTG mechanical stress decreased slightly at high APR ramp rates.
• The wind generation penetration levels and grid fault severity may significantly impact frequency stability of onshore main grid.
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 18
Thank you
26 November 2019 4-6 Sept 2019 ,2nd International Conference on Large-Scale Grid Integration of Renewable Energy in India 19