European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Wind Energy Penetration in Islands: Limitations and Prospects
N. Hatziargyriou S. Papathanassiou, T. Chaviaropoulos, I. Tsipouridis
NTUA CRES PPC
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Island Systems
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Installed Wind Power(ΜW)
Small Hydro (MW)
Biomass(MW)
PV(kW)
Hellenic Interconnected system
341 61 20.6 105
Crete 87 0.6 0.4 442
Cyclades 5.4 0 0 182
Dodecanesse 9.9 0 0 37.5
Rest Aegean Islands
26 .1 0 0 73
Total islands 128.4 0.6 0.4 735
Total 469.4 61.6 21 840
RES in GreeceRES in Greece (1) (1)
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
With authorization
Wind Power(ΜW)
Small Hydro (MW)
Biomass+Geothermal
(MW)
PV(kW)
Hellenic Interconnected system
3039.4 348.59 40.5 760
Crete 132.3 0 0 650
Cyclades 33.25 0 0 0
Dodecanesse 68.5 0 0.5 0
Rest Aegean Islands 17.15 3.8 8 100
Total islands 251.2 352.39 8.5 750
Total 3290.6 352.39 49 1510
RES in GreeceRES in Greece (2) (2)
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
– Small isolated Power system –2MW.
– 11% Annual RES penetration –Wind & PV
– Up to 100% instantaneous RES Penetration
Kythnos Island
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Number Type of Unit Capacity
5 Diesel units 5*400=2000kW /2500kVA
1 Wind Turbine 500kW
5 Wind Turbines 5*33=165kW
1 PV Power station 100kW
1 Battery Bank 400kWh/500kW
1 Phase Shifter 600kVA
1 Compensation bank 8*100=800kVAr
Kythnos Power System-todayKythnos Power System-today
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Crete Island
Largest isolated power system in GreeceLargest isolated power system in Greece3 Power Stations (Chania,Linoperamata,Atherinolakos)-3 Power Stations (Chania,Linoperamata,Atherinolakos)-26 thermal units, Peak 540 MW(2004), 26 thermal units, Peak 540 MW(2004), 87.1MW Wind capacity-Wind power penetration 10%87.1MW Wind capacity-Wind power penetration 10%
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Crete System Single-Line Diagram
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
W/F Production 1993-2000 [KWh]
0
50.000.000
100.000.000
150.000.000
200.000.000
250.000.000
1993 1994 1995 1996 1997 1998 1999 2000
0
20
40
60
80
100
Inst
all
ed
W/P
Ca
pa
city
[M
W]
W/F Production[MWh]
Installed W/F Capacity[MW]
Ye
arl
y P
rod
uc
tio
n [
KW
h]
Year
2%
5%
10%
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Penetration during the day of max. inst. output ( Dec.28.2000)
0,0
50,0
100,0
150,0
200,0
250,0
300,0
350,0
0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 0:00
Lo
ad-W
ind
Pro
du
ctio
n [
MW
]
0,0
5,0
10,0
15,0
20,0
25,0
30,0
35,0
Pen
etra
tio
n[%
]
Load W/P Penetration
Time
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Rokas W/F output (13 May 1998)
0
1
2
3
4
5
6
7
8
9
101:
00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:0
0
11:0
0
12:0
0
13:0
0
14:0
0
15:0
0
16:0
0
17:0
0
18:0
0
19:0
0
20:0
0
21:0
0
22:0
0
23:0
0
0:00
W/F
out
put
[MW
]
Hours
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Rokas W/F output ( 20 May 1998 )
0
1
2
3
4
5
6
7
8
9
10
1:00
2:00
3:00
4:00
5:00
6:00
7:00
8:00
9:00
10:0
0
11:0
0
12:0
0
13:0
0
14:0
015
:00
16:0
0
17:0
0
18:0
0
19:0
0
20:0
0
21:0
022
:00
23:0
0
0:00
W/F
out
put
[MW
]
Hours
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Frequency and production due to Gas Turbine Outage
.
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Summary of Experience from Wind Power Penetration in Crete
High efficiencies (Capacity Factor in 2000:37,33%)
Stable output but with serious exceptions
Normal Voltage fluctuation at connecting W/F bus
Higher yields during summer months but lower,or zero, at evening peaks
No problem for Flicker or Harmonics
Economical considerations.
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Large Scale Penetration of Increased Wind Power in Island Systems
• Wind Power - Intermittent Power Source• Wind Power – partly non-controllable
Effects→ Operation with increased uncertainty, requirements for
reliable short-term forecasts of renewable source production.
→ Effects on power system security both steady-state and dynamic, inability of conventional directly coupled Wind Turbines to provide ancillary services, requirements for on-line security assessment.
→ Effects on economic operation → Power Quality ???
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Fault Ride-Through Capability• Modern WG are
required to remain connected during a fault
• Various standards for voltage dips to be sustained
Frequency Requirements?
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
CARE&MORE CARE EC Projects: Advanced Control Advice for Power Systems with
Large-Scale Integration of RESJOULE JOR3-CT96-0119 & ENERGIE ERK5-CT1999-00019
• Minimise production costs through unit commitment and on-line economic dispatch of both conventional and RES also considering market and increased security.
• Provide short-term forecasts of load and wind for short-term (0-8 hr) and medium-term horizon (4-48 hrs).
• Maximise power system security by on-line security assessment modules, that supervise scheduling of the power units and monitor the system security margin. Also provide corrective control actions.
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
OPERATOR
SCADA system
DATA-BASE
SCHEDULER
SECURITYASSESSMENT
RENEWABLESFORECASTING
MAN-MACHINEINTERFACE
SECURITYMONITORING
ECONOMICDISPATCH
UNIT COMMITMENT
LOAD FORECASTING
The CARE System Architecture
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Execution Cycles of MORE CARE
For Crete
H=48 hrs, h=4 hrs,
t1=1 hr, t2=20 min
START
Load & renewable power forecasts ( H
D hours ahead)
Unit Commitment ( H1
hours ahead)
Dynamic Security Assessment
Economic Dispatch
Set-Points of Power Units
Ev
ery t1 h
ou
rs
Ev
ery t2 m
inu
tes
Load & renewable power forecasts (h hours ahead)
Dynamic Security Monitoring
Unit Commitment ( hD
hours ahead)
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Current System Operation and Economic DispatchCurrent System Operation and Economic Dispatch
Wind ParksWind ParksLoadsLoads
Current ProductionCurrent ProductionEconomic DispatchEconomic Dispatch
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
• Off-line execution of Economic Scheduling functions assuming:– Spinning Reserve at least equal to wind power – no wind
power forecasting– Spinning reserve at least equal to 50% of wind power – 50%
maximum forecasting error – Spinning reserve at least equal to 20% of wind power to face
very short wind fluctuations – very advanced WF with 20% maximum forecasting error.
– Evaluation of economic impacts
Economic Appraisal of Wind Power Forecasting
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
More accurate wind power forecasting reduces operating costs as follows:
• Monthly cost savings with thermal spinning reserve equal to 50% of wind power
1.8-3.5% (163-480 kEuro)• Monthly cost savings with thermal spinning reserve equal to
20% of wind power 2.3-5.3% (217-758 kEuro)
Economic Appraisal of Wind Power Forecasting - Results
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
• Unit Commitment Average gain 3.1%
• Economic Dispatch Average gain 1.7%
Economic Scheduling EvaluationEconomic Scheduling Evaluation
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Relative gain provided by GA Economic
Scheduling Functions
ED OPF UC A UC B August 2001 1.7 1.67 2.2 3.15 September 2001 1.3 1 1.1 2.75 October 2001 0.6 1.02 3.85 3.5 November 2001 0.1 0.58 3.44 5.73 January 2002 2.35 2.73 3.76 3.22 February 2002 0.95 1.30 5.2 6
Economic Scheduling EvaluationEconomic Scheduling Evaluation
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Actual Operation Proposed Operation
Dynamic Security EvaluationDynamic Security Evaluation
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Short term flicker (Pst) at W/P bus of Sitia S/S ( 12 Aug. 1998 )
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
9:53
9:56
9:59
10:0
2
10:0
5
10:0
8
10:1
1
10:1
4
10:1
7
10:2
0
10:2
3
10:2
6
10:2
8
10:3
1
10:3
4
10:3
7
10:4
0
10:4
3
10:4
6
10:4
9
10:5
2
10:5
5
10:5
8
Time
Shor
t ter
m f
lick
er
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Long term flicker (Plt) at W/F bus of Sitia S/S ( 12 aug. 1998 )
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
9:53
9:56
9:59
10:0
2
10:0
4
10:0
7
10:1
0
10:1
3
10:1
5
10:1
8
10:2
1
10:2
4
10:2
6
10:2
9
10:3
2
10:3
5
10:3
7
10:4
0
10:4
3
10:4
6
10:4
8
10:5
1
10:5
4
10:5
7
10:5
9
Time
Lon
g te
rm fl
icke
r
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
PROJECT: Integration of Wind Turbines into Electricity Supply Networks with Limited Power Transportation Capacity –Wiring (JOR3-CT98-0245)
Electrical network of the Greek island Samos
VESTASWINDMATICNEG MICONNEG MICON
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Frequency behaviour of the island grid of Samos during one week
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Diesel generator production during 13 days
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
The measurement campaign gave some unexpected results:
Most important is the fact that the voltages are highly distorted in
the flicker producing frequency region, due to firing harmonics of
the power station diesel engines. This background distortion is large
enough to completely mask the effect of the flicker emitted by the
WTs. The connection of the WTs leaves more or less unaffected the
overall flicker levels, and in certain cases even reduces them.
The effect of the Vestas wind turbines on the frequency spectrum
of voltage and power at the diesel power station was investigated.
The same spectrum of voltages occurs with and without the wind
turbines.
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
Voltage PSD before cut-in of WTs
Voltage PSD after cut-in of WTs
Firing of diesel engines
European Wind Energy Conference & Exhibition, EWEC2006, 27 Febr-2 March 2006, Athens
CONCLUSIONS
Wind power installations in islands provide economical benefits compared to diesel
Increased requirements for robust Wind Turbines equipped with Low Voltage Ride Through capabilities and able to withstand frequency varaitions
Need for advanced control systems to deal with optimal operation and management of power systems with large integration from wind power.
Application of the MORE CARE control software on Crete has shown clear economic gains and timely warning for more secure operation.
Flicker levels do not seem to be affected by the operation of WTs.