Power System Frequency Support of Wind Turbines with ...
Transcript of Power System Frequency Support of Wind Turbines with ...
Power System Frequency Support of Wind Turbineswith Virtual Synchronous Machine Control
Liang LuPhD student
Centrale Nantes, Nantes, France29-10-2019
Power System Frequency Stability
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Three-phase Alternating Current (AC) Power System
Synchronous Generator
Power System Frequency Stability
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WT
Three-phase Alternating Current (AC) Power System
Synchronous Generator
Power System Frequency Stability
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๐๐๐๐
๐๐๐๐
๐๐
๐๐
๐๐๐๐ โ ๐๐๐๐ = ๐ฝ๐ฝ๐๐๐๐๐๐๐๐๐๐
Type-4 wind turbine
Power System Frequency StabilityVirtual Synchronous Machine (VSM) Control
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โข A control scheme for a converter to enable renewable power sources to behave as a synchronous machine (SM) by adding the model and control of an SM within the control scheme;
๐๐๐๐
๐๐๐๐
๐๐
๐๐
๐๐๐๐ โ ๐๐๐๐ = ๐ฝ๐ฝ๐๐๐๐๐๐๐๐๐๐
Type-4 wind turbine
Prabha Kundur, Neal J. Balu and Mark G. Lauby. Power system stability and control. Vol. 7. New York: McGraw-Hill, 1994.
Synchronous Generator (SG) Model and Control
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โ๏ฟฝฬ๏ฟฝ๐โ๏ฟฝฬ๏ฟฝ๐ฟโฮจฬ๐๐๐๐โฮจฬ1๐๐โฮจฬ1๐๐โฮจฬ2๐๐
=
๐๐11๐๐21
0000
๐๐120๐๐32๐๐42๐๐52๐๐62
๐๐130๐๐33๐๐43๐๐53๐๐63
๐๐140๐๐34๐๐44๐๐54๐๐64
๐๐150๐๐35๐๐45๐๐55๐๐65
๐๐160๐๐36๐๐46๐๐56๐๐66
โ๐๐โ๐ฟ๐ฟโฮจ๐๐๐๐โฮจ1๐๐โฮจ1๐๐โฮจ2๐๐
+
๐๐1100000
00๐๐32000
โ๐๐๐๐โ๐ธ๐ธ๐๐๐๐
Motivation 1
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Qualified simplicity
WT application
Frequency controlSG Model
Swing equation
Governor
ExciterStator windings
Field circuit
Yong Chen et al. Comparison of methods for implementing virtual synchronous machine on inverters. International conference on renewable energies and power quality. 2012.
Salvatore DโArco et al. Small-signal modeling and parametric sensitivity of a virtual synchronous machine. Power Systems Computation Conference. IEEE, 2014.
More Complex VSM Control
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Modelling & Simulation
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25%, 50%, 75%, 100%
10 ๐๐๐๐
1 ๐๐,๐๐,๐๐, ๐๐
2 Simulation time
Grid-side converter
Conclusions 1
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โข A simpler but qualified VSM control scheme is proposed for frequency control;
โข The proposed VSM control scheme is adapted for WT application;
โข To achieve VSM control for frequency control capability of WTs, to emulate the swing equation and governor is enough;
โข Including the modeling of exciter and stator windings does not improve much, while increasing dynamics of voltage;
โข Including the modeling of field circuit will make things more complex, not necessary;
โข The proposed VSM control scheme works better in voltage control;
Motivation 2
/ 2214https://orbit.dtu.dk/en/activities/a-virtual-synchronous-machine-control-scheme-for-wind-turbines(4cdc26fd-1829-4c00-af62-5775529c73f3).html
The VSM Control Scheme for WTs Power Angle Small Signal Stability
โข Focusing on the power loop while idealizing inner voltage and current loops;
โข State space representation and block diagram of an inverter connected to an infinite bus;
โข Influence of parameters on the stability by analyzing eigenvalue trajectories;
Power Angle Small Signal Stability (PAS) Model
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1 12 2 2 2
0 0 01 1 00
s
n m
dr dr
g r g
KDH H H Hd T
dtT T
T D T
ฯ ฯฮด ฯ ฮด
โ โ โ โ โ โ = โ + โ โ โ โ
0cosbs
E EKX
ฮดโฒ
=
Verification
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Grid-side converter Voltage source
โข ๐๐ = 1๐ ๐ , ๐๐๐๐ is dropped by 0.5 pu, or ๐๐๐๐is dropped by 5 ๐๐๐๐
Parameter Design โ Inertia Constant ๐ฏ๐ฏ
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โข 0.1 ~ 0.5;
โข Little influence on ๐๐3;
โข Stability margin reduced by increasing ๐ป๐ป;
โข A larger ๐ป๐ป is better for inertia response;
โข A compromise;
โข Exact value also depends on grid code requirements and converter rating;
๐๐1
๐๐2
๐๐3
Parameter Design โ Damping Coefficient ๐ซ๐ซ
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โข 10~53: stable, 54~100: unstable;
โข Little influence on ๐๐3;
โข Stability margin improved by increasing ๐ท๐ทin the stable range;
โข Positive effects of a smaller ๐ท๐ท;
โข A trade-off;
๐๐1
๐๐2๐๐3
Parameter Design โ Droop ๐ซ๐ซ๐๐
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โข 1% ~ 100%;
โข Much influence on ๐๐3;
โข Stability improved by increasing ๐ท๐ท๐๐;
โข Constraint and most likely determined by grid code requirements, converter rating and capacity of energy storage;
๐๐1
๐๐2
๐๐3
Parameter Design โ Response Time ๐ป๐ป๐๐
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โข 0.01 ~ 10;
โข Much influence on ๐๐3;
โข Stability is worse when increasing ๐๐๐๐;
๐๐3๐๐1
๐๐2
Conclusions 2 & Future Work
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โข Power angle small signal stability (PAS) is proposed as a simpler way of analyzing the small signal stability of VSM-controlled grid-forming inverters;
โข Helpful for analyzing the rotor angle small signal stability of a big power system with large share of converter-interfaced renewable power sources;
โข A larger inertia constant ๐ป๐ป or damping coefficient ๐ท๐ท reduces the stability margin, but enhances the inertial response and frequency control capability;
โข A larger droop ๐ท๐ท๐๐ or a smaller response time ๐๐๐๐ helps improving the stability;
Overall and systematic design of all parameters simultaneously considering practical constraints;
What is the optimal or acceptable power response from a non-synchronous power source for fast frequency regulation?
Thank you !
Liang [email protected]
This work has received funding from the European Unionโs Horizon 2020 research and innovation program under grant agreement No. 727680 (TotalControl).
This work has also received funding from project PowerKey (EUDP Project No. 12558).