Reactive Power Optimal Control of a Wind Farm for Minimizing Collector System Losses
Abstract
:1. Introduction
2. The Proposed Reactive Power Control System
2.1. Sensitivity Coefficient Matrix
2.2. Objective Functions
2.3. Constraints
3. Algorithm to Solve the Model
3.1. Genetic Algorithm
3.2. Particle Swarm Optimization Algorithm
3.3. Constraints Handling
- --
- indicates the control variables involving the reactive power setting of all WTs.
- --
- represents the dependent variables, including all bus voltages and the reference reactive power of the PCC.
- --
- , and are called the penalty factors in this study; they increase gradually and have little influence on the initial iterations.
- --
- is the absolute value of the difference between and .
4. Case Study
4.1. Wind Farm Model Description
4.2. Case 1: V = 9 m/s,
4.3. Case 2: V = 9 m/s,
4.4. Total Annual Losses in the WF
4.5. Environmental Indicators Analysis
5. Conclusions
- Combining the reactive power/voltage control with the loss reduction control of the collector system reduces the operating loss of the WF effectively; this is verified by a simulation based on an actual wind farm.
- Both the GA and PSO optimization methods designed in this paper can reduce the operating loss effectively but the GA has a better performance of energy savings with regard to the annual loss in this case.
- The control strategy proposed in this paper would be used to improve the automatic control level, reduce the cost of electricity production, and improve the energy savings under various operating conditions of a WF, which has good application prospects.
Author Contributions
Acknowledgments
Conflicts of Interest
Appendix A
Parameter | 5 MW NERL Wind Turbine |
---|---|
Cut-in, Rated, Cut-out Wind Velocity | 3 m/s, 11.4 m/s, 25 m/s |
Rotor, Hub Diameter | 126 m, 3 m |
Rated Power | 5 MW |
Cut-in, Rated Rotor Velocity | 6.9 rpm, 12.1 rpm |
Gearbox Ratio | 97:1 |
Cable Types | Cross Section (mm2) | Specific Resistance (Ω/km) | Specific Capacitance (μF/km) | Specific Inductance (μH/km) |
---|---|---|---|---|
Type 1 | 95 | 0.1842 | 0.18 | 0.44 |
Type 2 | 150 | 0.1167 | 0.21 | 0.41 |
Type 3 | 240 | 0.0729 | 0.24 | 0.38 |
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Strategy of Dispatch | Proportional Dispatch | ORPD Strategy | ||
---|---|---|---|---|
WF Loss (kW) | Optimized by GA | Optimized by PSO | ||
Cable + Package Transformers | 529.03 | 452.44 | 452.35 | |
Main Transformer | 682.30 | 681.15 | 681.15 | |
Total | 1211.34 | 1133.59 | 1133.49 |
Proportional Dispatch (GWh) | Proportion of Losses | ORPD Strategy | ||||
---|---|---|---|---|---|---|
GA (GWh) | Proportion of Losses | PSO (GWh) | Proportion of Losses | |||
−0.2 | 9.57 | 2.12% | 8.81 | 1.94% | 8.86 | 1.96% |
−0.1 | 9.37 | 2.07% | 8.7 | 1.92% | 8.74 | 1.93% |
0 | 9.37 | 2.07% | 8.74 | 1.93% | 8.77 | 1.93% |
0.1 | 9.58 | 2.12% | 8.91 | 1.97% | 8.94 | 1.97% |
0.2 | 9.9 | 2.21% | 9.18 | 2.04% | 9.22 | 2.06% |
Annual Loss Reduction (GWh) | Standard Coal (t/year) | CO2 Emissions (t/year) | Carbon Emissions (t/year) | |
---|---|---|---|---|
−0.2 | 0.77 | 308 | 604.45 | 209.44 |
−0.1 | 0.67 | 272 | 533.8 | 182.24 |
0 | 0.63 | 256 | 502.4 | 171.36 |
0.1 | 0.66 | 268 | 525.95 | 179.52 |
0.2 | 0.73 | 284 | 557.35 | 198.56 |
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Xiao, Y.; Wang, Y.; Sun, Y. Reactive Power Optimal Control of a Wind Farm for Minimizing Collector System Losses. Energies 2018, 11, 3177. https://doi.org/10.3390/en11113177
Xiao Y, Wang Y, Sun Y. Reactive Power Optimal Control of a Wind Farm for Minimizing Collector System Losses. Energies. 2018; 11(11):3177. https://doi.org/10.3390/en11113177
Chicago/Turabian StyleXiao, Yunqi, Yi Wang, and Yanping Sun. 2018. "Reactive Power Optimal Control of a Wind Farm for Minimizing Collector System Losses" Energies 11, no. 11: 3177. https://doi.org/10.3390/en11113177