Vietnam is a long coast country with high potential for wind energy development. However, the cost for wind farm project is a big challenge for the power system planning, while the location and capacity of the wind turbines have the large impact on the operation efficiency of the wind farm. Therefore, problem of optimal placement and size of wind farm attracts great interest of the practitioner and researchers. In this paper, the particle swarm optimization algorithm has been applied to optimize the placement and sizing of wind farm. The model has been tested on the simplified Vietnamese power system to determine the optimal location as well as installation capacity of the wind farm in order to minimize system operation cost while ensuring the capacity limit of transmission lines, power balance, and other constraints. The results in the paper can be applied for power system planning, design, and wind farm projects
Trang 1Optimal Placement and Sizing of Wind Farm in Vietnamese Power System Based on Particle Swarm
Optimization
Dinh Thanh Viet
The University of Danang
Da Nang, Vietnam
dtviet@ac.udn.vn
Tran Quoc Tuan
Alternative Energies and Atomic Energy Commission (CEA), National Institute for Solar Energy (INES)
Le Bourget-du-Lac, France quoctuan.tran@cea.fr
Vo Van Phuong
Da Nang Power Company, Ltd
Da Nang, Vietnam phuongvv@cpc.vn
Abstract—Vietnam is a long coast country with high
potential for wind energy development However, the cost for
wind farm project is a big challenge for the power system
planning, while the location and capacity of the wind turbines
have the large impact on the operation efficiency of the wind
farm Therefore, problem of optimal placement and size of wind
farm attracts great interest of the practitioner and researchers
In this paper, the particle swarm optimization algorithm has
been applied to optimize the placement and sizing of wind farm
The model has been tested on the simplified Vietnamese power
system to determine the optimal location as well as installation
capacity of the wind farm in order to minimize system operation
cost while ensuring the capacity limit of transmission lines,
power balance, and other constraints The results in the paper
can be applied for power system planning, design, and wind
farm projects
Keywords— particle swarm optimization; power system
planning; Vietnamese power system; renewable energy; wind
farm
I INTRODUCTION With the rapid pace of urbanization and industrialization
in the last 10 years, many experts predict that in the next 10
years, Vietnam is in high risk of power shortage The demand
for energy in Vietnam, especially electricity in the period
2020-2030, is huge Demand for energy is increasing, while
energy supply is facing many challenges, especially domestic
traditional energy sources such as hydropower, coal, oil and
gas are gradually depleted and difficult to develop
In this context, the exploitation of renewable energy
sources is very important for Vietnam in terms of economy,
society, energy security and sustainable development [1], [8]
Under Revised National Power Development Master Plan for
the 2011-2020 period with the vision to 2030, the Government
of Vietnam set a target of producing 10.7% of electricity from
renewable sources by 2030 [1], [10] Specifically, by 2020,
the total wind power capacity will reach about 800 MW and
by 2030 is 6,000 MW [1] as showed in Table I
TABLE I DATA OF WIND ENERGY DEVELOPMENT
PLANNING IN VIETNAM
Energy
source
Power (MW) Percentage of energy
production (%)
2020 2025 2030 2020 2025 2030
In order to encourage investors to invest in wind power
projects in Vietnam, the Government of Vietnam has many
preferential mechanisms and policies Typically, the
Government has issued feed-in-tariff (FIT) prices according
to Decision No 39/2018/QD-TTg on the mechanism to support the development of wind power projects in Vietnam
In addition to the FIT price, the government encourages the Electricity of Vietnam to prioritize the purchase of all electricity generation by wind power plants Besides, these plants are able to receive tax incentives at the highest level, while some other taxes, such as equipment import tax, environmental tax, land tax, etc are reduced [2]
With great potential to exploit such incentive mechanisms,
in the coming years, wind energy sources in Vietnam are expected to be strongly invested and developed Currently, the total installed capacity of wind power in Vietnam is 197 MW;
263 MW of wind power capacity is under construction; 412
MW is in the process of approval of basic appraisal Approximately 4,236 MW has been approved and the total registered wind power capacity is 10,729 MW The total wind potential in Vietnam is estimated at 27,200 MW, as shown in Table II [12]:
TABLE II WIND POTENTIAL BY WIND GRADE AND REGION
Low Medium High
There were some studies on integrating renewable energy sources into Vietnamese power system and Vietnamese electricity market, such as [7], [8], [10], [12], [13], [14], [15] However, investigation of these publications leads to an essential need of building a computational model to determine the optimal location and the installation capacity of wind power plants into the Vietnamese power system in the current period, especially for the calculation and approval of investment projects for wind power plants
A Objective function
It is assumed that the investment rate for 1 MW of wind power at all buses is equal, so this component can be ignored
in the objective function Hence, the objective function of the problem is to optimize the operating costs of power plants in the presence of wind power plants, as shown in the formula (1) [3], [11]:
min
Trang 2Where:
∂: voltage angle of generator,
U m: voltage magnitude of generator,
: active power injection of generator in bus k,
: reactive power injection of generator in bus k,
: cost of active power injection of generator in bus
k,
: cost of reactive power injection of generator in bus
k,
: cost of active power injection of wind generator in
bus k
B Constraints in power system
The optimization process must ensure that the system
parameters meet the conditions of power balance, stability and
transmission constraints, including:
Power balance constraints:
where s k is the power of the power plant at bus k; d k is the load
at bus k; M k,b is the incident matrix of the power grid and f b is
the power transmitted through branch b
Limitation on power generation capacity of power plants:
, ≤ ≤ , (3)
Constraints on transmission capacity of lines
Limit on voltage at the buses:
The limit on total installation capacity of wind power
plants in the whole network:
Constraints on maximum capacity of wind power plant at
each bus:
C Particle Swarm Optimization
Particle swarm optimization (PSO) is one of the optimal
algorithms proposed by J Kennedy and R Eberhart in 1995
PSO is an optimal tool that provides a swarm-based search
process in which each individual changes its position over
time A potential solution for each problem can be represented
as an individual in the swarm, flying in the search space with
d dimensions The speed and position adjustment of each
individual can be calculated using the current velocity and the
distance from pbest to gbest by formulas (9) and (10) [4]:
Where:
i = 1,2 n, in which n is the population size, : the inertia weight,
c1, c2: the acceleration coefficients,
rand1, rand2: random numbers within 0 and 1, : position of particle i in the iteration k, : velocity of particle i in the iteration k, : the best position of particle i to the iteration k, : the best position of the swarm to the iteration k
In this paper, the binary particle swarm optimization has been used in combination with the selective method to create the optimal placement and sizing of wind farm model [5], [6] The flow chart diagram of the proposed algorithm is shown in Fig 1
Fig 1 Flow chart diagram of the proposed algorithm
Trang 3III CASESTUDY:OPTIMALPLACEMENTAND
A Vietnamese power system in the year of 2030
In order to study and evaluate the possibility of optimally
integrating wind energy into Vietnamese power system in the
future, stemming from the research and evaluation of the
actual power grid [7], the authors have built the simplified
Vietnamese 500kV power system model consists of 31 buses,
41 branches as shown in Fig 2 Buses number and name of
each bus are listed in Table VII in Appendix
Fig 2 Simplified-Vietnamese power system in the year of 2030
In particular, the power source and load parameters in each
area are referred to the nearest bus In Fig 2, the buses in the
power system are represented by a blue circle, the size of the
circle is drawn proportionally to the load referred to that bus
Buses are linked together through transmission lines
B System parameters
In the paper, the data set of the installed capacity of power
plants, parameters of transmission lines and actual demand
have been collected Based on this data set and information on
the 500kV power development plan by 2030, data from the
Revised National Power Development Master Plan for the
2011-2020 period with the vision to 2030 [1], the authors built
the data set for the simplified power system in Fig 2
C Simulation and results
The methodology, described in part II has been applied to
solve the problem of optimal placement and sizing of wind
power plants model The calculation scenarios are given by
the authors based on the Revised National Power
Development Master Plan for the 2011-2020 period with the
vision to 2030 and the development strategy of renewable
energy of Vietnam by 2030 with a vision to 2050 [9], with the
different penetration levels of wind power plants into the
Vietnamese power system The three specific scenarios have been investigated as follows:
Scenario of the year 2020: maximum penetration of wind power plants into Vietnamese power system is limited to 800 MW
Scenario of the year 2025: maximum penetration of wind power plants into Vietnamese power system is limited to 2000 MW
Scenario of the year 2030: maximum penetration of wind power plants into Vietnamese power system is limited to 6000 MW
Each scenario has been simulated with 100 iterations using proposed algorithm (Fig 1)
First, we run the simulation for the first scenario (scenario
of the year 2020) Fig 3 and Table III show the performance and results of the model From the first iteration to 100th iteration, the objective function is reduced from
$2,694,233.907 to $2,618,864.524 (-2.80%) As we can see from the Fig 3, the model almost reaches its optimum after 44 iterations
Fig 3 Optimization performance of the model in scenario of the year
2020
TABLE III SCENARIO OF THE YEAR 2020–SIMULATION
RESULTS
Scenario
Total optimized wind capacity installation
Operation cost (USD)
Percent-age of cost saving
Before optimization
After optimization
Scenario of the year
2020
780 2,694,233 2,618,864.5 2.80%
Iteration 2.61
2.62 2.63 2.64 2.65 2.66 2.67 2.68 2.69
Trang 4In the scenario of the year 2020, after running the
simulation with 100 iterations, the model proposed to install
the total of 780MW wind power plants at the buses 3, 5, 6, 18,
29, 30 The proposed installation capacity at each bus is shown
in Table IV
TABLE IV PROPOSED LOCATION AND CAPACITY OF
WIND POWER PLANTS IN SCENARIO OF THE YEAR 2020
Bus Wind power plants capacity (MW)
We run the same simulation for scenario of the year 2025
and scenario of the year 2030 Fig 4 and Fig 5 show the
performance of the model for the two scenarios In the
scenario of the year 2025, the model almost reaches the
optimum after 72 iterations, while it takes 84 iterations to
reach optimum in the scenario of the year 2030
Summary results for all scenarios are shown in Table V
Thus, it can be seen that when the penetration of wind power
plants into the power system increases, the percentage of cost
saving in optimization performance increases
Fig 4 Optimization performance of the model in scenario of the year
2025
Fig 5 Optimization performance of the model in scenario of the year
2030 TABLE V SIMULATION RESULTS FOR ALL SCENARIOS
Scenario
Total optimized wind capacity installation
Operation cost (USD)
Percent-age of cost saving
Before optimization
After optimization
Scenario of the year
2020
780 2,694,233 2,618,864.5 2.80% Scenario of
the year
2025
1,980 2,694,233 2,506,265.5 6.98% Scenario of
the year
2030
6,000 2,694,233 2,159,906.8 19.83%
In the scenario of the year 2030, when the installed capacity of wind power plants reaches 6,000 MW, the optimal economic operation of wind power plants help reducing the total operation cost nearly 20%, showing the importance of the integration of wind power plants and other renewable energy sources into the Vietnamese power system
Table VI summarized the result of the optimal location and installation capacity of wind power plants at buses in the Vietnamese power system in the three mentioned scenarios
TABLE VI OPTIMAL PLACEMENT AND INSTALLATION
CAPACITY OF WIND FARMS
Bus
Wind power installation capacity (MW)
Scenario of the year 2020
Scenario of the year 2025
Scenario of the year 2030
Iteration
2.52
2.54
2.56
2.58
2.6
Iteration
2.16 2.165 2.17 2.175 2.18 2.185 2.19 2.195 2.2
Trang 5Wind power installation capacity (MW)
Scenario of the
year 2020
Scenario of the year 2025
Scenario of the year 2030
Tot
Fig 6, Fig 7 and Fig 8 show the voltage diagrams at buses
in the mentioned power system corresponding to the three
scenarios It can be seen that the voltage at buses in the power
system is within the allowable limits with the participation of
wind power plants Moreover, the voltage difference between
the buses tends to decrease thanks to the participation of these
wind farms
Fig 6 Buses voltage in scenario of the year 2020
Fig 7 Buses voltage in scenario of the year 2025
Fig 8 Buses voltage in scenario of the year 2030
IV CONCLUSION
In the paper, a model to optimize the location and installation capacity of the wind farms has been built in order
to optimally integrate wind power plants into the power system The optimization model was developed based on the binary particle swarm optimization algorithm, combined with selective algorithms to optimize the operating costs of power plants in the system The proposed model has been used to calculate and test on simplified 500kV power system in
Bus
1 1.01 1.02 1.03 1.04 1.05 1.06
Before wind power installation After wind power installation
Bus
1 1.01 1.02 1.03 1.04 1.05 1.06 1.07
Buses voltage
Before wind power installation After wind power installation
Trang 6Vietnam The collected data has been used to build a compact
grid consisting of 31 nodes and 41 branches This grid then
has been tested with the proposed model with 03 scenarios
corresponding to the different penetration level of wind power
plants according to the Revised National Power Development
Master Plan for the 2011-2020 period with the vision to 2030
The program has calculated and provided the results of the
optimal location as well as the optimal installation capacity of
wind power plants at each bus in the power system in
accordance to the objective function, while ensuring the
constraints on power balance in the power system, ensuring
compliance with the transmission limits of 500kV lines and
ensuring the voltage at the buses within the allowed limits
The simulation results show that the greater the degree of
penetration of wind energy sources into the power system, the
higher the economic efficiency of the power plants operation,
while the voltage stability of the buses is maintained
The research results as well as the model proposed in the
paper can be applied to the optimal placement and sizing of
wind farms and can be useful for the power system
development planning and approval
REFERENCES
[1] The Vietnamese Prime Minister, “Approval of the Revised National
Power Development Master Plan for the 2011-2020 Period with the
Vision to 2030”, Decision No 428/QD-TTg dated March 18, 2016
[2] The Vietnamese Prime Minister, “Amending several articles of
Decision no.37/2011/QD-TTg dated June 29, 2011 of the Prime
Minister on provision of assistance in development of wind power
projects in Vietnam”, Decision No 39/2018/QD-TTg dated September
10, 2018
[3] S Frank, S Rebennack, "An introduction to optimal power flow:
Theory, formulation, and examples", IIE Transactions, vol 48, no 12,
pp 1172-1197, 2016
[4] J Kennedy, R Eberhart, “Particle Swarm Optimization”, Proceeding
IEEE International Conference on Neural Networks, vol 4, pp 1942–
1948, 1995
[5] J Kennedy, R Eberhart, “A decrete binary version of Particle Swarm
Algorithm”, Proceeding IEEE International Conference on System, pp
4104–4109, 1997
[6] T M Khalil, A V Gorpinich, “Selective Particle Swarm
Optimization”, International journal of multidisciplinary sciences and
engineering, vol 3, no 4, April 2012
[7] D T Viet, V V Phuong, M Q Duong, M P Khanh, A Kies, B
Schyska, "A Cost-Optimal Pathway to Integrate Renewable Energy
into the Future Vietnamese Power System", 4th International
Conference on Green Technology and Sustainable Development
(GTSD), pp 144-149, 2018
[8] A Kies, B Schyska, D T Viet, L Bremen, D Heinemann, S
Schramm, “Large-Scale Integration of Renewable Power Sources into
the Vietnamese Power System”, Energy Procedia, vol 125, pp 207–
213, 2017
[9] The Vietnamese Prime Minister, “Approving the development strategy
of renewable energy of Vietnam by 2030 with a vision to 2050”,
Decision No 2068/QD-TTg dated November 25, 2015
[10] D T Viet, V V Phuong, M Q Duong, A Kies, B Schyska, Y.K Wu,
“A Short-Term Wind Power Forecasting Tool for Vietnamese Wind
Farms and Electricity Market”, 4th International Conference on Green
Technology and Sustainable Development (GTSD), pp 130-135, 2018
[11] R D Zimmerman, C E Murillo-Sanchez, Matpower 6.0 User’s
Manual, December 2016
[12] N Q Khanh, N T Hang, N T Khanh, N T Hoan, “Analysis of future
generation capacity scenarios for Vietnam”, Green Innovation and
Development Centre (GreenID), 2018
[13] T P Nam, D T Viet, Development of distributed generation in power
market - Proc Conf UK-VN CECE, 2012
[14] M Q Duong, T V Dinh, H V P Nguyen, V T Nguyen, N T N Tran, T T M Le, Effects of FSIG and DFIG Wind Power Plants on
Ninh Thuan Power Grid, Vietnam, GMSARN International Journal,
2018
[15] D T Viet, P C Tien, Impact of Ancillary Services and Its Prices on Large-Scale Solar and Wind Power Penetration in Electricity Market,
4th International Conference on Green Technology and Sustainable Development (GTSD), pp 114-121, 2018
APPENDIX
TABLE VII NAMEOF31BUSES