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DYNAMIC SIMULATION OF A PV-DIESEL-BATTERY HYBRID
PLANT FOR OFF GRID ELECTRICITY SUPPLY
Presented by: Basem Idlbi
Prof. Dr.-Eng. Siegfried Heier
Prof. Dr.-Eng. Ahmed El-Koussi
Prof. Dr.-Eng. Mohammad El-Sobki
Examining Committee:
Contents
1. Introduction
2. Frequency control
3. Modelling of the plant
4. Simulations and results
5. Conclusions
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1. Introduction
Problem Adverse effects of
power variations in the
grid caused by the load
and the renewable
energy source.
Hybrid plants Off grid supply
Objective Analysis of different
control strategies to
improve the operation
of the plant and power
supply quality.
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1. Introduction
Economical comparison based on the difference of fuel consumption between the control strategies.
4 criterions for the comparison between the control strategies.
4 control strategies in relation to primary and secondary control.
Modelling the plant with PowerFactory.
Economical overview
Comparison criterions
Control strategies
Developing the model
Work steps
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2. Frequency control
Droop control of active power Frequency of the grid is dependant on active power
Droop Characteristics of a power source
The droop control is a common technique for parallel power sources
The droop characteristics define the power sharing of different parallel power sources.
Ideal droop characteristics of a generator*
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* P. Kundur, Power System Stability And Control : McGraw-Hill, 1994.
2. Frequency control
Inertial response
Primary control and governor action
Secondary control.
Frequency deviation of a generator following a load increase *
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* PowerFactory, Version 14.1, User's Manual: DIgSILENT, 2011, vol. 2.
3. Modelling of the plant
Model of diesel generator in PowerFactory Model of synchronous generator
Model of diesel governor
Model of voltage controller
Developing a model of fuel consumption measurement
Model of battery energy storage system (BESS) In
PowerFactory Model DC voltage source
Model of Converter
Model of BESS controller
Model of PV field in PowerFactory Model of static generator in the mode of current source
Model of PV controller.
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3. Modelling of the plant
Model of the hybrid plant
Single line diagram of the plant in PowerFactory and the capacities of the main components
Main components capacity unit
diesel generators × 3 1.02 [MVA]
PV field 3 [MWp]
BESS 23 [MWh]
Transformer × 3 1 [MVA]
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3. Modelling of the plant
Developing a model of secondary controller
Physical description of secondary control
Model of secondary controller
Mechanism of the secondary controller
with drooping power source
General diagram of the secondary control
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4. Simulations and Results
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Control strategies
Dynamic simulation of control strategies
Simulation of one example day
Comparison Criterions
Economical overview
4. Simulations and Results
Control strategies
Primary control sharing:
The higher the droop value of a power source, the lower the share of primary control
Secondary control sharing:
A power source provides secondary control according to the control signal from the secondary controller.
parallel units with droop characteristics*
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* P. Kundur, Power System Stability And Control : McGraw-Hill, 1994.
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4. Simulations and Results
Control strategy Primary control of active power Secondary control of active power
1 BESS & diesel generators BESS
2 BESS & diesel generators BESS & diesel generators
3 mainly BESS BESS
4 mainly BESS BESS & diesel generators
Control strategies
Dynamic
simulation control strategy (1)
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4. Simulations and Results
Control strategy Primary control of active power Secondary control of active power
1 BESS & diesel generators BESS
2 BESS & diesel generators BESS & diesel generators
3 mainly BESS BESS
4 mainly BESS BESS & diesel generators
Control strategies
Dynamic
simulation control strategy (2)
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4. Simulations and Results
Control strategy Primary control of active power Secondary control of active power
1 BESS & diesel generators BESS
2 BESS & diesel generators BESS & diesel generators
3 mainly BESS BESS
4 mainly BESS BESS & diesel generators
Control strategies
Dynamic
simulation control strategy (3)
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4. Simulations and Results
Control strategy Primary control of active power Secondary control of active power
1 BESS & diesel generators BESS
2 BESS & diesel generators BESS & diesel generators
3 mainly BESS BESS
4 mainly BESS BESS & diesel generators
Control strategies
Dynamic
simulation control strategy (4)
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4. Simulations and Results
Simulation of one example day
Distribution of the generated energy in the simulated day for control strategy (3)
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4. Simulations and Results
Simulation of one example day
Charging and discharging of the BESS in the simulated day for control strategy (3)
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4. Simulations and Results
Simulation of one example day
Output power of the diesel generators in the simulated day
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4. Simulations and Results
Criterion 1: frequency deviation
Control strategy (3) leads to lower frequency deviations.
Frequency at the main bus bar in the simulated day
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4. Simulations and Results
Criterion 2: fuel consumption
Control strategy (3) leads to less fuel consumption
Fuel consumption in control strategy (3) is less than strategy (2) by 3.5%.
Fuel consumption in the simulated day according to the control strategies
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4. Simulations and Results
Criterion 3: Long battery lifetime
Lifetime of the battery bank is dependent on the cycled energy in the battery
The lifetime of the Battery bank is expected to be longer in control strategy (2).
Energy cycled in the battery bank in the simulated day
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4. Simulations and Results
Criterion 4: performance of the diesel generators
Low loading of diesel generators is not recommended
Overloading of diesel generators is restricted and not recommended
Frequent load ramping leads to transient torques on the shaft
The control strategy (3) leads to approximately constant loading of the diesel generators close to the rated power. Therefore, leads to better performance.
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4. Simulations and Results
Economical overview
Based on the difference of fuel consumption between the control strategies.
Control strategy (3) leads to less energy cost
Energy cost in control strategy (3) is 1% less than strategy (2).
Levelized cost of energy in the simulated day according to the control strategies
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5. Conclusions
Control strategy (3), when the power fluctuations is provided mainly by the BESS, leads to preferable operation of the plant, because:
The output power of the diesel generator is almost constant close to the nominal power
The frequency deviations are lower
The fuel consumption is lower
The performance of the diesel generators is better
But the lifetime of the battery bank is expected to be shorter
Note: the savings in the cost can be higher in lower irradiations or higher price of fuel.
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Recommendation for future work
Developing a dispatch control in order to run one year simulation To analyse different dispatch strategies
To consider the lifetime of the battery in the cost comparison
Integrating the model of BESS with the effect of
battery aging
INTEGRATING THE MODEL OF DIESEL GENERATOR WITH THE MAINTENANCE ESTIMATION
CASE STUDY IN SYRIA (Arwad).
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