ABSTRACT:
Renewable integrated DC Microgrids (DCMGs) are gaining
popularity by feeding remote locations in qualitative and quantitative manner.
Reliability of autonomous DC microgrids (ADCMG) depend on battery capacity and
size due to stochastic behavior of renewables. Over charging and discharging
scenarios compel the microgrid into insecure zone. Increasing the storage capacity
is not an economical solution because of additional maintenance and capital
cost. Thus interconnecting neighbor microgrids increases virtual storing and
discharging capacity when excess power and deficit scenario arises respectively
in any of the DCMG. Control strategy plays vital role in regulating the power
within and between microgrids. Power control and management technique is
developed based on bus signaling method to govern sources, storages and loads
to achieve effective coordination and energy management between microgrids. Proposed
scheme is simple and reliable since bus voltages are utilized in shifting the
modes without having dedicated communication lines. Proposed scheme is
validated through real time simulation of two autonomous DC grids in real time
digital simulator (RTDS) and its results are validated by hardware experimentation.
KEYWORDS:
1.
Autonomous DC
Microgrid
2.
Bus signaling
method
3.
Power control
and management scheme
4.
Renewable
sources
5.
Real time
simulation
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. System architecture for interconnection of two ADCMGs.
EXPECTED SIMULATION RESULTS
Fig.
2. Operating zones of ADCMG1: (a) Bus voltage, (b) Irradiation, (c) PV
output
power, (d) Battery terminal voltage, (e) Battery output power, and (f) Load
power.
Fig.
3. Operating zones of ADCMG2: (a) Bus voltage, (b) Irradiation, (c) PV
output
power, (d) Battery terminal voltage, (e) Battery output power, and (f)
Load
power.
Fig.
4. Operation of BDC using PCMS: (a) ADCMG1 voltage, (b) ADCMG2
voltage,
(c) Power exported from ADCMG1, (d) Power exported from
ADCMG2,
(e) Powers within ADCMG1, and (f) Powers within ADCMG2.
CONCLUSION:
A
PCMS is developed based on bus signaling technique for inter DC grid power flow
in case of ADCMGs to increase the system reliability and efficient utilization
of resources. Two practical DC grid voltages (380V, 48V) are considered for evaluating
the performance of developed scheme in simulation. PCMS is explored under
normal and extreme scenarios including the over and under loading conditions of
ADCMGs, further more with over charging and discharging of battery. It can be
observed from above analysis that proposed PCMS is stable, efficient and
effective in realizing communication independent control even under dynamic
power variations during the power exchange. This statement is also justified
with experimental results obtained through prototype model developed in the
laboratory with reduced voltage of ADCMG1. Proposed system provides isolation
and also enhances system reliability. Application potential of system suits low
and medium voltage customers like domestic consumers, data centers,
telecommunication systems, etc. in isolated locations where utility connection
is not present or feasible.
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