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Isolated Grid with Micro-Hydro Power
Plant , PV System and
Diesel Genset as Back up System
R. Saiju
under the supervision of
S. Heier, University of Kassel
1
Agenda
Aims
New HPS Possibility
Models
Control Structure
Conclusion
Aims of the Research Work
 Exploring possibilities to develop new HPS without batteries
For that following models has been developed

PV Plant

Diesel generator Plant

Micro-Hydro Power Plant

HPS – PV+Micro-Hydro
 Implementation of Hybrid Power System (HPS) model to develop, test
and verify new control strategies
 Development of new hardware prototype using micro-controller, test
and verify
New HPS without battery
Formation of mini-grid
AC-Coupled
Hybrid Power System
System Layout
Water flow from
the river
Water
Reservoir
Water
turbine
SM
PW
Vfield
Voltagefrequency
controller
fgrid
Vgrid
PW
Isolated
Grid
E
CB
MCB
3~
Vpv
Power
Controller
 Modular: with same
control structure
Ppv
Ppvref
ASM
Diesel
Tank
PD
Vfield
frequency
controller
E
T
WL
Load Management Unit
 Expandable: Possible to
connect other sources like
WTG, Loads
fgrid
Vgrid
PD
Wf
Pf
Sgrid
State variables formation
by micro-hydro
Suitability
The new concept is suitable for the developing,
mauntainous countries
Focus country: Nepal
Remote area:
No road access, No grid connection, small rivers
available, and sufficient radiation through out the year,
specially in dry winter season
For example: 1000 W/m2 nearly 300 days/ year
Some Remote Areas
Present Micro-Hydro
Example: Khani Khola Micro-Hydro Village
Electrification Project
Maximum discharge in Jan: 390 lps
Average Discharge: 151.03 lps
Designed discharge: 113 lps
Installed Capacity: 18 kW
No. of electrified Houses: 219
Frequency controller: Electronic Load Controller (No
water flow regulation)
It means the rural electrification is only focused where
water flow is more than requirement.
Advantages from new philosophy
 Possible to electrify villages where water
discharge is not much high
 Utilisation of maximum solar energy which is
available nearly 300 days/year
 Possible to avoid expansive and complicated
battery system
 Guarantee of electricity with help of diesel genset
Models
Micro Hydro Power Plant
PV Power Plant
Diesel Genset
HPS-PV+Micro-Hydro
Micro-Hydro Power Plant
Pwater   * Q * H * g *100(Watts)
  0.6
Q  0.11m3 s 1
H  15m
g  9.81m 2 s 1
Voltage control through AVR
Frequency control through water regulation
Results
PV Power Plant
Control System1:
Grid load comparison with available solar Irradiation,
Voltage guard (If grid voltage is less then lower
Level, PV system is disconnected.)
Capacity: 10 kW
Inside PV System
Results
For constant load and increasing irradiation
Diesel Genset
Due to low cost, robust construction 3 phase induction
generator is used in diesel genset.
A capacitor is used to excite the generator at no load
condition.
Mathematical representation
U d1
U q1
d d 1
 R1 I d 1 
 1 q1
dt
d d 1
 R1 I d 1 
 1 d 1
dt
d ' d 2
dt
d ' q 2

dt
0  R'2 I 'd2 
0  R ' 2 I ' q2
 d 1  L1 I d 1  Lh I ' d 2
 ' d 2  L' 2 I ' d 2  Lh I d 1
 d 1  L1 I q1  Lh I ' q 2
 ' q 2  L' 2 I ' q 2  Lh I q1

M el  p.  ' q 2 .I ' d 2   ' d 2 .I ' q 2
 d 1   L1 0 Lh 0   I d 1 
  

 
 q1    0 L1 0 Lh  *  I q1 
 ' d 2   L 0 L' 0   I ' d 2 
2

  h

 
'
 q 2   0 Lh 0 L'2   I ' q 2 

Isolated Operation
NLC
->
U0
I c  U 0 . jC   I  
jLh
LC
->
I c  I   I rec
C
1
1

 Lh 2f 2 Lh
2
Results.. Showing behaviour of system
Fig. 1: Ramp Load Increment
For given constant capacitor voltage
collapse.
Fig. 1
Fig. 2: Voltage establishment by
increasing capacitor.
Fig. 2
Isolated Grid, PV-Micro-Hydro System
In this model, diesel genset is to be integrated.
Synchronous generator runs at no load , if diesel genset has to deliver power in absence
of sufficient water flow.
Results
Control Structure for Microcontroller System
Start
Sgrid
Isolated
Grid
Pgrid Qgrid
Pf
PP
Pw
Dynamics
PD
fgrid Vgrid
Is
fgrid>fref
?
Is
Vgrid>Vref
?
Yes
Is
PD>0
?
Yes
Reduce PD and
check fgrid up to
PD = 0
Do not store
Water
No
Is
PW>0
?
Yes
No
Reduce PW and
check fgrid up to
PW = Pw_nl
No
Is
W L<W max
?
Yes
Store the available
water
Is
PP>0
?
Yes
Reduce PP and
check fgrid up to
PP = 0
No
Yes
Decrease the
field current
No
No
Is
Vgrid<Vref
?
Is
fgrid>fref
?
No
Yes
Is
W f<W av
?
No
Increase the
field current
No
PQ
Yes
Increase the
water flow and Pw
Is
W L>W min
?
Yes
Open the
reservoir valve
increase PW
PW
Start the diesel
genset ID =Ie
PD
PW
Conclusion
Such HPS explores the possibility to electrify remote areas using
locally available renewable energy sources
System is economical and compact due to absence of batteries
Simulation models show good results and it is possible to develop
hardware system based upon this model