Kaco proLOG M Operator's Manual - page 33
8.3.1 Basic principle of monitoring
This example is based on the physical ratio between
the solar radiation (insolation) and the generated power;
under ideal conditions, this ratio would be as follows:
[generated power] = [Insolation * Area
Module
* eta
Module
*
eta
inverter
]
Assuming a PV module having a degree of efficiency of
12%, an inverter efficiency of 91% and a module area
of 10 square meters, the ideal ratio is shown in the
graph below:
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
1,1
0
100
200
300
400
500
600
700
800
900
1000
1100
Einstrahlung in [W/m²]
Leistung in [kW
]
Pac = Gmod * eta mod * eta WR * Fläche
As in reality this ratio is not exactly linear over the
entire range (smaller amount of solar radiation =>
lower degree of efficiency), a solution must be
found to obtain a functional error messaging
criterion.
We are therefore “opening up” a range in which two
read values can occur. This requires two formulas
for calculating straight curves, which form the upper
and lower limits of a “plausible” range.
-0,4
-0,2
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0
100
200
300
400
500
600
700
800
900
1000
Einstrahlung in [W/m²]
L
e
is
tu
n
g
in
[
k
W]
ideal
Grenze unten
Grenze oben
gültiger Bereich
Störmeldung:
obere Gernzüberschreitung
Störmeldung:
untere Gernzüberschreitung
To gain more freedom and flexibility when selecting a
range, two different gradients can be defined.
The shift of the straight line by t
upper
and t
lower
is to be
defined as an absolute value (e.g.: 0.2kW).
The limiting lines are now defined by the following
formulas:
Lower limit:
upper
lower
t
X
m
Y
⊕
⊗
<
(
)
(
)
nenn
WR
PV
Arry
Module
P
tlower
eta
eta
A
G
mlower
Pac
⊗
⊕
⊗
⊗
⊗
⊗
<
Upper limit:
upper
upper
t
X
m
Y
⊕
⊗
>
(
)
(
)
nenn
WR
PV
Arry
Module
P
tupper
eta
eta
A
G
mupper
Pac
⊗
⊕
⊗
⊗
⊗
⊗
>
With: m
lower
= 0.85
t
lower
= - 0.25
m
upper
= 1.1
t
upper
= 0.15
8.3.2 Parameterization of the measuring device
Settings via the menu item: “Admin – monitoring –
formulas / criterion X”:
First the general definitions are determined for this
alarm parameter:
y Designation: “Power generated by solar insolation”
y Status: “active“
y Time: “Interval“
y Alarm target (contact) “Standard contact“
y Type of message: E-Mail
y Delay: “8“
(triggering an alarm delay of 2 hours
at a measuring interval of 2 hours).
To send an alarm message the
contact must be defined in the menu
under: [ Admin – Monitoring /
Contact addresses / contact x ] !
Then the formula entries are as follows:
Y
Generation PVA
(dig_0)
m (lower limit)
0.85
m (upper limit)
1.1
x
Insolation module
(ana_0);plant
surface; *
;etaPV;*;etaINV;*
c (lower limit)
200
c (upper limit)
200
KACO SOLAR INC.
33
Operator’s Instructions KACO-proLOG