15
6.2 Operation modes
EA33/40KTLSI supports unattended monitoring, automatic operation and judges if grid-connection power generation
is required according to the output power of PV arrays. The system operation process includes five work status:
startup, grid-connected operation, standby, sleep, shutdown and troubleshooting. Figure 6 presents the operation
mode conversion process for EA33/40KTLSI grid-connected inverter (Vpv means the DC output voltage of PV array)
Startup
De
tec
t fa
ult
or s
hu
tdo
wn
in
stru
ctio
n
V
p
v
>
3
2
0
V
a
n
d
P
V
p
o
w
e
r
c
o
m
p
li
e
s
w
it
h
s
ta
rt
u
p
c
o
n
d
it
io
n
No warning and compliant with operation condition
Insuff
icient
illum
inated
found
Vpv < 200V
and normal power grid voltage
Fau
lt r
em
ov
ed,
afte
r 2
0s
Vpv > 200V
and normal power grid voltage
Det
ect
fau
lt o
r sh
utd
ow
n in
stru
ctio
n
Standby
Sleep
Shutdown/Fault
Grid-connection
operation
Fig. 6 Operation mode conversion process
Startup
Startup refers to the preparation stage from standby mode to grid-connected operation mode. In this mode,
grid-connected inverters constantly detect if PV modules have sufficient energy to generate power connected to the
grid, namely when the open-circuit voltage of PV modules is up to 320V and the output power of solar panels is up to
above 200W, PV grid-connected inverters will convert from startup state to grid-connected operation state.
Grid-connected operation
Grid-connected operation mode is that grid-connected inverters convert DC power of PV arrays into AC power and
connect to the power grid. In order to maximize the use of PV arrays energy, the system is designed with maximum
power point tracking (MPPT) control, namely no matter what condition of sunshine and temperature, the system
constantly enable PV arrays to maximize power output.
Standby
Standby refers to the state in which the input voltage of the inverter is more than 200V and less than 320V,
meanwhile parameters of grid voltage and frequency are within allowable range and the inverter has no fault. In this
mode, the inverter constantly detects open-circuit voltage of PV arrays, and accesses to startup state when detects
that its open-circuit voltage is more than 320V.
Sleep
Sleep refers to the state in which the output voltage of PV arrays is less than 200V, fails to support auxiliary power
supply and power grid is normal. When the system detects the output voltage of PV arrays is less than 200V and no
demand for SVG scheduling in night, it will automatically access to sleep state to reduce system energy
consumption.
Normal shutdown or fault
Normal shutdown or fault refers to the specific state in which the system will protect itself when the output power of
PV arrays is low or has shutdown failure.