RU , GSE, FOTO CONTROL, QUATROFREM v.2.53x
15. apríla 2019
Page 19 from 97
Name [ID]
Description
Dim.
[361]
control. When off-grid operation is present, AC voltage is controlled.
DC
Voltage
[46]
Voltage of the DC bus. After START command this voltage is continuously increased
up to the value of DC voltage reference [293] (page 41) and this voltage is then
maintained by voltage controller.
V
AC
voltage
[221]
RMS value of phase-to-phase voltage of supply grid (terminals L1,L2,L3).
V
Grid
current
[313]
RMS value of the grid-side current.
It is calculated in the mathematical model of LCL filter from the values Current INV
[515] (page 19) and AC voltage [221] (page 19).
Current
INV
[515]
RMS value of the inverter current (current flowing through the power elements of the
inverter).
A
Modulation
index [750]
PWM duty cycle of the switching power elements.
%
INV
voltage
[1194]
RMS value of phase-to-phase voltage on IGBT tranzistors - on inverter terminals.
V
Grid frequency
[47]
Grid frequency. Excessive fluctuations of this frequency can mean an instability in the
control loop of Phase Locked Loop ( Bandwidth w0f [301] (page 47), Damping bf [302]
(page 47)).
Cos(phi)
ref.
[106]
Power factor cos(phi) reference on the grid-side. Positive value represents the
capacitive nature and negative value the inductive nature of generated current. It is
calculated from Phi angle ref. [356] (page 18).
Cos(Phi) grid-
side [530]
Power factor on the grid side.
Cos(Phi)
inv.
[312]
Power factor on the inverter side.
Power
restriction
[809]
Coefficient of power restriction from external effects.
At maximal allowed power or current the value 1 is acquired and when power
restriction is in effect, this value is decreased to 0. Individual conditions of the power
restriction can be selected in Power restriction (PR) [700] (page 45).
4.4.1 Symmetry of INV currents
Group of parameters number [855]
Quantities which can be used for symmetry evaluation of inverter currents.
MENU \ DIAGNOSTICS \ CONTROL \ SYMMETRY OF INV CURRENTS
Name [ID]
Description
Dim.
Curr. IGBT L1
[856]
RMS value of the current flowing through the IGBT module in L1 phase.
It is used for symmetry evaluation of inverter currents.
A
Curr. IGBT L2
[857]
RMS value of the current flowing through the IGBT module in L2 phase.
It is used for symmetry evaluation of inverter currents.
A
Curr. IGBT L3
[858]
RMS value of the current flowing through the IGBT module in L3 phase.
It is used for symmetry evaluation of inverter currents.
A
I-AC
asymmetry
[868]
Maximum permissible difference between any phase RMS values of the output currents.
High current asymmetry can be caused by unbalance of input voltages or faulty current
sensors. When the asymmetry of AC currents is high, sustained oscillations in controller
quantities or instability of control may occur. Asymmetry check can be turned on/off in
[860] (page 76).
A
4.4.2 I Harmonics
Group of parameters number [223]
Values of harmonics of inverter current.
High harmonic currents check can be turned on in [191] (page 75).
MENU \ DIAGNOSTICS \ CONTROL \ I HARMONICS
Name [ID]
Description
Dim.
THD current [532]
Total harmonic distortion of grid current measured in the phase corresponding to
the parameter Measured curr. phase [225] (page 20).
%
