Yaskawa Solectria Solar
DOCR-071070
Page 27 of 30
Control of Reactive Power
Reactive power can be controlled by the PMC via Modbus messages at the output of the ACS. The
absorption of reactive power has a negative sign, the insertion of reactive power to the grid has a positive
sign. If none of the three reactive power modes are turned on, the flow of reactive power is zero.
The total reactive energy absorbed and provided by each inverter can be read by summing up two of the
four Modbus variables:
Table 4-9 Reactive Power Modbus Addresses
MESSAGE
MODBUS ADDRESS
DATA TYPE
SCALE FACTOR
TOTAL REACTIVE ENERGY
CTR QUADRANT 1 (VARH)
40257
Acc64
-
TOTAL REACTIVE ENERGY
CTR QUADRANT 2 (VARH)
40261
Acc64
-
TOTAL REACTIVE ENERGY
CTR QUADRANT 3 (VARH)
40265
Acc64
-
TOTAL REACTIVE ENERGY
CTR QUADRANT 4 (VARH)
40269
Acc64
-
One of these three methods to control the flow of reactive power can be chosen:
4.6.1
Method 1: Volt-VAr configuration
The Volt-VAr feature is meant to run permanently, if desired. When enabled, the inverters absorb or
provide a certain amount of reactive power to keep the AC terminal voltage within limits, independently
from the real power output, while limited to the allowable power factor limit. The Volt-VAr function
competes directly with the production of Watts and has the priority. The Volt-VAr-delay feature allows
customers to coordinate the voltage response of the inverter with other voltage regulating assets on the
grid. Your local utility can help you with the correct settings.
Table 4-10 Volt-VAr Modbus Addresses
MESSAGE
MODBUS ADDRESS
DATA TYPE
SCALE FACTOR
VOLT-VAR ENABLE/DISABLE
40931
uInt16
-
VOLT-VAR AUTO ENABLE
30707
uInt16
-
VOLT-VAR RESPONSE DELAY [S]
31649
Float32
-
VOLT-VAR REFERENCE [V]
30705
Float32
-
VOLT-VAR REFERENCE DELAY [S]
30708
uInt16
-
