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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
TOTAL REACTIVE ENERGY
CTR QUADRANT 1 (VARH)
TOTAL REACTIVE ENERGY
CTR QUADRANT 2 (VARH)
TOTAL REACTIVE ENERGY
CTR QUADRANT 3 (VARH)
TOTAL REACTIVE ENERGY
CTR QUADRANT 4 (VARH)
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
VOLT-VAR ENABLE/DISABLE
VOLT-VAR AUTO ENABLE
VOLT-VAR RESPONSE DELAY [S]
VOLT-VAR REFERENCE [V]
VOLT-VAR REFERENCE DELAY [S]
Yaskawa Solectria Solar
MODBUS ADDRESS
40257
40261
40265
40269
MODBUS ADDRESS
40931
30707
31649
30705
30708
DOCR-071070
DATA TYPE
SCALE FACTOR
Acc64
Acc64
Acc64
Acc64
DATA TYPE
SCALE FACTOR
uInt16
uInt16
Float32
Float32
uInt16
-
-
-
-
-
-
-
-
-
Page 27 of 30
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