SMA SC 500CP-US-10 600V - Manual (Page 72)

9 Grid Monitoring SMA America, LLC
72 SCCP-US-BE-US_en-52 Operating Manual
9 Grid Monitoring
9.1 How Grid Monitoring Works
The inverter has an integrated grid monitoring function. This means that the inverter monitors the utility grid to ensure that
it remains within a definable range of limiting values. If the configured limiting values for the line voltage and the power
frequency are exceeded or are not met for a specific time, the inverter disconnects from the utility grid.
Some parameters can be adjusted (see Section 13.1.2 "Grid Monitoring/Grid Limits", page 101).
9.2 Monitoring the Line Voltage
For grid monitoring, two limiting values in percent are defined for the minimum line voltage and two for the maximum line
voltage respectively in accordance with IEEE 1547. The percentage is based on the nominal voltage of the inverter.
If the line voltage falls below the value defined in the parameters VCtllLim or VCtlllLim, the inverter waits for the period
defined in the parameters VCtllLimTm and VCtlllLimTm and disconnects from the utility grid.
If the line voltage increases above the value defined in the parameter VCtlhLim or VCtlhhLim, the inverter waits for the
period defined in the parameter VCtlhLimTm or VCtlLimhhTm and disconnects from the utility grid.
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Operation failure of the inverter due to incorrectly set parameters
If the parameter settings for grid management services are incorrect, the inverter may not be able to meet the grid
management requirements. This may lead to yield losses and disconnection of the inverter by the grid operator.
• When setting the mode of grid management services, ensure that the control procedures are parameterized as
agreed with the grid operator.
•
Example: Inverter behavior in the event of undervoltage
The first limiting value for undervoltage is defined in the parameter VCtllLim and is 88% of the nominal voltage of the
inverter. The associated period is set to 2,000 ms in the parameter VCtllLimTm. The second limiting value for
undervoltage is defined in the parameter VCtlllLim and is 50% of the nominal voltage of the inverter.
The associated time is set to 160 ms in the parameter VCtlllLimTm.
The line voltage is 85% of the inverter nominal voltage and has therefore fallen below the first limit for undervoltage.
The inverter waits 2,000 ms. If the line voltage does not increase above the first limiting value within this period, the
inverter disconnects from the utility grid. If the line voltage falls below the second limiting value, the inverter switches off
after 160 ms.