State Variables
Table 2 lists all the state variables of the Storage element. The state variables can be monitored by setting a monitor for the Storage element in mode 3.
Table 2: State Variables of the Storage Element
State Variable |
Description |
kWh |
Stored Energy in kWh. |
State |
Storage state. 1 for discharging, -1 for charging and 0 for idling. |
kWOut |
Power flowing out of the element, in kW. It is a result from the power flow. For discharging state. |
kWIn |
Power flowing into the element in kW. It is a result from the power flow. For charging and idling states. |
kvarOut |
Power flowing out of the element in kvar as a signed-value. Positive for vars generation and negative for vars absorption. |
DCkW |
DC power flowing into the storage inverter in kW at the DC side of the inverter as a signed-value. Positive for power flowing into the grid and negative for power flowing into the Storage element. |
kWTotalLosses |
Total losses in kW. |
kWInvLosses |
Inverter losses in kW. |
kWIdlingLosses |
Idling losses in kW. |
kWChDchLosses |
Charging and discharging losses in kW. |
kWh Chng |
Energy variation from the last time step, in kWh. Corresponds to the power that effectively charges/discharges the storage medium/battery multiplied by the time step length. |
InvEff |
Inverter efficiency. |
InverterON |
Flag indicating the inverter status. See [3]. |
Vref |
Reference voltage used by the voltage-dependent InvControl function- alities. Equal to 9999 if there is no InvControl controlling the Storage element. See [3]. |
Vavg (DRC) |
Average voltage of the moving window used in InvControl’s DRC func- tion. Equal to 9999 if there is no InvControl controlling the element. See [3]. |
VV Oper |
Flag variable that indicates the status of InvControl’s Volt-Var function operation. Equal to 9999 if there is no InvControl controlling the element. See [3]. |
VW Oper |
Flag variable that indicates the status of InvControl’s Volt-Watt func- tion operation. Equal to 9999 if there is no InvControl controlling the element. See[3]. |
DRC Oper |
Flag variable that indicates the status of InvControl’s DRC function operation. Equal to 9999 if there is no InvControl controlling the element. See [3]. |
VV DRC Oper |
Flag variable that indicates the status of InvControl’s VV + DRC function operation. Equal to 9999 if there is no InvControl controlling the element. See [3]. |
kWDesired |
Nominal power desired or requested by the dispatch mode selected, in kW, if there is enough energy capacity left. Otherwise, it is 0. |
kW VW Limit |
Active power limit imposed by Volt-Watt function, in kW. See [3]. Equal to 9999 if the function is disabled due to inverter status. |
Limit kWOut Function |
Active power limit imposed by “Limit DER output function” (%kWRated × kWRated), in kW. See [3]. |
kVA Exceeded |
Flag indicating if inverter kVA rating has been exceeded. See [3]. |