4 Settings of Grid Management Services: Fault Ride-Through (FRT)
SMA Solar Technology AG
Technical Information 11STP60-SHP75-10-Parameter-TI-en-12
Figure 4: FRT_IQ_MODE = 1: as per SDLWind (IEC 62850-90-7)
In both operating modes, there is a common set of parameters which have to be set for the FRT functionality to work
properly:
1. The deadband is defined by two thresholds: the lower threshold FRT_ULOW and the upper threshold FRT_UUP.
2. For the positive sequence component, the gradient K for the slope of voltage dips is defined by
FRT_DIDU_POS_LVRT and for the slope of voltage increase by FRT_DIDU_POS_HVRT.
3. For the negative sequence component, the gradient K for the slope of voltage dips is defined by
FRT_DIDU_NEG_HVRT and for the slope of voltage increase by FRT_DIDU_NEG_HVRT.
The additional reactive current is added to the pre-fault reactive current value.
The positive sequence components have priority over the negative sequence components. Thus, first the negative
sequence component is limited if the current limitation is reached. In case that Id has higher priority than Iq, the reactive
currents will be limited in such way as the total current does not exceed the limit.
After fault clearance, reactive current feed-in stays active for a certain transition period. This period can be set with the
grid code parameter FRT_T_TRANS.
Active current is fed in under the following conditions:
1. Active current feed-in is activated in accordance with the selection made in FRT_MODE (operating modes 3, 4,
and 5).
2. The current reactive power value allows additional active current without the total current being greater than the
nominal current.
3. There is enough primary input power.
Restriction: active power feed-in during fault is upwards limited to the pre-fault active power, even if higher primary
input power is (or becomes) available during the fault.
After the fault, the active power returns to its initial level with first order dynamic. The recovery time can be set via the
parameter FRT_T_P_RECOV.
If required, it is possible to set up a so-called blocking zone during the grid fault: if the voltage falls below a
configurable limit FRT_U_BLK, power generation is ceased after a configurable time FRT_T_BLK. Over the blocking
zone FRT_U_BLK there is the hysteresis band determined by FRT_U_BLK_HYS. Once voltage exceeds this hysteresis
band again, power generation is continued.
Parameter name Setting range/setting option Increment/explanation
FRT_ULOW 10% to 100% 1%
To Next Page
Loading...
