Rule 21 Default Frequency Ride-Through Settings Requirement: DER systems stay connected to the Area EPS if possible while the grid is within the stay connected” frequency-time range, and shall disconnect from the “must electric grid during a high or low frequency event that is outside that frequency-time range. The default underfrequency and overfrequency values are shown in Table 3 and Figure 16. These values provide default interconnection system response to abnormal frequencies as proposed for IEEE 1547a. The frequency trip points are optionally adjustable by authorized personnel for DER systems below 300W and required for DER systems above that size. Microgrids may need different default frequency settings. Table 3: Default interconnection system response to abnormal frequencies (IEEE 1547a) System frequency Default frequency Range of Default clearing Range of settings (Hz) adjustability (Hz) time (s) adjustability (s) f < 57.0 57 53 - 59 0.16 0 - 2 57.0 < f < 60.0 58.5 53 - 60 2 0 300 (or 600 – for islands) 60.0 < f < 61.5 60.5 60 - 62 2 0 - 300 60.2 < f < 61.5 DER power reduction permitted f > 61.5 62 60 - 66 2 0 - 300 Figure 16: Proposed frequency parameters in IEEE 1547a Dynamic Volt/Var Operation Purpose of Dynamic Volt/Var Operation DER systems can counteract voltage deviations from the nominal voltage level (but still within normal operating ranges) by consuming or producing reactive power. The amount of reactive power can be established by a defining voltage versus “curve” percentage of reactive power. Percentage of reactive power can be calculated as: Percentage of available reactive power for the measured percentage of the reference voltage. vars” implies the consumption or production of reactive power that “Available does not affect the real power output. Percentage of maximum reactive In this case, consumption or production of reactive power may affect the real power output.
Rule 21 Default Frequency Ride-Through Settings Requirement: DER systems stay connected to the Area EPS if possible while the grid is within the “must stay connected” frequency-time range, and shall disconnect from the electric grid during a high or low frequency event that is outside that frequency-time range. The default underfrequency and overfrequency values are shown in Table 3 and Figure 16. These values provide default interconnection system response to abnormal frequencies as proposed for IEEE 1547a. The frequency trip points are optionally adjustable by authorized personnel for DER systems below 300W and required for DER systems above that size. Microgrids may need different default frequency settings. Table 3: Default interconnection system response to abnormal frequencies (IEEE 1547a) System frequency Default frequency settings (Hz) Range of adjustability (Hz) Default clearing time (s) Range of adjustability (s) f < 57.0 57 53 - 59 0.16 0 - 2 57.0 < f < 60.0 58.5 53 - 60 2 0 – 300 (or 600 for islands) 60.0 < f < 61.5 60.5 60 - 62 2 0 - 300 60.2 < f < 61.5 DER power reduction permitted f > 61.5 62 60 - 66 2 0 - 300 Figure 16: Proposed frequency parameters in IEEE 1547a Dynamic Volt/Var Operation Purpose of Dynamic Volt/Var Operation DER systems can counteract voltage deviations from the nominal voltage level (but still within normal operating ranges) by consuming or producing reactive power. The amount of reactive power can be established by a “curve” defining voltage versus percentage of reactive power. Percentage of reactive power can be calculated as: Percentage of available reactive power for the measured percentage of the reference voltage. “Available vars” implies the consumption or production of reactive power that does not affect the real power output. Percentage of maximum reactive In this case, consumption or production of reactive power may affect the real power output.