This block is used to detect abnormal conditions in the grid’s frequency. For this purpose, a set of regions can be specified by the user as per [1]. A maximum of 8 different regions can be specified for over and under frequency events, respectively. Also, this block detects when the average ROCOF is above a specific threshold.
Mask and Parameters
Configuration
| Name | Description | Unit |
|---|---|---|
Sample Time (s) | Computational time step | s |
Over-Frequency Range
| Name | Description | Unit |
|---|---|---|
Number of Over-Frequency Points | Number of over-frequency regions delimited by a set of frequency points | - |
Frequency Points (Hz) [Point1,…, Point 8] | Limit frequency values before reaching the respective over-frequency trip region | Hz |
Frequency Points (s) [Point1,…, Point 8] | Amount of time that the converter must operate in a frequency region before tripping | s |
Under-Frequency Range
| Name | Description | Unit |
|---|---|---|
Number of Under-Frequency Points | Number of under-frequency regions delimited by a set of frequency points | - |
Frequency Points (Hz) [Point1,…, Point 8] | Limit frequency values before reaching the respective under-frequency trip region | Hz |
Frequency Points (s) [Point1,…, Point 8] | Amount of time that the converter must operate in a frequency region before tripping | s |
ROCOF
| Name | Description | Unit |
|---|---|---|
ROCOF Threshold | Maximum allowed ROCOF value before activating trip signal | Hz/s |
Averaging Time Window (sec) | Time constant for the first order average filter block for the ROCOF estimation. | s |
Inputs, Outputs and Signals Available for Monitoring
Inputs
| Name | Description | Unit |
|---|---|---|
Freq | Grid frequency | Hz |
Outputs
| Name | Description | Unit |
|---|---|---|
U/O F | Trip signal for under or over frequency events | - |
ROCOF | Trip signal for ROCOF events | - |
References
[1] | IEEE, "IEEE Standard for Interconnection and Interoperability of Distributed Energy Resources with Associated Electric Power Systems Interfaces," IEEE Std 1547-2018 (Revision of IEEE Std 1547-2003), no. doi: 10.1109/IEEESTD.2018.8332112, pp. 1-138, 2018. |
[2] | IEEE, "IEEE Standard Conformance Test Procedures for Equipment Interconnecting Distributed Energy Resources with Electric Power Systems and Associated Interfaces," IEEE Std 1547.1-2020, pp. 1-282, 2020. |
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