LOAD_SHED_UF
Staged under-frequency load shedding with a rate-of-change fast stage, a stage count that only rises, and restoration one stage at a time.
When to use it
Use LOAD_SHED_UF when an island or a standby plant can be left with more load than generation, and blocks of load must be shed in priority order fast enough to arrest the frequency slide before the machines trip.
Interface
The published port signature. This is the whole of what the block exposes to your program — the implementation body is not shown here and ships with the download.
Inputs
| Port | Type | Unit |
|---|---|---|
| ENABLE | BOOL | — |
| FREQ | REAL | Hz |
| FREQ_OK | BOOL | — |
| BUS_LIVE | BOOL | — |
| F_NOM | REAL | Hz |
| F1 | REAL | Hz |
| F2 | REAL | Hz |
| F3 | REAL | Hz |
| DELAY | TIME | — |
| DFDT_EN | BOOL | — |
| DFDT_SET | REAL | Hz/s |
| FILT_T | REAL | s |
| AUTO_RESTORE | BOOL | — |
| RESTORE_BAND | REAL | Hz |
| RESTORE_T | TIME | — |
| RESET | BOOL | — |
| ACK | BOOL | — |
Outputs
| Port | Type | Unit |
|---|---|---|
| STAGE | USINT | — |
| SHED_1 | BOOL | — |
| SHED_2 | BOOL | — |
| SHED_3 | BOOL | — |
| SHED_ACTIVE | BOOL | — |
| DFDT | REAL | Hz/s |
| RESTORE_PERM | BOOL | — |
| VALID | BOOL | — |
| ALM_STAGE_3 | BOOL | — |
| ALM_FREQ_FAULT | BOOL | — |
| ALM_CFG_ERR | BOOL | — |
Validation evidence
- Tests
- 12
- Simulated scans
- 400
- Simulator
- v0.1.0
Complete IEC 61131-3 implementation with a published test suite that runs on the vplant simulator. The counts above are that suite, executed on this build.
- Conforms to IEC 61131-3
Download LOAD_SHED_UF — free
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