Content of Settings
Frequently Asked Questions
In the event that the configurations of internal protection or the configurations of the Auto Connection Switch of the station(s) are more flexible than the required configurations indicated in the Letter (i.e. slower times and/or for larger voltage/frequency deviations), then they remain as they are.
The homopolar voltage protection on the ACS shall be set to 0,3 A with a time delay of 10 s, where provided.
The configurations on the Auto Connect Switch of the station(s) are required to be modified according to the table within the Letter sent to you.
The configurations on the Auto Connect Switch of the station(s), are required to be changed according to the table below, if the protection configurations applied result in the station(s) disconnecting at faster times and/or for smaller voltage/frequency deviations from the values in the Table.
| Protection | Stimulation setting | Time delay setting |
| Under-voltage | 0.80 A | 1.0 s |
| Over-voltage | 1.10 A | 0.5 s |
| Sub-frequency | 47.5 Hz | 0.5 s |
| Hyper-frequency | 51.5 Hz | 0.5 s |
In addition, the configurations of the corresponding internal protections of the production units should be checked and configured appropriately, to ensure they also comply with the settings in the Table.
In addition, power converters of the production units should have the “active” anti-islanding protection activated, to ensure that if an islanding condition is identified, the converters are immediately disconnected (without time delay) from the network. The homopolar voltage protection on the ACS shall be set at 0,3 A with a time delay of 10 s, where provided.
In this case the time delay of the under-voltage protection must be set at 0.5 s (instead of 1 s). Please see below some characteristic examples of voltage and frequency protection resets:
| Α/Α | Existing configurations | New configurations | ||
|---|---|---|---|---|
| Excitation | Time delay | Excitation | Time delay | |
| 1) | Uc: 0.92 p.u. | 0.5 s | Uc: 0.8 p.u. | 1 s |
| Uc: 1.1 p.u. | 0.5 s | Uc: 1.1 p.u. | 0.5 s | |
| f<: 49.5 Hz | 0.3 s | f<: 47.5 Hz | 0.5 s | |
| f>: 50.5 Hz | 0.4 s | f>: 51.5 Hz | 0.5 s | |
| 2) | Uc: 0.9 p.u. | 0.5 s | Uc: 0.8 p.u. | 1 s |
| Uc: 1.08 p.u. | 0.5 s | Uc: 1.10 p.u. | 0.5 s | |
| f<: 49 Hz | 0.5 s | f<: 47.5 Hz | 0.5 s | |
| f>: 51 Hz | 0.5 s | f>: 51.5 Hz | 0.5 s | |
| 3) | Uc: 0.9 p.u. | 0.8 s | Uc: 0.8 p.u. | 3 s |
| Uc: 1.08 p.u. | 5 s | Uc: 1.10 p.u. | 0.5 s | |
| f<: 49 Hz | 1 s | f<: 47.5 Hz | 1 s | |
| f>: 51 Hz | 1 s | f>: 51.5 Hz | 1 s | |
| 4) | Uc: 0.7 p.u. | 0.8 s | Uc: 0.8 p.u. | 3 s |
| Uc: 1.08 p.u. | 5 s | Uc: 1.10 p.u. | 5 s | |
| f<: 49 Hz | 1 s | f<: 47.5 Hz | 1 s | |
| f>: 51 Hz | 1 s | f>: 51.5 Hz | 1 s | |
| 5) | Uc: 0.92 p.u. | 0.1 s | Uc: 0.8 p.u. | 1 s |
| Uc: 1.1 p.u. | 0.1 s | Uc: 1.1 p.u. | 0.5 s | |
| f<: 49.5 Hz | 0.1 s | f<: 47.5 Hz | 0.5 s | |
| f>: 50.5 Hz | 0.1 s | f>: 51.5 Hz | 0.5 s | |
| 6) | Uc: 0.92 p.u. | 0.5 s | Uc: 0.8 p.u. | 1 s |
| Uc: 1.1 p.u. | 0.1 s | Uc: 1.1 p.u. | 0.5 s | |
| f<: 49.5 Hz | 0.1 s | f<: 47.5 Hz | 0.5 s | |
| f>: 50.5 Hz | 0.1 s | f>: 51.5 Hz | 0.5 s | |
| 7) | U<_1o στάδιο: 0.9 p.u. | 0.1 s | U<_1o στάδιο: 0.8 p.u. | 1.5 s |
| U<_2o στάδιο: 0.3 p.u. | 0.5 s | U<_2o στάδιο: 0.3 p.u. | 1 s | |
| Uc: 1.15 p.u. | 0.5 s | Uc: 1.15 p.u. | 0.5 s | |
| f<: 49.5 Hz | 0.1 s | f<: 47.5 Hz | 1 s | |
| f>: 50.5 Hz | 0.1 s | f>: 51.5 Hz | 1 s | |