Overview
To combine fast fault clearance, as well as sensitivity and selectivity, the “Generator differential protection” is normally the best choice for phase-to-phase generator short circuits.
For more detailed information on “Generator differential protection”, refer to ABB, Relion 670 Series manuals.
To see other supported functions, click here.
Function Identification
| Function description | IEC 61850 identification |
IEC 60617 identification |
ANSI/IEEE C37.2 device number |
| Generator differential protection | GENPDIF | Id > | 87G |
Signals & Setting Parameters
GENPDIF function block
GENPDIF Input signals
| GENPDIF Input signals | |||
| Name | Type | Default | Description |
| I3PNCT1 | GROUP SIGNAL | – | Neutral side input1 |
| I3PNCT2 | GROUP SIGNAL | – | Neutral side input2 |
| I3PTCT1 | GROUP SIGNAL | – | Terminal side input1 |
| I3PTCT2 | GROUP SIGNAL | – | Terminal side input2 |
| BLOCK | BOOLEAN | 0 | Block of function |
| BLKRES | BOOLEAN | 0 | Block of trip command by the restrained diff. protection |
| BLKUNRES | BOOLEAN | 0 | Block of trip by unrestrained "instantaneous" diff. prot. |
| BLKNSUNR | BOOLEAN | 0 | Block of trip for unrestr. neg. seq. differential feature |
| BLKNSSEN | BOOLEAN | 0 | Block of trip for sensitive neg. seq. differential feature |
| DESENSIT | BOOLEAN | 0 | Raise pick up: function temporarily desensitized |
GENPDIF Output signals
| GENPDIF Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | General, common trip signal | |
| TRIPRES | BOOLEAN | Trip signal from restrained differential protection | |
| TRIPUNRE | BOOLEAN | Trip signal from unrestrained differential protection | |
| TRNSUNR | BOOLEAN | Trip signal from unrestr. neg. seq. diff. protection | |
| TRNSSENS | BOOLEAN | Trip signal from sensitive neg. seq. diff. protection | |
| START | BOOLEAN | Common start signal from any phase | |
| STL1 | BOOLEAN | Start signal from phase L1 | |
| STL2 | BOOLEAN | Start signal from phase L2 | |
| STL3 | BOOLEAN | Start signal from phase L3 | |
| BLKH | BOOLEAN | Common harmonic block signal | |
| OPENCT | BOOLEAN | An open CT was detected | |
| OPENCTAL | BOOLEAN | Open CT Alarm output signal. Issued after a delay … | |
| IDL1 | REAL | Instantaneous differential current L1; in primary Amperes | |
| IDL2 | REAL | Instantaneous differential current L2; in primary Amperes | |
| IDL3 | REAL | Instantaneous differential current L3; in primary Amperes | |
| IDNSMAG | REAL | Negative Sequence Differential current; in primary Amperes | |
| IBIAS | REAL | Magnitude of the common Bias current; in primary Amperes | |
| IDDCL1 | REAL | DC component of diff. current, phase L1; primary Amperes | |
| IDDCL2 | REAL | DC component of diff. current, phase L2; primary Amperes | |
| IDDCL3 | REAL | DC component of Diff. current, phase L3; primary Amperes | |
GENPDIF Non group settings (basic)
| GENPDIF Non group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| InvertCT2Curr | No Yes |
– | – | No | Invert CT 2 curr., yes (1) or no (0). Default is no (0). |
| GlobalBaseSel | 1 – 12 | – | 1 | 1 | Selection of one of the Global Base Value groups |
GENPDIF Group settings (basic)
| GENPDIF Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| IdMin | 0.05 – 1.00 | IB | 0.01 | 0.25 | Section 1 sensitivity, multiple of generator rated current |
| IdUnre | 1.00 – 50.00 | IB | 0.01 | 10.00 | Unrestr. prot. limit, multiple of generator rated current |
| OpNegSeqDiff | Off On |
– | – | On | Negative Sequence Differential Enable Off/On |
| IMinNegSeq | 0.02 – 0.20 | IB | 0.01 | 0.04 | Neg. sequence curr. limit, as multiple of gen. rated curr. |
GENPDIF Group settings (advanced)
| GENPDIF Group settings (advanced) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| EndSection1 | 0.20 – 1.50 | IB | 0.01 | 1.25 | End of section 1, multiple of generator rated current |
| EndSection2 | 1.00 – 10.00 | IB | 0.01 | 3.00 | End of section 2, multiple of generator rated current |
| SlopeSection2 | 10.0 – 50.0 | % | 0.1 | 40.0 | Slope in section 2 of operate-restrain characteristic, in % |
| SlopeSection3 | 30.0 – 100.0 | % | 0.1 | 80.0 | Slope in section 3 of operate-restrain characteristic, in % |
| OpCrossBlock | Off On |
– | – | On | Operation On / Off for cross-block logic between phases |
| NegSeqROA | 30.0 – 120.0 | Deg | 0.1 | 60.0 | Operate Angle of int/ext neg. seq. fault discriminator, deg |
| HarmDistLimit | 5.0 – 100.0 | % | 0.1 | 10.0 | (Total) relative harmonic distorsion limit, percent |
| TempIdMin | 1.0 – 5.0 | IdMin | 0.1 | 2.0 | Temp. Id pickup when input raisePickUp=1, multiple of IdMin |
| AddTripDelay | 0.000 – 60.000 | s | 0.001 | 0.100 | Additional trip delay, when input raisePickUp=1 |
| OperDCBiasing | Off On |
– | – | Off | Operation DC biasing On / Off |
| OpenCTEnable | Off On |
– | – | Off | Open CT detection feature Off/On |
| tOCTAlarmDelay | 0.100 – 10.000 | s | 0.001 | 1.000 | Open CT: time to alarm if an open CT is detected, in sec |
| tOCTResetDelay | 0.100 – 10.000 | s | 0.001 | 0.250 | Reset delay in s. After delay, diff. function is activated |
| tOCTUnrstDelay | 0.100 – 100.000 | s | 0.001 | 10.000 | Unrestrained diff. protection blocked after this delay, in s |
GENPDIF Monitored data
| GENPDIF Monitored data | ||||
| Name | Type | Values (Range) | Unit | Description |
| IDL1MAG | REAL | – | A | Fund. freq. differential current, phase L1; in primary A |
| IDL2MAG | REAL | – | A | Fund. freq. differential current, phase L2; in primary A |
| IDL3MAG | REAL | – | A | Fund. freq. differential current, phase L3; in primary A |
| IDNSMAG | REAL | – | A | Negative Sequence Differential current; in primary Amperes |
| IBIAS | REAL | – | A | Magnitude of the common Bias current; in primary Amperes |
Logics & highlights
Position of current transformers; the recommended (default) orientation
Fundamental frequency differential & bias currents
Internal fault
External fault
Operate-restrain characteristic
NegSeqROA determines the boundary between the internal and external fault regions
Simplified principle design of the Generator differential protection GENPDIF
Generator differential logic diagram 1
Generator differential logic diagram 2
Generator differential logic diagram 3
Generator differential logic diagram 4
