Overview
By the “100% Stator earth fault protection, 3rd harmonic based” either the 3rd harmonic voltage differential principle, the neutral point 3rd harmonic undervoltage principle or the terminal side 3rd harmonic overvoltage principle can be applied. However, differential principle is strongly recommended. Combination of these two measuring principles provides coverage for entire stator winding against earth faults.
For more detailed information on “100% Stator earth fault protection, 3rd harmonic based” function, 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 |
| 100% Stator earth fault protection, 3rd harmonic based | STEFPHIZ | 59THD |
Signals & Setting Parameters
STEFPHIZ function block
STEFPHIZ Input signals
| STEFPHIZ Input signals | |||
| Name | Type | Default | Description |
| U3PNEUT | GROUP SIGNAL | – | Voltage connection neutral side |
| U3PTERM | GROUP SIGNAL | – | Open-Delta connection on Terminal side |
| BLOCK | BOOLEAN | 0 | Complete block of the stator earth fault protecion function |
| BLOCK3RD | BOOLEAN | 0 | Block of the 3rd harmonic-based parts of the protection |
| BLOCKUN | BOOLEAN | 0 | Block of the fund. harmonic-based part of the protection |
| CBCLOSED | BOOLEAN | 1 | TRUE means breaker between gen. & trafo is closed |
STEFPHIZ Output signals
| STEFPHIZ Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | Main, common trip command | |
| TRIP3H | BOOLEAN | Trip by one of two 3rd harmonic voltage-based prot. | |
| TRIPUN | BOOLEAN | Trip by fund. freq. neutral over-voltage protection | |
| START | BOOLEAN | Main, common start signal | |
| START3H | BOOLEAN | Start by one of two 3rd harmonic voltage-based prot. | |
| STARTUN | BOOLEAN | Start signal by fund. freq. neutral over-voltage prot. | |
| UT3 | REAL | Mag. of 3rd harm. voltage at generator terminal side, Volts | |
| UN3 | REAL | Mag. of 3rd harm. voltage at generator neutral side, Volts | |
| E3 | REAL | Total induced stator 3rd harmonic voltage, primary Volts | |
| ANGLE | REAL | Angle between 3rd harmonic votage phasors, radians | |
| DU3 | REAL | Diff. between 3rd harm. volt. at both sides of gen., Volts | |
| BU3 | REAL | Bias voltage, a part of voltN3rdHarmonic, primary Volts | |
| UN | REAL | Fund. frequency voltage at generator neutral, primary Volts | |
STEFPHIZ Group settings (basic)
| STEFPHIZ Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| Beta | 0.50 – 10.00 | – | 0.01 | 3.00 | Portion of voltN3rdHarmonic used as bias |
| CBexists | No Yes | – | – | No | Defines if generator CB exists (between Gen & Transformer) |
| FactorCBopen | 1.00 – 10.00 | – | 0.01 | 1.00 | Beta is multiplied by this factor when CB is open |
| UN3rdH< | 0.5 – 10.0 | %UB | 0.1 | 2.0 | Pickup 3rd Harm U< protection (when activated) % of UB/1,732 |
| UT3BlkLevel | 0.1 – 10.0 | %UB | 0.1 | 1.0 | If UT3 is below limit 3rdH Diff is blocked, in % of UB/1,732 |
| UNFund> | 1.0 – 50.0 | %UB | 0.1 | 5.0 | Pickup fundamental UN> protection (95% SEF), % of UB/1,732 |
| t3rdH | 0.020 – 60.000 | s | 0.001 | 1.000 | Operation delay of 3rd harm-based protection (100% SEF) in s |
| tUNFund | 0.020 – 60.000 | s | 0.001 | 0.500 | Operation delay of fundamental UN> protection (95% SEF) in s |
STEFPHIZ Non group settings (basic)
| STEFPHIZ Non group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| TVoltType | NoVoltage ResidualVoltage AllThreePhases PhaseL1 PhaseL2 PhaseL3 |
– | – | ResidualVoltage | Used connection type for gen. terminal voltage transformer |
| GlobalBaseSel | 1 – 12 | – | 1 | 1 | Selection of one of the Global Base Value groups |
STEFPHIZ Monitored data
| STEFPHIZ Monitored data | ||||
| Name | Type | Values (Range) | Unit | Description |
| UT3 | REAL | – | kV | Mag. of 3rd harm. voltage at generator terminal side, Volts |
| UN3 | REAL | – | kV | Mag. of 3rd harm. voltage at generator neutral side, Volts |
| E3 | REAL | – | kV | Total induced stator 3rd harmonic voltage, primary Volts |
| ANGLE | REAL | – | deg | Angle between 3rd harmonic votage phasors, radians |
| DU3 | REAL | – | kV | Diff. between 3rd harm. volt. at both sides of gen., Volts |
| BU3 | REAL | – | kV | Bias voltage, a part of voltN3rdHarmonic, primary Volts |
| UN | REAL | – | kV | Fund. frequency voltage at generator neutral, primary Volts |
Logics & highlights
Protection principles for STEFPHIZ function
Relation between the amplitude of the generator earth fault current and the fault time
Broken delta voltage transformer measurement of 3U0 voltage
Neutral point voltage transformer measurement of neutral point voltage (that is U0 voltage)
Neutral point current measurement
Residual current measurement
Generator 3rd harmonic voltage characteristic at normal operation & protection algorithm
Simplified logic diagram for stator earth fault protection
Simplified Start and Trip logical diagram of the 100% Stator earth fault protection, 3rd harmonic based STEFPHIZ protection
Generator block with generator circuit breaker
Technical data
