Overview
The “Average power transient earth fault protection” is a transient measuring directional earth-fault protection. Determination of the earth fault direction is based on the short-term built-up transient at the beginning of the earth fault. This transient is to a large extent independent of the neutral point treatment. This means that the function can be used without any modification in all types of high-impedance grounded, resonant grounded or isolated power systems.
For more detailed information on “Average power transient earth fault protection” 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 |
| Average Power Transient Earth Fault Protection | APPTEF | Io > → TEF | 67NT |
Signals & Setting Parameters
APPTEF function block
APPTEF Input signals
| APPTEF Input signals | |||
| Name | Type | Default | Description |
| I3P | GROUP SIGNAL | – | Group signal for current input |
| U3P | GROUP SIGNAL | – | Group signal for voltage input |
| BLOCK | BOOLEAN | 0 | Block of the function |
| BLKTR | BOOLEAN | 0 | Block of trip output |
| RESET | BOOLEAN | 0 | Reset of the function including all internal calculations and all outputs |
APPTEF Output signals
| APPTEF Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | Trip for earth fault in forward direction | |
| STFW | BOOLEAN | Start in forward direction | |
| STRV | BOOLEAN | Start in reverse direction | |
| STUN | BOOLEAN | Start of the residual overvoltage stage 3Uo> | |
| STIEF | BOOLEAN | Intermittent earth fault detetcted | |
| WRNFW | BOOLEAN | Warning, a transient corresponding to the forward fault has been detected | |
| ALMCC | BOOLEAN | Alarm when cross country fault condition is detected by 3Io measurement. Transient EF function will be prevented to make any directional decision while this signal is active. | |
| ALMCIRI | BOOLEAN | Alarm when 3Io circulating current is detected, which can influence the Io*cos(Phi) calculations. Pickup for Io*cos(Phi) part will be adjusted accordingly. 3Io circulating current shall be reduced by appropriate action in the primary system. | |
| IFUNDRE | REAL | Integrated real part (proportional to active power) of the fundamental frequency phasor in the residual current 3Io, given in primary amperes | |
| IFUNDIM | REAL | Integrated imaginary part (proportional to reactive power) of the fundamental frequency phasor in the residual current 3Io, given in primary amperes | |
| IHARMIM | REAL | Integrated imaginary part (proportional to harmonic reactive power) of the lumped harmonic phasors in the residual current 3Io, given in primary amperes | |
APPTEF Non group settings (basic)
| APPTEF Non group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| GlobalBaseSel | 1 – 12 | – | 1 | 1 | Selection of one of the Global Base Value groups |
APPTEF Group settings (basic)
| APPTEF Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| OperationMode | Start Only Start and Trip |
– | – | Start Only | Operation mode ( Start Only / Start and Trip ) |
| tPulseMin | 0.02 – 1.00 | s | 0.01 | 0.15 | Minimum pulse length duration in seconds, for trip and/or start outputs |
| UN> | 5 – 80 | %UB | 1 | 30 | Minimum threshold level for residual overvoltage start condition 3Uo> |
| IN> | 3 – 100 | %IB | 1 | 5 | Minimum threshold level for residual overcurrent start condition 3Io> |
| IMinForward | 1.5 – 100.0 | %IB | 0.1 | 2.5 | Minimum operate level for integrated current in order to declare the forward direction |
| IMinReverse | 1.0 – 100.0 | %IB | 0.1 | 1.5 | Minimum operate level for integrated current in order to declare the reverse direction |
| tStart | 0.04 – 2.00 | s | 0.01 | 0.15 | Minimum time delay to declare EF direction in seconds. Timer will be activated with STUN signal. |
| tReset | 0.05 – 5.00 | s | 0.01 | 0.5 | Drop off time delay added to 3Uo overvoltage condition start signal STUN, after which the function will be fully reset |
| tTrip | 0.00 – 20.00 | s | 0.01 | 2.00 | Minimum trip time delay in seconds after STFW signal has been issued |
| UN>StartsNo | 2 – 20 | – | 1 | 4 | Minimum number of consequitive 3Uo> start conditions to detect intermitten EF. Note that this counting will only be active while reset timer is running. |
APPTEF Group settings (advanced)
| APPTEF Group settings (advanced) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| OperationCC | Off On |
– | – | On | Operation of cross country fault detection On/Off |
| CrossCntry_IN> | 20 – 1000 | %IB | 1 | 120 | Operate 3Io current level for cross country fault detection |
| tCC | 0.02 – 1.00 | s | 0.01 | 0.03 | Time delay in seconds to activate cross country fault detection |
| Circulate_IN> | 2 – 200 | %IB | 1 | 10 | Operate 3Io current level for circulating current detection |
| tCircIN | 5.0 – 60.0 | s | 0.1 | 10.0 | Time delay in seconds to activate circulating current detection |
APPTEF Monitored data
| APPTEF Monitored data | ||||
| Name | Type | Values (Range) | Unit | Description |
| INRMS | REAL | – | A | RMS value of residual current 3Io |
| UNMAG | REAL | – | kV | Magnitude of fundamental frequency phasor for measured neutral voltage 3Uo in primary kV |
| ANGDIF | REAL | – | deg | Phase angle difference between rotated -3Uo voltage phasor and 3Io current phasor in degrees |
| DIR | INTEGER | 0=None 1=Forward 2=Reverse |
– | Detected earth fault direction (0 = None, 1 = Forward, 2 = Reverse) |
| IFUNDRE | REAL | – | A | Integrated real part (proportional to active power) of the fundamental frequency phasor in the residual current 3Io, given in primary amperes |
| IFUNDIM | REAL | – | A | Integrated imaginary part (proportional to reactive power) of the fundamental frequency phasor in the residual current 3Io, given in primary amperes |
| IHARMIM | REAL | – | A | Integrated imaginary part (proportional to harmonic reactive power) of the lumped harmonic phasors in the residual current 3Io, given in primary amperes |
Logics & highlights
Example Substation
Simplified zero-sequence equivalent circuit during an EF in Feeder 1
Flow of active power in the zero-sequence system at the moment when EF happens
Active power based on fundamental frequency
Deriving Iocos(ɸ) and Iosin(ɸ) quantities from -Uo and Io phasors
Example how waveforms and the active power signals may look like for a faulty feeder
Example how waveforms and the active power signals may look like for a healthy feeder
Reactive power calculation
Example how waveforms and the summed harmonic reactive power signals may look like for a faulty feeder
Example how waveforms and the summed harmonic reactive power signals may look like for a healthy feeder
Simplified logic for measurement part of the APPTEF function
Residual over-voltage start logic and reset logic
Intermittent EF start logic
Start and Trip logic for an EF in forward direction
Start logic for an EF in reverse direction
Cross country fault logic
Circulating current detection logic
