Overview
The “Under impedance protection” function is a three zone full scheme impedance protection using offset mho characteristics for detecting faults in the generator, generator-transformer and transmission system. The three zones have fully independent measuring loops and settings.
For more detailed information on “Under impedance protection for generators and transformers”, 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 |
| Under impedance function for generators and transformers | ZGVPDIS | Z < | 21G |
Signals & Setting Parameters
ZGVPDIS function block
ZGVPDIS Input signals
| ZGVPDIS Input signals | |||
| Name | Type | Default | Description |
| I3P | GROUP SIGNAL | – | Connection for current sample signals |
| U3P | GROUP SIGNAL | – | Connection for voltage sample signals |
| BLOCK | BOOLEAN | 0 | Block of the function |
| BLKZ | BOOLEAN | 0 | Block due to fuse failure |
| BLKUV | BOOLEAN | 0 | Block of the under voltage seal in |
ZGVPDIS Output signals
| ZGVPDIS Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | General Trip | |
| TRZ1 | BOOLEAN | Trip signal Zone 1 | |
| TRZ2 | BOOLEAN | Trip signal Zone 2 | |
| TRZ3 | BOOLEAN | Trip signal Zone 3 | |
| TRUV | BOOLEAN | Trip from Under voltage seal in | |
| START | BOOLEAN | General start | |
| STZ1 | BOOLEAN | Start signal Zone 1 | |
| STZ2 | BOOLEAN | Start signal Zone 2 | |
| STZ3 | BOOLEAN | Start signal Zone 3 | |
| STUV | BOOLEAN | Start of under voltage seal in | |
ZGVPDIS Group settings (basic)
| ZGVPDIS Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| ImpedanceAng | 5 – 90 | Deg | 1 | 80 | Impedance angle in degrees, common for all zones |
| IMinOp | 5 – 80 | %IB | 1 | 10 | Minimum operate phase current |
| OpModeZ1 | Off PP Loops |
– | – | PP Loops | Operation mode of Zone 1: Off/Ph-Ph loops |
| Z1Fwd | 3.0 – 100.0 | % Zb | 0.1 | 8.0 | Zone 1 forward reach in % of rated impedance, 100%=full load |
| Z1Rev | 3.0 – 100.0 | % Zb | 0.1 | 8.0 | Zone 1 reverse reach in % of rated impedance, 100%=full load |
| tZ1 | 0.000 – 60.000 | s | 0.001 | 0.000 | Time delay to operate for Zone 1 |
| OpModeZ2 | Off PP Loops EnhancedReach |
– | – | EnhancedReach | Operation mode of Zone 2: Off/Ph- Ph/EnhancedReach |
| Z2Fwd | 3.0 – 200.0 | % Zb | 0.1 | 15.0 | Zone 2 forward reach in % of rated impedance, 100%=full load |
| Z2Rev | 3.0 – 200.0 | % Zb | 0.1 | 8.0 | Zone 2 reverse reach in % of rated impedance, 100%=full load |
| tZ2 | 0.000 – 60.000 | s | 0.001 | 0.500 | Time delay to operate for Zone 2 |
| OpModeZ3 | Off PP Loops EnhancedReach |
– | – | EnhancedReach | Operation mode of Zone 3: Off/Ph- Ph/EnhancedReach |
| Z3Fwd | 3.0 – 200.0 | % Zb | 0.1 | 75.0 | Zone 3 forward reach in % of rated impedance, 100%=full load |
| Z3Rev | 3.0 – 200.0 | % Zb | 0.1 | 8.0 | Zone 3 reverse reach in % of rated impedance, 100%=full load |
| tZ3 | 0.000 – 60.000 | s | 0.001 | 1.500 | Time delay to operate for Zone 3 |
| OpModeU< | Off Z2Start Z3Start |
– | – | Off | Enable under voltage seal in (Off/ Z2Start/Z3Start) |
| U< | 5 – 90 | %UB | 1 | 70 | Start value of under voltage seal in |
| tU< | 0.000 – 60.000 | s | 0.001 | 5.000 | Time delay to operate for under voltage seal in |
ZGVPDIS Group settings (advanced)
| ZGVPDIS Group settings (advanced) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| RLd | 5 – 120 | % Zb | 1 | 50 | Resistive reach in % for load encroachment charateristics |
| ArgLd | 5 – 85 | Deg | 1 | 38 | Load encroachment inclination of load angular sector |
| LoadEnchModZ2 | Off On |
– | – | Off | Enable load encroachement for Zone 2 Off/On |
| LoadEnchModZ3 | Off On |
– | – | On | Enable load encroachement for Zone 3 Off/On |
ZGVPDIS Non group settings (basic)
| ZGVPDIS 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 |
ZGVPDIS Monitored data
| ZGVPDIS Monitored data | ||||
| Name | Type | Values (Range) | Unit | Description |
| UL1 | REAL | – | kV | Voltage in phase L1 |
| UL2 | REAL | – | kV | Voltage in phase L2 |
| UL3 | REAL | – | kV | Voltage in phase L3 |
| IL1 | REAL | – | A | Current in phase L1 |
| IL2 | REAL | – | A | Current in phase L2 |
| IL3 | REAL | – | A | Current in phase L3 |
Logics & highlights
Base value of impedance calculation
Offset mho characteristics of three zones
Block diagram of ZGVPDIS
Block diagram of zone 1
Simplified offset mho characteristics for L1-L2 fault in zone 1
Block diagram of zone 2
Logic diagram for the selection of the maximum current loop
Simplified offset mho characteristics for L1-to-E fault in zone 2
Simplified offset mho characteristics for L1-to-L2 fault in zone 2
Load encroachment characteristics
Under voltage seal-in for zone 2 and zone 3
