Overview
The “Voltage unbalance protection of shunt capacitor bank” function uses the neutral voltage measurement of an ungrounded single or double WYE configuration of SCB. The protection arrangements are based on the terminal voltage limit and the current limit of the capacitor units.
For more detailed information on “Voltage unbalance protection of shunt capacitor bank” 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 |
| Voltage unbalance protection of the shunt capacitor bank | SCUVPTOV | Uub > | 60V |
Signals & Setting Parameters
SCUVPTOV function block
SCUVPTOV Input signals
| SCUVPTOV Input signals | |||
| Name | Type | Default | Description |
| U3P | GROUP SIGNAL | – | Group signal for three phase bus voltage |
| U3NEUT | GROUP SIGNAL | – | Group signal for capacitor bank neutral voltage |
| BLOCK | BOOLEAN | 0 | Block of function |
| BLKTR | BOOLEAN | 0 | Block of trip |
| BLKALM | BOOLEAN | 0 | Block of alarm |
| BLKWRN | BOOLEAN | 0 | Block of warning |
| INHIBIT | BOOLEAN | 0 | Inhibit the function |
| TRIGCOMP | BOOLEAN | 0 | Trigger input to store the calculated compensation factors into the IED memory. The stored values will be used for future compensation in the function. |
| RESETCOMP | BOOLEAN | 0 | Force the stored compensation factors to zero. |
SCUVPTOV Output signals
| SCUVPTOV Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | Trip signal | |
| START | BOOLEAN | Start signal | |
| ALARM | BOOLEAN | Alarm signal | |
| WARNING | BOOLEAN | Warning signal | |
| BLKD | BOOLEAN | Block due to bus voltage in any phase is lower than the set UMin> value or SCB disconnection is detected | |
| COMPEXED | BOOLEAN | Indicates that a trigger was made for compensation | |
| PUNUNBAL | REAL | Capacitor bank neutral unbalance voltage in % of UBase | |
SCUVPTOV Non group settings (basic)
| SCUVPTOV 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 |
SCUVPTOV Group settings (basic)
| SCUVPTOV Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| UMin> | 5.0 – 100.0 | %UB | 0.1 | 75.0 | Minimum bus voltage for operation
in % of UBase |
| CompEnable | Disable Enable |
– | – | Enable | Selection of neutral voltage unbalance compensation |
| UNUnbalWrn> | 1.0 – 95.0 | %UB | 0.1 | 1.0 | Neutral voltage unbalance warning level in % of UBase |
| tDefWrn | 0.00 – 60.00 | s | 0.01 | 5.00 | Definite time delay to warning |
| UNUnbalAlm> | 1.0 – 95.0 | %UB | 0.1 | 2.5 | Neutral voltage unbalance alarm level in % of UBase |
| tDefAlm | 0.00 – 60.00 | s | 0.01 | 5.00 | Definite time delay to alarm |
| UNUnbal> | 1.0 – 95.0 | %UB | 0.1 | 5.5 | Neutral voltage unbalance trip level
in % of UBase |
| CurveType | Definite time Programmable |
– | – | Definite time | Selection of time delay curve type for trip |
| tDefTrip | 0.00 – 60.00 | s | 0.01 | 5.00 | Definite time delay for trip |
| k | 0.05 – 15.00 | – | 0.01 | 0.05 | Time multiplier for programmable curve for trip |
| tMin | 0.00 – 60.00 | s | 0.01 | 0.10 | Minimum operate time for programmable curve for trip |
| tReset | 0.00 – 60.00 | s | 0.01 | 0.02 | Reset time delay for warning, alarm and trip |
| tPCrv | 0.000 – 3.000 | – | 0.001 | 1.000 | Parameter P for programmable curve for trip |
| tACrv | 0.005 – 200.000 | – | 0.001 | 1.000 | Parameter A for programmable curve for trip |
| tBCrv | 0.50 – 100.00 | – | 0.01 | 1.00 | Parameter B for programmable curve for trip |
| tCCrv | 0.0 – 1.0 | – | 0.1 | 0.0 | Parameter C for programmable curve for trip |
| tDCrv | 0.000 – 60.000 | – | 0.001 | 0.000 | Parameter D for programmable curve for trip |
| CrvSat | 0 – 100 | – | 1 | 0 | Tuning parameter for programmable curve |
SCUVPTOV Non group settings (advanced)
| SCUVPTOV Non group settings (advanced) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| BlockTrip | Trip disabled Trip enabled |
– | – | Trip enabled | Trip blocked / enabled |
SCUVPTOV Monitored data
| SCUVPTOV Monitored data | ||||
| Name | Type | Values (Range) | Unit | Description |
| LASTCOMP | GROUP SIGNAL | – | – | Indicates date and time when the last trigger was made for compensation |
| UNUNBAL | REAL | – | kV | Instantaneous magnitude of capacitor bank neutral unbalance voltage |
| PUNUNBAL | REAL | – | % | Capacitor bank neutral unbalance voltage in % of UBase |
| UL1 | REAL | – | kV | Bus voltage of phase L1 |
| UL2 | REAL | – | kV | Bus voltage of phase L2 |
| UL3 | REAL | – | kV | Bus voltage of phase L3 |
| UNSCB | REAL | – | kV | Capacitor bank neutral voltage |
| K1USED | REAL | – | – | Used compensation factor of K1 for unbalance neutral voltage calculation |
| K2USED | REAL | – | – | Used compensation factor of K2 for unbalance neutral voltage calculation |
| K1MON | REAL | – | – | Monitored compensation factor of K1 for unbalance neutral voltage calculation |
| K2MON | REAL | – | – | Monitored compensation factor of K2 for unbalance neutral voltage calculation |
Technical data
Logics & highlights
Protection scheme for ungrounded double WYE capacitor bank
Single line diagram for an ungrounded double WYE capacitor bank
Units arrangement in an ungrounded double WYE connected capacitor bank
Single line diagram for an ungrounded single WYE capacitor bank
Units arrangement in an ungrounded single WYE connected capacitor bank
Ungrounded single WYE SCB connected to function block
Programmable curve
SCUVPTOV block diagram
Simplified Warning, Alarm, and Trip logic
Reporting over IEC 61850
