03 ptcc under over voltage protection
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Transcript of 03 ptcc under over voltage protection
Under/Over Voltage ProtectionFor automatic circuit reclosers with PTCC controllers
Under/Over Voltage Protection
Under/over Voltage Protection can be configured to cause the recloser to trip, if the measured system voltage goes outside preset limits for a preset time.
The recloser uses logic based on ‘AND’, ‘OR’ or ‘AVERAGE’ evaluation to determine if the system voltage maintains a ‘normal voltage’ state.
A recloser can be configured to automatically reclose after an under or over voltage protection trip, if the system voltage has returned to an acceptable value.
Voltage Protection can also be configured to:
Force ‘voltage protection’ off in the case of excessive voltage protection sequences.
Force ‘normal voltage close’ off in the case of a voltage protection recovery timeout.
Under/Over Voltage Protection Capability
Accessing Under/Over Voltage Protection settings via WSOS
Making Under/Over Voltage Protection Available via WSOS
Launching the Under/Over Voltage Protection Setting Screen via WSOS
Over Voltage Protection Timing
VOLTAGE
tSwitchgear Status
6300V
7560V
6930V
Over Voltage Pickup
Over Voltage Reset 7434V
Over Voltage Normal Over Voltage Normal Reset 7056V
CLOSEDOPENCLOSED
Over Voltage Pickup at this time
Over Voltage Reset at this time
Over Voltage Trip Delay Timer
Trip at this time
Normal Voltage Close Time
Close at this time
Under and Over Voltage Phase Logic
Under and Over Voltage Phase Logic Options
Phase Logic controls the method in which measured voltages are evaluated against the under/over Voltage Threshold.
The Options are:
AND All measured phase voltages must deviate beyond the
Pickup Threshold for pickup to occur. OR
Any measured phase voltage which deviates beyond the Pickup Threshold will cause pickup to occur.
AVERAGE The numerical average of all three measured phase
voltages must deviate beyond the Pickup Threshold for pickup to occur.
Normal Voltage Close
Normal Voltage Close Events
Normal Voltage Close ON/OFF
Normal Voltage Close ON enables the controllers normal voltage close functionality which causes the ACR to automatically close when:
The most recent trip was a UOV protection trip, The switchgear source side voltages have returned to a
‘Normal Voltage’ state, ‘Normal Voltage Close’ was ON before the UOV trip and is still
ON,
AND
The ‘Normal Voltage’ state has persisted for the duration of the Normal Voltage Close Delay time period.
Voltage Protection Recovery Timeout
Voltage Protection Recovery Timeout Operation
If Normal Voltage Close is ON
and the switchgear does not
‘Normal Voltage Close’
subsequent to a
‘UOV Protection Trip’
in less than or equal to the
‘Normal Recovery’ period
then:
‘Normal Voltage Close’ will be forced OFF
And
The Switchgear will go to ‘Lockout’
Range 0 – 1000s
Setting Recovery Time Out to
Off
Will inhibit this feature
Excess UOV Protection Sequences
Excess UOV Protection Sequences
If the number of Voltage Protection sequences equals the
‘excess sequence’ count threshold
within the voltage sequence count accumulation period then:
Under Voltage Trip
Over Voltage Trip
Normal Voltage Close …….. Will all be forced OFF
Single Sided CVT Switchgear
If UOV Protection is Available on the controller
and the attached switchgear is only fitted with CVT’s on one side
and if the controllers Source/Load designation is set such that the designated Load side has the CVT’s fitted
Then UOV Protection ‘Normal Voltage Close’ will be forced to OFF
and if the switchgear is in a UOV Protection tripped state,
Then the switchgear will go to Lockout.
Protection Menu Navigation
6x Earth Protection Settings
6x NPS Protection Settings
3x Global Protection Settings
2x Protection Features Settings
2x Frequency Protection Settings
6x Phase Protection Settings
3x Under/Over Voltage Settings
UOV Protection OCPM Screens
Questions?
On which screen can Under/Over Voltage Protection be made available via the OCPM? Options 3 in the System Status menu.
With UOV Phase Logic set to ‘Average’, what voltage value will the protection use for A = 0V B = 15000V C = 16000V? 15500V
At which voltage will the Normal Voltage Close timer start following an Over Voltage trip with the following settings?Over Voltage trip at: 15000VOver Voltage normal at: 14000VNominal Phase to Earth 12600V 14000V
How many UOV Protection screens are on the OCPM and where? Three screens at the end of the Protection menu.