In the P63x a three-stage definite-time overcurrent protection function (DTOC protection) is available for up to three transformer ends. The measured values to be monitored by the respective DTOC functions are selected using a setting parameter. With the P633 and P634, these values can also be quantities formed by summation of the current values from two user-selected transformer ends. With the P631 and P632, the 'Current summation' setting has no effect. Phase current values as well as negative-sequence and residual current measured values are monitored. Function group DTOC1 will serve as an example to illustrate the operation of the DTOC protection functions. The same will apply to function groups DTOC2 and DTOC3.
3-99 Selection of measured values for DTOC protection
(Selection of end d applies to the P634 only, selection of end c and of 'Current summation' applies to the P633 and P634 only)
Enabling or disabling DTOC protection
DTOC protection can be disabled or enabled using setting parameters. Moreover, enabling can be carried out separately for each parameter set.
3-100 Enabling or disabling DTOC protection
P63X/EN M/Ba4 // AFSV.12.09701 D /// P631-305-403/404-610 // P632-305-403/404-610 // P633-305-404/405/406-610 // P634-305-403/404-610 3-159 Phase current stages
The three phase currents are monitored by the P63x with three-stage functions to detect when they exceed the set thresholds. One of two different threshold types can be active.
The "dynamic" thresholds are active for the set hold time for the "dynamic parameters"
(see section "Activation of dynamic parameters") and the "normal" thresholds are active when no hold time is running. If the current exceeds the set thresholds in one phase, timer stages are started. Once the time delays have elapsed, a trip signal is issued.
The timer stages can be blocked by appropriately configured binary signal inputs.
The first stage of the DTOC protection function can optionally be blocked by the inrush stabilization function of differential protection.
P63X/EN M/Ba4 // AFSV.12.09701 D /// P631-305-403/404-610 // P632-305-403/404-610 // P633-305-404/405/406-610 // P634-305-403/404-610 3-161 Negative-sequence current
stages
The P63x calculates the negative-sequence current from the three phase current values according to this equation. This is based on the setting at MAIN: Phase sequence.
Phase sequence A-B-C: Phase sequence A-C-B:
( 2 B C)
A
neg I a I a I
3
I = 1⋅ + ⋅ + ⋅ neg (IA a IB a2 IC)
3
I = 1⋅ + ⋅ + ⋅
a e= j120° a2 =ej240°
The negative-sequence current is monitored by the P63x with three-stage functions to detect when it exceeds the set thresholds. One of two different threshold types can be active. The "dynamic" thresholds are active for the set hold time for the "dynamic parameters" (see section "Activation of dynamic parameters") and the "normal"
thresholds are active when no hold time is running. If the current exceeds the set thresholds, timer stages are started. Once these time delays have elapsed, a trip signal is issued. The timer stages can be blocked by appropriately configured binary signal inputs.
The first stage of the negative-sequence current protection function can optionally be blocked by the inrush stabilization function of differential protection.
MAIN: Phase sequence [ 010 049 ]
Parameter set 1 set 2 set 3 set 4
DTOC1: Ineg>>
PSx 076 198 077 198 078 198 079 198 DTOC1: Ineg>
dynamic PSx 076 200 077 200 078 200 079 200 DTOC1: Ineg>
PSx 076 197 077 197 078 197 079 197
DTOC1: Ineg>>
dynamic PSx 076 201 077 201 078 201 079 201
DTOC1: Rush restr.enabl PSx 076 063 077 063 078 063 079 063 Parameter
set 1 set 2
DTOC1: tIneg>
PSx 076 203 077 203 DTOC1: Ineg>>>
dynamic PSx 076 202 077 202 DTOC1: Ineg>>>
PSx 076 199 077 199
DTOC1: tIneg>>
PSx 076 204 077 204
DTOC1: tIneg>>>
PSx 076 205 077 205
DTOC1: Gen.
starting modePSx 076 066
077 066
DTOC1: Trip signal tIneg>>
[ 036 152 ] DTOC1: tIneg>>
elapsed [ 036 149 ] DTOC1: Starting Ineg>>
[ 036 146 ]
DTOC1: Trip signal tIneg>>>
[ 036 153 ] DTOC1: tIneg>>>
elapsed [ 036 150]
DTOC1: Starting Ineg>>>
[ 036 147 ] DTOC1: Starting Ineg
[ 036 144 ] DTOC1: Trip signal tIneg>
[ 036 151 ] DTOC1: tIneg>
elapsed [ 036 148 ] DTOC1: Starting Ineg>
[ 036 145 ] DTOC1: Gen.
starting modePSx [ * ]
DTOC1: Block.
tIneg> EXT [ 036 141 ] DTOC1: Rush restr.enabl PSx [ * ] 1: With start. IN/
Ineg
1: yes
DIFF: Harm.block 1 trigg.
[ 041 118 ] DIFF: Harm.block 2 trigg.
[ 041 119 ] DIFF: Harm.block 3 trigg.
[ 041 120 ]
MAIN: Dynam.
param. active [ 040 090]
DTOC1: Enabled [ 035 102 ] MAIN: Protection active
306 001
IA,y IB,y IC,y DTOC1: Block.
tIneg>> EXT [ 036 142 ]
DTOC1: Block.
tIneg>>> EXT [ 036 143 ]
DTOC1: Ineg>
PSx [ * ] DTOC1: Ineg>
dynamic PSx [ * ]
DTOC1: Ineg>>
PSx
[ * ] DTOC1: Ineg>>
dynamic PSx [ * ]
DTOC1: Ineg>>>
PSx
[ * ] DTOC1: Ineg>>>
dynamic PSx [ * ]
DTOC1: tIneg>>
PSx
[ * ]
DTOC1: tIneg>>>
PSx
[ * ] DTOC1: tIneg>
PSx
[ * ]
Ineg,y
P63X/EN M/Ba4 // AFSV.12.09701 D /// P631-305-403/404-610 // P632-305-403/404-610 // P633-305-404/405/406-610 // P634-305-403/404-610 3-163 Residual current stages
The residual current is monitored by the with three-stage functions to detect when it exceeds the set thresholds. One of two different threshold types can be active.
The "dynamic" thresholds are active for the set hold time for the "dynamic parameters"
(see "Activation of Dynamic Parameters") and the "normal" thresholds are active when no hold time is running. If the residual current exceeds the set thresholds, timer stages are started. Once the time delays have elapsed, a signal is issued. If the operating mode of the general starting decision is set to 'With starting IN', a trip signal is issued as well.
The timer stages can be blocked by appropriately configured binary signal inputs.
In addition these timer stages can also be automatically blocked by single-pole or multi- pole starting (depending on the setting).
P63X/EN M/Ba4 // AFSV.12.09701 D /// P631-305-403/404-610 // P632-305-403/404-610 // P633-305-404/405/406-610 // P634-305-403/404-610 3-165 General starting
If the current exceeds one of the set thresholds of the phase current stages, a general starting decision is issued. The user can select whether the starting of the negative- sequence and residual current stages should be taken into account in the general starting decision. The general starting triggers a timer stage. A signal is issued when the time delay of this stage has elapsed.
3-104 General starting
Counters of the DTOC protection function
The number of general starts is counted. The counter can be reset individually.
3-105 Counters of the DTOC protection function