The P63x features an inverse-time overcurrent protection function (IDMT protection) for up to three transformer ends. The measured variables to be monitored by the respective IDMT function are selected by a setting parameter. With the P633 and P634 this can also be quantities formed by summation of 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 IDMT1 will serve as an example to illustrate the operation of the IDMT protection functions. The same will apply to function groups IDMT2 and IDMT3.
3-106 Selection of measured variables for IDMT 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 IDMT protection
IDMT protection can be disabled or enabled via setting parameters. Moreover, enabling can be carried out separately for each parameter subset.
3-107 Disabling or enabling IDMT protection
Time-dependent characteristics
The measuring systems for the evaluation of the three phase currents, the negative- sequence current and the residual current operate independently and can be set separately. The user can select from a large number of characteristics. The tripping characteristics available for selection are shown in figures 3-108 Tripping characteristics as per IEC 255-3 to 3-11 RI-type inverse and RXIDG-type inverse tripping
characteristics.
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 3-169 No
.
Tripping Characteristic
Formula for the Tripping
Characteristic
Constants Formula for the Reset Characteristic Characteristic settable
factor:
k = 0.05 to 10.00
a b c R
0 Definite Time t k= Per IEC 255-3
1
⎟⎟ −
⎠
⎞
⎜⎜⎝
⋅⎛
= b
Iref
I k a t
1 Standard Inverse 0.14 0.02
2 Very Inverse 13.50 1.00
3 Extremely Inverse 80.00 2.00
4 Long Time Inverse 120.00 1.00
Per IEEE C37.112
⎟⎟
⎟⎟
⎟⎟
⎠
⎞
⎜⎜
⎜⎜
⎜⎜
⎝
⎛
+
⎟⎟ −
⎠
⎜⎜ ⎞
⎝
⋅ ⎛
= c
I I k a
t b
ref
1
1
2
⎟⎟ −
⎠
⎞
⎜⎜⎝
⋅⎛
=
ref r
I I k R t
5 Moderately Inverse 0.0515 0.0200 0.1140 4.85
6 Very Inverse 19.6100 2.0000 0.4910 21.60
7 Extremely Inverse 28.2000 2.0000 0.1217 29.10
Per ANSI
⎟⎟
⎟⎟
⎟⎟
⎠
⎞
⎜⎜
⎜⎜
⎜⎜
⎝
⎛
+
⎟⎟ −
⎠
⎜⎜ ⎞
⎝
⋅ ⎛
= c
I I k a
t b
ref
1
1
2
⎟⎟ −
⎠
⎜⎜ ⎞
⎝
⋅⎛
=
ref r
I I k R t
8 Normally Inverse 8.9341 2.0938 0.17966 9.00
9 Short Time Inverse 0.2663 1.2969 0.03393 0.50
10 Long Time Inverse 5.6143 1.0000 2.18592 15.75
11 RI-Type Inverse
⎟⎟⎠
⎜⎜ ⎞
⎝
−⎛
⋅
=
Iref
I k
t 0.339 0.236
1
12 RXIDG-Type Inverse
⎟⎟⎠
⎜⎜ ⎞
⎝
⎛ − ⋅
⋅
=
Iref
k I
t 5.8 1.35 ln
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/IB t/s
S8Z50K1B k=1 k=10
k=0.1 k=0.05 IEC 255-3. Standard Inverse
I/Iref
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K2B k=1 k=10
k=0.1 k=0.05 IEC 255-3. Very Inverse
Characteristic No. 1 Characteristic No. 2
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K3B k=1 k=10
k=0.1 k=0.05 IEC 255-3. Extremely Inverse
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K4B k=1 k=10
k=0.1 k=0.05 IEC 255-3. Long Time Inverse
Characteristic No. 3 Characteristic No. 4
3-108 Tripping characteristics as per IEC 255-3
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 3-171
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K5C k=1 k=10
k=0.1 k=0.05 IEEE C37.112. Moderately Inverse
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K6C k=1 k=10
k=0.1 k=0.05 IEEE C37.112. Very Inverse
Characteristic No. 5 Characteristic No. 6
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K7C k=1 k=10
k=0.1 k=0.05 IEEE C37.112. Extremely Inverse
Characteristic No. 7
3-109 Tripping characteristics as per IEEE C37.112
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50K8C k=1 k=10
k=0.1 k=0.05 ANSI. Normally Inverse
0.01 0.1 1 10 100 1000
I/Iref t/s
S8Z50K9C k=1 k=10
k=0.1 k=0.05 ANSI. Short Time Inverse
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Characteristic No. 8 Characteristic No. 9
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50KAC k=1 k=10
k=0.1
k=0.05 ANSI. Long Time Inverse
Characteristic No. 10
3-110 Tripping characteristics as per ANSI
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 3-173
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 I/Iref
t/s
S8Z50KBB k=1 k=10
k=0.1 k=0.05 RI-Type Inverse
0.01 0.1 1 10 100 1000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
I/Iref t/s
S8Z50KCB k=1 k=10
k=0.1 k=0.05 RXIDG-Type Inverse
Characteristic No. 11 Characteristic No. 12
3-111 RI-type inverse and RXIDG-type inverse tripping characteristics
Phase current stage
The three phase currents are monitored by the P63x to detect when they exceed the set thresholds. Alternatively, two different thresholds can be active. The “dynamic”
threshold is active for the set hold time of the “dynamic parameters” (see “Activation of Dynamic Parameters”); the “normal” threshold is active when no hold time is running.
The IDMT protection function will be triggered when the 1.05-fold of the set reference current value is exceeded in one phase. The P63x will then determine the maximum current flowing in the three phases and this value is used for further processing.
Depending on the characteristic selected and the current magnitude, the P63x will determine the tripping time. Furthermore, a minimum tripping time can be set; the tripping time will not fall below this minimum independently of the magnitude of the current.
The IDMT 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 3-175
3-112 Phase current stage
Negative-sequence current stage
The P63x calculates the negative-sequence current from the three phase current values according to this formula. 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⋅ + ⋅ + ⋅ ( 2 C)
B A
neg I a I a I
3
I = 1⋅ + ⋅ + ⋅
a e= j120° a2=ej240°
The negative-sequence current is monitored by the P63x to detect when it exceeds the set thresholds. Alternatively, two different thresholds 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. The IDMT protection will trigger when the 1.05-fold of the set reference current value is exceeded. Dependent on the characteristic selected and the negative-sequence current magnitude the P63x will determine the tripping time. Furthermore, a minimum tripping time can be set; the tripping time will not fall below this minimum independent of the magnitude of the current.
The negative-sequence current stage of the IDMT protection function can be blocked optionally by the inrush stabilization function of the 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 3-177
MAIN: Phase sequence [ 010 049 ]
64Z5076C_EN Parameter
set 1 set 2 set 3 set 4
IDMT1: Hold time neg PSx 081 115 082 115 083 115 084 115 IDMT1: Min. trip t. neg PSx 081 117 082 117 083 117 084 117 IDMT1: Factor
kt,neg PSx 081 114 082 114 083 114 084 114
IDMT1: Release neg PSx 081 116 082 116 083 116 084 116
IDMT1: Gen.
starting modePSx 081 059
082 059 083 059 084 059 Parameter
set 1 set 2 set 3 set 4
IDMT1: Iref,neg dynamic PSx 081 112 082 112 083 112 084 112 IDMT1: Iref,neg
PSx 081 111 082 111 083 111 084 111 IDMT1: Rush
restr.enabl PSx 081 060 082 060 083 060 084 060
IDMT1: Character.
neg. PSx 081 113 082 113 083 113 084 113 IDMT1: Rush
restr.enabl PSx [ * ]
IDMT1: Iref,neg PSx
[ * ] IDMT1: Iref,neg dynamic PSx
[ * ]
IDMT1: Gen.
starting modePSx [ * ]
IDMT1: Character.
neg. PSx [ * ] IDMT1: Factor kt,neg PSx
[ * ]
[ * ]
[ * ] [ * ] IDMT1: Min. trip t.
neg PSx
IDMT1: Hold time neg PSx
IDMT1: Release neg PSx
DIFF: Harm.block 1 trigg.
[ 041 118 ] DIFF: Harm.block 2 trigg.
[ 041 119 ] DIFF: Harm.block 3 trigg.
[ 041 120 ]
IDMT1: Enabled [ 038 125 ]
MAIN: Dynam.
param. active [ 040 090 ] MAIN: Protection active
306 001
IA,y IB,y IC,y
IDMT1: Block.
tIref,neg> EXT [ 038 178 ]
1: With start. IN/
Ineg
Ineg/Iref,neg
IDMT1: Release neg PSx Setting
1: Without delay 2: Delayed as per char.
Ineg 1.05 * Iref 1: yes 0: no
Setting
IDMT1: Character. neg. PSx 1: IEC Standart Inverse 2: IEC Very Inverse 3: IEC Extr. Inverse 4: IEC Long Time Inv.
5: IEEE Moderately Inv.
6: IEEE Very Inverse 7: IEEE Extremely Inv.
8: ANSI Normally Inv.
9: ANSI Short Time Inv.
10: ANSI Long Time Inv. 11: RI-Type Inverse 12: RXIDG-Type Inverse
IDMT1: Memory 'neg' clear [ 038 176 ] IDMT1: Trip sig.
tIref,neg>
[ 038 177 ] IDMT1: tIref,neg>
elapsed [ 038 174 ] IDMT1: Hold time neg runn.
[ 038 175 ] IDMT1: Starting Iref,neg>
[ 038 173 ]
3-113 Negative-sequence current stage
Residual current stage
The residual current is monitored by the P63x to detect when it exceeds the set thresholds. Alternatively, two different thresholds can be active. The "dynamic"
threshold is active for the set hold time for the "dynamic parameters" (see section
"Activation of dynamic parameters") and the "normal" threshold is active when no hold time is running. The IDMT protection will trigger when the 1.05-fold of the set reference current value is exceeded by the residual current. Dependent on the characteristic selected and the residual current magnitude the P63x will determine the tripping time.
Moreover the tripping time will under no circumstances fall below a settable minimum time threshold irrespective of the residual current flow magnitude.
The inverse-time stage can be blocked by an appropriately configured binary signal input. In addition the inverse-time stage 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 3-179
3-114 Residual current stage
Hold time
The setting of the hold time defines the time period during which the IDMT protection starting time is stored after the starting has dropped out. Should starting recur during the hold time period then the time of the renewed starting will be added to the time period stored. When the starting times sum reach the tripping time value determined by the P63x then the corresponding signal will be issued. Should starting not recur during the hold time period then, depending on the setting, the memory storing the accumulated starting times value will either be cleared without delay or according to the characteristic set. In figure 3-115 the effect of hold time is shown by the example of a phase current stage.
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 3-181
3-115 The effect of the hold time illustrated for the phase current stage as an example Case A: The determined tripping time is not reached.
Case B: The determined tripping time is reached.
General starting
A general starting is triggered if the current in one phase exceeds the 1.05-fold of the set reference current value. It can be selected 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 period of this stage has elapsed.
3-116 General starting
Counters of the IDMT protection function
The number of general starts is counted. The counter can be reset individually.