Lineprotection 1600CT Rati
Lineprotection 1600CT Rati
                                               0
                                                                Rev
                                                                                                                                      Client :
                                                                              Project :
                                                                                                         Designer
                                               For approval
                                                                Description
                                                                Date
                                               03-01-2015
                                               MR
                                                                Checked
                                                                                                                                       OPGS
                                               TS
                                                                Approved
                                                                                2*150MW COAL BASED TPP
                                                                                                          VOLTECH ENGINEERS PVT LTD
Tilte :
Doc.No :
                                                      Description:
VE-J-234-D-E-001
                                                      LINE PROTECTION
INPUT DETAILS
           system voltage                                     220               kV
           CT Details
           CT Ratio                                        1600-800/1A
           Adopted CT Ratio                                  800/1A                           1600
           CT Primary                                         1600              A
           CT Secondary                                         1               A
           Class                                               PS
           System Details
           VT Ratio                                         220kV/√3                          2000
                                                            110V/√3
           VT Primary                                        220000             V
           VT Secondary                                        110              V
           Frequency                                          50HZ
           fault current                                      40.00      kA
           OHL Details
           Condutor type                                     AL-59
           Line Length                                        14         km
           Line impedence
           Positive sequence impedence (Z1)                  0.0021             +j           0.219
           Zero sequence impedence ( Z0 )                    0.0063             +j           0.657
           Line Length                                         14              km
           Current rating in Amps                             1600       (Max.CT Primary Current is considered)
           Line impedences
                                               Z1             0.219             L            89.450       Ω/km
                                               Z0             0.657             L            89.450       Ω/km
                                              Z0/Z1           3.000             L             0.000       °
           Therefore set Line Impedence and Line Angle =                       2.45             L             89.0 Ω secondary
 Zone 1 Phase Reach Settings
 Required Zone 1 reach is to be 85% of the Protected line
            Zone 1 Reach = (0.85*2.45)
                                                                                     °
                        Z1=        2.08                  L                 89                        Ω secondary
           The Line Angle =                 89 °
 Therefore actual Zone 1 reach, Z1                     2.08                L                 89      Ω secondary
                                                                   (0.0063+j0.657)-(0.0021+j0.219)
                                    Z0-Z1                =              0.0042            +j       0.438
                                                                         0.438            L        89.450
                                                                   (0.438/(3*0.219))                  L      89.45-89.45
                                (Z0-Z1) / 3Z1            =
                                                                   0.667                             L    0.00 °
      kZ0 Res. Comp,               │kZ0│                 =               0.667
        kZ0 Angle,                 L kZ0                 =                0.0        °
                                                        (110V/√3 /1)
Minimum Load impedence to the relay =
                                                    63.51     Ω secondary
 Typically,phase fault distance zones would avoid the minimum load impedence by a margin of ≥ 40%,earth fault zones
 would use a ≥ 20% margin.
 This allows maximum resistive reaches for Phase faults              =     38.11    Ω secondary
 This allows maximum resistive reaches for Earth faults              =     50.81    Ω secondary
                           Ra = (28710 x L) / If^1.4
                  Where:      If = Minimum expected phase-phase fault current (A);
                              L = Maximum phase conductor separation (m);
                              Ra = Arc resistance, calculated from the van Warrington formula (W).
3-phase faults:
               Source Impedance, Zs                =           kV/ √3 * I SCC
                                                   =          220/(1.732*40)
                                                   =                3.18      Ω
positive sequence Line Impedance                   =               3.066
                                      Ztot         =                 6        Ω
The minimum three-phase fault current without fault resistance
                                  I 3ph min        =         220000/(1.732*6)
                                                   =                20350.48 A
fault current                    =                     20.350          kA
Conductor spaces                 =                        5            mtrs
Primary resistive coverage for phase
                                                       0.133                   Ω
faults
assuming a typical earth fault coverage                  40                    Ω
RPH (min)-secondary              0.133*0.8             0.107                   Ω
RG (min)                          40*0.8                 32                    Ω
SOTF
SOTF Protection operates 120% of fault current with breaker closing command
                                                       Fault current           =             20350     A
                                                                               =          1.2*20350.4794062777
                                                                               =           24420.5753
                                                                               =           15.2628596 A
Breaker Fail
GROUP 1 SUPERVISION
VT Supervision
VTS Time Delay             5                 s
VTS I2>IO>inhibit         0.2                A
Detect 3P               Enabled
Threshold 3P              10V
Delta I>                  0.2                A
PROJECT:   2*150MW COAL BASED TPP                                                                                                DOC.NO
CLIENT:    OPGS                                                                                                              VE-J-234-D-E-001
                                                                                                                            PRPD:         AJ
TITLE:     Relay setting calculation                                              DATE                         REV
                                                                                                                            CKD:          MR
                  220KV MOKHA LINE FEEDER                                       03-01-2015                      0          APPRVD         TS
220kV MOKHA LINE DISTANCE PROTECTION                                                                              RELAY TYPE : REL650
INPUT DETAILS
           System Data
           System Voltage                                                       220 kV
           System Frequency                                                      50 Hz
           Fault Level                                                           40 kA
           CT Details
           CT Primary                                                        1600 A
           CT Secondary                                                         1A
           PT Details:
           PT Ratio                                                         =       220000/110V
           PT Primary Voltage                                               =       220000            V
           PT Secondary Voltage                                             =       110               V
           System Frequency                                                 =       50                HZ
           Zone 1 Settings
           Required Zone 1 reach is to be 85% of the Protected line
           X1-Z1 prim = 85% * X1prim                                        =                 2.606
           X1-Z1 sec = Nct/Nvt * X1prim                                     =                 2.085
Zone 2 Settings
Zone 2 element setting with a reach of 120% of Protected line reactance accounts for effect of infeed.This point must be verified
using a fault study to calculate
the apparent ohms at the local terminal for a fault at the remote end of transmission line. In our case 120% is considered for the
assurance that all faults in the protected line are detectable,even with infeed from remote terminals.
Assuming the zone-1 reach for the adjacent line protection is set at 85% of that line reactance, and it is to be verified such that the
zone-2 reach of 120%
 (protected line) shall not extend beyond the max.effective zone-1 reach of the adjacent line protection.
Zone-2 setting limit                                                     =       Protected line reactance + 0.85 * adjacent line reactance
                                                                         =       15.437
Zone-2 setting with 120% reach                                           =       2.943
Since 120%, 2.701 is lower than zone-2 limit, 8.744, then the zone-2 setting of 120% will not overreach beyond zone-1 setting of
adjacent line protection.
 Therefore we can consider 120% of protected line reactance for zone-2.
Hence set X1 -Z2 prim                                                    =                 3.679
Hence set X1-Z2 sec                                                      =                 2.943
Zone 3 Settings
For Zone3 setting , it is customery to select (Protected line + 50% Adjacent longest line)
X1-Z3 prim, reach                                                      =               14.644
X1-Z3 sec = Nct/Nvt * X1prim*IN/A                                      =               11.715
Zone 5 Settings
For Zone5 setting, reverse reach impedence is typically 20% Zone 1 reach Impedance.
X1-Z5 prim, reach                                                     =                   0.521
X1-Z5 sec = Nct/Nvt * X1prim*IN/A                                     =                   0.417
Zone-2 setting
zone-2 time delay should be set to discreminative with the primary line protection of the next line sections
including circuit breaker trip time
Adjoining line protection operating time                                  =                 0.04
Breaker opening time                                                      =                 0.08
Local relay reset                                                         =                 0.03
Grading margin                                                            =                 0.25
Required zone-2 time delay                                                =                   0.4
set zone-2 at                                                             =                   0.4 sec
Zone-3 setting
zone-3 time delay shall be such that zone-2 time delay plus grading margin
zone-2 time delay                                                       =                       0.4
Grading margin                                                          =                       0.4
Required zone-3 time delay                                              =                       0.8
set zone-3 at                                                           =                       0.8 sec
Zone-5 setting
zone-5 might be used to provide back up protection for the local bus bar. zone-5 time delay shall be such that LBB time delay
plus grading margin
LBB time delay                                                           =                  0.2
Grading margin                                                           =                 0.25
Required zone-5 time delay                                               =                 0.45
set zone-5 at                                                            =                  0.5 sec
                                                                 Ifault   =          Usource
Arc Resistance Calculation:                                                          √3*Ztot
3-phase faults:
         Source Impedance, Zs                                             =        kV/ √3 * I SCC
                                                                          =       220/(1.732*40)
                                                                          =            3.18          Ω
           positive sequence Line Impedance                               =            0.029         +J        3.066
                                                                          =            3.066         Ω
                                                                Ztot      =                      6   Ω
The minimum three-phase fault current without fault resistance
                                                            I 3ph min     =      220000/(1.732*6)
                                                                          =           20350.48 A
The arc resistance will be calculated with the following equation
                                                                 Rarc     =         Uarc/IF1.4
The arc voltage will be calculated using the following rule of thumb which provides a very conservative estimate
(the estimate Rarc is larger than the actual value)
                                                                 Uarc     =      28707 * L
                                                             Where
                                                                    L     =      Length of the arc(for Phase to phase faults)
                                                                          =                 5.00 m            (Assumed)
                                                    ∴Rarc (Primary)       =      (28707*5)/(20350.48)^1.4
                                                                          =                 0.13 Ω
Setting of the resistive reach for the under reaching zone-1 should follow this condition.
            Fault resistance for Ph-E fault Rf                            <       4.5 * X1PE
                                                                          <       4.5*2.085
                                                                          <                 9.38 Ω
           Total Fault resistance (RFPE) for Ph-E fault zone 1            =      RT + Rarc + R1PE
                                                                          =      8+0.189+0.02
                                                                          =                8.21 Ω
           Rf is lower than 80% of the load, we take Rf value,
           Maximum allowable Resistive reach for Zone 1                 =                 9.38 Ω
           Our set value should be less than the above value and to get Zone segrication.
           Setting of RFPE- Zone 1                                      =                 4.00 Ω
Setting of the resistive reach for the under reaching zone-2 should follow this condition.
            Fault resistance for Ph-E fault Rf                            <       4.5 * X2PE
                                                                          <       4.5*2.943
                                                                          <                 16.56 Ω
           Total Fault resistance (RFPE) for Ph-E fault zone 2            =      RT + Rarc + R2PE
                                                                          =      8+0.19+0.028
                                                                          =                8.22 Ω
           Rf is lower than 80% of the load, we take Rf value,
           Maximum allowable Resistive reach for Zone 2                 =               16.56 Ω
           Our set value should be less than the above value and to get Zone segrication.
           Setting of RFPE- Zone 2                                      =                 8.00 Ω
Setting of the resistive reach for the under reaching zone-3 should follow this condition.
            Fault resistance for Ph-E fault Rf                            <       4.5 * X3PE
                                                                          <       4.5*11.715
                                                                          <                52.72 Ω
           Total Fault resistance (RFPE) for Ph-E fault zone 3            =      RT + Rarc + R3PE
                                                                          =      8+0.19+1.867
                                                                          =               10.06 Ω
           Rf is lower than 80% of the load, we take Rf value,
           Maximum allowable Resistive reach for Zone 3                 =               52.72 Ω
           Our set value should be less than the above value and to get Zone segrication.
           Setting of RFPE- Zone 3                                      =               16.00 Ω
Setting of the resistive reach for the under reaching zone-5 should follow this condition.
            Fault resistance for Ph-E fault Rf                            <       4.5 * X5PE
                                                                          <       4.5*0.417
                                                                          <                 1.88 Ω
           Total Fault resistance (RFPE) for Ph-E fault zone 5            =      RT + Rarc + R5PE
                                                                          =      8+0.19+0.004
                                                                          =                8.19 Ω
           Rf is lower than 80% of the load, we take Rf value,
           Maximum allowable Resistive reach for Zone 5                 =                 1.88 Ω
           Our set value should be less than the above value and to get Zone segrication.
           Setting of RFPE- Zone 5                                      =                 0.40 Ω
To avoid load encroachment for the phase to earth measuring elements, the set resistive reach of any distance zone must be less
than 80%of the
minimum load impedance.
                                                          RFPE       =       0.8 * Zload
                                                                     =       0.8*57.159
                                                                     =                  45.73 Ω
    Limit the setting of the zone 1 reach in resistive direction for ph-ph loop measurement
                Fault resistance for Ph-Ph fault Rf                             <     3* X1Z1
                                                                                <     3*2.085
                                                                                <               6.25    Ω
                Total fault resistance (RFPP) for Ph-Ph Fault (Zone 1)          =     Rarc + R1PP
                                                                                =     0.107+0.02
                                                                                =               0.13    Ω
                Rf is lesser than 160% of the load, we take Rf value,
                Maximum allowable Resistive reach for Zone 1                    =               6.25    Ω
                Our set value should be less than the above value and to get Zone segrication.
                Setting of RFPP- Zone 1                                         =               6.00    Ω
    Limit the setting of the zone 2 reach in resistive direction for ph-ph loop measurement
                Fault resistance for Ph-Ph fault Rf                             <     3 * X1Z2
                                                                                <     3*2.943
                                                                                <               8.83    Ω
                Total fault resistance (RFPP) for Ph-Ph Fault (Zone 2)          =     Rarc + R2PP
                                                                                =     0.107+0.028
                                                                                =               0.13    Ω
                Rf is lesser than 160% of the load, we take Rf value,
                Maximum allowable Resistive reach for Zone 2                    =               8.83    Ω
                Our set value should be less than the above value and to get Zone segrication.
                Setting of RFPP- Zone 2                                         =               4.00    Ω
    Limit the setting of the zone 3 reach in resistive direction for ph-ph loop measurement
                Fault resistance for Ph-Ph fault Rf                             <     3 * X1Z3
                                                                                <     3*11.715
                                                                                <              35.14    Ω
                Total fault resistance (RFPP) for Ph-Ph Fault (Zone 3)          =     Rarc + R3PP
                                                                                =     0.107+1.867
                                                                                =               1.97    Ω
                Rf is lesser than 160% of the load, we take Rf value,
                Maximum allowable Resistive reach for Zone 3                    =              35.14    Ω
                Our set value should be less than the above value and to get Zone segrication.
                Setting of RFPP- Zone 3                                         =               8.00    Ω
    Limit the setting of the zone 5 reach in resistive direction for ph-ph loop measurement
                Fault resistance for Ph-Ph fault Rf                             <     3 * X1Z3
                                                                                <     3*0.417
                                                                                <               0.06    Ω
                Total fault resistance (RFPP) for Ph-Ph Fault (Zone 5)          =     Rarc + R3PP
                                                                                =     0.107+0.004
                                                                                =               0.11    Ω
                Rf is lesser than 160% of the load, we take Rf value,
                Maximum allowable Resistive reach for Zone 5                    =               0.06    Ω
                Our set value should be less than the above value and to get Zone segrication.
                Setting of RFPP- Zone 5                                         =               0.02    Ω
    To avoid load encroachment for the phase to phase measuring elements, the set resistive reach of any distance zone must be less
    than 160%of the
    minimum load impedance.
                                                             RFPP       =       1.6 * Zload
                                                                        =       1.6*57.159
                                                                        =                  91.45 Ω
PHASE SELECTION:
It is possible to set the reach of the phase- selection elements to cover with sufficient margin only the protected line and secure tripping of a
      correct phase for the faults on the protected line only.
    setting instructions:
    The phase selection elements need not cover all distance protection zones with in the terminal. The main goal should be a correct
    and
    realiable phase selection for faults on the entire protected line.
    The phase selection measuring elements must always cover the first corresponding overreaching zone (in most application cases :
    zone-2)
    for different fault loops.
    A safety margin between 10% and 15% is recommended.
                                                            X1PP          >     X1PPZm2
                                                                          >                2.94 Ω
                                                                          >                3.00 Ω
X1InFw = 12.89 Ω
R1LIn = 2.05 Ω
R1FInFw = 8.80 Ω
       Set the used principle forback-up tripping, with or without contact resp current checks
                                                              FunctionMode        =            Current
       Set an additional time delay for a second back-up trip step if used. Will be added to t2 B-u trip time without checks
                                                                         t3       =                 0.03 Sec
       Set the current level above which the contact base operation (if selected) is blocked
                                                               I>BlkCont        =                     20 %IB
SOTF
       Setting of under current
                                                                        Iph<     =                    20 %UB
       Setting of the U< voltage
                                                                       Uph<        =                   70 %UB
       Set the required duration of low UI check to achieve operation
                                                                   tDuration       =                 0.02 Sec
       Set the time during which the fault is considered being a Switch Onto Fault case
                                                                      tSOTF        =                     1 Sec
       Set the required time for all currents and all voltages to be low to Auto Initiate the SOTF function.
                                                                        tDLD       =                  0.2 Sec
Settings Table
DISTANCE PROTECTION:
         NAME                 RECOMMENDED SETTING
        General
   GlobalBaseSel                1
   Setting Group1
       Operation              On
      IMinOpPP                 20 %IB
      IMinOpPE                 20 %IB
       IMinOpiN                 5 %IB
      Line Angle                0 Deg
ZONE-1
         NAME                 RECOMMENDED SETTING
        RFPE1                4.00 ohm/l
        RFPP1                6.00 ohm/l
            Z1               2.08
        KNMag1               0.67
        KNAng1                  0 Deg
    OpModetPE1                On
    OpModetPP1                On
       DirMode1          Forward
          tPE1              0.000 s
          tPP1              0.000 s
       OpMode1    Enable Ph-E PhPh
ZONE-2
         NAME                 RECOMMENDED SETTING
        RFPE2                8.00 ohm/l
        RFPP2                4.00 ohm/l
            Z2               2.94
        KNMag2               0.67
        KNAng2                  0 Deg
    OpModetPE2                On
    OpModetPP2                On
       DirMode2          Forward
          tPE2              0.400 s
          tPP2              0.400 s
       OpMode2    Enable Ph-E PhPh
ZONE-3
         NAME                 RECOMMENDED SETTING
        RFPE3               16.00 ohm/l
        RFPP3                8.00 ohm/l
            Z3              11.86
    OpModetPE3                On
    OpModetPP3                On
       DirMode3          Forward
          tPE3              0.800 s
          tPP3              0.800 s
       OpMode3    Enable Ph-E PhPh
ZONE-5
         NAME                 RECOMMENDED SETTING
        RFPE5                0.02 ohm/l
        RFPP5                0.40 ohm/l
            Z5               0.42
    OpModetPE5                On
    OpModetPP5                On
       DirMode5          Reverse
          tPE5              0.500 s
          tPP5              0.500 s
       OpMode5    Enable Ph-E PhPh
PHASE SELECTION:
         NAME                 RECOMMENDED SETTING
     OperationZ<              ON
     OperationI<             OFF
      INBlockPP             40.00 %Iph
    INReleasePE             20.00 %Iph
         RLdFw              43.73 ohm/p
         RLdRv              43.73 ohm/p
         ArgLd              32.00 0
          Iph>             120.00 %IB
           IN>              20.00 %IB
            X1               3.00 ohm/l
            X0               9.00 ohm/l
       RFFwPP                4.00 ohm/l
       RFRvPP                4.00 ohm/l
       RFFwPE                9.00 ohm/l
       RFRvPE                9.00 ohm/l
       TimerPP                Off
           tPP               3.00 s
       TimerPE                Off
           tPE               3.00 s
      IMinOpPP              10.00 %IB
      IMinOpPE               5.00 %IB
POWER SWING DETECTION:
      NAME                  RECOMMENDED SETTING
    Operation               ON
     X1InFw               12.89 ohm
      R1LIn                2.05 ohm
     R1FInFw               8.80 ohm
      X1InRv              12.89 ohm
     R1FInRv               8.80 ohm
  OperationLdCh             ON
    RLdOutFw              43.73 ohm
      ArgLd               32.00 0
    RLdOutRv              43.73 ohm
     kLdRFw                0.75 Multi
     kLdRRv                0.75 Multi
       tP1                0.045 S
       tP2                0.015 S
        tW                 0.25 S
         tH                0.50 S
       tR1                 0.30 S
       tR2                 0.20 S
BROKEN CONDUCTOR:
     NAME                    RECOMMENDED SETTING
     IBase               1600.00 A
      Iub>                 10.00 % IM
       IP>                 20.00 % IB
     tOper                  5.00 s
BREAKER FAILURE:
         NAME                 RECOMMENDED SETTING
          Ibase          1600.00 A
     FunctionMode        Current
      BUTripMode       1 Out of 3
      RetripMode  CB Position check
           IP>              10.00 %IB
           IN>              10.00 %IB
            t1               0.06 sec
            t2               0.12 sec
         t2MPh               0.12 sec
            t3               0.03 sec
         tPulse              0.20 sec
       I>BlkCont            20.00 %IB
       tCBAlarm              2.00 sec
SOTF
  NAME            RECOMMENDED SETTING
   Mode               impedance
  AutoInit                    On
    Iph<                    20.00 % IB
   Uph<                     70.00 % UB
 tDuration                   0.02 sec
  tSOTF                      1.00 sec
   tDLD                      0.20 sec