Generator Relay Protection Setting Calculation 3q5h2i

Generator relay protection setting calculation instruction

注：本定值计算书是基于保护装置原理以及国内外同容量机组运行的经验数据， 主要作为现场调试以及定值设定的参考，而并非最终结果。发电机保护实际运 行所需定值，应根据印方确定的定值清单或者电厂实际运行情况（继电保护人 员校验）予以修正，最终由印方确认。 Instruction: This setting calculation instruction is only for reference, protection device running setting is confirmed by .

XJ Electricity Co., Ltd 2010.11

Catalog 1. Generator Differential Protection（87G） .................................................................................3 2. Overall Differential（87ALL） ...................................................................................................4 3. Generator Inter-turn Fault（95G） ............................................................................................6 4.Generator Inadvertent Energize protection，Stator Earth Fault Protection of startup condition

（99V） ...........................................................................................................................................7 5. Generator Over-voltage（59G） ................................................................................................7 6. Reverse Power Protection（32G）; Low Forward Power Protection（37G） .........................8 7. Generator Stator Overload（49G） ............................................................................................9 8. Generator Negative-Sequence Over-current（46G） ...............................................................10 9. Generator Pole Slipping（78G） .............................................................................................. 11 10. Generator loss of excitation protection（40G） .....................................................................13 11. Generator Under & Over Frequency（81G）.........................................................................14 12. Generator Over Fluxing（24G） ............................................................................................15 13. Generator Under-voltage（27G） ..........................................................................................16 14. Stator Earth Fault 100%（64G1） .........................................................................................16 15. Stator Earth Fault 100%（64G2） .........................................................................................17 16. Stator Earth Fault 95%（64G3） ...........................................................................................17 17. Field Winding Earth Fault(（64F） ........................................................................................18 18. Generator 95% Voltage Check（59GB） ................................................................................18 19. Back Up Impedance（21G）...................................................................................................18 20. TV Fuse-failure（160G） ........................................................................................................19

1. Generator Differential Protection（87G） 1.1 Basic parameter CT ratio（ nTA ） rated primary current（

8000/5

I gn1

rated secondary current（

）

I gn 2

7060A

I gn1 7060 I = = = 4.41A ） gn 2 nTA 1600

1.2 Setting calculation 1）Min operation current I op.0

Setting by the max unbalanced current under the condition of avoid the normal generator rated load.

I op.0 = K rel × 2 × 0.03I gn 2 = 1.5 × 2 × 0.03I gn 2 = 0.09 I gn 2 Suggest to select： I op.0 = 0.2 I gn 2 2）Min brake current I res.0

I res.0 = I gn 2 3）Ratio brake coefficient S External three-phase short-circuit the maximum short-circuit current: ) = I k( 3. max

Sb 100000 = = 32.69 X × 3 × 13.8 × nTA 0.08 × 3 × 13.8 × 1600 ,, d

) I res. max = I k( 3. max = 32.69 A

The max unbalanced current of differential protection when the generator is outer short circuit： ) I unb. max = K ap × K er × K cc × I k( 3. max = 2 × 0.1 × 0.5 × 32.69 = 3.27 A

Therein：K ap is the non-periodic branch coefficient， select 1.5～2.0；K cc is the same type coefficient of transformer， select 0.5； K er

is the error coefficient of

transformer ratio， select 0.1； Put the condition of the differential protection won’t error operate under the max outer short circuit current，the secondary current value I op .max of correspondent max operation current：

I op.max = K rel I unb.max = 1.5 × 3.27 = 4.9 A Therein： K rel is the reliable coefficient, select 1.3～1.5. The ratio brake coefficient S is： S=

I op.max − I op.0 I

(3) max

− I res.0

=

4.9 − 1.324 = 0.12 32.69 − 3.53

Suggest to select：S=0.3。 4）Sensitivity check Sensitivity check principle : Generator terminal side of two-phase metallic short-circuit occurs when generator is parallel off: I k . min =

I res =

0.866 × S b 0.866 × 100000 = = 28.3 A X × 3 × 13.8 × nTA 0.08 3 × 13.8 × 1600 ,, d

I k . min = 14.15 A 2

I op = I op.0 + S ( I res − I res.0 ) = 1.324 + 0.3 × (14.15 − 3.53) = 4.51A K sen =

I k . min 28.3 = = 6.27 > 2 I op 4.51

5）Output model : Trip All CBs

2. Overall Differential（87ALL） 2. 1 Basic parameter Name

M.T. HV Side

Generator terminal

A.T. HV Side

Rated Voltage（kV）

230

13.8

13.8

Rated Current（A）

452.4

7539.6

7539.6

CT ratio

1000/1

8000/5

8000/5

Second side Current（A）

0.45

4.71

4.71

2.2 Setting Calculation 1）Min operation current

I op .0

Setting by the max unbalanced current under the condition of avoid the normal main transformer rated load.：

I op.0 = K rel (f i ( n ) + ∆U + ∆m)I b = 1.5 × (0.06 + 0.05 + 0.05) I b = 0.24 I b Suggest to select： I op .0 = 0.5 I b b Therein：

I b is the value of rated current of transformer norm side converted to the TA

secondary side. K rel is the reliable coefficient， K rel = 1.3 ~ 1.5 ； f i( n )

is the transformer ratio error of the current transformer under rated current.

∆U is the error caused due to the regulation of transformer tapping (relative to the percent of the rated voltage).

∆m is the error caused due to the incomplete matching of transformer ratios of TA and

TAA,

∆m takes 0.05 in general.

2）Min brake current

I res.0

Suggest to select： I res .0 = I b 3）Ratio brake coefficient S The calculation of three-phase main transformer high-voltage busbar metallic short-circuit occurs current when generator is parallel off: ) I k( 3. max =

Sb 1 1 100000 × = × = 1.674 A X + XT 3 × 230 × nTA 0.08 + 0.07 3 × 230 ×1000 ,, d

External three-phase short-circuit the maximum short-circuit current:

I unb . max = ( K st K aper f i + ∆ U + ∆ m ) I (3) k . max

= (1 × 1 . 5 × 0 . 1 + 0 . 05 + 0 . 05 ) × 1 . 674 = 0 . 4185 A 式中： K st is the same type coefficient of TA， K st = 1.0

K aper or

is non-periodic coefficient of TA ，

K aper = 1.0

K aper = 1.5 ~ 2.0

（ 5P or 10P type TA ）

（TP type TA）

Setting of ratio braking coefficient S：

S=

K rel I unb.max - I op.0 I res.max - I res.0

=

1.5 × 0.4185 − 0.225 = 0.31 1.674 − 0.36

Suggest to select: S = 0.4 4）Sensitivity check

Sensitivity check principle : Main transformer high-voltage side of two-phase metallic short-circuit occurs when generator is parallel off: I k . min =

0.866 × S b 0.866 × 100000 = = 1.45 A ( X + X T ) × 3 × 230 × nTA (0.08 + 0.07) × 3 × 230 × 1000 ,, d

I res. min = I k . min = 1.45 A I op = I op.0 + S ( I res − I res.0 ) = 0.225 + 0.4 × (1.45 − 0.36) = 0.661A K sen =

I k . min 1.45 = = 2.19 > 1.5 0.661 I op

5）Setting of second harmonic braking coefficient Suggest to select: 15%

6）Difference current quick brake Select: I op = 5 I b 7）Difference current quick brake sensitivity check

Sensitivity check principle : Main transformer low-voltage side of two-phase metallic short-circuit occurs: Ik =

0.866 × S b 0.866 × 100000 = = 5.08 A X //( X S + X T ) × 3 × 230 × nTA 0.08 //(0.022 + 0.07) × 3 × 230 × 1000 ,, d

K sen =

Ik 5.08 = = 2.26 > 1.2 I op 2.25

8）Output model: Trip all CBs

3. Generator Inter-turn Fault（95G） 3.1 Basic parameter Rated secondary current（ I gn 2 ）

I gn 2 =

PT ratio（ nTV ）

I gn1 nTA

13.8 3

=

7060 = 4.41A 1600 0.1 0.1 3 3

3.2 Setting Calculation 1）Zero-sequence Voltage

Setting by the max unbalanced zero-sequence voltage under the condition of avoid the normal generator rated load. U op = 2V 2) Fault branch negative-sequence direction elements

ε i = 3% I gn 2 = 3% × 4.41 = 0.13 A ε u = 1%U gn 2 = 1% × 110 / 3 = 0.63V

εp =

0.1% Pgn nTV × nTA

= 0.1% × 3 × I gn 2 × U gn 2 = 0.1% × 3 × 4.41 × 100 = 0.76VA

3) Time delay： t = 0.1s 4）Output model: Trip All CBs

4.Generator Inadvertent Energize protection，Stator Earth Fault Protection of startup condition（99V） 4.1 Basic parameter Rated secondary current（ I gn 2 ）

4.41A

Rated secondary voltage（ U gn 2 ）

110V

4.2 Setting calculation 1）Low impedance element setting

Z set =

0.8U gn 2 3 × 0.3I gn 2

=

0.8 × 110 3 × 0.3 × 4.41

= 38.4(Ω )

Rset = 0.85Z set = 0.85 × 38.4 = 32.6(Ω ) 2）Over current element setting

I op = 0.3I gn 2 = 0.3 × 4.41 = 1.32( A ) 3）Stator Earth Fault Protection of startup condition operation voltage

U op = 10V Time delay： t = 2 s 4）Output model Generator Inadvertent Energize protection: Trip 220kV CB & excitation CB Stator Earth Fault Protection of startup condition: Trip excitation CBs。

5. Generator Over-voltage（59G） 5.1 Basic parameter Rated secondary voltage（ U gn 2 ）

110V

5.2 Setting Calculation 1）Operation voltage I:

U op = 1.05U gn 2 = 1.05 × 110 = 115 .5V

II:

U op = 1.1U gn 2 = 1.1 × 110 = 121V

III:

U op = 1.2U gn 2 = 1.2 × 110 = 132V

2）Time delay Select：

t = 30 s I: II: t = 10 s III: t = 0.5s 3）Output model: Trip all CBs

6. Reverse Power Protection（32G）; Low Forward Power Protection（37G） 6.1 Basic parameter Generator rated power（ Pn ）

135WM

Generator rated secondary power（ Pn 2 ）

672.6W

6.2 Setting Calculation 1）Min operation power

Pop = K rel（ P1 + P2 ) = 0.5 × (3% + 1 − 98 .6%) × 672 .6 = 14 .8W Suggest to select： Pop = 10W Therein： K rel is the reliable coefficient，select 0.5~0.8；

P1 is the min loss when steam turbine is in reverse power operation，generally

select 2％~4％ of the rated power； P2 is the min loss when steam turbine is in reverse power operation，generally select

(1 - η )P gn ， Pgn is the rated capacity of generator. 2）Time delay Reverse Power Protection（32G）： t1 = 5s (32G )

t 2 = 60s(32G ) Low Forward Power Protection（37G）：

t = 1s (37G ) 3）Output model Reverse Power Protection（32G）: Time delay t1 : Alarm Time delay t 2 : Trip All CBs Low Forward Power Protection（37G）: Trip All CBs

7. Generator Stator Overload（49G） 7.1 Basic parameter Rated secondary current（ I gn 2 ）

4.41A

allowed heat time constant of stator winding（ K ）

37.5

7.2 Setting calculation 1）Time specified overload

Stator winding time specified over-load can be set by the condition of the long term allowed loading current can reliable return.

I op =

K rel 1.05 × I gn 2 = × 4.41 = 5.14 A Kr 0.9

Therein：

K rel is the reliable coefficient， select 1.05；

Kr is the return coefficient， select 0.9； Time specified overload time delay: t = 9 s 2）Reverse time specified overload

Reverse time specified over-current can be set by the over-load ability allowed by stator winding，it should be determined by the over-load ability allowed by the stator winding of the motor manufacturer. The relation of allowed duration time is :： t=

K I −(1+α ) 2 *

Therein：K is the allowed heat time constant of stator winding，it should be based on the parameter provided by the motor manufacturer；

I * is the per-unit value based on stator rated current； α is the heat radiation constant and related to the stator winding temperature rising and temperature margin，generally select 0.01~0.02. 3）Reverse time specified startup current

Reverse time specified startup current I op . min should be set by the condition of matched with time specified over-load protection：

I op . min = K C 0I op = 1.05 × 5.14 = 5.4 A Therein：

I op

is the set value of time specified startup current； K C 0 is the matching

coefficient，select 1.05。 Reverse time specified delay lower limit: t min = 120 s Reverse time specified delay upper limit current

I op . max

three phase metal short circuit at generator side：

can be set by the condition of

I op. max = t max =

I

Ign 2 4.41 = = 32.7 A X d" 0.135 2 op . max*

K 37.5 = 0.7 s = 2 − (1 + α ) ⎛ 55.1 ⎞ ⎜ ⎟ − (1 + 0.01) ⎝ 4.41 ⎠

4）Output model Time specified overload: Alarm Reverse time specified overload: Programming Trip

8. Generator Negative-Sequence Over-current（46G） 8.1 Basic parameter Rated secondary current（ I gn 2 ）

4.41A

The per-unit value of generator long term allowed negative-sequence current（ I 2∞ ） time constant of withstanding negative-sequence current ability of rotor surface（A）

0.08 P.U .

10

8.2 Setting calculation 1）Time specified overload

The negative-sequence time specified over-load should be set on the condition of under the generator long term allowed negative-sequence current I 2 ∞ can reliable return

I op = K rel Therein：

I 2 ∞ Ign 2 Kr

= 1.05 ×

0.08 × 4.41 = 0.39 A 0.95

K rel is the reliable coefficient， select 1.05； K r is the return coefficient，

select 0.85～0.95；

I 2 ∞ is the per-unit value of generator long term allowed negative-sequence current； Time specified overload time delay: t = 5s 2）Reverse time specified overload

The reverse time specified negative-sequence over-load was confirmed by the allowed negative-sequence over-current ability of the generator rotor surface. The relation mode between the generator short time withstanding negative-sequence over-current multiple and allowed duration time is ：

t=

I 22*

A − I 22∞

Therein：is the per-unit I 2∞

value of generator negative-sequence current；

is the per-unit value of generator long term allowed negative-sequence

current； A is the time constant of withstanding negative-sequence current ability of rotor surface。 Reverse time specified startup current

The reverse time specified startup current I op . min ， generally be set by the operation current in correspondent with specified delay lower limit：

I op . min = I gn 2

delay1000s （ set value of reverse time

A 10 + I 22∞ = 4.41 × + 0.08 2 = 0.56 A 1000 1000

Reverse time specified delay upper limit current I op . max should be set by the condition of main transformer HV side two phase metal short circuit：

I op. max = t min =

Ign 2 4.41 = = 8.38 A X + X G 2 + 2 X t 0.135 + 0.141 + 2 × 0.125 " d

A 10 = = 2.76s 2 I − I 2∞ ⎛ 8.38 ⎞ 2 2 ⎜ ⎟ − 0.08 ⎝ 4.41 ⎠ 2 2*

3）Output model Time specified overload: Alarm Reverse time specified overload: Programming Trip

9. Generator Pole Slipping（78G） 9.1 Basic parameter Generator neutral CT ratio 8000/5=1600 Generator terminal CT ratio 13.8/0.11=125.4 9.2 Setting calculation 1）Reduced generator、transformer、system reactance etc. to the named unit (ohm)value with the generator side voltage is 13.8kV. '

Generator： X d = 0.237 ×

13800 = 0.267(Ω ) 3 × 7060

Main transformer： X t = X k ×

System： X s =

7.8

(220 ÷ 13.8)2

U gn Sn

2

13.8 2 = 0.125 × = 0.132(Ω ) 180

= 0.031(Ω )

X st setting of system relation impedance： X st = X t + X s = 0.132 + 0.031 = 0.163(Ω ) '

2）Reduce X d 、 X t & X st to the secondary side value of generator side TV、TA.：

Xd

'

2

'

= Xd ×

Xt2 = Xt ×

nTA 1600 = 0.267 × = 3 .4 ( Ω ) 125.4 nTV

nTA 1600 = 0.132 × = 1.68(Ω) 125.4 nTV

X st 2 = X st ×

nTA 1600 = 0.163 × = 2.08(Ω) 125.4 nTV

3）Setting lens principal axis obliquity Select system impedance angle : Ψz = 85

0

4）Setting of operation power angle δset

R1. min =

0.9U n 0.9 × 13800 COSϕ = × 0.8 = 0.71(Ω) 3 × 1.15I n 3 × 1.15 × 7060

1.54 RL. min 1.54 × 0.71 δset = 180° − 2arctg = 180 0 − 2arctg = 180 0 − 2 × 68.50 = 430 ′ │X st│+│X d│ 0.163 + 0.267 Suggest to select δ set = 120 0 5）Tripping blocking current setting This protection use generator neutral CT, CT ratio is 8000/5，Main transformer high side circuit breaker rated breaking current is 40kA：

I set = 0.5 ×

40000 230 × = 208A 1600 13.8

Suggest to select I set = 180 A 6）Slipper times setting Outer zone，Slipper times setting:N =4； Inner zone, Slipper times setting:N =1（#1Generator）、2（#2 Generator）、3（#3 Generator）、4（#4 Generator）。 7）Reactance line position Z C

Z C = 0.9 X t 2 = 0.9 × 1.53 = 1.377(Ω) 8）Startup current

I st = 1.2 I n 2 = 1.2 × 4.41 = 5.3( A) 9）Time delay Outer zone :0.5s Inner zone :0.1s 10）Output model Outer zone :Alarm Inner zone :Trip all CBs

10. Generator loss of excitation protection（40G） 10.1 Basic parameter Generator neutral CT ratio 8000/5=1600 Generator terminal CT ratio 13.8/0.11=125.4 10.2 Setting calculation Reduced generator、transformer、system reactance etc. to the named unit (ohm)value with the generator side voltage is 13.8kV. Generator： X d = 2.065 ×

'

X d = 0.237 ×

13800 = 2.33(Ω ) 3 × 7060

13800 = 0.267(Ω ) 3 × 7060

Main transformer： X t = X k ×

System： X s =

U gn Sn

2

= 0.125 ×

13.8 2 = 0.132(Ω ) 180

7.8 = 0.031(Ω ) (220 ÷ 13.8)2

X st setting of system relation impedance： X st = X t + X s = 0.132 + 0.031 = 0.163(Ω ) As X d = X q ，Salient pole power equal 0W。 1）Set of static and stable boundary impedance

Z 1B = X d ×

nTA 1600 = 2.33 × = 29.7(Ω ) 125 .4 nTV

Z 1 A = X st ×

nTA 1600 = 0.163 × = 2.1(Ω ) 125 .4 nTV

2）Set of stable asynchronous impedance

Z 2B = X d ×

nTA 1600 = 2.33 × = 29.7(Ω) 125.4 nTV

Z 2 A = 0.5 X ' d ×

nTA 1600 = 0.5 × 0.267 × = 1.7 ( Ω ) 125.4 nTV

3）Set of generator terminal low voltage

U st = 0.8U n 2 = 0.8 × 110 = 88(V ) 4）Time delay Select t1=1.5S 、t2=1.5S 、t3=3S 5）Output model loss of excitation zone 1: Alarm； loss of excitation zone 2: Trip all CBs； loss of excitation zone 3: exit；

11. Generator Under & Over Frequency（81G） 11.1 Basic parameter

Generator under & over frequency capability tables provided by the equipment manufacturing factor: Allow run-time Frequency（Hz）

accumulated

Each

time (min)

time(s)

51.0 < F ≤ 51.5

30

30

50.5 < F ≤ 51

180

180

48.5 < F ≤ 50.5 48 < F ≤ 48.5

Run Continuously 300

Allow run-time Frequency（Hz） accumulated

47.5 < F ≤ 48 47 < F ≤ 47.5

46.5 < F ≤ 47

300

11.2 Setting calculation 1）Under frequency zone I under-frequency zone I frequency setting： f1.set = 48.5 Hz under-frequency zone I accumulated time： ∑ t1.set = 18000s under-frequency zone I time delay： t1.set = 300 s 2）Under frequency zone II under-frequency zone II frequency setting： f 2.set = 48 Hz under-frequency zone II accumulated time： ∑ t 2.set = 3600s

Each

time (min)

time(s)

60

60

10

20

2

5

under-frequency zone II time delay： t 2.set = 60 s 3）Under frequency zone III under-frequency zone III frequency setting： f 3.set = 47.5 Hz under-frequency zone III accumulated time： ∑ t 3.set = 600 s under-frequency zone III time delay： t 3.set = 20 s 4）Under frequency zone IV under-frequency zone IV frequency setting： f 4.set = 47 Hz under-frequency zone IV time delay： t 4.set = 20 s 5）Over-frequency over-frequency setting： f set = 51Hz over-frequency time delay： t set = 30 s 6）Generator terminal low voltage setting， U set = 0.8U n = 88V 7）Output model: Programming Trip

12. Generator Over Fluxing（24G） 12.1 Basic parameter

Generator over excitation capability tables provided by the equipment manufacturing factor: Stator voltage/Frequency

1.25

1.19

1.15

1.12

1.10

1.09

1.08

1.07

Time(sec)

5

7.5

10

15

20

30

45

60

12.2 Setting calculation 1）Time specified over fluxing Over fluxing times: N 0 = 1.06 , time delay: t 0 = 5s Select rated voltage as reference voltage 110V。 2）Reverse time specified over fluxing Over fluxing times: N1 = 1.07 ，time delay: t1 = 60 s Over fluxing times: N 2 = 1.08 ，time delay: t 2 = 45s Over fluxing times: N 3 = 1.09 ，time delay: t 3 = 30s Over fluxing times: N 4 = 1.10 ，time delay: t 4 = 20 s

1.05 ∞

Over fluxing times: N 5 = 1.12 ，time delay: t 5 = 15s Over fluxing times: N 6 = 1.15 ，time delay: t 6 = 10 s Over fluxing times: N 7 = 1.19 ，time delay: t 7 = 7.5s Over fluxing times: N 8 = 1.25 ，time delay: t8 = 5s 3）Output model: Trip all CBs

13. Generator Under-voltage（27G） 13.1 Basic parameter Generator terminal PT ratio：

13.8 3

0.11 0.11 3 3

13.2 Setting calculation

U set = 0.6U n = 66V Time delay: 0.5s 13.3 Output model: Alarm

14. Stator Earth Fault 100%（64G1） 14.1 Basic parameter

13.8 / 0.3kV

Neutral earthing transformer ratio Neutral earthing transformer secondary resistance

( Rn )

1.3Ω

Neutral earthing transformer primary resistance ( RN )

2750.8Ω

Neutral earthing transformer secondary CT ratio( nTA 0 )

100 / 1

Generator 3 relative capacitance ( 3C0 )

1.392µF

Generator capacitive reactance ( X C 0 )

6860Ω

14.2 Setting calculation 1) earthing resistance

The setting of earthing resistance low set value should be set by the principle of one point earthing in the distance within 20% of generator neutral, the earthing fault point current 3I0 ≤ safe earthing current Is(1A). Means： 3I 0 =

0.2 × 3U gn

3

3Rg + 3RN //(− jX C 0 )

≤ IS

0.2 × 3U gn

3

3Rg .set + 3RN //(− jX C 0 )

= IS

0.2 × 3 × 13800 3 =1 3Rg .set + 3 × 2750.8 //( − j 6860)

R g .set = 5.2kΩ Suggest to select： Earthing resistance high value: Rhg .set = 10kΩ Earthing resistance low value: Rlg .set = 5kΩ Time delay: high value time delay:3s low value time delay:0.5s

I 50.set =

α ×U 2n Rn × K I × nTA 0

=

0.2 × 300 = 0 .5 A 1.3 × 1.1× 100

Therein α can generally be selected as 20％； K I is the reliable coefficient， generally select 1.1. 2) Output model high value : Alarm low value : Trip all CBs

15. Stator Earth Fault 100%（64G2） 15.1Basic parameter Generator terminal PT ratio：

Generator neutral PT ratio：

13.8 3

0.1 0.1 3 3

13.8 0.1 3

15.2 Setting calculation Setting value by the protection device according to measured data Time delay : 5s 15.3 Output model: Alarm

16. Stator Earth Fault 95%（64G3） 16.1 Setting calculation

The fundamental wave zero-sequence voltage has two sections protection including high value and low set value. Principle ,the low setting value zero-sequence voltage should be set by the max

unbalance fundamental wave zero-sequence voltage of neutral single phase voltage transformer when normal operation or three phase voltage transformer open triangle winding at generator side. The setting value applied in the project should avoid the max zero-sequence unbalance voltage that transmitted to the generator side when system HV side and plant transformer LV side earthing short circuit. The setting of high set value zero-sequence voltage is 20～30V. ，According to the Suggest to select: U op. H = 20V （high value），U op.l = 10V （low value） measured maximum value of zero sequence voltage imbalance adjustment 。 Time delay: High value: 0.1s Low value: 0.3s 16.2 Output model High value: Trip all CBs Low value: Trip all CBs

17. Field Winding Earth Fault(（64F） Non-electrical，time delay is setting by the owner

18. Generator 95% Voltage Check（59GB） 18.1 Basic parameter rated secondary voltage（ U gn 2 ）

110V

18.2 Setting Calculation 1）Operation voltage

U op = 0.95U gn 2 = 0.95 × 110 = 104V 2）output model: Alarm

19. Back Up Impedance（21G） Based on actual engineering experience, this protection is valueless ,we suggest don’t use it. 19.1 Basic parameter Generator neutral CT ratio 8000/5=1600 Generator terminal CT ratio 13.8/0.11=125.4 19.2 Setting calculation 1）Reduced generator、transformer to the named unit (ohm)value with the generator side voltage is 13.8kV. '

Generator： X d = 0.221 ×

13800 3 × 7060

Main transformer： X t = X k × '

U gn Sn

2

= 0.25(Ω )

13.8 2 = 0.125 × = 0.132(Ω ) 180

2）Reduce X d 、 X t to the secondary side value of generator side TV、TA.：

Xd

'

2

'

= Xd ×

Xt2 = Xt × 3）

nTA 1600 = 0.25 × = 3.19(Ω) 125.4 nTV

nTA 1600 = 0.132 × = 1.68(Ω) 125.4 nTV '

Rset1 = X d 2 × 1.2 = 3.83(Ω)

Rset 2 = X t 2 × 1.2 = 2.01(Ω) 20. TV Fuse-failure（160G） 21.1 Basic Parameter rated secondary current（ I gn 2 ）

4.41A

21.2 Setting Calculation Blocking current： I set = 1.2 I gn 2 = 1.2 × 4.41 = 5.3( A)