Template For Micom P746 Bus Bar Differential Protection Calculation

SETTINGS

Independent bar IloadMin (1 feeder) IloadMax (1 CT) ILoadMax (1 bar) Biggest PW Icc min (1 bar) VT criteria ? (Y/N)

2 100 A 1500 A 3000 A 2000 A 2500 A N

ID>1 = k1 (ID>1) = ID>2 = k2 (ID>2) = IDCZ>2 = kCZ = Box mode Phase Comp =

Recommended 80 A 10 % 2000 A 60 % 2000 A 30 % 1 32 %

10

80 10% 1800 60% 1800 30% 27%

Idiff / ILoadMax

DATA

% of In

Fill in "CTRatio" page

CHECK LIST Minimum

Maximum

40

OK

ID>1 = 80

or

1500 1800

OK OK

ID>2 = 2000

or

1500 1800

OK OK

0.10

OK

IDCZ>2 = 2000 kCZ = 0.30

OK

80

9 8 7 6 5 4 3

OK

2000

OK

2000

OK

0.30

2 1 0 0

1

2

3

4

5

6

Ibias x ILoadMax

or 2% of the Biggest PW < 1.2 x IloadMax (1CT) (or use VT) < 1.2 x IloadMax (1CT) (or use VT) <

ID>1 = ID>2 = IDCZ>2 =

< < <

0.8 x IloadMin min of (2 x IloadMax & 0.5 (or 0,8) x Icc min) min of (2 x IloadMax & 0.5 (or 0,8) x Icc min)

ID>1 = 0.05 x ILoadMax ID>2 = 1.33 x ILoadMax IDCZ>2 = 1.33 x ILoadMax

7

8

9

10

k (ID>1) <

kCZ =

<

Icc min (1 bar) / (((Independant bar - 1) x IloadMax (1 bar)) + Icc min (1 bar)) See Check Zone Slope calculation.doc for further details In the event of a half-breaker scheme: see Setting Guide

Busbar (100%) ID>1 30 60 ID>2 IDCZ>2

9

10

ONE box mode

CT Ratio Z1 Infeeds Z2 Infeeds Z3 Infeeds Z4 Infeeds

CTs of the biggest Zone 1 then 2 then 3 then 4 CT 1 CT 2 CT 3 CT 4 CT 5 CT 6 CT 7 2000 2000 2000 1500 1000 1000 1000 2000 2000 0 0 1000 1000 0 0 0 2000 1500 1000 0 1000 0 0 0 0 0 0 0 0 0 0 0 0 0 0

sum. In CTs infeeds Phase Comp. CT 1 to 7 ID>2 2000 6000 27% Zone 1 5500 29% Zone 2 0 100% Zone 3 0 100% Zone 4 27%

Note 1: For the feeders that can not contribute to the external fault (load only) put 0

THREE box mode

CT Ratio Z1 Infeeds Z2 Infeeds Z3 Infeeds Z4 Infeeds

CTs of the biggest Zone 1 then 2 then 3 then 4 (when ex CT 1 CT 2 CT 3 CT 4 CT 5 CT 6 CT 7 CT 8 CT 9 CT 10 CT 11 CT 12 2000 2000 2000 2000 2000 2000 1500 1500 1500 1500 1500 1000 2000 2000 0 0 0 2000 1500 0 1500 0 1500 1000 0 0 2000 2000 0 2000 1500 1500 0 0 1500 1000 0 2000 2000 0 2000 0 1500 1500 0 0 1500 1000 0 2000 0 2000 2000 2000 1500 1500 0 0 1500 1000

Note 1: For the feeders that can not contribute to the external fault (load only) put 0

Zone 1 Zone 2 Zone 3 Zone 4

en 2 then 3 then 4 (when existing) CT 13 CT 14 CT 15 CT 16 CT 17 CT 18 CT 19 1000 1000 1000 1000 1000 1000 1000 0 1000 0 1000 0 0 0 0 1000 1000 1000 0 0 0 0 0 1000 0 1000 0 1000 1000 1000 0 0 0 1000 0

CT 20 1000 1000 1000 1000 0

CT 21 1000 0 1000 0 1000

sum. In CTs infeeds Phase Comp. Feeder 1 to 7 ID>2 2000 14500 11% Zone 1 16500 10% Zone 2 15500 10% Zone 3 17500 9% Zone 4 9%

DATA

Bias limit =

2000 /1 2640

10 Idiff / ILoadMax

CT ratio

TRIPPING CHARACTERISTIC WITH 1 infeed

9 8 7 6 5 4 3 2 1 0 0

1

2

3

4

5

6

Ibias x ILoadMax

=2*IdiffIbias!G11/100/(1-IdiffIbias!G7/100)*C4

7

8

9

10

ARACTERISTIC WITH 1 infeed & 1 outfeed

Busbar (100%) ID>1 30 60 ID>2 IDCZ>2 Phase Comparison limit

4

5

6

s x ILoadMax

7

8

9

10

k1 (ID>1) = k2 (ID>2) = kCZ =

0.1 0.6 0.3

Ibias

100% 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10

Outgoing current threshold Bias limit =

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10

ID>1 = Slope ID>1 0.05 0.00 0.05 0.05 0.10 0.10 0.15 0.15 0.20 0.20 0.25 0.25 0.30 0.30 0.35 0.35 0.40 0.40 0.45 0.45 0.50 0.50 0.55 0.55 0.60 0.60 0.65 0.65 0.70 0.70 0.75 0.75 0.80 0.80 0.85 0.85 0.90 0.90 0.95 0.95 1.00 1.00

0.64 2.64

IDCZ>2 = Slope IDCZ>2 1.33 0.00 1.33 0.15 1.33 0.30 1.33 0.45 1.33 0.60 1.33 0.75 1.33 0.90 1.33 1.05 1.33 1.20 1.35 1.35 1.50 1.50 1.65 1.65 1.80 1.80 1.95 1.95 2.10 2.10 2.25 2.25 2.40 2.40 2.55 2.55 2.70 2.70 2.85 2.85 3.00 3.00

ID>2 = 1.33 1.33 1.33 1.33 1.33 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80 5.10 5.40 5.70 6.00

Slope ID>2 0.00 0.30 0.60 0.90 1.20 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80 5.10 5.40 5.70 6.00

Phase Comparison limit 1.33 1.33 1.33 1.33 1.33 1.50 1.95 2.42 2.90 3.38 3.87 4.35 4.84 5.33 5.83 6.32 6.81 7.31 7.80 8.30 8.80