siemens - distance protection power swing

7/29/2019 SIEMENS - Distance Protection Power Swing

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Siemens AG 2006

Distance Protection Power Swing

Power Transmission

and Distribution


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Page 2 Symmetrical Components

Siemens AG 2006

Power Transmission and Distribution

Power swing:

Voltage diagram

LZS1 LZL LZS2

E2 = E'2E1UA UB

U'B

U'A

'L L

' E'1

E1 E2ZS1 ZS2ZL

UA UB

Two Machine Problem

If the angle becomes too large, the system stability can be lost


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Siemens AG 2006


Power swing locus and relay characteristic

in the impedance diagram

E1 = E2

E1 > E2

E1 < E2

X

R

ZS2

B

ZL

A

ZS1

ZLoad

'

load point


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Siemens AG 2006


Dynamic system stability, equal area criterion

ZS1

U1

E1

U2

E2ZS2

ZL

ZL

D PTP = sinE1 E2

XT

1

D

2

D

3

D

A

C

1

3

2

1

2

30

4

5

6

0 1 20 90 180

PT

P

B


5/12Page 5 Symmetrical Components

Siemens AG 2006


56

1

34

X

RZload

ZS1

ZS1

ZL

2

2

0

0

Power swing locus in the impedance plane



Siemens AG 2006


Power swing detection: Classic Method

(Not used in 7SA52 and 7SA6)

Classic power swing detection

is restricted to slow swings

The setting ofZ may not be too large

to avoid load encroachment (typ. 5 )

During fast swings the time available(t) for detection of impedance vector

in the power swing zone is too short.Z

t = time for transition of Z from outer to inner zone



Siemens AG 2006


Advanced Power swing blocking techniques

(7SA513, 7SA522, 7SA6)Novel space vector based principle

Self-setting

Small Z (1 Ohm at In=5 A)

Blocking up to high slip frequencies (7 Hz)

Recognition of all fault types during swing

Remains effective during single pole ARCopen time (3-phase set-up)

dZ/dt measurement

Calculation of swing centre

and plausibility check

(+90O<



Siemens AG 2006


Power Swing detection: New method

dR

dX

(k-n)

(k-n)

dR(k)dX(k)

Power swingX

R

Fault entry

Faultimpedance

Load

impedance

Transition from load to fault is fast

Power swing transition is slow

Continuos monitoring of the impedance trajectory

Monitoring of trajectory continuity

Monitoring of trajectory velocity

Evaluation of trajectory ellipse



Siemens AG 2006


Example:

i/kA

t/ms500

u/kV

t/ms500

200

-3

6

3

R

A ZA a Zl b ZB B

~ ~ ~ ~ ~

Evaluation of the power swing process

Power swing

locus(EA>EB)

-90O

180O

0O

90OXm

Slip

frequency

EBEARelay

Relay


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Siemens AG 2006


Novel power swing detection provides secure

operation with swing frequencies of up to 7 Hz

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

iL1/A

-4

-2

0

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

iL2/A

-2

0

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

iL3/A

-2

0

2

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

uL1/V

-50

0

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

uL2/V

-50

0

50

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

uL3/V

-50

0

50

t/s0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

DisTRIP3p Z1Bmf

Relay TRIP

Relay PICKUP

Dis. reverse

Dis. forward

Dis.T.SEND>DisTel Rec.Ch1

Power Swing

Example:400 kV400 kmfPS 2 Hz3-pole fault


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Siemens AG 2006


Fault detection during power swing

I1

I2

V1

Trip

The Power swing passes through

the trip characteristic several times.

Single phase fault is detected andcleared.


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Siemens AG 2006


Three phase fault during Power Swing

Three phase fault during power swing

is detected and cleared

Fault inception while swing is inside

trip characteristic

I1

V1

V2

V3

Trip

siemens - distance protection power swing

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