Oscillography analysis

Oscillography AnalysisOscillography Analysis

Oscillograph Analysis

IPSplot® PLUS Software

Features

Phasor & Time Domain Displays

Interpreting Data

Examples

Oscillography Analysis

Waveform Capture (Legend)

B C D

K NMLIG H

J

A

E

F


A) All analog traces. This view shows peak values. RMS values may also be displayed.

B) Controls for going to the beginning or end of a record, as well as nudging forward or backward in time in a record.

C) Zoom controlsD) Display controls for analog

traces, RMS traces, fundamental waveform display, frequency trace, power trace, power factor trace, phasor diagram, impedance diagram and power diagram.

E) Marker #1F) Marker #2G) Time at Marker #1H) Time at Marker #2I) Control status input and

contact output traces (discrete I/O)

J) Scaling for each analog trace. This can be set automatically or manually adjusted.

K) Date and timestamp for record

L) Time of trip commandM) Time at Marker #1N) Time at Marker #2


Waveform Capture (Legend)

PQ

R

O

S


O) Drop down window for view selection, diagram selection and zoom.

P) Delta value between Marker #1 and Marker #2

Q) Value at Marker #1

R) Value at Marker #2

S) Scaling for each analog trace. This can be set automaticallyor manually adjusted.


Waveform Capture (Phasor)


M-3311 Differential Function Tripped when Generator

Breaker ClosedDuring Relay Commissioning



M-3311

Winding 3

Winding 2

Winding 1

Delta-ac

60:1

600:1

600:1

M3311 One Line


Target ListIPScom: Version V02.01.03

Relay: M3311/V01.05.00Comments:

No. Date Time Event(s)----------------------------------------------------------------------------------------------------

02-Jul-2005 09:37:08.000 1 (87T) Phase Differential Current - Phase B Operated INPUTS: OUTPUTS: 1

W1 Currents: 1.36 A (A), 1.39 A (B), 1.44 A (C) W2 Currents: 0.03 A (A), 0.05 A (B), 0.04 A (C), 0.00 A (N) W3 Currents: 0.82 A (A), 0.81 A (B), 0.83 A (C), 0.01 A (N)


M-3311

Winding 3

Winding 2

Winding 1

Delta-ac

60:1

600:1

600:1

M3311 One Line

67.2MVA230kV / 13.8kVWye / Delta-ac

Relay System Setup Screen

Wye connected CT's

Transformer Rating


87 Trip Oscillography

No rolled phases on Winding 1

No rolled phases on Winding 3

Currents are out of phase


87 Function Settings

CT Tap Settings


M-3311

Winding 3

Winding 2

Winding 1

Delta-ac

60:1

600:1

600:1

M3311 One Line

Winding 1 Phase A Current = 1.36APer Unit Current = 1.36A / Winding 1 TapPer Unit Current = 1.36A / 4.7 = 0.29pu

Winding 3 Phase A Current = 0.82APer Unit Current = 0.82A / Winding 3 TapPer Unit Current = 0.82A / 2.81 = 0.29pu

67.2MVA230kV / 13.8kVWye / Delta-ac

Winding 1 Tap Winding 3 TapWinding 2 Tap

CTR = 600:1 CTR = 600:1 CTR = 60:1

Tap1 = Tap3 =Tap2 =

x 600Tap1 =

13.8 x 367.3 x 1000

x 60Tap3 =

230 x 367.3 x 1000

x 600Tap2 =

13.8 x 367.3 x 1000

4.69 4.69 2.81

Calculate Winding Tap Settings

Target ListIPScom: Version V02.01.03

Relay: M3311/V01.05.00Comments:

No. Date Time Event(s)----------------------------------------------------------------------------------------------------

02-Jul-2005 09:37:08.000 1 (87T) Phase Differential Current - Phase B Operated INPUTS: OUTPUTS: 1

W1 Currents: 1.36 A (A), 1.39 A (B), 1.44 A (C) W2 Currents: 0.03 A (A), 0.05 A (B), 0.04 A (C), 0.00 A (N) W3 Currents: 0.82 A (A), 0.81 A (B), 0.83 A (C), 0.01 A (N)

Tap1 = 4.70

Tap2 = 4.70

Tap3 = 2.81


87 Trip Phasor Diagram

Winding 1phase A current

Winding 3phase A current

Winding 3 relay input currentLags Winding 1 relay input

current by 210 degrees


67.2MVA230kV / 13.8kV

M-3311

Winding 3

Winding 2

Winding 1

Delta-ac

60:1

600:1

600:1

M3311 One Line

All CT's are wye

Wye / Delta-ac TransformerHigh side currents lead low side

currents by 30 degrees

Resulting relay currents taking CTpolaritiy into account,

Winding 3 currents lag Winding 1currents by 150 degrees

IH

IL

IH

IL

IW3

IW1

M3311 Relay Application

IW3

IW1

150 degrees


IW3

IW1

150 degrees

Vector angle shouldbe 150 degrees

Vector angle is 210 degrees

Assume transformer isactually a Delta -ab High

"LAGS" low by 30 degrees

IH

IL 30 degrees

IW3

IW1

210 degrees

Relay Currents


H1 X1

H2 X2

H3 X3

C

B

A a

b

c

IB

IA

Ic -Ia

Ib -Ic

Ia -IbIa

Ib

Ic

W3A = 0.82A W1A = 1.37A

W3C = 0.82A

Winding 1Winding 3

IA

IBIC Ic -IaIb -Ic

Ia -Ib

W3C = 0.82A -60

W3A = 0.82A 180 W1A =1.37A 30

Actual Transformer 3-Line


W1A =1.37A 30

W3C = 0.82A -60

W3A = 0.82A 180- W3C

W3A - W3C

0.82/2.81=0.29pu

0.82/2.81=0.29pu

IA-IC =

Convert to Per UnitW3A = 0.82A 180

W3C = 0.82A -60180

-60

Convert to Delta-ac

1800.29pu -600.29pu-3

150= 0.29pu

=

1.36/4.69=0.29pu 30

Convert to Per Unit

Calculate IDIFF & IRes

IDIFF= IAW1 +IAW2 +IAW3

1500.29pu 30 + 0 + 0.29pu=

0.29pu 90

M3311 with Delta-ac Configuration

IDIFF

W3A - W3C

W1A

W1A =1.37A 30

IDIFF =

IRES = IAW1 +IAW2 +IAW3

0.29pu + 0 + 0.29pu=2

2IRES = 0.29pu

M-3311


W1A =1.37A 30

W3B = 0.82A 60

W3A = 0.82A 180

- W3B

W3A - W3B

IDIFF = 0

W3A - W3B

W1A

W1A =1.37A 300.82/2.81=0.29pu

0.82/2.81=0.29pu

IA-IB =

Convert to Per UnitW3A = 0.82A 180

W3C = 0.82A 60180

60

Convert to Delta-ab

1800.29pu 600.29pu-3

210= 0.29pu

=

1.36/4.69=0.29pu 30

Convert to Per Unit

Calculate IDIFF

IDIFF= IAW1 +IAW2 +IAW3

2100.29pu 30 + 0 + 0.29pu=

0.0

M3311 with Delta-ab Configuration

IDIFF =

IRES = IAW1 +IAW2 +IAW3

0.29pu + 0 + 0.29pu=2

2IRES = 0.29pu

M-3311


Current was below 0.3 pu Pickup Setting

Was Trip Correct?

Why Only Phase B Differential?

Why not Phase A, B, and C?


M-3430 “40” Function Tripped Unit


M3430 Application One Line

1000:1

M-3430#1

M-3430#2

1000:1

120:1

M-3430#2 40Function tripped

88MVA

13.2kV


Oscillography


Expanded Oscillography


Phasor Diagram


PQ Plot


Impedance Plot


M-3430 “40” Function Setting (both relays)


- 5

- 10

- 15

- 20

- 25

- 30

5 10 15

5

- 5

X

R

>

>14.2

- j11.7

M-3430 Relay Loss of Field Operation40 Function SettingsOffset = -1.6 ohmZone 1 = 18 ohm, 5 cycleZone 2 = 30.2 ohm, 30 cycle

Impedance= 14.2 -j11.7


Was it a Correct Trip?

Zone 2 Time Delay was set at 30 cycles. Why did it take 90 Cycles to Trip?

Why did only 1 Relay Trip?

M-3310 Differential Function Tripped for

External Phase C Ground Fault



150/200/250MVA352kV / 15kV

M-3310

Winding 1

Winding 2Delta-ac

600:1

2400:1

All CT's are wye

IH

ILIH

IL

IW1

IW2

M3310 Relay Application

IW1

IW2

150 degrees

Phase C-g Fault

Line Relay 67G also tripped


87 Trip Oscillography


Sequence NetworksXG1 XT1

XXS1

XG2 XT2X

XS2

XG0 XT0X

XS0

VG VS

IT0 IS0

IS2IT2

IT1 IS1


Auto Scale & Voltages Removed

Oscillography AnalysisPhasor Pre fault

Oscillography AnalysisPhasor Post fault


System Setup Screen 87 Function Setup Screen


0.5

0.5

2.5

2.0

1.0

1.5

1.0 1.5 2.0 2.5 3.0

87 Slope Characteristic

ID

IR

BP = 1.0

Pickup = 0.27 pu

M1 = 27%

M2 = 60%

Phase A

Phase B

Phase C

IA Diff = W1(I a - I c) + W2I a

IC Diff = W1(I c - I b) + W2I c

IB Diff = W1(I b - I a) + W2I b


Expanded Phase A Scale

Waveshape Suspicious


Phasor Expanded Phase A Scale

Check Current Sum:IA + IB +IC = -IG


Check Current Sum:IA + IB +IC = -IG

Calculated IG = 15.19 -143.6 = 19.4 -147.0

IA + 1.97 11 12.66 43 - 19.4 -147+ =

IA 5.3 17.2=


Recalculated Differential Currents

IDIFF= IAW1(AC) +IAW2

571.38pu 240 + 1.34pu=

0.08 puIDIFF =

IRES = IAW1 (AC) + IAW2

1.38pu + 1.34pu=2

2IRES = 1.36pu

IDIFF= IBW1(BA) + IBW2

250.58pu -21.3 + 0.55pu=

0.04 puIDIFF =

IRES = IAW1(BA) +IAW2

0.58pu + 0 + 0.55pu=2

2IRES = 0.57pu

Phase A Phase B


0.5

0.5

2.5

2.0

1.0

1.5

1.0 1.5 2.0 2.5 3.0

87 Slope Characteristic

ID

IR

BP = 1.0

Pickup = 0.27 pu

M1 = 27%

M2 = 60%

Phase A

Phase B

Phase C

IA Diff = W1(I a - I c) + W2I a

IC Diff = W1(I c - I b) + W2I c

IB Diff = W1(I b - I a) + W2I b

With Calculated W1APhase APhase B

Oscillography analysis

Engineering

Transcript of Oscillography analysis