Diagnosis

of High Voltage Equipments

Suwarno

Institut Teknologi Bandung

2011

Beban (stress) yang penyebab penuaan

isolasi peralatan tegangan tinggi

Thermal Temperatur maksimum, gradien temperatur

Electrical Tegangan/medan , arus, frekuensi

Ambient Kelembaban, gas, radiasiUV, zat kimia

Mechanical Kompresi, vibrasi

LifeExtension:maintenance,

repair

SAFETY

MARGIN

LEVEL

KRITIS

NORMAL PENURUNAN KINERJA GANGGUAN

WAKTU

GAGAL

Lifetime cycle

Maintenance Strategy

Breakdown maintenance

Time based maintenance (TBM)

Condition based maintenance (CBM)

Reliability Centered Maintenance (RCM)

Cable GIS Generator Transformer

Partial Discharge

Internal Surface Corona

Partial Discharge

PD Signal Sensor Application

Gelombang EM Elektroda UHF, Antena GIS, Switchgear,

Saluran udara

Tegangan dari

impuls arus

Coupling Capacitor Mesin listrik, kabel

Arus Impuls Transformator arus

frekuensi tinggi (HF CT)

Kabel, transformator

Suara/

Vibrasi

Sensor Ultrasonic (AE) Transformator, GIS

Cahaya Sensor Pockels

UV (Corona) camera

GIS , isolator,

transformator

Panas IR Camera Isolator, Mesin listrik

Partial Discharge

LATAR BELAKANG

Partial Discharge (PD) dapat muncul pada

isolasi padat

PD menyebabkan degradasi isolasi

Diagnosis kondisi

Bentuk gel. PD

1 10 ns

INS.

VOID

Elektron

Ion

Rangkaian ekivalen Void

Whitehead

Cm

Cg

Cb

ELEKTRODA

VOID

LDPE

ELEKTRODA

Munculnya Void

1. Fabrikasi : Cross Linking

2. Instalasi : jointing

3. Operasi: short circuit

Persamaan-persamaan

)()( tVxCC

CtV

bg

bg

Muatan PD pada void : Qg = Cg . Vg

bg

bgmbmg

a

bg

bg

ma

CC

CCCCCCC

CC

CCCC

.

Tegangan Void

Kapasitansi total

Discharges in gas

1 10 ns

INS.

VOID

Tegangan-arus PD

Hubungan tegangan arus

Quantities Sensor type Application

EM wave UHF Electrode, Antenna GIS, Switchgear, OH Lines

Voltage Coupling Capacitor Rotating Machines, Cables

Current RF CT Cable

Sound/Vibration Ultrasonic sensor (AE) Transformer, GIS

Light Pockels sensor GIS

PD Detection

Capacitive Detector of PD

t

d

d dttiC

tV0

)(1

)(

Rk

Cp

Rd

Cd

Vd

Ca

Proportional to q

19

Spektrum Gelombang

Elektromagnetik

PD

Visual Electrical Discharge Activity Observations

Water Drop

Corona

Spot Corona /

Discharge

Dry Band Corona Dry Band

Discharge

CoroCAM Mark I

Example: HV CABLE

1. Conductor

2. Conductor Screen

3. XLPE Insulation

4. Insulation Screen

5. Lead Alloy Sheath

6. Copper Screen

7. Water Blocking Tape

8. Bedding

9. Armouring

10. Outer Sheath

ProtrusionVoid

Stator generator

PD Coupler

Overhead Lines & Outdoor insulators

Corona & surface discharges

Isolator surface discharge &

Flashover

Appearance of defects

1. Fabrication : Cross Linking

2. Installation : jointing

3. Operation: short circuit

ri 2

Lines of electrical field

Semicon layer protrusion

(Stress concentration at the tip)

Void

(Field strength doubling)

Protrusion on the inner semiconducting layer of an HV cable. The electric strength at the tip of the protrusion is estimated to be 1,100 kV/mm

r

dr

VEm 4

ln

2Local field enhancement

Em: maximum field

V : voltage

r : radius of protrusion

d: electrode separation

No treeing Early stage

Growing tree

DEVELOPMENT OF ELECTRICAL TREEING

Treeing equivalent circuit

(2.4)

tVCC

CV

bg

b

g

dt

tdVtV

CC

CCRV

bg

bg

R

Energy released by a discharge

Heat

Light emission

Chemical

processes

Mechanical

waves

Discharge

Current in external

circuit

Elektromagnetic

radiation

Reference or Validation : CIGRE TF 15.01.04 paper 15-302 Paris Session 2000

Elektroda CIGRE II untuk Void

RANGKAIAN PENGUKURAN

PD

Detector

HV Source

Sample

Wave

detector

PD

Analyzer

TDSSwitch PC

1. Osiloskop Digital TDS 220

2. Personal Computer Pentium II

3. RC Detector dan High Pass Filter

4. Arrester ( dipasang di channel 1 pada osiloskop )

PD pada Void rH 56 %

-10000

-8000

-6000

-4000

-2000

0

2000

4000

6000

8000

10000

Sudut Phasa [deg.]

Mu

ata

n P

D [p

C]

56%.rH

PD pada Void rH 92%

-10000

-8000

-6000

-4000

-2000

0

2000

4000

6000

8000

10000

Sudut Phasa [deg.]

Mu

ata

n P

D [p

C]

92%.rH

BESARAN PD

Muatan (q) [pC]

Sudut phasa terjadinya(q) [der.]

Banyaknya kejadian (n) [per siklus]

DISTRIBUSI PD

q-q-n

q-q

q-n

Muatan Maksimum

0

5000

10000

15000

20000

25000

30000

35000

0 10 20 30 40 50 60

Waktu [menit]

Mu

ata

n M

ak

sim

um

PD

[p

C]

Pos Neg Pos. Neg.

Jumlah PD per siklus

0

5

10

15

20

25

0 10 20 30 40 50 60

Waktu [menit]

Jum

lah

pu

lsa

PD

pe

r s

iklu

s

Pos.Neg.

[Pos.][Neg.]

Pengaruh tegangan thd q

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

0 1 2 3 4 5 6 7

Tegangan [kV rms]

Mu

ata

n P

D M

aks

imu

m [

pC

]

Pos. Neg. [Pos.] [Neg.]

No Sumber PD

Waktu antar

Kejadian PD

Rata-rata (ms)

Polaritas

1 Pemohonan

Listrik 2

Positif

dan

Negatif

2

Void 0.4

Positif

dan

Negatif

3 Korona 0.1 Negatif

Tipikal karakteristik urutan waktu PD

Frekuensi PD

Muatan PD

Polaritas

Pengaruh tegangan sisa

Beberapa perbandingan

0 60 120 180 240 300 360-100

-75

-50

-25

0

25

50

75

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-125

-100

-75

-50

-25

0

25

50

75

100

125

PD

Charg

e[p

C]

Phase Angle [deg.]

Inisiasi Aging Menjelang gagal

Electrical treeing mengeluarkan partial discharge

Pola Partial Discharge dapat menjadi indikasi

degradasi isolasi kabel

PD Parameters

Charge (q) [pC]

Phase of occrurrence(q) [deg.]

Number of envent (n) [per cycle]

PD Wave shape

PD distribution

q-q-n

q-q

q-n

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

P

D C

harg

e[p

C]

Phase Angle [deg.]

a.Treeingb. Void

c.Corona

Typical q-q-n patterns (a) treeing,

(b) void (c) corona

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

P

D C

harg

e[pC

]

Phase Angle [deg.]

0 60 120 180 240 300 360-75

-50

-25

0

25

50

75

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

PD

Charg

e[p

C]

Phase Angle [deg.]

PD Pulse Sequence

Treeing Void

Corona

Frequency of PD

PD Charge

Polarity

Effects of residual voltage

Statistical analysis

Trending

Analysis of PD data

Statatistical parameters

t

Nt

i

i

mN

x

x 1

t

Nt

i

mi

N

xx

1

2

2

Nt

i

mi

k

xxS

13

3

Mean

Variance

Skewness

Pulse Height freq distribution of Phase R

(example)

PD big enough

Positive PD dominant semi conductive

coating/surface.

Pulse Height Chart frequency distribution

phase T (example)

Small PD

not

significant

NQN for phase R,S T at 13 kV

Qmax for phase R,S and T at 13 kV

PD Parameters

Conventional : Charge (q)[pC]

Modern

Chage (q) [pC]

Phase(q) [deg.]

Frequency (n) [per cycle]

DISTRIBUTION of PD

q-q-n

q-q

q-n

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

P

D C

harg

e[p

C]

Phase Angle [deg.]

a.Treeingb. Void

c.Korona

f-q-n patterns (a) Electrical treeing,

(b) void and (c) corona

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

P

D C

harg

e[pC

]

Phase Angle [deg.]

0 60 120 180 240 300 360-75

-50

-25

0

25

50

75

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

PD

Charg

e[p

C]

Phase Angle [deg.]

PD Pulse sequence

Treeing Void

Korona

Ilustrasi skewness

Sk = 0 Sk > 0 Sk < 0

Kurtosis

3

4

1

4

Nt

i

mi

u

xx

K

Ku > 0 Ku = 0 Ku < 0

PD sources Corona on conductor

Surface discharges

Streamer in liquid

Treeing PD

Void PD

-How to distinguish PD sources & interpret the physical processes behind

f-q-n/f-n patterns, pulse-sequence and waveshape

-The role of applied voltage : sinusoidal, triangular, rectangular

nfq-n , pulse sequence and pulse waveshape of corona

discharge

q ~ v(t) , unbalance , n ~ v(t), Townsend process

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

PD

Charg

e[p

C]

Phase Angle [deg.]

-20.0n 0.0 20.0n 40.0n 60.0n 80.0n 100.0n 120.0n

0.0

0.2

0.4

0.6

0.8

1.0

1.2Rise time = 6.4 ns

Width = 41 ns

PD

Curr

ent (m

A)

Time (ns)0 60 120 180 240 300 360

-500

-400

-300

-200

-100

0

100

200

300

400

500

ch

arg

e (

pC

)

phase angle (deg)

Corona in air under sinusoidal voltage

f-q-n

f-n

Pulse

sequences

Corona in air under triangular

voltage

0 30 60 90 120 150 180 210 240 270 300 330 360

-20

-15

-10

-5

0

5

10

15

20

Ch

ag

e (

pC

)

Phase angle (deg)0 30 60 90 120 150 180 210 240 270 300 330 360

-200

-150

-100

-50

0

50

100

150

200

PD

nu

mb

er

(a.u

.)

Phase angle (deg)

Discharge magnitude as well as probability is

dependent on the instantaneous of the applied

voltage. Strongly unsymmetrical.

f-q-n f-n

Streamer PD in Silicone oil of 100 cSt

0 60 120 180 240 300 360-30

-20

-10

0

10

20

30

PD

Charg

e[p

C]

Phase Angle [deg.]

0 60 120 180 240 300 360-25

-20

-15

-10

-5

0

5

10

15

20

25

PD

Charg

e[p

C]

Phase Angle [deg.]

0.0 20.0n 40.0n 60.0n 80.0n 100.0n 120.0n

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

PD

Curr

ent (m

A)

Time (s)0 30 60 90 120 150 180 210 240 270 300 330 360-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

PD

nu

mb

er

(a.u

.)

Phase angle (deg)

Many

pulses

~ v

f-q-n

f-n

Pulse

sequences

streamer

fq-n , pulse sequence and pulse waveshape :q ~ v(t) ,

unsymmetrical , n ~ v(t), streamer process

f-q-n pulse sequences and f-n PD patterns of

streamer in silicone oil under triangular voltage

0 30 60 90 120 150 180 210 240 270 300 330 360

-150

-125

-100

-75

-50

-25

0

25

50

75

100

125

150

Ch

arg

e (

pC

)

Phase angle(deg)

0 90 180 270 360 450 540 630 720

-150

-125

-100

-75

-50

-25

0

25

50

75

100

125

150

Ch

arg

e (

pC

)

Phase angle(deg)

0 30 60 90 120 150 180 210 240 270 300 330 360

0

25

50

75

100

125

150

Puls

e n

um

be

r (

pe

r 1

00

cycle

s)

Phase angle (deg)

f-q-n

f-n

Pulse

sequences

f-q-n pulse sequences, pulse sequences, f-n PD

and waveforms patterns of treeing in LDPE under

sinusoidal voltage

0 60 120 180 240 300 360-125

-100

-75

-50

-25

0

25

50

75

100

125

PD

Charg

e[p

C]

Phase Angle [deg.]0 60 120 180 240 300 360

-100

-80

-60

-40

-20

0

20

40

60

80

PD

Charg

e[p

C]

Phase Angle [deg.]

-10.0n 0.0 10.0n 20.0n 30.0n 40.0n 50.0n

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.15

0.20

PD

Curr

ent (m

A)

Time (s)0 30 60 90 120 150 180 210 240 270 300 330 360

-50

-40

-30

-20

-10

0

10

20

30

40

50

PD

nu

mb

er

(a.u

)

Phase angle (deg)

~dv/dt

Few pulses

f-q-n

f-n

Pulse

sequences

fq-n , pulse sequence and pulse waveshape :q ~ v(t) ,

slightly unsymmetrical , n ~ dv/dt, streamer process

0 30 60 90 120 150 180 210 240 270 300 330 360

-60

-40

-20

0

20

40

60

Ch

arg

e (

pC

)

Phase angle (deg)

0 30 60 90 120 150 180 210 240 270 300 330 360

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

PD

nu

mb

er

(a.u

.)

Phase angle (deg)

0 30 60 90 120 150 180 210 240 270 300 330 360

-100

-90

-80

-70

-60

-50

-40

-30

-20

-10

0

10

20

30

40

50

60

70

80

90

100

Ch

arg

e (

pC

)

Phase angle (deg)

0 30 60 90 120 150 180 210 240 270 300 330 360

-180

-150

-120

-90

-60

-30

0

30

60

90

120

150

180

PD

nu

mb

er

(a.u

.)

Phase angle (deg)

f-q-n and f-n PD patterns of treeing in LDPE

under triangular and rectangular voltages

f-q-n

f-q-n f-n

f-n

Void PD under sinusoidal voltage

-10.0n 0.0 10.0n 20.0n 30.0n 40.0n 50.0n 60.0n-1

0

1

2

3

4

PD

Curr

ent (m

A)

Time (s)

0 60 120 180 240 300 360-100

-80

-60

-40

-20

0

20

40

60

80

100

PD

Charg

e[p

C]

Phase Angle [deg.]0 60 120 180 240 300 360

-75

-50

-25

0

25

50

75

PD

Charg

e[p

C]

Phase Angle [deg.]

f-q-n

Pulse

sequences

Townsend-

Streamer

Void PD under sinusoidal voltage

PD pattern is strongly dependent on the void

condition

f-q-n

Void under triangular voltage

At early stage q dependent on dv/dt but at

later stage the first PD pulses in each half

cycle the q dependent on v(t) but the

following pulses dependent on dv/dt

Condition Assessment

PD Parameter determination (f-Q-N, pulse sequence etc)

Determination of critical values

Trending

Assessment of condition: interpolation, pattern recognition (NN, ES etc)

Partial discharge location

in Generator

Pulse Height Chart : R

Large PD

Positive PD dominant location: semiconductive

coating/surface. Slot

discharge or end turns.

Pulse Height Chart : S

Medium PD

Positive PD

Gambar 19: Kurva q-q-n fasa R

Gambar 19: Kurva q-q-n fasa S

Results for normal machines Un=21 kV

Green-positive pulses, Unit 3

Black-negative pulses, Unit 3

Red-positive pulses, Unit 4

Blue-negative pulses, Unit 4

Results for normal machine Un = 19 kV

Red-positive pulses, the first test Blue-negative pulses, the first test Green-positive pulses, the second test Black-negative pulses, the second test Yellow-positive pulses, the third test Gray-negative pulses, the third test