MITSUBISHI ELECTRIC

Factory and Field Verification Tests ofControlled Switching System (CSS)

according to CIGRE WG13.07

H. Ito, H. Kohyama, K. Kamei, T. YonezawaTM T&D Corporation, Japan

H. Wilson, S. BillingsMitsubishi Electric Power Products, Inc. USA

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Outlines

1. CIGRE Testing Requirements2. Individual Component Testing3. Integrated System Testing4. Field Verification5. Conclusions

Factory and Field Verification Tests of CSS

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� CIGRE proposed the testing requirements andtheir procedures for CSS.

� The gu id e em ph as i ze s im por tan ce o fcompensation for operating time variations.

� Some mechanisms showed a significant delayafter idle times of breakers for only a few hours.

� The method of determining the optimum closetarget is proposed by pre-strike characteristic.

1. CIGRE WG13.07 Documents for Testing

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2. Individual Component Testing145kV independent-operated GCB with spring mechanisms

Controller

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Electrical performance tests� Dielectric characteristics (RDDS / RRDS)� Minimum arcing time for reignition-free window

Mechanical performance tests� Variations of operating time on operating conditions� Delay of operating time after an “idle time”

Factory Tests for Circuit Breakers

RDDS: Rate of Decrease of Dielectric StrengthRRDS: Rate of Rise of Dielectric Strength

✥✥✥✥

✥✥✥✥

✥✥✥✥

✥✥✥✥

Pre-strike voltage for a cycle of power frequency

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05

10 15 20

Making instants (ms)

0.5

1.0Pr

e-ar

cing

vol

tage

(P.U

.)Sourcevoltage

Makingvoltage

Pre-arcing Time

Pre-

stri

ke v

olta

ge

RDDS

✥✥✥✥

✥✥ ✥✥

✥✥ ✥✥

RDDS measured by pre-strike test

90 180 270 360

σσσσ=0.090

k=1.37+3σ

−3σ

σσσσ=0.095

k=1.34 +3σ

−3σ

0

-1.0

-2.0

0

1.0

2.0N

orm

aliz

ed R

DD

S

Phase angle at making instant (Deg.)

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Dielectric recovery characteristic of550kV 1-break GCB

0

500

1000

1500

0 2 4 6 8 Time (ms)

Peak recovery voltage forshunt reactor current switching

Recovery voltage forcapactive current switching

Minimum cold recovery characteristicat rated gas pressure

Breakdown voltage observedat shunt reactor switching

Thermal restrike at shunt reactor switching

Vol

tage

(kV

)

Reignition window

Reignition-free window

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✦✦✦✦

✥✥✥✥

✥✥✥✥

✥✥ ✥✥

Conditional Compensation

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Deviation from average closing time plotted as functionsof temperature and control voltage

Idle time dependence of circuit breaker with a conventionalhydraulic operating mechanism

-1.0

0.0

1.0

2.0

3.0

0.1 1.0 10 100 1000

Idle Time (hours)

Average Closing Time VariationMaximum Closing Time Variation

2.0ms x (1-Exp(t/8 hours))

Var

iatio

n (m

s)Hydraulic Operating Mechanism (300kV)

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Idle Time Compensation

2ms delay

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Idle time dependence of circuit breaker with the springoperating mechanisms

-2.0

-1.0

0.0

1.0

2.0

0.1 1.0 10 100 1000

Idle Time (hours)

Average Closing Time Variation

Maximum Closing Time Variation

Var

iatio

n (m

s)Spring Operating Mechanism (145kV-362kV)

Idle Time Compensation

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3. Integrated System Testing

245kV independent-operated GCB with spring mechanisms

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Complete performance tests� Compatibility of circuit breaker, controller & sensor� Age related “drift” of operating time� Distribution of switching instant� Maximum making voltage for voltage zero target� Verification of reignition-free

Factory Tests for Integrated System

✥✥✥✥

✥✥✥✥

✥✥✥✥✥✥✥✥

✥✥✥✥

Drift of the closing time measuredwith and without adaptive control

Number of operations (Times)

Varia

tion

of c

losi

ng ti

me

(ms)

15001000500

6.05.0

4.03.02.0

1.0

0-1.0

-2.0

Without adaptive control

15001000500

Number of operations (Times)

Varia

tion

of c

losi

ng ti

me

(ms)

4.03.0

2.01.0

0

-1.0

-2.0

6.05.0

With adaptive control

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Without Adaptive Control With Adaptive Control

Distribution of making voltages and closing instants using 145kV and 362kV GCB

0.0

0.2

0.4

0.6

0.8

1.0

-4 -2 0 2 4

Mak

ing

volta

ge (P

.U.)

0

5

10

Time (msec)

Freq

uenc

y

1ms 1ms

Target point

20 1-1

1pu=118kV

0.0

0.2

0.4

0.6

0.8

1.0

-4 -2 0 2 4

Mak

ing

volta

ge (P

.U.)

1ms 1ms

Target point1pu=296kV

0

5

10

Time (msec)

Freq

uenc

y

20 1-1

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Controlled Switching Tests for voltage zero

13 deg. 20 deg.

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Commissioning Tests at Site

Commissioning tests of 145kV spring operated GCB

Three independent operating mechanisms

Controller

Waveforms of 2nd making test

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Vol

tage

(kV

)

0

75

-75

12

(a) Voltage waveform of 2nd making test

1st

pha

se m

ake

→

← 2

nd p

hase

mak

e

←3r

d ph

ase

mak

e

6 18 Time (ms)C

urre

nt (k

A)

0

0.75

-0.75

6 121120A

(b) Current waveform of 2nd making test

340A

410A

18 24Time (ms)

Waveforms of 3rd making test

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Cur

rent

(kA

)

0

0.75

-0.75 Time (ms)

20 40

Vol

tage

(kV

)

0

75

-75

Time (ms)

20 40

(a) Voltage waveform

1st p

hase

mak

e →

←2n

d ph

ase

mak

e

←3rd

phas

e m

ake

820A

(b) Current waveform

480A

240A

Waveforms of 6th making test

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Cur

rent

(kA

)

0

0.75

-0.75 Time (ms)

20 40

Vol

tage

(kV

)

0

75

-75

Time (ms)

20 40

(a) Voltage waveform

1st p

hase

mak

e →

←2n

d ph

ase

mak

e

←3r

d ph

ase

mak

e

470A

(b) Current waveform

370A

260A

Waveforms of 10th making test

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Cur

rent

(kA

)

0

0.75

-0.75 Time (ms)

20 40

(b) Current waveform

Vol

tage

(kV

)

0

75

-75Time (ms)

20 40

(a) Voltage waveform

1st p

hase

mak

e →

←2n

d ph

ase

mak

e

←3r

d ph

ase

mak

e260A270A

320A

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4. Field Verification Test

Commissioning tests of 204kV hydraulic operated GIS

Controlled shunt reactor de-energization and energization

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Operating records of temperature, hydraulicpressure, closing and opening times over one year

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Days passed-over after the commissioning

Summer

Winter

0 100 200 300

Am

bient

tem

pera

ture

(Deg.

Cels

ius)

30

20

10

Summer

Winter

0 100 200 300

Days passed-over after the commissioning

Oper

atin

g pre

ssur

e(M

Pa)

34

32

30

36

0 100 200 300

Days passed-over after the commissioning

+1ms

0

-1ms

from the optimal target (ms)

+5%

0

-5%

Measured opening time (PU)

Deviations of the opening time

+5%

0

-5%

Measured closing time (PU)

Deviations of the closing time

0 100 200 300

Days passed-over after the commissioning

+2ms

0

-2ms

from the optimal target (ms)

Idle time characteristic of 204kVGISwith hydraulic drives

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24 48

Idle time of close operationsince the last opening operation (hours)

Dela

y of

clo

sing

tim

edu

e t

o

idle

tim

e (

ms) +3ms

0

-1ms

72 96

+2ms

+1ms

O16hrs 16hrs

C

8hrs

16hrsC O

8hrs

16hrsC O

8hrs

C

Idle time characteristic measured at factory

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� Effective compensation for deviations of operating timeassociated with past operations has been demonstrated.� The requirement of idle time compensation can be judgedfrom the measurement up to 100 hours.� Innovative operating mechanisms do not show any delayof the operating times for idle time up to 1000 hours.� Controlled shunt capacitor switching in the field showedmore successful results due to the adaptive control.� Commissioning test demonstrates successful reactoropening without any reignition.

Summary of Results

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� C I G R E W G 1 3 . 0 7 r e c o m m e n d a t i o nsuccessfully covers all the testing requirementsand their procedures.� CSS verified according to the CIGRErecommendation demonstrates successful resultsin the field.

5. Conclusions

Thank you very much for your attention