Special Requirement of IEEE C37.013 for Generator Circuit Breaker Applications

8/10/2019 Special Requirement of IEEE C37.013 for Generator Circuit Breaker Applications

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Schutzvermerk / Copyright-Vermerk

November 20, 2009

Sector Energy, Business Unit Medium Voltage Siemens AG 2009

Special Requirements

of IEEE C37.013 forGenerator Circuit Breaker Applications


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Sector Energy, Business Unit Medium Voltage

Siemens AG 2009November 09Folie 2

Generator Circuit Breaker Applications

What is different about generatorcircuit breakers?

Applicable standards Special considerations Vacuum versus SF6 technology

Questions.


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Generator and Distribution Circuit Breakers

Generator circuit breaker Distribution circuit breaker


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Circuit Breakers for Distribution

Requirements

Standards:IEEE C37.04 Rating structure for HV circuit breakersIEEE C37.09 Tests for HV circuit breakersIEEE C37.10 Application guide for HV circuit breakers.

X/R ratio: 17 (60 Hz).

Time constant of dc decay: 45 ms.

TRV typical values (15 kV, class S1 cable):Peak voltage (uc) = 25.7 kVTime-to-peak (t3) = 66 sRRRV 0.39 kV/ s.

Duty cycle: O t CO t CO

t = 0.3 s for reclosing / 15 s for non-reclosingt = 3 minutes.


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Circuit Breakers for Generation

Requirements

Standards:IEEE C37.013 Generator circuit breaker.

X/R ratio: 50 (60 Hz).

Time constant of dc decay: 133 ms.

TRV typical values (15 kV, 100 MVA machine):Peak voltage (E2) = 1.84 V = 1.84 x 15.0 = 27.6 kVTime-to-peak (T2) = 0.62 V = 0.62 x 15.0 = 9.3 sRRRV 3.5 kV/ s.

Duty cycle: CO 30 min CO.


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IEEEC37.04 for distribution circuitbreakers expresses TRV in termsharmonized with IEC with peak voltageuc, andtime-to-peak t3.

IEEE C37.013 still uses old TRVexpressions with peak voltage E2 andtime-to-peak T2. Peak voltage is notchanged, but t3 is approximately 0.88 xT2.

The physics are not changed, just therepresentation.

Notes on TRV Representation


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IEEE C37.04-1999 Scope

IEEE Standard Rating Structure for AC High-Voltage Circuit Breakers

1. Scope

This standard establishes a symmetrical current rating structure and construction

requirements for all indoor and outdoor types of ac high-voltage circuit breakersrated above 1000 V. It is only applicable to three-pole circuit breakers used inthree-phase systems and single-pole circuit breakers used in single-phasesystems.

This standard does not cover circuit breakers used at frequencies other than50 Hz or 60 Hz, or generator circuit breakers that are covered in IEEEStandard C37.013-1997.


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IEEE C37.013-1997 Scope

IEEE Standard for AC High-Voltage Generator Circuit Breakers Rated on aSymmetrical Current Basis

1. Scope

This standard applies to all ac high-voltage generator circuit breakers rated on a

symmetrical current basis that are installed between the generator and thetransformer terminals...

Note: Since no other national or international standard on generator circuitbreakers exists, this standard is used worldwide.


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IEEE C37.013 t h e International Standard

for Generator Circuit Breakers

IEEE C37.013 Revision PAR (Project) PAR approved by IEEE-SA

Standards Board, March, 2009 Joint development with IEC SC 17A(HV Switchgear and Controlgear)

IEEE WG chair is convenor (WG chair) ofIEC working group.

IEC has no standard for a generator circuit breaker.The IEEE and IEC intent has been that IEEEC37.013 would be the global standard.

IEC SC 17A WG 52 WG scope: Joint IEC/IEEE revision ofIEEE C37.013: IEEE Standard for AC High-

Voltage Generator Circuit Breakers Rated on a Symmetrical Current Basis


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X/R = 17, = 45 ms X/R = 50, = 133 ms

X/R Ratio Determines %dc Component

%dc vs Contact Part for X/R = 17 and X/R = 50

0.0

20.0

40.0

60.0

80.0

100.0

120.0

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

Contact Part time (ms )

% d c

C o m p o n e n

t

X/R = 17X/R = 50


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X/R Ratio Effect on Asymmetrical InterruptingX/R Ratio Effect on Asymmetrical Interrupting

-2.00

-1.50

-1.00

-0.50

0.00

0.50

1.00

1.50

2.002.50

3.00

0

1 8 0

3 6 0

5 4 0

7 2 0

9 0 0

1 0 8 0

1 2 6 0

1 4 4 0

1 6 2 0

1 8 0 0

1 9 8 0

2 1 6 0

2 3 4 0

2 5 2 0

2 7 0 0

2 8 8 0

3 0 6 0

3 2 4 0

3 4 2 0

3 6 0 0

Time (in degrees)

C u r r e n

t ( I s c =

1 . 0

0 )

Instantaneous (total) current

dc component

S-factor (C37.04-1979)

dc component (in decimal form) (multiply by 100 for %dc component) (C37.04-1999)

Symmetrical current (ac component)


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X/R Ratio Effect on Asymmetrical Interrupting

S factor (from IEEE C37.04-1979)

Ratio of rms asymmetrical current to rms symmetrical current

Assume contact part time of 55 ms, and 50 kA symmetrical current

X/R = 17 %dc = 29.5 S = 1.084 I = 54.2 kA

X/R = 50 %dc = 66.1 S = 1.369 I = 68.5 kAover 26% higher

)100/(%21 dc I

I S

l symmetrica

total +==


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Short-Circuit Currents

Consider system shown:

Transformer 1,000 A full load (self-cooled)impedance = 10%

Generator 1,000 A full load Xd (subtransient reactance) = 20%

For fault at F2, circuit breaker sees transformerfault current, roughly 1,000 A / 0.10 = 10 kA

For fault at F1, circuit breaker sees generatorfault current, roughly 1,000 A / 0.20 = 5 kA

Note:

Fault current for generatorsource fault is only about50% of fault current forsystem (transformer)source fault

F1

F2

G


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Generator Circuit Breaker Ratings

32.24.5 / 4.5 / 4.51.4 / 1.8 / 1.8

27.63.5 / 4.51.6 / 1.8

kVkV/ skV/ s

TRV parameters Peak voltage (1.84 V) RRRV transformer source RRRV generator source

30 / 30 / 3040 / 30msDelayed current zero*

75 / 65 / 6573 / 61%%dc component

50 / 63 / 7225 / 31.5 / 3640 / 6320 / 31.5kAkA

Short-circuit current

Transformer source Generator source

50 / 11038 / 95kV/kVDielectric 60 Hz / BIL

17.515.0kVMaximum voltage

Fixed-Mounted

Drawout(Metal-Clad)

UnitCharacteristic

* Higher values may be available


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Generator Circuit Breakers


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Generator Circuit Breakers


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Out-of-Phase Switching

Circuit Breakers for Standard Applications:

IEEE C37.04 (clause 5.12):

Out-of-phase switching is optional, not required for general purpose circuitbreakers

If a rating is assigned, the preferred rating is 25% of the rated symmetricalinterrupting rating, with recovery voltage of (250% rated voltage / 1.732).Therefore, out-of-phase ratings are not typically assigned to general purposecircuit breakers rated per IEEE C37.04 and tested to IEEE C37.09.


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Out-of-Phase Switching

Circuit Breakers for Generator Switching Applications:

IEEE C37.013 (clause 6.2.9):

Out-of-phase switching is optional, not required for generator circuit breakersIf a rating is assigned, the assigned rating is shall be 50% of the rated

symmetrical interrupting rating (transformer or system source).Out-of-phase switching recovery voltage values are based on a maximumout-of-phase condition of 90 degrees between generator and system. This isreasonable as more extreme angles would result in damage to the machine.The likelihood of out-of-phase switching is influenced by generator inertia, i.e.,low-inertia machines are more likely to be subject to out-of-phase switchingconditions.Generator circuit breakers should have an assigned out-of-phase switchingrating.


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Other Differences

Reclosing:Reclosing duty not required for generator circuit breakers.

Short-time current duration:Normal circuit breakers

3 seconds (metal-clad switchgear = 2 seconds)

Generator circuit breakers1.0 second (typically test to 3 seconds).

Closing & latching rating:Normal circuit breakers

Peak current 260% of symmetrical short-circuit (60 Hz)With X/R = 17, real peak is 259.3%

Generator circuit breakersPeak current 274% of symmetrical short-circuit (60 Hz)

With X/R = 50, real peak is 274.2%.


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Delayed Current Zero Example C37.013

-4.000

-3.500

-3.000

-2.500

-2.000

-1.500

-1.000

-0.500

0.000

0.500 0 1

0 2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

1 1 0

1 2 0

1 3 0

1 4 0

1 5 0

1 6 0

Time (ms)

C u r r e n

t ( u n

i t i z e

d )


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Delayed Zero Test Example

20.6 ms 30.0 ms

40.1 ms 57.7 ms


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Generator Circuit Breaker Technologies

VacuumWell-suited to smaller units(up to 6,000 A or so)

Most economic for small units

Derived from proven distribution unitoperators and interrupters

High experience-base

Very low arc voltage (20 - 50 V)Little affect on X/R ratioLower arc voltage = less arc energy =

lower contact erosion

Extremely rapid recovery of dielectricstrength between contacts afterinterruption good for extreme TRV levels

SF 6Only option for very large units

VERY expensive

Unlike distribution products

Lower experience-base

SF 6 low arc voltage (several 100 V)Somewhat higher impact on X/R ratioHigher arc voltage = higher arc energy =

greater contact erosion

Less able to cope with high TRV levels

Special Requirement of IEEE C37.013 for Generator Circuit Breaker Applications

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