2017 Annual ConferenceNovember 2nd, 2017

Hybrid Circuit Breaker for HVDC Grids with ControllablePulse Current Shape for Fast Fault Clearing

Laboratory for High Power Electronic Systems

Andreas Jehle and and Jürgen BielaLaboratory for High Power Electronic SystemsZürich, Switzerlandjehle@hpe.ee.ethz.ch

This poster presents two new hybrid Circuit Breaker (hCB) with current injection circuit to extin-guish the arc in the MCB after opening. Compared to other hCBs, this hCBs uses a current injection circuit, which is able to adapt the pulse current and so ensures a low current slope at the arc extinc-tion to prohibit a reignition. Additionally, it is shown that with the increased controllability the volume of the passive components can be decreased compared to existing solutions.

AD

rR

rL

rCMCB

1IGBT

nIGBT

nM

OV

1M

OV

CMOV

+

-

Con

trol

LC−IGBT

pulseI

ECELEMOVEgrid

IGBT-allThyr-LC IGBT-APC1IGBT-APC2

30

20

10

E[MJ]

0

[kV]blockV

BD−IGBT

8

16

24

0

[kA]maxI

200

400

600ADAD

0Semiconductor

Blocking Voltages

BD

SemiconductorMaximum Currents

BD

IGB

TsTh

yris

tors

Thyr

isto

rsIG

BTs

Capacitor Cr 27 µF 11 µF 11 µF

Inductor Lr 950 µH 300 µH 120 µH

Control IGBT-all IGBT-APC1 IGBT-APC2

hCB with adaptable pulse current Adaptable pulse current control

Comparison to existing solutions

hCB with adaptable pulse current and controllable MCB voltageAD

rR

rL

rC

1IGBT

nIGBT

nM

OV

1M

OV

MCB

BD

+

-

Con

trol

BD−IGBT

pulseI

rL

rC

MCB

CMOV

Thyr

LC−Thyr

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL CMOV CMOV

CMOV CMOV

faultI faultI

pulseI

faultI faultI

1IGBT

nIGBTnMOV

1MOV

1IGBT

nIGBTnMOV

1MOV

1IGBT

nIGBTnMOV

1MOV

1IGBT

nIGBTnMOV

1MOV

1. 2.

4. 5.

CMOV

faultI

pulseI1IGBT

nIGBTnMOV

1MOV

3.

+

-+

-

+

-

-

+

-

+

MCB

MCB

MCB

MCB

MCB

Turn off procedure:

1. Open MCB with arc during increasing fault current2. Generate zero current in MCB with current pulse3. DA conducts to avoid ITIV4. Charge Cr with fault current and turn off IGBTs5. Dissipate remaining energy in lines

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL

aD

rR

rC

rL1IGBT

nIGBTnMOV

1MOVBD

pulseI

faultI

faultI

faultI

pulseI

faultI

1IGBT

nIGBTnMOV

1MOVBD

1IGBT

nIGBTnMOV

1MOVBD

1IGBT

nIGBTnMOV

1MOVBD

faultI

pulseI1IGBT

nIGBTnMOV

1MOVBD

1. 2. 3.

4. 5.

+

-

+

-

+

-

MCB

MCB

MCB

MCB

MCB

Turn off procedure:

1. Open MCB with arc during increasing fault current2. Generate zero current in MCB with current pulse3. DA conducts to avoid ITIV4. Turn off IGBTs while DB conducts5. Dissipate remaining energy in lines

Controllable number of varistors in pulse current path

►Adaptable pulse current ►Partial MCB voltage control with IGBTs

DA conducts after arc extinction

►No initial transient interruption voltage (ITIV)

Transient interruption voltage shared by IGBTs & Cr

►Lower number of series connected IGBTs required

Due the possibility to turn IGBTs independent on and off, the pulse current circuit can be adapted to the fault current by changing the number of varis-tors. Several switching strategies can be used:

IGBT-all: Turn on all IGBTs

►High Lr to limit current slope, ►High Cr to reach maximum pulse current in Lr

IGBT-APC1: Turn on a fault current dependent number of IGBTs

►Places arc extinction near pulse current maximum ►Lower Lr required at flat pulse current maximum ►Lower Cr to reach maximum pulse current in Lr

►Lower rise time

IGBT-APC2: Change the number of turned on IGBTs during the pulse

►Stronger damping near maximum pulse current possible ► Even lower Lr and Cr required ► Even lower rise time

0

1

2

3

4

5

]kA[MCBI

IGBT-allI

IGBT-APC1I

sµ55=1APC,pulset

Time until the MCB is open after a fault at t = 0 mssµ100=all,pulset

IGBT-APC2I

sµ35=2APC,pulset

Arc extinction

Number of turned on IGBTs is changed

4.18 4.2 4.22 4.24 4.26 4.28 4.3 4.32

12345678

0]ms[t

]kA[pulseI

IGBT-allI

IGBT-APC1I

IGBT-APC2I

Number of turned on IGBTs is changed

blocksaD

Arc extinction

Controllable number of varistors in pulse current path and additional diode DB parallel to RrLrCr-circuit

►Adaptable pulse current ►Complete MCB voltage control with IGBTs

DA conducts after arc extinction

►No initial transient interruption voltage (ITIV)

Transient interruption voltage blocked by IGBTs

►Lower maximum capacitor voltage ►Higher number of IGBTs

Existing solutions use a precharged capacitor in series with a inductor, which is triggered with thyristors and so generate always the same pulse current

Nominal direct voltage Vdc 320 kV

Rated Power P 200 MW

Maximum overvoltage 480 kV

Length of line 100 km

Current limiting inductances Llim 146.8 mH

Peak current (mechancial switch) 10 kA

dI/dtMCB,max=70 A/µs dVMCB/dt =1000 kV/ms

34.6 24.8Dissipated energyfrom the VSC

8.82 7.9Inductive energy-storage requirement

3.15 1.25Capacitive energystorage requirement

33.3 25.1Energy dissipationin MOVs

Thyr-LC

24.9

7.9

0.002

24.9

IGBT-APC2 IGBT-DB

EVSC [MJ]

ELlim [MJ]

EC [MJ]

EMOV [MJ]

160 161Thyristor/IGBTblocking voltage 643Vsemi, max [kV]

11.96 10.38Thyristor/IGBTmaximum current 10.38Isemi, max [kA]

56.6 6.45 11.2ELr [kJ]

- 0.5Diode maximum current DA / DB

0.9/20

- 480Diode blocking voltage DA / DB

480/60Vdiode, max [kV]

Idiode, max [kA]

32.5 24.8Time to interrupt current from VSC 24.9to� [ms]

This project is carried out in the frame of the Swiss Centre for Competence in Energy Research on the Future Swiss Electrical Infrastructure (SCCER-FURIES)with the �nancial support of the Swiss Commission for Technology and Innovation (CTI - SCCER program)