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Paris Palais des

Congrès

Workshop on DC Grid modeling – August 28, 2012

SEBASTIEN DENNETIERE (B4-57)

Modeling of a preliminary

CIGRE DC Grid test system in

EMTP-RV

From average value models to full

detailed models

Workshop on DC Grid modeling – August 28, 2012 - 2 -

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Test system initially proposed by B4-58

A1

B4

F1

E1

C2

C1

DC Grid Test System version 2012, March 5

B1

B2

B3

B5

B6

A0

B0

D1

DC Overhead DC Cable AC Overhead

AC Cable

DC Grid Test System version 2012, March 5

Bipole configuration has been decided by CIGRE SC B4

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 3 -

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Network data

DC overhead lines

30 m

sag : 20 m

Soil resistivity : 500 Ω.m

9 m

10 m

37 m

sag : 14 m

45 cm

Conductors :

For B2-B5 2 X 2312 MCM

For all others 2 X 1780 MCM

AC overhead lines

30 m

sag : 20 m

Soil resistivity : 500 Ω.m

14 m

10 m

37 m

sag : 14 m 45 cm

Conductors : 3 X 795 MCM

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 4 -

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Network data

DC cables Following assumptions are used for submarine

cables :

• sea temperature 20°C

• maximum temperature 90°C

• XLPE insulation

• single core wide spacing

• Distance between cables : 500 mm

• resistivity of ground is close to

resistivity of sea water = 0.2 Ω.m

• Depth measured from the center of

cable and the ground surface is 1.5 m

Scable

Core (Copper)

Dcore, ρcore

Insulation 1

r1, tan1

Insulation 2

r2, tan2

Sheath

(Lead)

Rin, Rext, sh

Armour (Steel)

R'in, R'ext, 'arm

Insulation 3

r3, tan3

Lines Section (mm²)

A1-C1 800

A1-C2 800

B1-E1 800

B2-B3 630

B6-F1 800

C2-D1 630

D1-E1 1000

E1-F1 630

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 5 -

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Converters data

Converters (except DC-DC converter) Modular Multi-level Converters

AC voltage 380 kV RMS LL or 155 kV RMS LL

DC voltage +/- 400 kV

X converter transformer 0.18%

X arm (Ls) 0.075%

Capacitor Energy in each Sub Module 40 kJ/MVA (8.3 mF for 400 SM per

valve)

Number of SM per half arm 400

Star point reactor (RL shunt branch

between converter Tfos and converter)

R = 4 kΩ

L = 6500 H

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 6 -

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Converters data – control systems

High level controls (described in details) :

Vdc control P control V/f control P/Vdc droop control

G +

Vdc

-

VSC - MMC 401L Iv I

V PCC

Idc

V f

e j

gate signal

Vac

NLC

Capa . Balancing

algorithm (CBA)

Outer P/Q/ Vdc and

Inner Control

PLL

Iv I V PCC V f

abc

d - q

L

acb CCSC d - q

d - q acb

d - q

d - q

abc

SM

j low v _

SM

j up v _ and

VSC

control

Converter

Control

Low level controls (not described) :

CCSC CBA Modulation

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 7 -

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DC-DC converter

Average value model Based on ideal Tfos

Preliminary test system

Workshop on DC Grid modeling – August 28, 2012 - 8 -

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Simulation of the DC Grid test system

Issues to be address

Simulation time can be huge due to the number of semi-conductors : 18 converters = 86400 IGBT

Detailed versus simplified models :

Do every converter need to be modeled in details ?

How to validate simplified models ?

DC grid = multi vendors how to integrate models developed in different simulation tools

Workshop on DC Grid modeling – August 28, 2012 - 9 -

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Type 2 model

Id

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

Vd

Ls

LsLsLs

Ls Ls

Sub-

Module

Multi-

valve

Arm

iua

ibic

vc

iub iuc

ila ilb ilc

vsua

vb

iava

vsla

+

vci

-

p

n

g

C

g

p

n

S1

S2K2K1

+R

LC

0 1000 2000 3000 4000 5000 60000

0.2

0.4

0.6

0.8

1

Current (A)

Voltage (

V)

Workshop on DC Grid modeling – August 28, 2012 - 10 -

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Type 4 model

Id

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

Vd

Ls

LsLsLs

Ls Ls

Sub-

Module

Multi-

valve

Arm

iua

ibic

vc

iub iuc

ila ilb ilc

vsua

vb

iava

vsla

SMv t

MVi t

_SM eqr t

_SM eqv t T

++

_1

_1

SM

eq

v t

r t

_ 2

_ 2

SM

eq

v t

r t

_3

_3

SM

eq

v t

r t

_ 4

_ 4

SM

eq

v t

r t

_5

_5

SM

eq

v t

r t

_ 6

_ 6

SM

eq

v t

r t _6eqr t

_5eqr t

_4eqr t

_3eqr t

_ 2eqr t

_1eqr t

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+

+ + +

DC_PLUS

DC_MINUS

a

b

cAC

Workshop on DC Grid modeling – August 28, 2012 - 11 -

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Type 5/6 model

Id

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

SM-1

SM-2

SM-400

:

Vd

Ls

LsLsLs

Ls Ls

Sub-

Module

Multi-

valve

Arm

iua

ibic

vc

iub iuc

ila ilb ilc

vsua

vb

iava

vsla

suav subv sucv

slcvslbvslav

av

bv

cv

+ + +

+ + +

cI lossI

+

+

++

on AC side

on DC side

Workshop on DC Grid modeling – August 28, 2012 - 12 -

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Test system – EMTP-RV model

500 MW

100 MW

1000 MW

400 MW

600 MW

500 MW

1700 MW

1300 MW

1100 MW

1700 MW

600 MW

100 MW

1500 MW

1500 MW

+

AC_C1

+

AC_C2

+

AC_D1

+

B0

+

AC_F1

DCline_2X1780MCM_200km

DC

line

_2

X1

78

0M

CM

_5

00

km

DC

line

_2

X2

31

2M

CM

_3

00

km

DC

line

_2

X1

78

0M

CM

_4

00

km

DC

line

_2

X1

78

0M

CM

_4

00

km

DCline_2X1780MCM_100km

ACline_3X795MCM_200km

ACline_3X795MCM_200km

P Q

155kVRMSLL100MW0.1MVAR

Load_E1

ACline_3X795MCM_300km

ACline_3X795MCM_300km

PQ_C2

PQ_C1PQ_A1

PQ_B3

PQ_B1

P Q

380kVRMSLL900MW0.1MVAR

Load_B1

PQ_B3_B2_1

PQ_B3_B2_2

PQ_B3_B0

PQ_B2_B0

PQ_B1_B0_1

AC

line

_3

X7

95

MC

M_

20

0km

BR

K_

A1

_B

4

DC

DC

_B

5

BR

K_

B4

_A

1

BR

K_

A1

_B

1_

1

BR

K_

A1

_B

1_

2

BR

K_

B1

_A

1_

1

BRK_B5_B1

BRK_B1_B5

BRK_B1 BRK_B1_E1

BR

K_

B1

_A

1_

2

BRK_E1_B1 BRK_E1

BR

K_

E1

_F

1

BR

K_

E1

_D

1

BRK_F1BRK_B3

BR

K_

F1

_E

1

BRK_D1

BRK_C2

BRK_C1BRK_A1

BRK_B3_B2BRK_B2_B3

BRK_B2

PQ_LoadB3

PQ_B3_B1

PQ_B1_B3

PQ_LoadB1

PQ_LoadB2

PQ_B2

PQ_B2_B3_1

PQ_B2_B3_2

PQ_B0_B1_1

PQ_B0_B2

PQ_B0_B3

PQ_AC_C1

PQ

_C

2_

C1

PQ_A1_A0_2

PQ_A0_A1_1

PQ_A0_A1_2

BRK_C2_A1

BRK_A1_C2

BR

K_

D1

_C

2

BR

K_

D1

_E

1

PQ_B0_B1_2

PQ_B1_B0_2

A1_C1_800MM2_200KM

A1_C2_800MM2_200KM

B1_E1_800MM2_200KM

B6_F1_800MM2_100KM

C2

_D

1_

63

0M

M2

_3

00

KM

D1

_E

1_

10

00

MM

2_

20

0K

ME

1_

F1

_6

30

MM

2_

20

0K

M

B2_B3_630MM2_200KM

ACline_3X795MCM_400km

AC

line

_3

X7

95

MC

M_

30

0km

P Q

Load_B3

P Q

Load_B2

ACline_3X795MCM_200km

ACline_3X795MCM_200km

MMC

bipoletype520 SM

VSC_A1

MMC

bipoletype520 SM

VSC_C1

MMC

bipoletype520 SM

VSC_C2

MMC

bipoletype520 SM

VSC_D1

MMC

bipoletype520 SM

VSC_E1

MMC

bipoletype520 SM

VSC_F1

MMC

bipoletype520 SM

VSC_B1

MMC

bipoletype520 SM

VSC_B3

MMC

bipoletype520 SM

VSC_B2

AC

ca

ble

_3

X1

85

mm

2_

50

km

V

Vmeter_A1

V

Vmeter_C1

V

Vmeter_C2

V

Vmeter_D1

V

Vmeter_E1

V

Vmeter_F1

V

Vmeter_B3

V

Vmeter_B2

V

Vmeter_B1V

Vmeter_B0

PQ_B0

PQ_A0_A1

PQ_AC1_A1

+

A0

+

AC2V

Vmeter_A0

PQ_A1_A0_1

BR

K_

C2

_D

1

P Q 155kVRMSLL10MW0.1MVAR

Load_E1_b

PQ_AC_C2

PQ_AC_D1

PQ_AC_F1

PQ_E1_a

PQ_E1_b

PQ_D1

PQ

_C

1_

C2

PQ_E1

PQ_F1

BR

K_

B5

_2

BRK_B5_1

AC

DC_plus

DC_minus

MMC

monopoletype420 SM

VSC_1

MMC

monopoletype420 SM

VSC_2

Bipolar configuration

Workshop on DC Grid modeling – August 28, 2012 - 13 -

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Test system in EMTP-RV

Converter and Control systems

These devices are Exported Masks, do not modify

AC1 2

-30

Exported Mask

1/1

Converter_Tfos

+

Sta

r_p

oin

t_re

acto

r

4k,6

50

0

PageVdc

Va_ref

Vb_ref

Vc_ref

Page Vabc_refPageV_Primary_Transfo

PageI_Primary_Transfo

PageV_Secondary_Transfo

PageI_Secondary_Transfo

Page Vc_up_C

Page Vc_up_B

Page Vc_up_A

Page Vc_low_C

Page Vc_low_B

Page Vc_low_APageS_up_A

Page i_up_A

Page i_low_A

Page i_up_B

Page i_low_B

Page i_up_C

Page i_low_C

PageS_low_A

PageS_up_B

PageS_low_B

PageS_up_C

PageS_low_C

Page S_up_A

Page S_low_A

Page S_up_BPage S_low_B

Page S_up_C

Page S_low_C

PageVc_up_C

PageVc_up_B

PageVc_up_A

PageVc_low_C

PageVc_low_B

PageVc_low_A

Pagei_up_A

Pagei_low_A

Pagei_up_B

Pagei_low_B

Pagei_up_C

Pagei_low_C

MMC 401Levels

Capa.Voltages

Gate signals

Input Ouput

CurrentArms

Vc_up_BS_up_B

Vc_up_AS_up_AS_low_A Vc_low_A

S_up_C Vc_up_C

S_low_B Vc_low_B

S_low_C Vc_low_C

AC

i_up_A

P

i_up_B

i_up_C

N

i_low_C

i_low_B

i_low_A

MMC_400SM

Page P_meas

Page Q_meas

MMC ControlCCSC+CBA

Capa.Voltages

CurrentArms

Gate signals

Va_refVb_refVc_ref

Vc_low_AVc_up_A

Vc_up_B

S_up_A

Vc_low_B

Vc_up_C S_up_CVc_low_C S_low_C

S_up_BS_low_B

S_low_A

theta

i_up_C

i_up_B

i_low_C

i_low_B

i_up_Ai_low_A

MMC_Control

v i

Secondary1

v i

Primary1

VSC Control

V_Secondary_Transfo

I_Secondary_Transfo

Vabc_ref

V_Primary_Transfo

I_Primary_Transfo

Vdc_measVdc

theta

P_measQ_meas

VSC_Control1

AC_Converter

• Type 2 – Full detailed

• Type 4 – Detailed equivalent

• Type 5 – AVM with switching functions

• Type 6 – AVM based on power frequency

• Vdc control

• P control

• P / Vdc droop control

• V/f control

+Real-Time Workshop

DLL

Workshop on DC Grid modeling – August 28, 2012 - 14 -

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DC grid test system – test cases

Test cases defined on the DC grid test system Used to test and validate models : Check abnormal behaviors Cross compare simulation results to validate models Proposed by KTH Royal Institute of Technology in Sweden 20 cases classified in 5 categories : Steady state solution Faults on AC grids References changes (Pref, Vdc) DC disturbances (trip and reclose lines)

Workshop on DC Grid modeling – August 28, 2012 - 15 -

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Test system – validation

Example : test case 5.1 (open and reclose line A1 and B1)

Workshop on DC Grid modeling – August 28, 2012 - 16 -

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Test system – validation

Type4 model validated against full detailed model* (Type2)

*Network data summary :

Electrical nodes: 173 000

IGBT : 86 400

Workshop on DC Grid modeling – August 28, 2012 - 17 -

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Test system – mixed levels of modeling

Average value / detailed models :

Converter models have to be adapted to :

the type of transients

the location of events

Few studies require detailed models of every converters

To limit the calculation time :

The test system can be made up of some detailed models and some average value models

Some converters far away from the transient event can be modeled with monopole configurations

Workshop on DC Grid modeling – August 28, 2012 - 18 -

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Test system – mixed modeling levels

Simulations cases with mixed levels of modeling

A1 B1 B2 B3 C1 C2 D1 E1 F1

1 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5

2 TYPE5 TYPE4 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5

3 TYPE4 TYPE4 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5

4 TYPE4 TYPE4 TYPE5 TYPE5 TYPE5 TYPE5 TYPE5 TYPE4 TYPE5

5 TYPE4 TYPE4 TYPE5 TYPE5 TYPE5 TYPE4 TYPE5 TYPE4 TYPE5

6 TYPE4 TYPE4 TYPE5 TYPE5 TYPE4 TYPE4 TYPE5 TYPE4 TYPE5

7 TYPE4 TYPE4 TYPE5 TYPE5 TYPE4 TYPE4 TYPE4 TYPE4 TYPE5

8 TYPE4 TYPE4 TYPE4 TYPE5 TYPE4 TYPE4 TYPE4 TYPE4 TYPE5

9 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE5

10 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4 TYPE4

Converters modelsSimulation

cases

Workshop on DC Grid modeling – August 28, 2012 - 19 -

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Test system – mixed modeling levels

Example : test case 5.1 (open and reclose line A1 and B1)

Cases 10, 9, 8, 7, 6

Workshop on DC Grid modeling – August 28, 2012 - 20 -

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Test system – mixed modeling levels Simulation times* vs modeling levels (18 converters)

0

500

1000

1500

0 2 4 6 8 10 12 14 16 18

89 165 253 343 447 563

692 820

966 1122

Number of detailed converter models used in the test system

Sim

ula

tio

n t

ime

(s)

400 SM / valve

*Simulation of 2s with EMTP-RV v2.4 done on a computer with a Intel Core i7 2720 QM

0

50

100

150

200

0 2 4 6 8 10 12 14 16 18

89 101 110 123 135 147 160 175 182 195

Sim

ula

tio

n t

ime

(s) 20 SM / valve

Number of detailed converter models used in the test system

Workshop on DC Grid modeling – August 28, 2012 - 21 -

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Conclusions

DC Grid test system model in EMTP-RV 4 types of models have been developed 20 test cases are implemented and automatically configured Simulation times can be reduced by mixing types of models Low level controllers developed in Matlab-Simulink

Perspectives DC Grid test system modeling based on the final specifications Models validation Protection system design and settings Wind turbine models