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Junio 10Sistemas HVDC

SESIÓN 2 : Operación e impacto de Sistemas HVDC en redes existentes

Un evento:

Issues derived from the Multiplicity of new HVDC Links Embedded to AC Transmission Grids

Experience in Brasil

MARCIO SZECHTMANPresident - Technical Council CIGREEletrobras Chief Transmisson Officer

2

Philosophy for Implementing new HVDC Schemes in Brazil

Differently from China, Brazil has been planning the HVDC links in a pair of Bipoles

Two standards in the country:

± 600 kV 3,150 MW 2,625 A; Itaipu and Madeira Bipoles

± 800 kV 4,000 MW 2,500 A: Belo Monte Bipoles

In parallel, they can transmit, respectively:

6300 MW

8000 MW

Itaipu and Madeira links: were designed to allow bipolar parallel operation

Belo Monte links: the receiving end terminal selected differently for each Bipole: greater

concern of loosing the entire two Bipoles for an AC fault at the receiving end terminal

Differently from China, Brazil has been planning the HVDC links in a pair of Bipoles

Two standards in the country:

± 600 kV 3,150 MW 2,625 A; Itaipu and Madeira Bipoles

± 800 kV 4,000 MW 2,500 A: Belo Monte Bipoles

In parallel, they can transmit, respectively:

6300 MW

8000 MW

Itaipu and Madeira links: were designed to allow bipolar parallel operation

Belo Monte links: the receiving end terminal selected differently for each Bipole: greater

concern of loosing the entire two Bipoles for an AC fault at the receiving end terminal

Philosophy for Implementing new HVDC Schemes in Brasil

4

0.8 1 1.2 1.4 1.6 1.8 2-1000

-500

0

500

1000

IPC

C_L1

[A

]

IPC

C_L2

[A

]

IPC

C_L3

[A

]

0.8 1 1.2 1.4 1.6 1.8 2-400

-200

0

200

400

UP

CC

_L1_P

RIM

SID

E [kV

]

UP

CC

_L2_P

RIM

SID

E [kV

]

UP

CC

_L3_P

RIM

SID

E [kV

]

File: TFR CL_S2PCP1B1 1 20131113 02;49;30_368000.CFG

0.8 1 1.2 1.4 1.6 1.8 2158.7726

479.9612

UP

CC

_P

RIM

SID

E_R

MS

[kV

]

0.8 1 1.2 1.4 1.6 1.8 2-0.5

0

0.5

1

UD

_M

EA

N_F

[p

u]

HVDC response due to a mid-line pole DC fault: left VSC System; right typical LCC Scheme

Fault current cleared by AC breaker (3 cycles); full recovery time, from 700 to 1500 ms; with DC breakers or full bridge, time will be less

Fault current cleared by Thyristor control in 10 ms; typical straight forward recovery time in the range of 400 ms, including arc deionization

VSC x LCC: Recovery from a DC line fault

Madeira

ProjectBelo Monte

Project

Configurations of Madeira and Belo Monte HVDC Projects

Need for a further HVDc link to power flow control in avery meshed network

Therefore after completion of the Madeira and Belo Monte projects, we will have 4 PoC in the Southeastregion (SE) where major load is placed.

The Brazilian Transmission Grid New Paradigms

Northeast

Region

Northern

Region

Southern

Region

Southeast

Region • Madeira and Itaipu: assinchronous• Belo Monte: system embedded

and bi-directional

Itaipu

Bipoles

Madeira

Bipoles

Belo Monte

Bipoles

System Effect of HVDC Links

Norteast

Region

Northern

Region

Southeast

Region

Southern

Region

The Effect upon diferente markets (or sub-markets in Brasil)

The Benefit of close integration of regions

Frequency Decoupler AC AC

DC line

Zero Hz

Zero Hz: no oscillation modes transfers

Zero “km”: approximation effect of sending and receiving end terminals

3500 MW

3500 MW

Main AC Grid

X

For a pole outage, apply the overload in the

other 3 Poles, so as to keep the same Pdclevel.

Madeira

Project

Overload Cycles Specified

11000 MW

For any AC or DC contingency, apply the

overload in all avaliable Poles or Bipoles.

Main AC Grid

Belo

Monte

Parallel AC Grid

Belo Monte

Project

Overload Cycles Specified

Main Configuration:Hydro Gen of

18000 MWHydro Gen of

18000 MW

Main Load AreaMain Load Area

BM Bipoles 1 and 2

3.000 MW

7.000 MW

4.000 MW

Fault at two 500 kV circuits

Fault at two 500 kV circuits

Stability Studies Results (Belo Monte)

Stability Studies Results

Reference Machines:

N = Northern System (H)

NE = Northeastern (H + WP + T)

SE = Southeastern (H + T)

Main Load AreaMain Load Area

~

~

~

N

SE

NE

44

105

165

226

286

0, 0,5 1, 1,5 2, 2,5

DELT 6419 10 TUCURUI1-4GR 501 10 I.SOLTE-18GR

DELT 6419 10 TUCURUI1-4GR 5022 10 PAFO-4G1-3GR

Time (s)

Machin

eA

ngle

s

N - SE

N - NE

Results with no overload

Time (s)

AC

Voltages

500 k

V

lines

(pu)

0,737

0,888

1,04

1,191

1,343

0, 0,5 1, 1,5 2, 2,5

VOLT 5580 P.DUTR-PI500

VOLT 7100 GURUPI-TO500

VOLT 7200 MIRACE-TO500

Out-of-stepProtection

System islanding

Results with no overload

Time (s)

Machin

eA

ngle

s

Results with no overload - worst

Time (s)

Machin

eA

ngle

s

-12,3

5,8

23,9

42,

60,1

0, 3, 6, 9, 12, 15,

DELT 6419 10 TUCURUI1-4GR 501 10 I.SOLTE-18GR

DELT 6419 10 TUCURUI1-4GR 5022 10 PAFO-4G1-3GR

N - SE

N - NE

Results with 33% overload

Time (s)

AC

Voltages

500 k

V

lines

(pu)

0,737

0,83

0,923

1,016

1,109

0, 3, 6, 9, 12, 15,

VOLT 5580 P.DUTR-PI500

VOLT 7100 GURUPI-TO500

VOLT 7200 MIRACE-TO500

Results with 33% overload

Conclusions

1. HVDC links cannot longer be considered as separate “entities” in the Grid.

2. Coordination studies to assess the external signals (from the AC system) that may require

run-up or run-down of the HVDC dispatch, are becoming of greater importance.

3. HVDC overload requirements have to be carefully analyzed.

4. HVDC embedded in the AC Grid may provide fundamental contributions to system stability

and security.

5. Current studies contemplate: key external signals to be considered by the Master Control;

flexibility in the overload level and ramp time to be set.

6. Objective is to minimize the number of Hydro machines to be dropped to maintain system

stability.

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Muchas Gracias!!

21

Gracias