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CO
NV
ER
SA
TO
RIO
:
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.
20
Muchas Gracias!!
21
Gracias