Download The Vital Role of Utilities in Providing Transmission Grid Stability

The Vital Role of Utilities in
Providing Transmission Grid
Stability
Presentation to the Southern Africa Energy
and Infrastructure Summit
Segomoco Scheppers
Eskom
4 May 2016
Contents of the presentation
Introduction to Eskom
SAPP Transmission Context
Grid Stability
Closing Remarks
2
Introduction to Eskom
3
About Eskom
• Strategic 100% state-owned
electricity utility, strongly supported by
the government
• Supplies approximately 95% of South
Africa’s electricity
• Performed 159 853 household
electrification connections during the
year
• As at 31 March 2015:
– 5.3 million customers (2014: 5.2
million)
– Net maximum generating capacity
of 42.0GW
– 17.4GW of new generation
capacity being built, of which
6.2GW already commissioned
– Approximately 368 331 km of
cables and power lines
– 41 787 employees in the group
(2014: 46 919)
4
Generation capacity – 31 March 2015
Hydro
Pumped Storage
1.4%
3.4%
4.4%
5.7%
Nuclear
Gas
Coal
42.0GW
of nominal
capacity
85.1%
SAPP Transmission Context
5
The Regional Energy Big picture
In 1995 the SAPP was
principally formed to cooperate
to ensure electricity security for
the members
Ethiopia
Kenya
DRC
Tanzania
Angola
Zambia
Namibia
“Hydro North”
During times of drought the thermal
south can support the hydro north
During good rainfall seasons coal
could be conserved as the hydro
north support the thermal south
“Thermal South”
South Africa
6
Current SAPP Transmission
The main interconnectors for regional power
transfer:
1. Cahora Bassa (HCB) to Apollo
2. Motraco
Democratic Republic of Congo
3. Matimba-Phokoje-Insukamini
Tanzania
4. Aries/Aggeneis
5. Caprivi Link
8
6. Songo-Bindura
Zambia
7
7. Kariba North – Kariba South
6
5
8. Zambia – DRC
Internal transfer capacity limitations within each
of the countries apply
Mozambique
Angola
Namibia
Zimbabwe
1
Botswana
3
2
4
South Africa
7
SAPP interconnectors
SNEL
DRC
TANESCO
TANZANIA
Peak = 1,507MW
Peak = 1,070 MW
483MW
600MW
RNT
ANGOLA
ZESCO/CEC/LHPC
ZAMBIA
ESCOM
MALAWI
Peak = 1,599 MW
Peak= 2,287 MW
Peak= 326 MW
190MW
120MW
642MW
642MW
142MW
ZESA
ZIMBABWE
Peak = 1,589 MW
500MW
288MW
EDM/HCB/MOTRACO
MOZAMBIQUE
375MW
Peak = 1,780 MW
157MW
1328MW
NAMPOWER
NAMIBIA
BPC
BOTSWANA
SEC
SWAZILAND
Peak = 629 MW
Peak = 610 MW
Peak = 227 MW
533kV DC
400kV
243MW
361MW
340MW
81MW
168MW
477MW
190MW
600kV
330kV
275kV
ESKOM
SOUTH AFRICA
LEC
LESOTHO
Peak = 34,481 MW
Peak = 150 MW
127MW
220kV
132kV
8
SAPP Control Areas
• 3 x Control Areas:
– ZESCO: ZESCO, CEC and SNEL
– ZESA : ZESA and EDM North
– Eskom : Eskom, BPC, NP, EDMs, LEC, SEC
• Obligation to provide AGC to manage
tie-line flow, frequency and voltage
within its area
ZESCO
ZESA
ESKOM
Grid Stability
10
Grid Stability – the system operators’ challenge
• Frequency instability
• Transient instability
• Voltage instability
• Small signal instability
• Thermal limits
SADC transmission system is relatively weak
•
Very long distances, but lightly loaded
•
Low power transfer capacity
•
No single contingency capacity
•
Low fault levels
•
Susceptible to oscillations and quality of supply concerns
11
Potential transmission capacity projects
Additional transmission interconnectors are necessary:
•7
MOZISA
•8
BOSA
Democratic Republic of Congo
12
•9
Tanzania
STE
11
Mozambique
Angola
10
•
11
•
Kariba north-south
Zambia
10
6
5
Zambia – DRC strengthening
1
Zimbabwe
7
Namibia
12
•
Botswana
9
3
Grand Inga evacuation
8
2
+ Internal strengthening in each country where
required
South Africa
4
A robust transmission system will ensure regional power transfer with
adequate security and reliability of supply
12
Closing Remarks
•
Current SAPP network is susceptible to various forms of stability, which the system
operators are managing
•
Medium to long term solutions require investment in infrastructure
•
Sustaining and strengthening SAPP technical competencies, processes and
systems is critical. This also applies to national utilities
•
Retention and development of skilled power system engineers is essential in all
instances
•
Continued joint technical planning and collaboration is required
•
Development of thermal generation (coal and gas) in Tanzania, Zambia and
Mozambique is expected to improve system resilience
•
Envisaged developments will change system dynamics, which will require to be
proactively studied and mitigation measures put in place
– Inter-connecting SAPP and EAPP
– Inter-connecting hEdM North and South
– Higher penetration of sonlar and wind generation
13
Thank you
Muito Obrigado’