Battery Storage in the NEMDr Nilesh Modi
Australia Energy Market Operator
Grid scale energy storage
2
Applications
Frequency Control
SpecialProtectionScheme
Inertia substitution
Reliability
SA
VIC
NSW
Hornsdale Power Reserve (Tesla Battery)
3
March 2017
Energy Arbitrage
System Security
Nov 2017
70 MW / 10 MWh
30 M W / 119
MWh
• Change in set point through AGC
• Large steam turbine : Complex dynamic system, inner and outer control systems, lead lag controllers
• Battery Energy Storage: Relatively simple dynamics
Frequency Control - Regulation
4
Battery
Battery
Frequency Control - Contingency
• Faster sustained responses are generally achieved with inverter connected generation, due to
avoidance or decoupling of mechanical components
• Change in the direction of flow (generation to load)
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50 Hz to 49.5 Hz at 0.5 Hz/s
Frequency Control – Island mode
• Frequency control in an island
• Size of the battery relative to the demand
6Data provided by ElectraNet
System Integrity Protection Scheme7
• Detect unstable power swings between South
Australia and Victoria
Stage 1 Stage 2 Stage 3~800 km
(~500 miles)
Heywood AC I/C
EnergyDischarge
Pre-emptive
Load Shedding
Separation
System Integrity Protection Scheme
• Effectiveness of BESS on overall system security
• System separation avoided
• Increased effectiveness of load shedding
8
System inertia
• Factors to consider
• Availability and capability of PrimaryFrequency Response (PFR) / FrequencyContainment Reserve (FCR)
• Maximum contingency size
• Possible further loss of inertia
• Maximum RoCoF
9
Inertia substitution
• FFR is more effective for low inertia systems compared to high inertia systems
• As an example, for a contingency size of 300 MW, dispatching 20% FFR from total FCR,
• 6.5% reduction in the inertia requirements for a system with 20,000 MWs total inertia
• 17% reduction in the inertia requirements for a system with 15,000 MWs inertia, respectively
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Relationship between FFR and Inertia Relationship between FFR and RoCoF
Reference: Inertia requirements methodology, inertia requirements & shortfalls, AEMO 2018
Questions?