Contingency Reserve Quantities
Contingency Reserve Raise (CRR) and Contingency Reserve Lower (CRL) quantities are determined by AEMO according to WEM Procedure: ESS Quantities to maintain the frequency of the SWIS within the Credible Contingency Event Frequency Band set out in Appendix 13 of the ESM Rules.
For further details, please refer to the fact sheets provided below.
Contingency Reserve Raise
The Dynamic Frequency Control Model (DFCM) is an offline simulation of the SWIS power system frequency that calculates the quantity of the Contingency Raise Offset and Facility Performance Factors for a set of ESS System Configurations comprising following parameters:
- Underlying System Load;
- System Inertia;
- Load Relief Factor;
- Facility Speed Factor;
- Largest Credible Supply Contingency;
- Distributed Photovoltaic (DPV); and,
- any other factors that AEMO determines necessary to accurately predict frequency performance for system operations.
The latest version of the DFCM is available for download below.
| DFCM ID | Link | Changes | Effective date |
|---|---|---|---|
| 0015 | DFCM_0015.json |
This version of the DFCM primarily includes: • Addition of DPV axis. • Upgrading the DFCM to a Closed-Loop model. • Including tau = 0.5 and 1 seconds. • Changes to other parameters are available in the explainer within the DFCM file. |
From 15/05/2024* |
| 0016 | DFCM_0016.json | DPV axis is extended to include higher level. The related range is available in the explainer within the DFCM file. | From 07/11/2024* |
| 0017 | DFCM_0017.json | • Increase to Contingency Size range. • Improvement to the methodology to account for load inertia and load relief. |
From 06/03/2025* |
| 0018 | DFCM_0018.json | • Removal of RoCoF Safe Limit considerations from DFCM as this is now managed via RoCoF Safe Limit constraints within WEMDE. • Increase to Contingency Size range. |
From 26/02/2026* |
* Market Participants are notified by a Market Advisory for the exact effective Dispatch Interval.
Contingency Reserve Lower
The Contingency Lower Offset is defined as:
Contingency Lower Offset = LCLC – CRLR
where:
- LCLC is the Largest Credible Load Contingency; and,
- CRLR is the Contingency Reserve Lower Requirement, which is derived from the DFCM.
The CRL service does not incorporate Facility Speed Factor and instead applies a uniform Performance Factor of 1 across all Facilities. This simplification allows CRL to be expressed linearly.
Margin for Operation
Margin for Operation is defined as a margin applied by AEMO when determining frequency co-optimised essential system services (FCESS) quantities to account for uncertainty in real time operations. The Margin for Operation used for CRR and CRL (in the DFCM) is 0.05 Hz.
Minimum RoCoF Control Service Requirement
AEMO calculates the Minimum RoCoF Control Requirement under paragraph 4.1 of WEM Procedure: ESS Quantities.
Further information and questions
Refer to the WEM Procedure: ESS Quantities for further information.
For any engineering-related queries on DFCM, please contact the WA System Engineering team via [email protected].
For any WEMDE solution related queries associated with the DFCM, please contact the WA Real-Time Market Monitoring team via [email protected].