SSM_CONTRACT_UNIT_AVAIL

The variable parameters associated to the Unit within an SSM Contract, allowing changes to the base contract values due to unit availabilities (e.g Maintenance, Outages).

Column Schema

CONTRACT_ID

Unique Contract Identifier

SQL Type: VARCHAR2(20) Polars Type: str

This column is mandatory, and a primary key.

DUID

Dispatchable Unit Identifier

Warning

This column may contain funny characters such as / (slash) or # (hash). This may break hive-style partitioning.

For more information, see the dedicated documentation page.

SQL Type: VARCHAR2(20) Polars Type: pl.Categorical

This column is mandatory, and a primary key.

Example: W/HOE#2

INTERVAL_DATETIME

The starting Dispatch Interval for the availability change. This will be the active availability until the next INTERVAL_DATETIME record for this Contract and DUID.

SQL Type: DATE Polars Type: pl.Datetime()

This column is mandatory, and a primary key.

Example: 2026/01/20 00:05:00

VERSION_DATETIME

Effective Date and Time of this record.

SQL Type: DATE Polars Type: pl.Datetime()

This column is mandatory, and a primary key.

Example: 2026/01/20 00:05:00

ACTIVATION_LEAD_TIME

The expected maximum lead time for the system security service to be enabled from a non-operational state in minutes.

SQL Type: NUMBER(6,0) Polars Type: pl.UInt32

This column is not mandatory.

AVAILABLE

Indicates if DUID is available for the INTERVAL_DATETIME (1 = True, 0 = False).

SQL Type: NUMBER(1,0) Polars Type: pl.Boolean

This column is not mandatory.

LASTCHANGED

Last time record was changed

For more information, see the dedicated documentation page.

SQL Type: DATE Polars Type: pl.Datetime()

This column is not mandatory.

Example: 2026/01/20 00:05:00

MIN_DISPATCH_MW

Minimum Dispatch Target required for DUID to enable the contract.

SQL Type: NUMBER(18,8) Polars Type: pl.Float64

This column is not mandatory.

MIN_ENABLEMENT_DURATION

Minimum duration a unit must be active to enable the contract in minutes.

SQL Type: NUMBER(6,0) Polars Type: pl.UInt32

This column is not mandatory.

UNIT_COUNT

Number of sub-units within a DUID that are available for enablement.

SQL Type: NUMBER(4,0) Polars Type: pl.UInt16

This column is not mandatory.

New Data Timing

On change of the Contract Availability

Code Examples

Polars

Casting is enums, categoricals etc is not essential, but may speed up parsing. Swapping int for pl.UInt16, pl.Int32 would also speed up parsing. However some of the datatypes are inferred, so they may be wrong.

This code deduplicates for you. Deduplication is normally only required across multiple months.

This code assumes that all columns are present, which may not be true for older files.

import polars as pl
import polars.selectors as cs

# e.g. "2029/03/15 00:05:00"
dt_s_fmt = "%Y/%m/%d %H:%M:%S"

csv_paths = ["SOMEFILE.CSV", "OTHERFILE.CSV"]

lf = (
    pl.concat(
        [
            pl.scan_csv(
                csv_path,  # must be unzipped beforehand
                skip_rows=1,  # skip the header
                infer_schema=False,  # much faster
            )
            .filter(cs.by_index(0) == "D")  # drop the footer
            .select(~cs.by_index(range(4)))  # drop metadata columns
            for csv_path in csv_paths
        ],
        how="diagonal_relaxed",
    )
    .with_columns(
        pl.col("INTERVAL_DATETIME", "VERSION_DATETIME", "LASTCHANGED").str.strptime(
            pl.Datetime, dt_s_fmt
        ),
    )
    # Polars can't cast string straight to bool. Need to go via something else.
    .cast({"AVAILABLE": pl.UInt8})
    .cast(
        {
            "CONTRACT_ID": str,
            "DUID": pl.Categorical,
            "ACTIVATION_LEAD_TIME": int,  # or pl.UInt32
            "AVAILABLE": pl.Boolean,
            "MIN_DISPATCH_MW": pl.Float64,
            "MIN_ENABLEMENT_DURATION": int,  # or pl.UInt32
            "UNIT_COUNT": int,  # or pl.UInt16
        }
    )
    # Deduplicate
    # We want one row per ['CONTRACT_ID', 'DUID', 'INTERVAL_DATETIME', 'VERSION_DATETIME']
    # Tie-breaker: greatest value of LASTCHANGED
    .sort(LASTCHANGED, descending=False)
    .unique(
        subset=["CONTRACT_ID", "DUID", "INTERVAL_DATETIME", "VERSION_DATETIME"],
        keep="last",
    )
)

Nemosis

This table is not yet available in Nemosis.

Availability

Visibility: Private

This table is not available in the public monthly MMSDM archive. Is is only available to registered market participants over FTP inside a VPN.

Deduplication and PDR Loader Configuration

The primary keys are:

• CONTRACT_ID

• DUID

• INTERVAL_DATETIME

• VERSION_DATETIME

The transaction type is "insert", which means that you will usually not see duplicate data. If you do, you can deduplicate based on the primary keys, without sorting first. Rows from different files with the same primary keys should have the same values.

PDR Loader configuration is:

Report Name	Report Subtype	Version
SSM	CONTRACT_UNIT_AVAIL	1

This means that the CSV files start with metadata columns:

I,SSM,CONTRACT_UNIT_AVAIL,1,...
D,SSM,CONTRACT_UNIT_AVAIL,1,...

Links

This page as JSON (schema documented here, but may change)

Download a JSON Schema specification for this table.

Official AEMO schema documentation

Other Information

Package: SYSTEM_SECURITY_MANAGEMENT

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