SSM_INSTRUCTION

An enablement of an SSM Contract that instructs a Dispatchable Unit is to provide a System Security Service.

Column Schema

INSTRUCTION_ID

Unique Instruction Identifier.

SQL Type: VARCHAR2(20) Polars Type: str

This column is mandatory, and a primary key.

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

CONTRACT_ID

Unique Contract Identifier used to create enablement.

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

This column is not mandatory.

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 not mandatory.

Example: W/HOE#2

DUID_PARTICIPANTID

Primary recipient (SSM Service Provider) of enablement instruction.

SQL Type: VARCHAR2(10) Polars Type: pl.Categorical

This column is not mandatory.

END_INTERVAL_DATETIME

The last Dispatch Interval of the enablement.

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

This column is not mandatory.

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

EQUIPMENT_TYPE

Dispatchable Unit resource (for example, GENERATOR, LOAD, BIDIRECTIONAL, SYNCHRONOUS CONDENSER).

SQL Type: VARCHAR2(40) Polars Type: pl.Categorical

This column is not mandatory.

INITIAL_INSTRUCTION_ID

Unique transaction identifier of initiating transaction if instruction related to an amendment or cancellation.

SQL Type: VARCHAR2(20) Polars Type: str

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. Value of zero means cancellation of instruction.

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

This column is not mandatory.

SERVICE_TYPE

Requested Service to provide(System strength-combination,System strength-coefficient,NSCAS-voltage control,NSCAS,Inertia,Transitional service-type 1 MSL,Transitional service-type 1,Transitional service-type 2).

SQL Type: VARCHAR2(40) Polars Type: pl.Categorical

This column is not mandatory.

START_INTERVAL_DATETIME

The first Dispatch Interval of the enablement.

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

This column is not mandatory.

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

TNSP_PARTICIPANTID

Participant ID of TNSP if contract procurer is TNSP.

SQL Type: VARCHAR2(10) Polars Type: str

This column is not mandatory.

UNIT_COUNT

Number of sub-units within a DUID that are required for enablement. Value of zero means cancellation of instruction.

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

This column is not mandatory.

New Data Timing

On enablement of a contract to provide System Security Services

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(
            "VERSION_DATETIME",
            "END_INTERVAL_DATETIME",
            "LASTCHANGED",
            "START_INTERVAL_DATETIME",
        ).str.strptime(pl.Datetime, dt_s_fmt),
    )
    .cast(
        {
            "INSTRUCTION_ID": str,
            "CONTRACT_ID": pl.Categorical,
            "DUID": pl.Categorical,
            "DUID_PARTICIPANTID": pl.Categorical,
            "EQUIPMENT_TYPE": pl.Categorical,
            "INITIAL_INSTRUCTION_ID": str,
            "MIN_DISPATCH_MW": pl.Float64,
            "SERVICE_TYPE": pl.Categorical,
            "TNSP_PARTICIPANTID": str,
            "UNIT_COUNT": int,  # or pl.UInt16
        }
    )
    # Deduplicate
    # We want one row per ['INSTRUCTION_ID', 'VERSION_DATETIME']
    # Tie-breaker: greatest value of LASTCHANGED
    .sort(LASTCHANGED, descending=False)
    .unique(subset=["INSTRUCTION_ID", "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:

• INSTRUCTION_ID

• 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	INSTRUCTION	1

This means that the CSV files start with metadata columns:

I,SSM,INSTRUCTION,1,...
D,SSM,INSTRUCTION,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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