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TRANSMISSIONLOSSFACTOR

TRANSMISSIONLOSSFACTOR shows the Transmission Loss factors applied at each connection point.

TRANSMISSIONLOSSFACTOR is public data, and is available to all participants.

Source

TRANSMISSIONLOSSFACTOR updates when new connection points are created or loss factors change.

Column Schema

CONNECTIONPOINTID

Connection Point ID

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

This column is mandatory, and a primary key.

Examples:

  • QASSHU01
  • STB31T
  • VJL21W
  • VMWF

EFFECTIVEDATE

Effective date of record

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

This column is mandatory, and a primary key.

Example: 2026/09/08 00:00:00

Note that AEMO represents dates as datetimes with a midnight time component.

VERSIONNO

Version no of record for given effective date

SQL Type: NUMBER(22,0) Polars Type: pl.UInt128

This column is mandatory, and a primary key.

Example: 1

LASTCHANGED

Record creation timestamp

For more information, see the dedicated documentation page.

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

This column is not mandatory.

Example: 2026/09/04 15:07:18

REGIONID

Region Identifier

For more information, see the dedicated documentation page.

The SQL type is VARCHAR2(10). This is actually a factor/enum, with values:

  • QLD1

  • VIC1

  • TAS1

  • NSW1

  • SA1

  • SNOWY1

This column is not mandatory.

SECONDARY_TLF

Used in Bidding, Dispatch and Settlements, only populated where Dual TLFs apply. For Bidding and Dispatch, the TLF for the generation component of a BDU, when null the TRANSMISSIONLOSSFACTOR is used for both the load and generation components. For Settlements, the secondary TLF is applied to all energy (load and generation) when the Net Energy Flow of the ConnectionPointID in the interval is positive (net generation).

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

This column is not mandatory.

Examples: 0.9817, 0.9917

TRANSMISSIONLOSSFACTOR

Used in Bidding, Dispatch and Settlements. For Bidding and Dispatch, where the DUID is a BDU with DISPATCHTYPE of BIDIRECTIONAL, the TLF for the load component of the BDU. For Settlements, where dual TLFs apply, the primary TLF is applied to all energy (load and generation) when the Net Energy Flow of the ConnectionPointID in the interval is negative (net load).

SQL Type: NUMBER(15,5) Polars Type: pl.Float64

This column is mandatory (but not a primary key).

Examples: 0.9862, 1, 1.0036

New Data Timing

When new connection points are created or loss factors change

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"

# Dates are represented as datetimes at midnight

d_fmt = "%Y/%m/%d 00:00:00"

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",
    )
    .rename(
        {
            # These columns have names that conflict with metadata columns
            "TRANSMISSIONLOSSFACTOR_duplicated_0": "TRANSMISSIONLOSSFACTOR"
        }
    )
    .with_columns(
        pl.col("LASTCHANGED").str.strptime(pl.Datetime, dt_s_fmt),
        pl.col("EFFECTIVEDATE").str.strptime(pl.Date, d_fmt),
    )
    .cast(
        {
            "CONNECTIONPOINTID": pl.Categorical,
            "EFFECTIVEDATE": pl.Date(),
            "VERSIONNO": int,  # or pl.UInt128
            "REGIONID": pl.Enum(["QLD1", "VIC1", "TAS1", "NSW1", "SA1", "SNOWY1"]),
            "SECONDARY_TLF": pl.Float64,
            "TRANSMISSIONLOSSFACTOR": pl.Float64,
        }
    )
    # Deduplicate
    # We want one row per ['CONNECTIONPOINTID', 'EFFECTIVEDATE', 'VERSIONNO']
    # Tie-breaker: greatest value of ['LASTCHANGED']
    .sort(["LASTCHANGED"], descending=False)
    .unique(subset=["CONNECTIONPOINTID", "EFFECTIVEDATE", "VERSIONNO"], keep="last")
)

Nemosis

This table is not yet available in Nemosis.

Example File

From PUBLIC_ARCHIVE_TRANSMISSIONLOSSFACTOR_FILE01_202609010000.zip

TRANSMISSIONLOSSFACTOREFFECTIVEDATEVERSIONNOCONNECTIONPOINTIDREGIONIDLASTCHANGEDSECONDARY_TLF
12026/09/08 00:00:001QASSHU01QLD12026/09/04 15:07:18
1.00362026/09/15 00:00:001STB31TSA12026/09/11 15:07:330.9917
0.98622026/09/15 00:00:001VJL21WVIC12026/09/11 15:39:120.9817
0.9892026/09/21 00:00:001VMWFVIC12026/09/18 14:37:150.989

CSETP.WORLDDVD_TRANSMISSIONLOSSFACTORAEMOPUBLIC2026/10/0916:36:24001791527784351MONTHLY_ARCHIVE001791527784351
IMARKET_CONFIGTRANSMISSIONLOSSFACTOR2TRANSMISSIONLOSSFACTOREFFECTIVEDATEVERSIONNOCONNECTIONPOINTIDREGIONIDLASTCHANGEDSECONDARY_TLF
DMARKET_CONFIGTRANSMISSIONLOSSFACTOR212026/09/08 00:00:001QASSHU01QLD12026/09/04 15:07:18
DMARKET_CONFIGTRANSMISSIONLOSSFACTOR21.00362026/09/15 00:00:001STB31TSA12026/09/11 15:07:330.9917
DMARKET_CONFIGTRANSMISSIONLOSSFACTOR20.98622026/09/15 00:00:001VJL21WVIC12026/09/11 15:39:120.9817
DMARKET_CONFIGTRANSMISSIONLOSSFACTOR20.9892026/09/21 00:00:001VMWFVIC12026/09/18 14:37:150.989
CEND OF REPORT7

TRANSMISSIONLOSSFACTOR,EFFECTIVEDATE,VERSIONNO,CONNECTIONPOINTID,REGIONID,LASTCHANGED,SECONDARY_TLF
1,"2026/09/08 00:00:00",1,QASSHU01,QLD1,"2026/09/04 15:07:18",
1.0036,"2026/09/15 00:00:00",1,STB31T,SA1,"2026/09/11 15:07:33",0.9917
0.9862,"2026/09/15 00:00:00",1,VJL21W,VIC1,"2026/09/11 15:39:12",0.9817
0.989,"2026/09/21 00:00:00",1,VMWF,VIC1,"2026/09/18 14:37:15",0.989

C,SETP.WORLD,DVD_TRANSMISSIONLOSSFACTOR,AEMO,PUBLIC,2026/10/09,16:36:24,001791527784351,MONTHLY_ARCHIVE,001791527784351
I,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,TRANSMISSIONLOSSFACTOR,EFFECTIVEDATE,VERSIONNO,CONNECTIONPOINTID,REGIONID,LASTCHANGED,SECONDARY_TLF
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,1,"2026/09/08 00:00:00",1,QASSHU01,QLD1,"2026/09/04 15:07:18",
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,1.0036,"2026/09/15 00:00:00",1,STB31T,SA1,"2026/09/11 15:07:33",0.9917
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,0.9862,"2026/09/15 00:00:00",1,VJL21W,VIC1,"2026/09/11 15:39:12",0.9817
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,0.989,"2026/09/21 00:00:00",1,VMWF,VIC1,"2026/09/18 14:37:15",0.989
C,"END OF REPORT",7

Availability

Visibility: Public

This table is in the public monthly MMSDM archive.

I have collated the list of all those files into one place, in this CSV metadata file. (Columns year, month, url, compressed_size in bytes).

The earliest available data is month 1 of 2015. The most recent available data is month 9 of 2026.

Warning

There are some months with no files.

Warning

The REPORT_SUB_TYPE metadata column has the same column name as an actual columns TRANSMISSIONLOSSFACTOR. So the raw CSVs have duplicate column names. You will need to be careful when reading this CSV.

Warning

The REPORT_SUB_TYPE metadata column has the same column name as an actual columns TRANSMISSIONLOSSFACTOR. So the raw CSVs have duplicate column names. You will need to be careful when reading this CSV.

Data Size

Each year of data is approximately 6 KB when zipped, 64 KB as unzipped CSV.

Deduplication and PDR Loader Configuration

The primary keys are:

The transaction type is "INSERT-UPDATE", which means that you will likely see duplicate data with different values.

You should deduplicate by sorting based on LASTCHANGED, within each group of primary keys.

PDR Loader configuration is:

Report Name Report Subtype Version
MARKET_CONFIG TRANSMISSIONLOSSFACTOR 1
MARKET_CONFIG TRANSMISSIONLOSSFACTOR 2

This means that the CSV files start with metadata columns:

I,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,1,...
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,1,...

or

I,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,...
D,MARKET_CONFIG,TRANSMISSIONLOSSFACTOR,2,...

ROW_FILTER_TYPE is LASTCHANGED

Indexes

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: MARKET_CONFIG