Simultaneous loss of controls on two DC interconnectors (Saturday 15th August 2026)

Posted by Paul McArdleSaturday 15th August 2026  1:58 PM   Topic: 2026-08-15

A short article to note simultaneous loss of control on the two x DC interconnectors on the mainland for a couple hours on Saturday morning 15th August 2026.  Both Directlink and Murraylink are operated by APA Group, so I wonder what the common factor was behind the simultaneous outage?

 

 

Directlink Murraylink

At 06:18:42 was MN144803:

‘——————————————————————-
MARKET NOTICE
——————————————————————-

From :              AEMO
To   :              NEMITWEB1
Creation Date :     15/08/2026     06:18:42

——————————————————————-

Notice ID               :         144803
Notice Type ID          :         INTER-REGIONAL TRANSFER
Notice Type Description :         Inter-Regional Transfer limit variation
Issue Date              :         15/08/2026
External Reference      :         Inter-Regional Transfer limit variation – Directlink control unavailable (NSW Region)

——————————————————————-

Reason :

AEMO ELECTRICITY MARKET NOTICE

Inter-Regional Transfer limit variation – Directlink control unavailable (NSW Region)

AEMO has been notified that the controls to vary Directlink output are unavailable until further notice.

Constraint set I-CTRL_ISSUE_TE invoked from 0615 hrs.

The constraint set contains equations with the following interconnector on the LHS:

N-Q-MNSP1

Manager NEM Real Time Operations

——————————————————————-
END OF REPORT
——————————————————————-’

Then at 09:35:24 was MN144804:

‘——————————————————————-
MARKET NOTICE
——————————————————————-

From :              AEMO
To   :              NEMITWEB1
Creation Date :     15/08/2026     09:35:24

——————————————————————-

Notice ID               :         144804
Notice Type ID          :         INTER-REGIONAL TRANSFER
Notice Type Description :         Inter-Regional Transfer limit variation
Issue Date              :         15/08/2026
External Reference      :         Cancellation Inter-Regional Transfer limit variation – Directlink control unavailable (NSW Region).

——————————————————————-

Reason :

AEMO ELECTRICITY MARKET NOTICE

Cancellation Inter-Regional Transfer limit variation – Directlink control unavailable (NSW Region).

Refer AEMO Electricity Market Notice 144803

AEMO has been notified that the controls to vary Directlink output are now available.

Constraint set I-CTRL_ISSUE_TE revoked at 0900 hrs.

Manager NEM Real Time Operations

——————————————————————-
END OF REPORT
——————————————————————-’

At 06:18:32 was MN 144802:

‘——————————————————————-
MARKET NOTICE
——————————————————————-

 From :              AEMO
To   :              NEMITWEB1
Creation Date :     15/08/2026     06:18:32

 ——————————————————————-

 Notice ID               :         144802
Notice Type ID          :         INTER-REGIONAL TRANSFER
Notice Type Description :         Inter-Regional Transfer limit variation
Issue Date              :         15/08/2026
External Reference      :         Inter-Regional Transfer limit variation – Murraylink control unavailable (SA Region)

 ——————————————————————-

 Reason :

 AEMO ELECTRICITY MARKET NOTICE

 Inter-Regional Transfer limit variation – Murraylink control unavailable (SA Region)

 AEMO has been notified that the controls to vary Murraylink output are unavailable until further notice.

 Constraint set I-CTRL_ISSUE_ML invoked from 0610 hrs.

 The constraint set contains equations with the following interconnector on the LHS:

 V-S-MNSP1

 Manager NEM Real Time Operations

 ——————————————————————-
END OF REPORT
——————————————————————-’

Then at 09:34:54 was MN144805:

‘——————————————————————-
MARKET NOTICE
——————————————————————-

 From :              AEMO
To   :              NEMITWEB1
Creation Date :     15/08/2026     09:34:54

 ——————————————————————-

 Notice ID               :         144805
Notice Type ID          :         INTER-REGIONAL TRANSFER
Notice Type Description :         Inter-Regional Transfer limit variation
Issue Date              :         15/08/2026
External Reference      :         Cancellation Inter-Regional Transfer limit variation – Murraylink control unavailable (SA Region)

 ——————————————————————-

 Reason :

 AEMO ELECTRICITY MARKET NOTICE

 Cancellation Inter-Regional Transfer limit variation – Murraylink control unavailable (SA Region)

 Refer AEMO Electricity Market Notice 144802

 AEMO has been notified that the controls to vary Murraylink output are now available.

 Constraint set I-CTRL_ISSUE_ML revoked at 0900 hrs.

 Manager NEM Real Time Operations

 ——————————————————————-
END OF REPORT
——————————————————————-’

 

Using ez2view to pull up two copies of the ‘Constraint Set’ details widget for each constraint side-by-side, a quick eyeball reveals some some overlap historically between other instances:

2026-08-15-at-13-45-ez2view-DCLinks

Once I started spotting some earlier overlaps, I stopped reading further …

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About the Author

Paul McArdle
Paul was one of the founders of Global-Roam in February 2000. He is currently the CEO of the company and the principal author of WattClarity. Writing for WattClarity has become a natural extension of his work in understanding the electricity market, enabling him to lead the team in developing better software for clients. Before co-founding the company, Paul worked as a Mechanical Engineer for the Queensland Electricity Commission in the early 1990s. He also gained international experience in Japan, the United States, Canada, the UK, and Argentina as part of his ES Cornwall Memorial Scholarship.

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