Network reliability

Regional Western Australia presents a challenging environment to provide reliable power to our customers Due to the long distances involved, many regional towns and customers are supplied by only a single radial feeder (power line) from the substation – some of which can be up to 200km long. These lines may go through bushland and forest, across waterways, and private farmland, and may be very difficult to access. These challenges, combined with the long distances involved, means that it can take our crews a long time to locate and fix faults when they occur. These repairs may be further hindered by severe weather and fire, as our crews can’t access and restore the fault until it is safe to do so. 

Localised unplanned outages are an interruption to the transmission or distribution of electricity that is unscheduled. These can be caused by storm-blown branches, wildlife, pole-top fires or bushfires anywhere along the line that trip the supply and result in an unplanned outage.  

In collaboration with local communities, Western Power is identifying  tailored solutions that will help improve reliability in the medium to long-term.  

Improvements we are making include: 

• New interconnections between feeders (including normally open points) to reduce restoration times and enable backfeeding  
• Installation of new Load Break Switches (LBSs) and reclosers to sectionalise long feeders and isolate faults faster  
• Network reconfiguration and operability changes to reduce restoration times and enable backfeeding 
• Automation of existing devices (e.g. Ring Main Units, voltage regulators and reclosers)  
• Protection upgrades and optimisation to isolate faults faster and reduce the number of customers affected 
• Advanced recloser controllers and communications  
• Distribution Automation and Protection Reconfiguration (DAPR) system on selected feeders to automate restoration  
• Installing Fuse Savers, a new, innovative device which temporarily stops power when a fault occurs, checks if the fault has resolve, and restores power if it was only a temporary issue — all without blowing the fuse. 
• Replacing equipment of ageing assets following a fault  (e.g. poles, conductors, equipment following faults 
• Rolling out enhanced maintenance programs, such as proactively siliconing conductors on targeted feeders 
• Improving SMS alerts for both planned and unplanned outages. An automated 24-hour SMS reminder for planned outages will be introduced in early 2026. 

We understand that outages, power interruptions and major weather events cause significant frustration for residential customers and businesses. Losing power can have health and safety impacts, cut off communications, cause refrigerated produce to spoil, and even result in a loss of income. This is why Western Power is committed to improving reliability and reducing the duration of unplanned outages in regional WA. 

To inform our planning, we compile data from across the South West Interconnected Network to identify the regional local government most impacted by outages. The data tells us how often the power went out in each area, how long the power was off for, and the average time power was off for each customer during an outage.    

The top 10 regional local government most impacted by all power supply interruptions in 2024/25, including the necessary planned outages to address maintenance etc., are listed below. The information is based on 2024/25 data analysis and statistics. 

• Bremer Bay
• Bullsbrook

As part of the Access Arrangement, Western Power must include service standard benchmarks for each of its reference services. These are monitored by the Economic Regulation Authority. 
 
The Western Power - Service Standard Report - 2024/2025 contains information about the performance of the Western Power network, localised by area. 

• Appendix A provides FY25 charts for each of the Service Standard Benchmarks, showing the trend of historical performance over various periods where data is available.
  
  
• Appendix B shows FY25 Reliability measures by individual feeder and by Local Government Area (LGA).

SAIDI and SAIFI

SAIDI and SAIFI are reliability metrics defined under the National Regulatory Reporting Requirements (NRRR). They help measure the overall reliability of the electricity network:

• SAIDI (System Average Interruption Duration) Index – Total number of minutes, on average, that a customer on a distribution network is without electricity in a year.
  
  
• SAIFI (System Average Interruption Frequency Index) – The average number of times a customer’s electricity supply is interrupted per year.

SAIDI Service Standard Benchmarks for Access Arrangement 5 (AA5)  FY22 - FY27