Western Power shelled out almost $4 million last year to 48,000 households and businesses affected by extended interruptions, a 65 per cent rise on the previous year.
The Economic Regulation Authority published its latest performance report for WA's energy distributors yesterday, noting Western Power had generally improved its customer service and reliability.
However, the watchdog also said that in the 12 months to June 30 last year Western Power had to pay out $3.8 million to 46,523 customers whose supply was cut for more than 12 hours.
It was two-thirds more than the previous year, the ERA said, but acknowledged about 37,000 of the payments stemmed from outages during storms in June 2012.
On the top of the blowout in interruption-related payments, the ERA said there had been a rise in the average length of interruptions affecting rural electricity customers. A typical interruption in these areas in 2012-13 lasted 979 minutes - or 16.3 hours - compared with 947 minutes in the previous reporting period.
Under national guidelines, the average length of interruptions in rural areas is supposed to last no longer than 290 minutes, meaning Western Power exceeded the benchmark by more than 11 hours.
"Western Power cited lightning strikes across geographically remote areas of the network as the primary contributor to the increases in the average length of time that customers were off supply in rural areas during 2013," the ERA said.
Overall, it found that though the average length of "extended" interruptions in rural areas increased last year, the number of customers affected fell 78.4 per cent to 38,820 premises.
There was also a fall in the number of CBD and urban customers who had multiple interruptions.
Conversely, the number of rural customers hit by multiple blackouts more than doubled in Western Power and regional provider Horizon Power's networks.
The number of complaints to Western Power under its customer code fell to a six-year low last year.