frequently asked questions
- What causes power blackouts?
- Why does the power drop out for only five or ten seconds?
- These short interruptions to the power system mean I have
to reset my clock radio, microwave, VCR and other appliances. This is both a
nuisance and an inconvenience. Can anything be done to prevent these devices
going out?
- Why does the power supply to my residence sometimes surge or spike?
- What causes my lights and other appliances to dim?
- Does breakdown of United Energy's equipment cause many blackouts?
- What specifically is United Energy doing to fix the problem of blackouts?
- With all this new technology, why does the system break down?
- If most of the blackouts are caused by interference to the overhead power lines, why don't you put the power lines underground?
What causes power blackouts?
The majority of outages are caused by tree branches brushing against power lines, interference by animals and birds, vandalism, vehicle accidents and weather, including high winds and lightning. Further details about these causes are contained in our Reliability of Supply Report and the section on Why Outages Occur located in this web site.Why does the power drop out for only five or ten seconds?
An important part of United Energy's electricity network system is "automatic reclose" which allows us to automatically restore electricity supply to customers following momentary interference with power lines. For instance, this occurs when a tree branch brushes or falls across a power line or a bird contacts the power line. The system that protects the electricity network has functioned correctly and has disconnected the supply for between 3 and 15 seconds. The interruption caused by this technology is normal and has reduced what was once a significant outage to less than 1 minute.These short interruptions to the power system mean I have to reset my clock radio, microwave, VCR and other appliances. This is both a nuisance and an inconvenience. Can anything be done to prevent these devices going out?
Unfortunately these irritating interruptions to clocks and other programmable logic controlled devices, cannot be avoided. Many electronic devices do come with battery back up which allow them to "ride through" such short-term interruptions. When purchasing electronic equipment like VCRs and clock radios you may wish to ask the salesperson for products with this feature.
Why does the power supply to my residence sometimes surge or spike?
Surges are fairly uncommon events on our network. Momentary dips in the power are the predominant cause of flickering lights. Momentary surges and dips in voltage can occur due to lightning, a fault in the local vicinity or switching of large devices on the network or even within your house or neighbourhood. These momentary surges on the electricity supply system can also occur due to a car hitting a power pole, lightning or interference by an animal or bird.What causes my lights and other appliances to dim?
Dim lights are a result of low voltage caused by a problem in a nearby substation. If these dips (sags) in power continue for more than a few seconds, we recommend that you disconnect your electrical appliances until the power is restored. Once the power supply is returned to normal, you can then reconnect those appliances.Does breakdown of United Energy's equipment cause many blackouts?
Historically, interruptions to power supply caused by equipment breakdown comprise around 20% of total outages. These faults can occur on equipment which then needs replacing or electrical assets which require repair. A regular maintenance program helps to minimise breakdown due to equipment failure.Many problems cannot be detected until it is too late or equipment is damaged, for example the electrical discharge that leads to pole fires or other electrical stresses that cause failure later.
Planned outages represent about 10% of the total amount of shutdowns on the United Energy network.
What specifically is United Energy doing to fix the problem of blackouts?
In 1997, United Energy acknowledged that its reliability of supply performance was below our and our customers' expectations. As a result, we started a program of improvement initiatives to fix many of the problems we have had in the past. We have spent over $40 million on these programs between 1997 and 2001 to improve our service delivery to customers over and above our normal maintenance program. More information on this work is available in United Energy's Community, Environment and Safety Report (PDF) (551kb) .
With all this investment in new technology and best practice, why can't we have a system that never breaks down?
Because United Energy's electrical system network is mainly overhead poles and wires, we can never totally prevent outages caused by the collapse of trees onto power lines, blackouts caused by lightning or powerful winds, or vehicles hitting poles.Our reliability of electricity supply is currently better than 99.98%. It needs to be recognised that weather, animal habits, vegetation and other external factors ultimately prevent 100% reliability.
If most of the blackouts are caused by interference to the overhead power lines, why don't you put the power lines underground?
There are three issues to note about underground power systems. First, they cannot guarantee 100% reliability of supply. They can break down, as has been experienced overseas and in Australia, and are still subject to outside influences such as being accidentally dug up.Second, the cost of converting to an underground system across the entire United Energy service area has been estimated to cost about $3 billion. This is not a cost that could reasonably be borne by the company or its customers.
Finally, United Energy proposed to spend $60 million on proactive undergrounding of assets in their Customer Value submission to the 2000 Electricity Price Review. However the Office of the Regulator-General (now known as the Essential Services Commission) disallowed this expenditure in their final ruling, not allowing us any major expenditure for undergrounding over the period 2001 to 2005.
