What's actually happening during a power cut?

There’s no other way to put it: power cuts stink. One snip of the electrical umbilical cord and just about every part of modern life grinds to a halt as we resort to things best left to the annals of history. Out come the candles, books and gas stoves, while conversations with your housemates inevitably lead to the million dollar question: when are we going to get our power back? 

In New Zealand, we’re blessed with strong electricity infrastructure, which means our blackouts are usually resolved in a matter of minutes or hours. But what’s to blame for these annoying power cuts? Read on to find out what’s actually happening when your power goes down and how you can prepare for such an event.

What is a planned outage?

There are two types of power cuts, with the most predictable and least disruptive being a planned outage. As the name implies, a planned outage occurs when the lines company deliberately cuts power in order to carry out repairs, maintenance or upgrades on some part of the electricity distribution network, such as:

• Transformers
• Power poles
• Power cables

...and more.  For safety reasons, this work often requires the power to be turned off. Your electricity retailer should give you plenty of warning of any planned outages to give you time to prepare.

What is an unplanned outage?

The loss of electricity during an unplanned outage is, well, unplanned, and usually occurs when something has unexpectedly damaged part of the network.

The flow of power into your home relies on a complex network of assets that are naturally susceptible to physical damage. While both energy generators and distributors have systems in place to protect the network, there’s always a risk that external elements such as stormy weather, high-wind conditions and fallen trees can damage the individual assets. Of course, Mother Nature isn’t solely to blame; car accidents can topple power poles while construction workers occasionally dig in the wrong spot and hit a critical line or cable.

Any of these scenarios can put excessive stress on certain network components and increase the risk of an overloaded circuit, which in turn may ultimately lead to a blackout.

New Zealand’s worst unplanned outage in recent history was the 1998 Auckland Power Crisis. At the time, the Auckland CBD relied almost entirely on four 110 kilovolt gas-insulated cables that powered two substations located at Quay Street and Liverpool Street.

Unfortunately, two of the cables failed in less than a month, putting incredible strain on the remaining two cables, which failed less than two weeks later. About 20 city blocks were plunged into darkness for five weeks as the lines company scrambled to repair the damage. All in all, the Auckland Power Crisis affected more than 60,000 employees and 6,000 residents who worked and lived in the area.

How to prepare for a power outage

Power outages can range from ‘annoying’ all the way through to ‘life threatening’. The good news is that there are a number of things you can do to maximise your comfort and safety during a blackout. Electra Operations Manager Baden Berry took the time to share some of his insights. 

When notified of an upcoming outage, plan what you need to do to avoid being inconvenienced. Think about what will be unavailable while the power is off. Ask yourself:

• Are my devices charged up to let me stay connected to the world?
• Will I be able to get the car out of the garage or should I park it on the driveway?
• Should I boil the jug for a cuppa or fill a thermos before the power goes off?
• If it is a cold day, will I be able to fill a hot water bottle to stay snug?

For people living out of town, there are extra concerns: 

• Will I be able to flush the loo?
• Should I fill some buckets with water before the pump stops working?
• Can I control my stock without electric fences or should I move them to a more secure location?

While the power is off, consider what you would do if the outage was not planned but had happened as the result of a storm or earthquake.

• How prepared am I to go for three of four days without power?
• Do I have enough food and water to get me through?
• Can I use the BBQ to make coffee and cook food?
• Do I have a torch or a headlamp with spare batteries? Avoid using candles as they can cause fires.
• Have I protected my sensitive appliances? Should I unplug them to avoid damage?

Finally, don’t forget to treat all power lines as dangerous before, during and after a power cut. Visually, it’s impossible to tell whether power is flowing through them or not.

Here at Grey Power Electricity, we know that any power cut can be annoying. To minimise disruption, we always make sure all our customers are aware of any planned outages at least 10 days in advance to allow plenty of time to prepare.