Showing Brownouts the Way Out
Jun 13, 2014
Eric Moutaux

The recent series of rotating brownouts that hit the Philippines last month exemplifies a common problem that still exists and is experienced both in developing and developed countries across the world. While brownouts do not disrupt service to the same extent as a blackout, they can severely damage electrical equipment and inhibit machines from working at optimum capacity; something which can gravely affect a country’s industrial and commercial output.

However, what exactly is a brownout? In short, it’s the temporary interruption to electrical grid service to an area caused by an intentional or accidental drop in voltage. When the AC supply drops below the nominal value of approximately 10%, normal flow of power is disrupted. Demand, therefore, cannot be met and a brownout occurs. There are many scenarios that can trigger a brownout; however, in the first of our two part series on the topic, we will explore the top 3 reasons why they still occur:

1) Overloads on the electrical system during peak times of electrical demand

Brownouts often occur during peak times of electrical consumption. For example, this happens during the summer months – particularly in hot countries - when large amounts of electricity is used to power cooling devices and the grid over-heats due to the hot weather. Take for example the brownouts in New York; after temperatures of 94 degrees Fahrenheit for several days in a row, many neighbourhoods experienced typical ‘symptoms’ of brownouts including dimmer lights and warm water instead of hot.

The surge in demand around this year’s FIFA World Cup has also caused analysts to predict a 20% chance of a brownout in Brazil during this time. This figure is well above the 5% that the national-grid operator thinks tolerable. 

2) Damages to power lines, substations or other parts of the distribution system, a short circuit or overloading of electricity mains

Natural weather occurrences such as storms and sometimes earthquakes can cause damage to parts of the distribution network. This can immediately affect the voltage output in a local power grid and thus cause a brownout.

3) Deliberately induced brownouts

Sometimes power companies intentionally drop voltage in certain areas if they sense that a disruption will cause serious problems. More often than not this action will be taken so engineers can perform vital maintenance on grid equipment such as transformers.

In part two of our series on brownouts, we will look at the three main areas energy companies and governments around the world need to address to reduce the frequency of brownouts and the damage they cause.

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Eric Moutaux

Eric Moutaux is the global HVDC business leader for GE's Power Conversion business, working across global teams to bring efficient and reliable solutions to T&D and power generation customers. Prior to this role, Eric was a commercial director for both HVDC and FACTS for Alstom Grid, also holding project management roles in the T&D space at Cogelex Alsthom and Cegelec. Eric is an electrical engineer and graduated from EN SIEG in France.