This article is intended primarily for electricians working in areas where lights flicker as a result of the supply authority signalling and reporting methods. Many are unaware of the true cause of flickering lights, and this article aims to provide more clarity on the root of this problem and how to solve it.
Electrical Supply Authority
Throughout Australia, the Electrical Supply Authority sends a signal via the power line of either 750Hz or 1050Hz in most areas; or 492Hz in a few regional areas. Ripple control has existed for many years and is used for controlling demand and implementing different customer tariffs; for example, switching a site between its on-peak and off-peak meter in the days before smart meters.
Ripple Control & Frequency Signals
In Australia, our electricity supply can range from 230 to 250 volts AC at 50 hertz. AC means alternating current, a type of electrical energy that flows in one direction for half a cycle, and then in the opposite direction for the other half a cycle. 50 hertz means there are fifty cycles per second. Ripple control will superimpose higher frequency signals on the 50 hertz mains supply so that they can be distributed throughout a local power grid.
These signals are understood by specific hardware that then turns on or off, such as off-peak hot water heaters. Electricity suppliers can use different frequencies at different times and therefore devices in one area/suburb may be affected whilst the same device in another area/suburb may not be.
The Effect on Electrical Devices
Unfortunately, many electrical devices including toasters, fridges, fans, fluorescent, halogen, and LED lighting can be sensitive to these frequencies. This may lead to buzzing sounds or other side effects from affected devices. In the case of LED lights, there can be a perceptible flicker, especially if its connected to a dimming device or driver.
Why are you telling me this? Do you have flickering or flashing lights?
Here at M-Elec we get calls every day from home-owners, tenants and electrical contractors wanting to replace downlights because they believe they are faulty.
Eliminating Flickering in LED Downlights
When you have lights flashing / flickering at regular intervals or at the same time each day, it is highly likely to be caused by the supply authority ripple frequency signalling. Installing a ripple frequency filter can reduce or eliminate the flicker / flashing of LED downlights.
Choosing the Appropriate Ripple Frequency Filter
The signal in South-East Queensland and areas of NSW can be sent in two basic signal formats; 750Hz and 1050Hz. It’s best to have the electrician contact the local supply authority to confirm which signal is being used in a particular area. Failing that, an electrician can simply install signal filters for both signal formats.
Several companies produce ripple frequency filters that can be installed either at the device you wish to protect, or on the entire circuit to protect many devices. These filters MUST be installed by a licensed electrician and the filter must be matched to the signals in your area (ie: 750Hz/1050Hz etc.).
Because signals vary significantly between providers and areas, it isn’t possible to build frequency filtering into every device, especially not small devices. If you are affected by ripple control, please contact your local electrician and they can select and purchase the appropriate filter.
Occasionally, the ripple control signals are so strong they cannot be sufficiently filtered. In some cases, additional sine wave correcting devices may also be required for optimal performance.
Suggested common and simple remedies to the Ripple Frequency Issue, for the more common signal frequencies:
We hope this article has cleared up any myths or ongoing concerns you may have around flickering LED lighting.
Wayne Crookes – Product Support