A fun way to think about a national electrical grid is as a massively upscaled electrical circuit, one in which you have multiple power supplies injecting AC power, with various bits and bobs involving resistors, inductors and capacitors in between working to synchronize and clean-up this power before it gets to the end users. Recently [Jordan Taylor], also known as [The Electric Brit] took a look at the grid’s harmonic filters that do a lot of this sinewave scrubbing after the HVDC to AC conversion.

Using a UK-based line-commutated converter (LCC) HVDC converter station as a physical example [Jordan] takes us through the elements of this harmonic filter, what it is, what it does and why it’s a necessity. The design considerations with components at this immense scale are also covered, along with the types of filters possible.

The Cliff’s Notes version is that following the conversion step from said HVDC there are harmonics introduced in the AC, not unlike in a much lower-voltage converter. This results in a noisy sinewave that can potentially cause harm to AC-powered devices, not to mention cause heating and other losses along the way. The answer is naturally to add an LC-filter, just on a slightly larger scale than for consumer electronics.

Also noted by [Jordan] is the nice synergy of these harmonic filters when it comes to absorbing and generating reactive power on the AC grid, due to their massive capacitors and inductors. This helps to dampen oscillations on the grid and thus further contributing to its stability.

In this modern age, if you want a truly swish garden that makes your friends sad when they visit, you need good lighting. [technocraftStudio] has been working on just such a project, creating custom wedge lights to illuminate garden beds in style.

You might look at the plastic housings involved and assume that they’re 3D printed, like the vast majority of such projects we cover these days. Instead, the enclosures are crafted out of PVC plastic, harvested by flattening sections of pipe with a heat gun. It has the benefit of being highly weather resistant, and cheap to boot. The lights themselves are small LED panels mounted on aluminium plate as a heatsink, and fitted with an acrylic diffuser to spread the light out more evenly. Power for the lights comes from an 18650 lithium-ion cell, charged by a pair of solar panels hooked up to an MPPT charge controller. A TP223 capacitive touch module is also included in the design to allow the lights to be turned on with just the touch of a finger.

The result is a surprisingly stylish bit of garden furniture which provides warm, even light and, ideally, needs a minimum of maintenance and attention since the sun provides the power. We’ve featured some other great solar lamps before, too, like this lovely Pokemon-themed build. If you’re building your own solar projects at home, or doing weird things with PVC, we’d probably love to hear about it on the tipsline!