For Mariza Butler, Senior Engineer for Grid Transformation at Western Power, that is a good start. "We want as many people as possible to use photovoltaics, feeding their energy into the grid and thus contributing to climate protection," she says. There is a problem, however. If the amount of electricity that is flowing from private consumers back into the low-voltage grid increases while the electrical load is low, the voltage in the grid also rises.

This is especially the case during the Australian spring and fall. When the use of climate control systems is lower, people spend time outdoors thanks to the mild temperatures, and the electricity demand is correspondingly lower. However, the sun does not care – it continues to shine on the solar panels. A certain amount of fluctuation in low voltage is normal, but there are limit values that must be maintained. For European grid operators, there is a leeway of 46 V (230 V, plus/minus ten percent), but for Western Power on the other side of the world, it is just 29 V (240 V, plus/minus six percent).

How do you stabilize distribution grids with a volatile energy supply? MR's answer is the ECOTAP® VPD® on-load tap-changer. It is the third generation of tap changers for regulated local grid transformers (VRDTs), which makes dispersed voltage regulation in the distribution grid possible. The Managing Director of Reinhausen Australia delivered a presentation on this topic in 2016 at a meeting of the work group for distributed power generation (C6) of Cigre Australia in Tasmania. This piqued the interest of Western Power. The electricity provider agreed to a pilot project with MR, in which eleven selected pole-mounted transformers would be equipped with the ECOTAP® VPD®.

The ECOTAP® VPD® is installed on the high-voltage winding of the transformer. It includes a measuring device that monitors both current and voltage on the low-voltage winding of the transformer and automatically makes a change to the transmission ratio if the voltage fluctuations go beyond the defined limits. "It was important to us that we find a set-and-forget solution to our problem," explains Butler. A centralized solution was less ideal in light of the sheer number of transformers in Australia – around 1.5 million distribution transformers, of which 90 percent are pole-mounted transformers.

The automatic regulation function of the power-dependent setpoint adjustment (TDSC — Tapcon Dynamic Setpoint Control) was especially appealing to Western Power. Using a current transformer, the power and direction of the current are measured and then the position of the on-load tap-changer is automatically adjusted. As a result, voltage drops and higher line voltages are offset.

 "With the regulated ECOTAP® VPD®, we may have found the ideal way to expand our measures for the regulation of our grid," says Butler. This puts the company at ease in the face of a future in which electric cars and home energy storage pose more new challenges for power grids. "We have to do our part for climate protection, in any case," says Butler. "And the products from MR make it easier to reach this goal."