The rise of renewable energy has put ammeter resistors back in the spotlight. This article explores ammeter-resistor operation and how to choose the right one for a particular application’s needs.

The world has turned to renewable energy in an attempt to wean itself from depleting carbon-based sources. The increase in the number of solar, wind, wave, and tidal power sources has pushed the need for a highly accurate method of measuring current. The solution is required for several reasons: to ensure accurate billing, have a more granular level of control, and, perhaps most importantly, to ensure the efficiency of the distributed power system.

There are a few ways to measure current. However, the one most suited for renewable applications looks to be conventional ammeters, using shunt resistors to handle the high currents.

Renewable power is not a recent phenomenon. Hydroelectric plants have been popular in some areas for many decades. But for countries trying to switch away from a carbon-based economy, large-scale use of solar and wind power has been the main focus of the new generation of renewable power sources.

Power from these renewable sources differs from conventional sources, such as coal, gas, and nuclear plants. This is because renewables either generate dc power directly, or the power they generate requires some conversion between ac and dc and back. Carbon-based generation inherently produces ac power, which can easily be fed into the grid using substation transformers.

Renewable energy travels a more complex route to the power grid. Photovoltaic panels generate pure dc energy, which must use an inverter to be converted to ac to feed into the grid. Some wind turbines also generate dc, especially the smaller installations seen near homes, farms, and industrial units.

In larger wind-farm installations, it’s possible for the turbines to produce ac power. However, connecting the power to the grid requires the voltage and frequency to be compatible with the grid. In many cases, though, this isn’t the case. The voltage and frequency of the output power is correlated with the rotational speed of the wind turbine, which depends on the wind speed.

Read more: Renewable Energy Revitalizes the Ammeter Shunt Resistor