Automatic contactor batteries are designed for automatic reactive energy compensation in networks with fluctuating load levels and power variations of a few seconds or several minutes. They are divided into steps, controlled by contactors.

This type of battery is installed at the head of a LV distribution or an important sector (workshop, production line, …). It allows a step by step regulation of the reactive energy.

The interlocking of the steps is controlled by a communicating varmetric relay, which measures the voltages and currents on the 3 phases simultaneously. This avoids over- or under-compensation phenomena in the event of a significant imbalance in the currents in the installation. Above all, it allows to check the level of harmonics in the installation, row by row, and thus to prevent dangerous situations such as harmonic resonance phenomena.