Reactors

GBE SpA is specialised in producing class F or H VPI, Cast Resin and Oil reactors, for indoor and outdoor applications up to 5000 A/52 kV. For outdoor applications, GBE SpA can supply Cast Resin reactors even without the protection box, thanks to the use of resin and special UV-resistant coatings.

CURRENT LIMITING / SHORT CIRCUIT REACTORS

The current-limiting reactors are used to limit the line current. They are normally used to ensure that the current does not exceed the values allowed by the protections in the event of a failure. They are connected in series with the line. They are single-phase coreless coils, three-phase connected one above the other, or provided individually and locally, three-phase connected

EARTHING REACTORS

Typically made in oil, they have a three-phase core with zig-zag winding. This type of reactor is used to create a false neutral directly connected to ground or through a resistor. The neutral formers are shunt-connected to the line.

FILTER REACTORS

These are single-phase or three-phase reactors used to reduce the harmonic content in the grid or inside plants with high voltage distortions. They are connected in series or in parallel to the capacitors on both the LV side and the MV side.

SHUNT

The shunt reactors compensate for the capacity of the long transmission lines, avoiding voltage rises in voltage at the end of the same line and are shunt-connected to the line.

SMOOTHING REACTORS

The smoothing machines are connected in series to the DC line, where there is a current ripple that must be reduced. The smoothing reactors are typically single-phase.

DETUNING REACTORS

These are reactors connected in series to capacitors, which allow the resonance frequency to be moved to a value that is not dangerous to these capacitors.

What is a reactor?

A reactor is an electrical inductor designed for power‑system duties. A single‑phase or three‑phase coil that adds controlled impedance into a circuit to shape currents and voltages. Reactors come in several functional types (current‑limiting/series, earthing/neutral‑forming, filter, shunt, smoothing and detuning) and can be built as VPI, cast‑resin or oil‑filled units to suit environmental and electrical requirements.

How do reactors work?

Reactors store energy in a magnetic field and present inductive reactance to alternating current; when placed in series, they limit fault or inrush currents, and when connected in shunt, they absorb reactive power to control voltage. Construction and connection (coreless single‑phase coils stacked for three‑phase, zig‑zag windings for earthing reactors, or tuned series reactors with capacitors) determine the electrical effect and where the device is applied in the network.

What are the benefits of using reactors?

Reactors protect equipment and improve power quality by limiting short‑circuit and inrush currents, reducing harmonics when used with capacitors, creating a controlled neutral for safe earthing, and smoothing DC ripple in converter circuits. Choosing the right construction (class F or H VPI, cast resin or oil) gives mechanical robustness, moisture resistance and suitability for outdoor use, including UV‑resistant coatings that allow cast‑resin reactors to be installed without extra enclosures.

Where are reactors used?

They are widely deployed across transmission and distribution networks, industrial plants, renewable‑energy sites and large converter installations: current‑limiting reactors sit in series with feeders and generators to protect protection systems; earthing reactors form or limit neutral currents; filter and detuning reactors are used with capacitor banks to control harmonics and avoid dangerous resonances.