Areva T&D HV Instrument Transformers

Reactors are either series or shunt connected with the feeding lines. Series connected reactors are used to limit currents while shunt connected reactors compensate reactive power. Typical applications include the following:

Current Limiting Reactors: Designed to limit short circuit currents to values compatible with equipment ratings connected after the reactor.

Filter Reactors: These reactors when connected in series with a shunt capacitor form a series resonant LC circuit for specified harmonic currents.

Inrush Current Limiting Reactors: Series connected with capacitor banks to limit the currents which occur during switching operations.

Neutral Grounding Reactors: Connected between the neutral terminal of transformers and ground to limit phase to ground short circuit currents.

Shunt Reactors: Used with static compensators and at the end of lightly loaded long transmission lines to avoid over-voltages.

Smoothing Reactors: Reduce the ripple superimposed by direct current systems and in series with big DC machines fed by rectifiers.

Duplex Reactors: Produce a small reactance under normal conditions and a large reactance under fault conditions. A small voltage drop thus occurs under normal conditions since the magnetic fields of the two halves of the coil are opposite resulting in a low reactance between the power supply and the load. During fault conditions in one of the feeding circuits the fault current flows through one half of the coil and consequently the opposing flux of the other half coil is insignificant. The short-circuit current is limited by the increased reactance of the half coil in series with the feeder under fault conditions.

Motor Starting Reactor: Limit the starting current of electrical machines in AC circuits.

Damping Reactor: Damping of the transients in series capacitor installations.

Load Balancing Reactors: Control the current into two or more parallel circuits.

AREVA offers two different construction techniques with the goal in mind to meet the technical specification at minimum cost. The customer may have alternate reasons to select one technology over the other. The design options are open style (OSD) or fiberglass encapsulated (FED).