Saturated reactors
AssigneeAssociated Electrical Industries Limited
InventorErich Siegfried Friedlander
Life of this patent
Estimating the term…
Abstract
A saturated reactor of the type, for example the treble-tripler reactor, in which groups of 3-phase windings are connected in series to produce multiple flux phases in respective core limbs to achieve harmonic compensation. The windings are connected between the line terminals and a star-point which cannot normally be earthed if large 3rd harmonic components are to be avoided. In this invention the zero-sequence impedance of the reactor is kept at a low value by duplicating the complete primary winding and connecting the two duplicates in zig-zag star. The resulting star point can then be earthed without upsetting the harmonic compensation of the reactor.
Claims10
A saturated reactor arrangement having three line-terminals and a star-point, for providing a reactive load with negligible zero-sequence reactance and the capability of earthing said star-point without reducing harmonic compensation, said reactor arrangement being of the kind comprising:
- A. a core structure having n core-limbs,
- I. where n is at least five,
- Ii. said n core-limbs being in p groups where p is at least one and where n/p is an integer,
- B. each of said p groups having primary windings connected between said three line-terminals and said star-point,
- I. the primary windings of each group being connected in series with the primary windings of each other group if any, and in such manner that fluxes in said core-limbs have phases spaced regularly throughout each half cycle for effecting harmonic current cancellation,
- C. the reactor arrangement further comprising a secondary winding on each of said n core-limbs,
- I. each said secondary winding being interconnected with each other secondary winding to form at least one mesh circuit, wherein the improvement comprises:
- D. constituting the primary windings of
- I. one set of two duplicate sets of primary winding components having said core structure in common,
- Ii. said two duplicate sets being connected in zig-zag star connection between said three line-terminals and said star-point to prevent any net magnetization of said core-limbs by zero-sequence current.
Dependencies are inferred from the claim text.