Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F29/00—Variable transformers or inductances not covered by group H01F21/00
  • H01F29/14—Variable transformers or inductances not covered by group H01F21/00 with variable magnetic bias

Definitions

• the present invention relates to a selectively controllable high power static
• power devices include those having a rated power ranging from a few hundred kVA up to
• devices is to allow exchange or control of electric energy in and between two or more electric
• windings often include taps making it possible to supply different voltage levels from the
• the invention provides a high power static electromagnetic or induction device with a
• rated power ranging from a few hundred kVA up to over 1000 MVA with a rated voltage
• the invention is based on the discovery that selective switchable control of the flux
• the control may be in the form of a switchable
• At least one of the windings is formed of one or
• the cover comprises a solid insulation
• the electric conductor is located within the inner layer. As a result the electric field is confined within the winding.
• the electric conductor according to
• the device has a flux
• the flux may be selectively admitted or
• regulation may be in discrete steps corresponding to discrete or selective
• the invention employs windings having semiconducting layers which exhibit similar characteristics
• the outer semiconducting layer exhibits such electrical properties that
• the semiconducting layer does not,
• the inner semiconducting layer exhibits sufficient electrical conductivity in order for
• the inner layer has such properties
• the layer may, as such, be formed with a varying thickness but to ensure an even
• the inner layer does not exhibit such a great conductivity that it contributes to induce voltages.
• the inner semiconducting layer for the inner semiconducting layer,
• a transformer according to the invention operates as a
• Such a transformer is capable of limiting
• the transformer is also
• the present invention allows for a flexible AC transmission system with control of
• the components wherein the power flow can be controlled.
• the components wherein the power flow can be controlled.
• the invention allows for dual use without significant
• a reactor may be switchably
• control equipment is generally low voltage equipment and thus, simpler
• the arrangement also avoids the problem of harmonics generation.
• the reactor can perform fast variable reactive power compensation.
• the reactor is capable of performing power flow control by redistribution of active or reactive effect between lines.
• the reactor can limit short circuit currents, provide
• the magnetic circuit of the regulator includes at
• At least one regulation leg having a flux bearing region switchable between open and closed
• regulation winding being connected to the main winding. It is also possible to place at least
• Fig. 1 shows the electric field distribution around a winding of a conventional
• inductive device such as a power transformer or reactor
• Fig. 2 shows an embodiment of a winding in the form of a cable in a high power
• Fig. 3 shows an embodiment of a power transformer according to the invention
• Fig. 3A illustrates a magnetic switch in accordance with the invention
• Fig. 3B shows an open and closed flux path corresponding to open and closed magnetic switches
• Fig. 4 is a schematic illustration of a regulation leg portion of the transformer of Fig.
• Fig. 5 is a schematic illustration of a reactor in accordance with the present invention.
• Figs. 6A and 6B are respective, perspective and sectional schematic illustrations of a
• Figs. 7A and 7B are respective, perspective and sectional schematic illustrations of a
• FIGs. 8 A and 8B are respective, perspective and sectional schematic illustrations of a device in accordance with yet another embodiment of the invention.
• Fig. 9 is a schematic illustration of a three phase transformer according to the
• the devices herein categorized may be designed as single-phase and three-phase
• devices have one or more windings (per phase) and may be designed
• the invention further relates more specifically to a controllable inductance wherein the magnetic flux is selectively redistributed among and between different flux paths by
• the invention operates as a
• Fig. 1 shows a simplified and fundamental view of the electric field distribution
• transformer/reactor 1 including a winding 2 and a core 3.
• Equipotential lines 4 show where
• the electric field has the same magnitude.
• the lower part of the winding is assumed to be at
• the core 3 has a window 4.
• the potential distribution determines the composition of the insulation system since it
• Fig. 2 shows an example of an exemplary cable 5 which may be used in windings
• 5 comprises at least one conductor 6 including a number of strands 6A with a covering 7
• the covering includes an inner semiconducting layer 8 disposed
• the cable 5 may be provided with other additional layers for
• Fig. 3 shows a high power inductive device in the form of a single phase core type
• the transformer 11 in accordance with the present invention.
• the transformer 11 comprises a
• core 12 which is formed with main or outer legs 14,16 and short or inner legs 18 and 20, and
• the core 12 may be made of
• laminated iron sheets having a main or large aperture or window 28 and a plurality of small or
• a primary winding 34 is wrapped around the
• a secondary winding 36 may be wrapped concentrically with the
• a regulation winding 37 formed of
• rings 40-1, 40-2 and 40-3 surround the middle arm
• rings 40-4, 40-5 and 40-n surround the upper arm 26 in the windows 30-1, 30-2 and
• ring 40 comprises one or
• switch 44 More turns of a conductor 42, e.g. copper terminated such as switch 44.
• control may
• the windings 34, 36 and 38 produce the flux ⁇ , which is carried by the core 12 along
• Fig. 4 is a fragmentary portion of the regulation region 32 of the transformer 11
• transformer 11 has the low voltage (LV) winding 34 (N LV turns), the high voltage (HV)
• N HV / ⁇ LV +N R transformer ratio N HV / ⁇ LV +N R ), where N R is an effective number of regulation turns. N R can
• the linking is performed with an
• switchable magnetic rings 40 in the core 12, each of which should as completely as possible exclude the flux from a selected region of the core, or admit the flux
• flux control occurs in a number of ways, each representing a single
• the regulation region 32 is dimensioned for maximum flux
• the regulation region 32 is at least twice the size of a
• a reactor 60 is shown in Fig.
• the reactor 60 has a main flux path 62 and a regulating flux path 64.
• a main winding 66 is a main winding 66
• magnetic contact switch 70 is in the regulating path 64 as shown. When closed, the magnetic
• An additional winding 72 and a magnetic switch 74 may be added to the main
• Figs. 6A - 6B; 7A - 7B; and 8A - 8B illustrate the regulation portion 70 of a transformer, reactor or regulator, as the case may be, depending on the application.
• Figs. 6 A - 6B illustrate a 1 :2:4 arrangement.
• the winding 72 in the form of a cable
• Fig. 2 is wound around a common axis A ppl parallel to the direction of the
• the number of switches 40 required is 2m, where m is the number of
• FIGS. 2 A, 6 A - 6B show sixteen
• Figs. 7A - 7B illustrate a 1 :3:9 arrangement.
• the cable is wound around alternate legs 90-1..., 90-n with axes AP, perpendicular to the main magnetic flux direction. Every second
• leg 50-2..., 50-(N-l) is left unwound as a bridge between the upper and the lower horizontal
• Switches 40-1A, 40-1B..., 40-NA, 40-NB are positioned on the sides of each leg
• Figs. 8A - 8B illustrate a 1 :3:7 arrangement.
• the cable is wound around legs 94-1...
• Switches 40-1 A, 40-1B..., 40-NA, 40-NB are
• each leg positioned on the sides of each leg so that the flux may be linked past or in both directions
• sub-coil 5 74-1..., 74-n with the restriction than in a sequence of incorporated coils
• Figs. 8A - 8B show an example with fifteen
• variable impedances of various kinds may be used. For example, a step function like flux response, variable impedances of various kinds may be used.
• variable or high resistance is used as a load for the ring 40, a variable or high flux distribution
• loading or activation may be provided by an active element, for
• an active filter for example, an active filter. Such a filter could be programmable.
• variable power source e.g., a voltage or current source
• Fig. 9 illustrates another embodiment of the invention wherein a three phase
• a one or more magnetic switches 120 may be employed as hereinabove described.
• switches 120 are located in yokes 114 and 116 to control the flux through the regulation windings 104.
• the windings may be in series or shunt

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Coils Of Transformers For General Uses (AREA)

Applications Claiming Priority (1)

Publications (1)

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• 1998
  • 1998-09-29 AU AU96401/98A patent/AU9640198A/en not_active Abandoned
  • 1998-09-29 EP EP98950250A patent/EP1131829A1/en not_active Withdrawn
  • 1998-09-29 CN CN98814339.9A patent/CN1327601A/zh active Pending
  • 1998-09-29 JP JP2000572870A patent/JP2002526912A/ja active Pending
  • 1998-09-29 WO PCT/IB1998/001777 patent/WO2000019459A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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