Patent EA-001877-B1 (EA)
Title: A method and an arrangement for regulating a transformer/reactor, and a transformer/reactor
Inventor: BERGGREN SOREN
IPC: H01F27/32
Filed: 1998-09-29
Abstract: 1. A method for regulating an induced voltage in a transformer, alternatively regulating the reactive power of a reactor, wherein a winding is achieved with an insulating electric conductor including at least one current carrying conductor, a first layer having semiconducting properties arranged to surround the conductor, a solid insulation layer arranged to surround said first layer, and a second layer having semi conducting properties arranged to surround the insulating layer, wherein a regulating winding is arranged around a magnetic flux carrier, and wherein the length of said regulating winding around the magnetic flux carrier is varied. 2. A method according to claim 1, characterized in that said regulating winding is arranged on a regulating winding means, said regulating means being rotatable around said magnetic flux carrier. 3. A method according to claim 1 or 2, characterized in that a variable part of the regulating winding is transferred to or from at least one storage means. 4. A method according to any one of the preceding claims, characterized in that the transformer/reactor includes a main winding with which the regulating winding may be connected. 5. A method according to claim 4, characterized in that starting from a zero position in which there is no winding on the regulating means, the induced voltage/reactive power of a transformer/reactor is increased in that the winding is wound onto the regulating winding means in the same direction as the direction of the main winding, and that the induced voltage/reactive power of a transformer/reactor respectively, is decreased in that the winding is wound onto the regulating winding means in the direction opposite to the direction of the main winding, whereby the maximum variation of the number of winding turns is +/-N, where N is the number of winding turns which are available on the regulating winding means. 6. A method according to any one of claims 4-5, characterized in that the existing length of winding on the regulating winding means is varied by stepless control, whereby the induced voltage and the reactive power respectively, are varied by stepless control. 7. A method according to any one claims 4-5, characterized in that the existing length of winding on the regulating winding means is varied by at least one winding turn at a time whereby the induced voltage and the reactive power respectively, are varied in steps corresponding to one winding turn. 8. A method according to any one of claims 3-7, characterized in that a storage means includes a rotatable storage drum, whereby the regulating winding means is rotated by means of a drive means so that the winding is transferred from the regulating winding means to the storage drum or vice versa. 9. A method according to any one of claims 2-8, characterized in that the regulating means includes a rotatable regulating winding drum. 10. An arrangement for regulating induced voltage in a transformer, alternatively regulating the reactive power of a reactor, wherein said transformer/reactor includes at least one magnetic flux carrier (1) and a winding (5; 26) achieved with an insulating electric conductor (50) including at least one current carrying conductor (51), a first layer (52) having semiconducting properties arranged to surround the conductor, a solid insulation layer (53) arranged to surround said first layer, and a second layer (54) having semiconducting properties arranged to surround the insulating layer, wherein said arrangement further includes a regulating winding (3; 22) arranged around the magnetic flux carrier and a regulating means, by means of which the length of said regulating winding around the magnetic flux carrier is varied. 11. An arrangement according to claim 10, characterized in that said layers (52, 53, 54) are arranged to adhere to one another even when the insulated conductor is bent. 12. An arrangement according to claim 10 or 11, characterized in that the regulating winding is arranged on said regulating means and that said regulating means is rotatable around said magnetic flux carrier. 13. An arrangement according to any one of claims 10-12, characterized in that it includes at least one winding storage means (12) and means for transferring a variable part of the regulating winding (3; 22) to or from at least said storage means (12). 14. An arrangement according to any one of claims 10-13, characterized in that the regulating means includes a rotatable regulating winding drum (6). 15. An arrangement according to any one of claims 13-14, characterized in that the storage means includes a rotatable storage drum (12). 16. An arrangement according to any one of claims 13-15, characterized in that the storage means includes a second winding arranged around a magnetic flux carrier. 17. An arrangement according to any one of claims 13-16, characterized in that the regulating winding is arranged on a magnetic flux carrier leg belonging to one phase of a polyphase system and that the storage means includes a wind ing, arranged on a magnetic flux carrier leg belonging to another phase of the polyphase system. 18. An arrangement according to any one of the preceding claims, characterized in that the transformer/reactor includes a main winding (2) and that the regulating winding (3; 22) is provided with means for electric connection to the main winding. 19. An arrangement according to claim 18, characterized in that, starting from a zero position in which there is no winding on the regulating winding drum, the induced voltage/reactive power of a transformer/reactor respectively, is increased in that said means for transferring the winding (5) are adapted to winding up the winding onto the regulating winding drum (6) in the same direction as the direction of the main winding, and that the induced voltage reactive power of a transformer/reactor respectively, is reduced in that said means for transferring are adapted to winding up the winding (5) onto the regulating winding drum (6) in the direction opposite to the direction of the main winding, whereby the maximum variation of winding turns is +/-N, where N is the number of winding turns which are available on the regulating winding drum. 20. An arrangement according to any one of claims 14-19, characterized in that said transferring means include drive means for the rotation of the regulating winding drum and drive means for the rotation of the storage drum. 21. An arrangement according to claim 20, characterized in that said drive means are in the form of at least one motor and a device for belt driving the respective drum. 22. An arrangement according to any one of claims 15-21, characterized in that the regulating winding drum (6) and storage drum (12) respectively, are rotatable in two directions. 23. An arrangement according to any one of claims 18-22, characterized in that the means for electric connection to the main winding include a diverter switch (15) by means of which the length of the winding is varied by one winding turn at a time. 24. An arrangement according to any one of claims 18-22, characterized in that the magnetic flux carrier is a solid core and that said core is interrupted by an insulating means (20), whereby connection of the regulating winding (22) takes place through said insulating means and through the core, thereby obtaining a stepless variation of the length of the regulating winding. 25. An arrangement according to claim 24, characterized in that the last turn (22a, 21, 21a) of the regulating winding surrounds a magnetic flux which may vary between zero and the flow through a full turn of the winding (22). 26. An arrangement according to any one of claims 24-25, characterized in that said insulating means is composed of a rotatable disk (20) made of an insulating material. 27. An arrangement according to any one of the preceding claims, characterized in that the second layer (54) of the insulating electric conductor is connected to a predetermined potential. 28. An arrangement according to any one of claims 15-27, characterized in that at least one of the regulating drum (6) and the storage drum (12) respectively, is provided with means (60; 28,29; 38,40) for connecting said second layer (54), having semiconducting properties, to a predetermined potential. 29. An arrangement according to claim 27-28, characterized in that the predetermined potential is earth potential. 30. An arrangement according to any one of claims 28 or 29, characterized in that the means for connecting the second layer to a predetermined potential comprise a sliding contact, including an outer tube (62) and an inner tube (63), situated inside the outer tube, which tubes are bent to form a substantially annular element surrounding the core, adjacent to one end of the regulating means, in that one of said tubes is arranged to rotate with said regulating means and in that the other of said tubes is connected to earth, further including at least one helicoidal spring (63) mounted between said tubes, said tubes and said spring being made of an electrically conducting material, such that electrical contact is maintained between the inner tube and the outer tube by means of said spring when the regulating means rotates and the length of said regulating winding around the core is varied, whereby earthing is achieved. 31. An arrangement according to claim 30, characterized in that it further includes an outgoing conductor (68), that the outer tube is provided with an axial slot (67) extending along its outer circumference, and that said conductor (68) extends freely through said slot while one of the tubes rotates with the regulating means. 32. An arrangement according to any one of claims 28-29, characterized in that said means for connection to a predetermined potential include at least one partly conducting ring (28) which is connected to the predetermined potential and located at the one end of the drum as well as extending