On-load tap changer

Abstract

The invention relates to an on-load tap-changer (1) having a switching tube (15), an energy accumulator (13) for adjusting a switch position of the switching tube (15), a detector (200) for detecting a switch position of the on-load tap-changer (1), and an on-load tap-changer mechanism (100). The switching tube (15) and the detector (200) are both mechanically coupled to the energy accumulator (13) via the on-load tap-changer mechanism (100).

Claims

1. An on-load tap changer comprising: a switching tube, a force-storing unit for setting a switch setting of the switching tube, a detector for detecting the switch setting of the on-load tap changer and for outputting an electronic signal indicating the switch setting of the on-load tap changer, an on-load tap changer transmission that mechanically couples the force-storing unit to the switching tube, and a mechanical coupling between the force-storing unit and the on-load tap changer transmission.

2. An on-load tap changer comprising: a switching tube, a force-storing unit for setting a switch setting of the switching tube, a detector for detecting the switch setting of the on-load tap changer, an on-load tap changer transmission that mechanically couples the force-storing unit to the switching tube, and a mechanical coupling between the force-storing unit and the on-load tap changer transmission; and a preselector of the on-load tap changer mechanically coupled by the on-load tap changer transmission with the force-storing unit for setting the switch setting of the preselector and with the detector for detecting the switch setting.

3. The on-load tap changer according to claim 1, wherein the detector comprises a cam-switching mechanism or transmitter system.

4. An on-load tap changer comprising: a switching tube, a force-storing unit for setting a switch setting of the switching tube, a detector for detecting the switch setting of the on-load tap changer and having at least one cam disk having a plurality of switch-positions and at least one lobe effective at each switch-setting position, an on-load tap changer transmission that mechanically couples the force-storing unit to the switching tube, and a mechanical coupling between the force-storing unit and the on-load tap changer transmission.

5. The on-load tap changer according to claim 4, further comprising: respective switches for detection of end positions of the on-load tap changer and so associated with the at least one cam disk that each switch is actuatable by at least one lobe.

6. The on-load tap changer according to claim 4, wherein the detector has a transmitter system provided with a plurality of wiper contacts and respective wipers each electrically connectable with the respective wiper and provided at a respective switch-setting position of the at least one cam disk.

7. The on-load tap changer according to claim 1, further comprising: a detector housing holding the detector and mounted on a cover of the on-load tap changer.

8. The on-load tap changer according to claim 1, further comprising: a movement detector for detecting rotation of a drive input shaft of the on-load tap changer transmission for loading the force-storing unit and associated with the shaft so that rotation of the drive input shaft can be outputted as an electronic signal.

9. The on-load tap changer according to claim 1, further comprising: a controller electrically connected with the detector for control with or without feedback of the on-load tap changer.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) The invention and advantages thereof are explained in more detail in the following with reference to the accompanying drawings, in which:

(2) FIG. 1 is a perspective view of an on-load tap changer according to the invention in an embodiment of a three-phase load selector with preselector;

(3) FIG. 2 is a perspective view of the on-load tap changer transmission of the on-load tap changer according to the invention;

(4) FIG. 3 is a further perspective view of the on-load tap changer transmission of the on-load tap changer according to the invention;

(5) FIG. 4 is a perspective view from below of the on-load tap changer transmission of the on-load tap changer according to the invention;

(6) FIG. 5 is a further perspective view of the upper part of the on-load tap changer in which the installed force-storing unit is visible;

(7) FIG. 6 is a perspective view of the cover of the on-load tap changer according to the invention of FIG. 1 in which a controller is illustrated;

(8) FIG. 7 is a perspective view of one embodiment of the detector for detecting the switch setting of the on-load tap changer; and

(9) FIG. 8 is a sectional perspective view of the embodiment shown in FIG. 7, of the detector for detecting the switch setting of the on-load tap changer.

SPECIFIC DESCRIPTION OF THE INVENTION

(10) Identical reference numerals are used for the same or equivalent elements of the invention. For the sake of clarity, only reference numerals are illustrated that are necessary for description of the respective figure. The embodiments that are illustrated by example, of the on-load tap changer according to the invention do not represent a restriction of the scope of protection defined by the claims, for the invention.

(11) FIG. 1 is a perspective view of an on-load tap changer according to the invention in the form of a three-phase load selector 1. The load selector 1 here comprises, as drive, an electric motor 3 with a transmission 5 that loads a force-storing unit (not illustrated). When the force-storing unit is fully loaded, i.e. stressed, it is unlatched, abruptly releases its energy and actuates a switching tube 15. The rotating switching tube 15 is rotatable in the oil tank 18 so that different switching positions can be set. The oil tank 18 is closed upwardly by a cover 19 and additionally carries a base 21.

(12) The load selector 1 according to the invention has three phases L1, L2, L3 that are one above the other in the oil tank 18. A preselector 37 is mounted on the switching tube above the three phases L1, L2, L3. Electrical terminal elements 39 are in that case so positioned at the load selector 1 that they pass through a wall 17 of the oil tank 18.

(13) FIG. 2 is a perspective view of the on-load tap changer transmission 100 of the on-load tap changer 1 according to the invention. The on-load tap changer transmission 100 is on a mounting plate 101 that is detachably connected with the sectionally illustrated cover 19 of the on-load tap changer 1. A drive input shaft 9 is coupled with an electric motor 3 by a motor transmission 5. The drive input shaft 9 drives a rotation translator 110 in order to load a force-storing unit 13 (see FIG. 5) coupled with the rotation translator 110. In that case the drive input shaft 9 typically executes half a revolution. A full revolution of the drive input shaft 9 is equally conceivable. As soon as the force-storing unit 13 is fully loaded it is unlatched and produces a rotation of the rotation translator 110. The rotation translator 110 on the one hand drives a Geneva wheel 120, with which the switching tube 15 and, via a preselector driver 140, a preselector 37 are connected. Through a suitable mechanical translation, the switching tube 15 in that case rotates through, for example, an angle of 30 per switching process. The preselector is, for example, switched from a plus position via a zero position to a minus position. On the other hand, the rotational translator 110 drives a rotation pick-up 130 that in turn drives an indicator driver 150. The indicator driver 150 causes a rotation in the detector 200 of, for example, a twentieth of a revolution per 30 rotation of the switching tube 15. In addition, the preselector driver 140 couples the switching movement of the preselector 37 into the rotation pick-up 130 that similarly acts by the indicator driver 150 on the detector 200. This action can consist of, for example, the rotational sense of the twentieth of a revolution produced by the switching tube 15, in the detector 200 being reversed. Depending on the respective design of the transmission it can be necessary to switch the switching tube 15 to a defined switch-setting position 201, 202 or 203 before the preselector 37 is connectable. This can be an additional zero position of the switching tube 15. Thus, by the on-load tap changer transmission 100 the switching movements of the switching tube 15 and the preselector 37 can be simultaneously coupled into the detector 200 and detected. Both the setting of the switching tube 15 and that of the preselector 37 are included in the thus-detectable switch setting of the on-load tap changer 1. If the switching tube 15 has, for example, eight switch settings and the zero position and the preselector 37 has a plus position and a minus position then a total of 19 switch settings that can be represented on the detector 200 as, for example, 8, 1, 0, +1, . . . , +8, arise for the entire on-load tap changer 1. In that case, for example, the switch setting 3 denotes that the preselector 37 is in minus position and the switching tube in the third of eight switch positions. Analogously to the preselector 37, a fine selector (not illustrated) can also be included in the switch setting detection by the on-load tap changer transmission 100.

(14) The force-storing unit 13 is loaded by a drive input shaft 9 by the electric motor 3. When it is completely loaded, it is unlatched so that it rapidly returns to its rest position. In that case the on-load tap changer transmission 100 couples the force-storing unit 13 in such a way to the switching tube 15 that at least a part of its movement energy is translated into a rotation of the switching tube 15. At the same time, the on-load tap changer transmission 100 couples the force-storing unit 13 in such a way to the detector 200 that it records a movement. The movement recorded by the detector 200 is correlated with the rotation of the switching tube 15 by the on-load tap changer transmission 100 and consequently is a measure for the rotation of the switching tube. For example, an indicator shaft 151 connected with the detector 200 rotates through an angle of 5 when the switching tube rotates through 30. Preferably, the drive input shaft 9 is, at the time of unlatching, decoupled from the force-storing unit 13 and on attainment of the rest position of the force-storing unit 13 is coupled again so that the drive input shaft 9 does not execute a movement in opposite sense to the relaxing force-storing unit 13. Alternatively, the coupling between force-storing unit 13 and its drive input shaft 9 can also be maintained and merely the electric motor 3 switched to be free of current so that it can be co-rotated by the force-storing unit 13 with little expenditure of energy.

(15) FIGS. 3, 4 and 5 show different perspective views of the on-load tap changer transmission 100 of the on-load tap changer 1. For the sake of clarity the force-storing unit 13 is illustrated only in FIG. 5.

(16) The drive input shaft 9 of the on-load tap changer transmission 100 is driven by an electric motor 3 via a motor housing 5. A drive input shaft gear 115 of the drive input shaft 9 drives a crank 113 of the rotation pick-up 110 by a rotation pick-up gear 116 of the rotation pick-up 110. The crank 113 stresses the force-storing unit 13. As soon as the crank 113 has fully loaded the force-storing unit 13, it is automatically unlatched by the drive input shaft gear 115 of the drive input shaft 9 and driven by the force-storing unit 13. The unlatched crank 113 drives the rotation translator 110. The rotation translator 110 on the one hand drives a first cam disk 131 of a rotation pick-up 130 by a first follower 111 with a first follower wheel 112 and on the other hand drives a Geneva disk 120 by a Geneva driver 114. The Geneva disk 120 on the one hand drives a switching tube 15 of the on-load tap changer 1 and on the other hand a preselector driver 150 for driving a preselector 37 of the on-load tap changer 1. The preselector driver 150 drives a second cam disk 132 of the rotation pick-up 130 by a second follower 141 with a second follower wheel 142. A rotation pick-up gear 145 of the rotation pick-up 140 drives, directly or by an intermediate gear 146, an indicator shaft gear 152 that is seated on an indicator shaft 151 to be axially and rigidly connected, so that a rotation of the indicator shaft 151 is produced. The indicator shaft 150 is mechanically coupled with the detector 200. The rotation of the indicator shaft 151 is detected by the detector 200 and converted into and output as an electrical signal. In addition, a movement detector 300 is at the drive input shaft 9. The movement detector is constructed as, for example, a transmitter system or cam-switching mechanism and detects the rotation of the drive input shaft 9 and thus, indirectly by the motor transmission 5, the drive movement of the electric motor 3.

(17) FIG. 6 is a perspective view of the cover 19 of the on-load tap changer 1 and the connection thereof with a controller 400. The indicator shaft 151 is led through an opening (not illustrated) in the cover 19 so that the detector 200 can be on the cover 19. A detector housing 240 for receiving the detector 200 is formed on the cover 19. The detector housing 240 is closable and openable by a detector housing cover 241 (see FIG. 1), so that the detector 200 can be easily accessed and in a given case exchanged without the cover 19 having to be demounted. Equally, the movement detector 300 is received in an intermediate housing 14. The detector 200, the movement detector 300, the electric motor 3 directly or a motor control 430 of the electric motor 3 and/or a transmission control 450 of the motor drive 50 are connected with a controller 400 for controlling and/or regulating the on-load tap changer 1. The controller 400 can regulate, for example, the electric motor 430 on the basis of the signals of the detector 200 and movement detector 300 in a regulating circuit.

(18) FIGS. 7 and 8 show a perspective view of one embodiment of the detector 200 for detecting the switch setting of the on-load tap changer 1 according to the invention. In FIG. 7 the cam disk 211 is illustrated in section. The detector 200 consists of an electronic circuit 230 with circuit contacts 231. The circuit 230 carries a cam-switching mechanism 210. This cam-switching mechanism 210 consists of at least one cam disk 211 with a plurality of switch-setting positions 201, 202, 203 and at least one lobe 212. The at least one lobe 212 is detachably connectable at each switch-setting position 201, 202, 203. A respective cam disk 211 is rotatably mounted on the upper side 232 and on the lower side (not able to be illustrated in this perspective view) of the circuit 230 and can be coupled with the indicator shaft 151 of the on-load tap changer transmission 100. This cam disk 211 executes, for example, a twentieth of a revolution per switching process of the switching tube 15. The rotational sense of this revolution is determined by means of the on-load tap changer transmission 100 from the setting of the preselector 37. At least one switch 220 for detecting an end position 201 of the on-load tap changer 1 is in that way associated with the at least one cam disk 211. Each switch 220 is in that way actuatable by at least one lobe 212.

(19) In addition, the detector comprises a transmitter system 250. The transmitter system 250 comprises a plurality of wiper contacts 14 and a wiper 215 rigidly connected with the circuit. At least one wiper contact 214 that can be electrically coupled to the wiper 215, is formed at each switch-setting position 201, 202, 203 of the at least one cam disk 210. In principle, one cam disk 211 according to the invention is sufficient in the detector 200 in order to detect the switch setting of the on-load tap changer 1. However, for reasons of reliability the detector 200 is redundantly provided with the second and possibly further cam disks 211. A wiper 215 can be associated with two adjacent cam disks 211. The electronic circuit 230 can, for example, further process the switch-setting positions 201, 202, 203 that are detected by the detector 200, into an electronic signal, for example, amplify and/or digitalize them.

(20) It will obvious to the expert that the device features of the embodiments described in the preceding can be used individually and in combination with one another in an on-load tap changer according to the invention in accordance with the following claims without departing from the scope of protection they define.