SE408606B - TRANSFORMER - Google Patents

Description

f: vv12o2u + 4 2 i oeras in the secondary windings and an ignition current pulse is applied to the thyristors in the series connection. To eliminate glare and control the field, an electrically conductive layer is applied to the outside of the cable at each ring core. and the union with the core.

To control the voltage gradient along the cable, semiconducting layers are arranged on the outside. cable. between the conductive layers. A similar device is known from Swedish Laid-Open Specification 352 224, in which high-resistance layers of voltage-dependent resistance material are used for voltage gradation along the cable.

It has been found, however, that the long-term properties of these resistive layers used for voltage gradation along the cable are less good. The invention therefore intends to provide a control pulse transformer of the type initially indicated, in which the previously used resistive layers for voltage gradation along the cable are not required. What characterizes a transformer according to the invention is apparent from the appended claims.

The voltage-controlling conductive profiles, which in a transformer according to the invention are arranged at each ring core, provide an efficient capacitive voltage gradation along the cable at the fast voltage transients which appear across the thyristors. Because the conductive profiles are directly connected to the insulation material located between the profiles and the primary conductor, the voltage control takes place in a homogeneous manner, thereby eliminating glare efficiency. A thyristor chain always has a resistive or a combined resistive-capacitive voltage divider of some kind which statically and dynamically determines the potentials of the thyristors and thus also the potential of the drainage cores connected to the thyristorxza. Because the voltage-controlled profiles according to the invention are electrically connected. with ring chemistry and / or their secondary charges, both dynamically and statically a good control of the voltage gradient in the longitudinal direction of the primary conductor is obtained. The invention will be described in more detail below in connection with the accompanying Figures 1-5. Fig. 1 shows an example of. a control pulse transformer according to the invention. Fig. 2 shows how the U-shaped primary conductor, for example, can be connected to the control pulse device and the thyristor chain. Fig. 3 shows an alternative embodiment - if intended for a liquid: gaseous oil.

Fig. 1 shows a number of series-connected thyristors 1-9, which can form part of a high-voltage thyristor chain or thyristor valve. In a known manner, voltage division resistors 11, 21, 51 and RC circuits 12, 13 are arranged in parallel with the thyristors 1-5. 22, 23; 32, 33. On. correspondingly, the other thyristors are: |. the chain equipped with voltage sharing resistors and RC circuits.

The figure shows a section through the control pulse transformer, which has a primary conductor 100 connected to a control pulse device, which may be a metal tube or metal screen with partially insulated conductors inside, a solid conductor or a multi-wire conductor.

The primary conductor is surrounded by a casing 101 of a solid insulating material, such as polyethylene, epoxy resin or other suitable material. The housing forms a rotating body (with the primary conductor as the axis of rotation).

Each thyristor is assigned one: around the primary conductor and the insulating material the rings (14, 24, 34 etc) are arranged. each of the rings is provided with a terminal arm (15, 25, etc.), the two sockets of which are connected via connection conductors (eg 16, 17 for the winding 15) to the control electrode and cathode of the corresponding thyristor (1).

The ring cores are arranged in groups of three cores. Between each group of cores and the element 101 is an epemmingeptyrenae 1eaanae pmm (29, 59, e9) arranged. The profile consists of a conductive coating on the surface of the insulating material 101.

The coating can, for example, consist of a graphite layer, of an electrolytically applied metal layer or of a conductive paint. The surface of the housing and thus the stress-controlling profile nee- evrunaeae utatbukteae parts (29e een 291 »hes ber-: gget 29) which extend outwards and partially enclose the cores (14, 24, 34). The profile 29 is conductively connected through a connecting line 28 to the connecting line 27 of the secondary winding 25 of the core 24. similarly, the profiles 59 and 89 are connected through the conductors 58 and 88 to the secondary windings 55 and 85 of the cores 54 and 84. The profiles thus come. to be in operation. the same potential as the cores 24, 54 ooh 84 and their secondary windings. The potential of the others. core 1 van-je group (eg 14, 34) will differ at most with nagen euer a fam kv from the potential of the core connected to the profile. Some glimmer in the air between the cores. and the profile can therefore not arise.

In the areas. between the profiles. the insulating material 101 is made with grooves R to increase the creep distance between adjacent conductive profiles.

For external voltage gradation, for example, toroidal shaped metal profiles 102, 103, 104 can be applied outside the thyristor chain.

The insulating material 101 can be manufactured in the form of parts of suitable length (eg between the sections A-A 'and B-B' in Fig. 1) with prefabricated electrode configurations. The parts are threaded on and the primary conductor 100, which may be a copper pipe, is crimped, after which the parts are vulcanized together. Fig. 2 shows sohematically how the control pulse transformer can be made with a 'II-shaped primary conductor 100, both of which. ends are connected to a control pulse generator 105, which emits a control signal Ufdïarazznan thyristor (1, 3, 5, 7) in the chain 1-7 is connected with its control electrode to a core (14, 34, 54, 74) on one of the primary conductors both exankiar and ae the other fyrietors (2, 4, 6) now core (24, 44, 64) on. the other leg. The insulation material and the voltage-controlling profiles are not shown in Fig. 2 for the sake of clarity.

Fig. 5 shows an alternative embodiment of a control pulse traction transformer according to the invention. Of the thyristor chain, the thyristors 1, 2, 3 are shown, which have the voltage ammeter bars 11, 21, 31 and the nc-networks 12, 15; 22, 25; 52, 33. "Centrally in a cylindrical vessel with a wall 106 of insulating material, the primary pulse transformer 100 of the control pulse transformer is arranged. The ring cores 14, 24, 34 are arranged concentrically around the conductor 100 and their secondary windings 15, 25, 55 are connected to the control electrodes of the thyristors. The connecting cables are routed. through vascular fluid 106 by means of sealing bushings 107, 108, 109. The voltage control profiles 102, 103, 104 are toroidal metal profiles, which may be. open outwards as in the figure, or alternatively completely closed. The profiles are on. in the same way as in the device in Fig. 1 connected to selmmdärlindningaz-rza, whereby potential similarity is achieved between the profiles. and windings / core orxm.

The vessel 6 is filled with a liquid (eg oil) or gaseous insulating medium. The function of the device is the same as that of the device according to Fig. 1.

In Fig. 3, a voltage controlling profile is provided for each ring core. In Fig. 1, a profile is provided for each group of three ring cores. Alternatively, for example, two. or four. cores included. in each group with a common voltage-controlling profile. With a transformer according to the invention, an effective voltage rating is obtained in a simple manner without the problems with long-term stability as previously known. devices shown. By minimizing the risk of glare, the diameter of the ring cores can also be reduced compared with previously known couplings, which is advantageous from a control power point of view.

Claims (4)

7712024-4 PATEEITICRAV A transformer for transferring energy to series-connected thyristors (eg 1), which comprises at least one conductor (100), which constitutes primary winding and is connected to a supply device (105), and a ring core (14) enclosing the conductor. , Which is provided with a secondary winding (15) for connection to a thyristor, wherein an insulating medium (101) is arranged between the core and the conductor, characterized in that a voltage-controlling conductive profile (29), which has utatbmctaae parts (29a, b) on either side of the core ps such that the profile at least partially encloses the core, is arranged between the core and the conductor on. such that the profile is directly connected to the insulating medium located between the profile and the conductor, and that the core and / or the secondary winding are electrically conductively connected to the profile. Transformer according to claim 1, which comprises a plurality of conductor cores (14-94) arranged along the conductor, characterized in that the cores are divided into groups (eg 14-54) with more than one core in each group, wherein the voltage control profile (29) is arranged between the conductor and the cores in a group and arranged to at least partially enclose the cores in the group. 3. A transformer according to claim 1, characterized in that the insulating medium consists of a solid insulating material and the voltage-controlling profile of a conductive layer applied to its surface facing the core. 4. A transformer according to claim 3, wherein a plurality of conductive profiles are arranged along the conductor, characterized in that the insulating material in the areas between the profiles is formed with grooves (R) for extending the creep distance. MENTIONED PUBLICATIONS: