DD289855A5 - ARRANGEMENT FOR THE ELECTRICAL CONNECTION OF OPERATING VOLTAGE CONNECTION AND WINDING OF ELECTRICAL MACHINES OR APPARATUS - Google Patents

Abstract

The invention "arrangement for the electrical connection of Betriebsspannungsanschlusz and winding electrical machines or apparatus" relates to the production of high voltage machines and is advantageously applicable in electrical engineering. The aim of the invention is to avoid in electric machines with windings from coils with concentric, mutually insulated turns with little effort, without changing the technology of coil production Ausfaelle the winding insulation by the action steepest transient transient overvoltages. The task is to achieve the goal while maintaining the technology of coil production and without the use of voltage-dependent resistors. This is achieved by arranging a coaxial arrangement in the terminal box by a conductor according to the invention instead of the usual connection between the winding and the terminal. {Electrical machine; High voltage; transient overvoltage; winding; Overvoltage protection; Isolation}

Description

Field of application of the invention The invention relates to the production of high-voltage machines and is advantageously applicable in electrical engineering. Characteristic of the known state of the art

The invention relates to a winding for electrical machines or apparatuses, comprising a plurality of coils with concentric, mutually insulated turns of one or more electrical conductors. Such windings are, for example, in Schopper, E .: surge stresses as a criterion for the design of rotating electrical machines. E and M, 100 (1983), H.5.

Furthermore, from Lutz, F .: Fundamental considerations on the influence of the type of switching device on the resulting when switching motors overvoltages. Electricity Industry 83 (1984) H. 24 is known that occur when using such switching devices, such as vacuum switches, SF6 switches, oil-poor circuit breakers, steep edge transient overvoltages very high amplitude. The author proposes external, but the volume of the capacitor-increasing or Varistorschutzbeschaltungen before, especially the insulation of the first operating voltage connection close coils is in accordance with the dissertation A Lippmann, R .: A contribution to the stress assessment of high voltage stator windings by steep pulse voltages, Technical University Karl Marx City 1987 uneven initial voltage distribution well-known. The insulation between two or more turns of a coil is particularly stressed electrically.

From Zwicknagel, W .: On the surge voltage resistance of high-voltage motors and their testing. E and M, 100 (1983) H.5 are known outer protective circuits, for example consisting of capacitors and Überspannungsabieltern, which reduce the entering into the winding transient overvoltages known. The application of the outer protective circuit is complicated because the components require a considerable additional volume of construction, since they are designed for the largest expected transient overvoltage. For example, in a β-kV mode, transient overvoltages of several 10kV are known. In addition, it is disadvantageous that the actual strength of the insulation of the winding with respect to transient overvoltages is unchanged.

An obvious enhancement of Windungeisolation operating voltage near coil to reduce the sensitivity to transient overvoltages is technologically complex.

Furthermore, according to EP0050091 it is known that voltage-dependent resistors in or directly at the coils reduce the stress of the insulation due to transient overvoltages. A disadvantage is the thermal aging of the voltage-dependent resistors. Further deficiencies are the switching delay and the additional technological effort, To reduce the thermal aging is known according to EP0298902 that voltage-dependent resistors are thermally isolated from the winding in the cooling air flow of the machine. The additional use of thermal insulators, the increase in the number of electrical contact points and the necessary additional technological effort are disadvantageous.

Especially with steep transient transient overvoltages known as lEC-Publlkutlon 60 * 2 (1973) known lightning voltage 1.2 / 50, hereinafter referred to as Steeilstflanklg, the switching characteristic of the epaulungsabhänglgen resistors is disadvantageous. It is known that translento overvoltages also occur with bump tents of only 100ns. The known from the voltage-dependent resistors delay the effect of the voltage limiting is of this order, so that the amplitude of such shock waves is hardly reduced.

Object of the invention

The object of the invention is, in electrical machines or apparatuses with windings, consisting of several coils with concentric, mutually insulated turns of one or more electrical conductors, with little effort, without changing the technology of coil production failures of the winding insulation by the action steepest lankiger transient Avoid overvoltages.

Explanation of the essence of the invention The object of the invention is to insulate the insulation stress of windings of electrical machines or apparatus

of several coils with concentric, mutually insulated turns of one or more electrical conductors, duch

low-cost, steep-slope voltage surges while maintaining coil manufacturing technology and without the use of voltage dependent resistors.

According to the invention the object with an arrangement for the electrical connection of operating voltage terminal and Winding electrical machinery or apparatus, wherein the winding of several coils with concentric, against each other

isolated turns of one or more electrical conductors, solved by the electrical connection of

Operating voltage terminal and winding of a first conductor or a first conductor system of a coaxial Conductor arrangement consists, the second conductor or the second conductor system to a known electrical Junction of successive coils or coil sections is electrically connected to this, that the head of the Conductor system are electrically conductively connected to each other, that the first conductor or the first conductor system relative to the

second conductor or the second conductor system is electrically insulated, that at least one conductor of the conductor system for the

Operating current is the known electrical connection of operating voltage terminal and winding. It has been found that the arrangement according to the invention the stress of the thus wound winding section

degrades by translational overvoltages.

The arrangement according to the invention capacitively couples part of the translational overvoltage to the end of the protected one Wicklungsabschnlttes about, whereby the transients voltage difference is reduced over this section. Further, it is expedient that the second conductor with the operating voltage terminal with respect to the current flow

adjacent electrical connection point of successive coils or sub-coils is electrically connected, because there occur the highest translational voltage differences.

Particularly favorable in the arrangement according to the invention is the low additional technological effort, since the Execution of the winding is virtually unchanged. exemplary The invention will be explained in more detail with reference to two Aueführungsbeispiele. The basis of the following explanations is a high-voltage asynchronous machine from VEB Elektromaschinenbau Dresden

of type DSRCJ 6023-6. The star-wound three-phase winding consists of several coils with concentric, mutually insulated turns of an electrical conductor.

As usual, the operating voltage connection of the machine consists of three connections in the terminal box of the machine. The

Electrical connection of the operating voltage connection and winding of the machine is made according to the manufacturer via three flexible insulated electrical conductors, which are designed for the nominal operating current of 107 A.

According to the invention, these conductors are replaced by three coaxial conductor arrangements. Hereinafter, the inventive Solution described on the basis of a strand of the winding. The first conductor of the coaxial conductor arrangement consists of a

flexible inner conductor of copper with a diameter of 6mm and a surrounding this inner conductor 2mm thick layer of electrically conductive material for homogenization of the electric field.

As the second conductor of the coaxial arrangement, an outer conductor made of copper braid is arranged. The outer conductor is in the machine DSRCJ 6023-6 at an easily accessible electrical connection point of the coils of the Stranges electrically connected. In a machine with two-disc coils, the outer conductor is simply good at one

accessible connection point between the sub-coils of a two-disc coil connected.

In the exemplary embodiment, the inner conductor is the electrical connection for the operating current between

Operating voltage connection and winding. The operating voltage connection is a terminal in the terminal box. The inner conductor is opposite to the outer conductor by a dielectric according to the expected Overvoltage amplitude electrically isolated. With 1 mm thick polyethylene as the dielectric of the coaxial arrangement has this

a capacity of 0.7 nF per meter.

The modifications of this Ausführungsbetspiels described below correspond to claim 1, differ

however, by the number of conductors.

A second modification of the coaxial conductor arrangement consists of a flexible Innonlelter of copper with a Diameter of 6m and a surrounding this inner conductor 2mm thick layer of electrically conductive material for Homogenization of the electric field. As the second conductor of the coaxial arrangement, a copper braid conductor is arranged, which is a third copper braid

follows, wherein the inner conductor and the third conductor a Leiterersyster. form.

The second conductor is electrically conductive at the easily accessible electrical connection point of the coils of the strand

connected.

With this modification of the Ausführungsbelspiels the inner conductor is also the electrical connection for the operating current

.walk voltage swath and winding. The inner conductor is with the third conductor near the

Betriebsspannungeanschlussee electrically conductively connected at one point.

The inner conductor is opposite the second conductor and the second conductor is opposite the third conductor through a dielectric

electrically isolated according to the expected overexpansion amplitude.

Each with 1 mm thick polyethylene as the dielectrics of the coaxial arrangement has a capacity of 1.5nF per meter.

A third modification of the first embodiment consists of a flexible inner conductor of copper with a diameter of 6 mm and a surrounding this inner conductor 2 mm thick layer of electrically conductive material for Homoger ication of the electric field.

As a second conductor of the coaxial arrangement, a copper wire conductor is arranged, followed by a third and a fourth copper wire conductor, the inner conductor and the third conductor forming the first conductor system and the second and fourth conductors forming the second LF ItQrsyatem.

The second Leitersyetem is _o n connected to an easily accessible electrical connection point of the coils of the strand electrically conductive.

In this third modification of the embodiment, the inner conductor is also the electrical connection for the operating current between the operating voltage terminal and winding.

The inner conductor is electrically conductively connected to the third conductor near the operating voltage terminal at one point.

The second and the fourth conductors are electrically connected in the vicinity of the connection to the winding.

The inner conductor is opposite the second conductor, the second conductor opposite the third conductor and the third opposite the

Fourth conductor electrically insulated in each case by a dielectric according to the expected overvoltage amplitude. Each with 1mm thick polyethylene as the coaxial arrangement dielectrics has a capacity of 2.6 nF per meter.

The second embodiment differs from the first embodiment only in that the connection point between the second conductor or the second conductor system and the winding is selected so that the most vulnerable winding section is protected.

For this purpose, the second conductor or the second conductor system is electrically conductively connected to the electrical connection point of successive coils or partial coils which is adjacent to the operating voltage connection with respect to the current flow.

In a winding embodiment with two-coil coils, the easily accessible electrical connection point between the first and the second partial coil can be used.

The length of the coaxial arrangement was chosen in all three modifications of the first embodiment so that a capacity of 2 nF was created. With this arrangement is a practically sufficient strength of the winding over known

Transient overvoltages reachable in most applications.

It has been found that the arrangement according to the invention the stress of the thus wound winding section

degraded by transient overvoltages.

The arrangement according to the invention capacitively couples part of the transient overvoltage to the end of the winding section to be protected, whereby the transient voltage difference across this section is reduced.

Next fet it appropriate that the second conductor is electrically connected to an operating voltage terminal with respect to the current flow adjacent electrical connection point of successive coils or sub-coils, because there the highest transient voltage differences occur.

The coaxial arrangement is always electrically insulated in a known manner against conductive parts of the machine in accordance with the highest voltage differences expected there.

Each of the conductors, which are not primarily involved in the operating current control, can also be embodied as a conductive layer, although it is also possible to use layers with less than metallic conductivity.

Particularly favorable in the arrangement according to the invention is the low additional technological effort, since the execution of the winding is almost unchanged and only instead of the usual connection between winding and terminal in the terminal box, the coaxial arrangement according to the invention is arranged.

Claims (2)

Claim: 1. An arrangement for the electrical connection of operating voltage terminal and winding electrical machines or apparatus, wherein the winding of a plurality of coils with concentric, mutually insulated turns of one or more electrical conductors, characterized in that the electrical connection of the operating voltage terminal and winding of a first conductor or a first conductor system of a coaxial conductor arrangement, the second conductor or the second conductor system of which is electrically conductively connected to a known electrical connection point of successive coils or partial coils, that at least one conductor of the operating system conductor system is the known electrical connection of the operating voltage connection and winding, in that the conductors of the conductor system are electrically conductively connected to one another, that the first conductor or the first conductor system relative to the second conductor or the second conductor system is electrically isolated. 2. Arrangement according to claim 1, characterized in that the second conductor or the second conductor system is electrically connected to the operating voltage terminal with respect to the current flow adjacent electrical connection point of successive coils or partial coils.