Reactive ballast arrangement

FIELD: electricity.

SUBSTANCE: invention is referred to electric engineering and can be used for supplemental reactivity of an arc furnace transformer. Reactive ballast arrangement (V) for the arc furnace consists of a choke coil (1) with an open switch (2) for load increment changing which is suitable for installation of the choke coil (1) reactance under load. Reactive ballast arrangement (V) is connected before the transformer of the arc furnace (O) used, in particular, for steel making.

EFFECT: simplifying and improving accuracy of reactivity installation.

12 cl, 3 dwg

 

The invention relates to reactive ballast device for an electric arc furnace, in particular for the installation of additional reactance transformer of an electric arc furnace.

Before electric arc furnace, as it is used, for example, for melting steel, usually included transformer, which sets the desired electric arc alternating voltage. As with the electric arc furnace are removed very high power and pre-enabled transformer must be transmitted to the high alternating voltages, such transformers are typically placed in an insulating means to avoid spark overlap.

Parameter which is important for AC voltage and AC is the reactivity, that is, the reactance of the conductor, for example a streamlined shock coil.

For various operating States of an electric arc furnace it is desirable to have the ability to set different reactivity. With this purpose, it is known that in the previously enabled transformer embedded device to install reactivity with a choke coil and switch speed load. In a typical case, such devices with coils and active part of the transformer placed in a vessel filled with an insulating medium.

To install an electric arc furnace without the integrated transformer tank additional reactivity, in addition, it is known that out of the transformer, for example in the outdoor switchgear, are mounted choke coils without ferromagnetic core as an additional reactivity.

But with so more reactively it is impossible to establish optimal for all operating States of an electric arc furnace reactivity under load.

Therefore, in practice, many of the installation of electric arc furnaces operate with a permanently pre-selected reactivity. Used for this choke coil has at least one outlet, which forks flowing through the coil current after a certain number of turns and thereby gives definitely set the reactance of the transformer. To give the desired reactivity of the exhaust is mounted permanently. However, it should be taken change, if after a long period of work revealed that the reactivity mode under load, i.e. when the furnace is installed not in the best way that, for example, leads to an undesirable increase in energy consumption, or that the reactivity should be adjusted depending on the process. For this disadvantageous way you want to turn off the power supply, thereby stopping the furnace and repair the transformer with another tap on the choke coil.

The first object of the invention is to create a device with which you can just install, in particular, the reactivity included before the transformer.

The second objective of the invention is to create a transformer through which reactivity can be set as accurately as possible.

The third objective of the invention is to create an electric arc furnace, in particular for melting steel, which mode under load possible optimally and economically supplied with energy.

The first task in accordance with the invention is solved by the fact that the proposed reactive ballast device, in particular for an electric arc furnace with a choke coil and open the switch speed of the load, and the switch speed of the load is made with possibility of installation of reactivity choke coils under load.

Corresponding to the invention the combination of choke coils with an open switch speed load provides the possibility of installing a pre-reactivity under load, so that in accordance with production needs can always be selected optimal preliminary or additional reactivity, especially as applied to the load mode of an electric arc furnace.

Jet ball is astoe device is not limited in its application to install reactivity for an electric arc furnace or electric arc furnace transformer. It can also be switched to other energy consumers or equipment, the parameters of which are determined, in particular by reactivity.

The preferred way for reactive ballast device selected is free, with dry insulation choke coil without a ferromagnetic core. In the case of choke coils without ferromagnetic core with dry insulation is not used insulating oil, so maintenance costs are reduced and reduced fire risk, resulting in increased efficiency and harmlessness to the environment.

In addition, the choke coil has a suitable number of seats allotment, which corresponds to a certain number of turns of the coil. Since the inductance and, thus, the impedance of the coil depends on the number of coils through which current flows in the coil, can be achieved through the branches of the AC current flowing in the coil, drain manual way to set the impedance of the coil and, thus, reactivity, i.e. reactive resistance with alternating current, in accordance with the stages of the places of diversion.

In a preferred further development of reactive ballast device combined with a choke coil free switch speed load has a number of input contacts at least one output contact, and a switching element.

When this switching element is configured to toggle between a variable connection, at least one of the input contact to the output contact. If several input pins of the switching element can thus be connected, respectively, one or more input contact to the output contact. By an appropriate installation switching element output, thus, operated on the same or any output pin. Switch speed load contains, in addition, a tank with an insulating medium, which is made with the possibility of placing him in the switching element. Due to the insulating means is eliminated spark breakdown due to high voltage. Due to the insulating properties of the insulating means is reduced spark gap, so that the constructive dimensions generally decrease.

The switching element includes a suitable way for some number of inputs and at least one output, and one or each output of correlated node bifurcation, which incorporate at least two branches of the bridge circuit, and the branches, respectively, are deactivatable in the inclusion, and the branches, respectively, are varied way connected with the inputs and is therefore, its, pairwise interconnected through a cross-connection is connected to the connection point of the load, in particular, the vacuum switch.

It is related to the output switching element node branching converge related to a bridge circuit branches, and bridge circuit contains at least two branches. Branch contact inputs switching element and may separately communicate with different inputs, which are applied to the inputs multiple branches or only, respectively, one branch on the respective one input. In particular, can be implemented by varying the contact due to displacement of branches between different inputs. If all branches are applied to one input of or all of the branches are in contact with this entry, you specify one position of the stage. If, on the contrary, the two branches attached to two different inputs, it is determined by the position of the bridge. With only two branches, there is only one position of the stage and one position of the bridge. Similarly performed switching element provides the capability of switching under load, and switching from one position level to another is carried out consistently through the formation position of the bridge.

The branches of the bridge circuit of the switching element are connected in pairs with cross-connections, which are deactivatable through, the respectively, the connection point of the load. Between nodes branching and cross-connections branch, for its part, provided, respectively, switch places. If you now place the switch on separate branches deactivated, for example, that these branches move with each one input on each of the other input, that are associated with those branches of the cross-connection take, first of all, load and can also align the fluctuations of current and voltage in the region of the branching node and to eliminate the existing congestion at the switch. Now the transverse connection locations for load switching can be disabled and disconnected from the current flow branches can move. Place the load is preferably determined by vacuum circuit breakers, vacuum circuit breakers as circuit breakers due to the screening action of the vacuum operated reliably and resistant to wear. Besides the branches between transverse joints and places of contact on the input side appropriately equipped with throttle elements that bridge configuration ensures essentially uniform distribution of the load in the circuit.

The desired execution reactive ballast device is largely due to the fact that the number of taps of the throttle is tuski coincides with the number of input contacts of the switch of load and speed, accordingly, the junction is connected to the input pin. While preferred is a linear mapping of the locations of the taps to the input pins, so that the reference input of contacts from the specified sequence corresponds to increasing or decreasing reactivity choke coils. Thus is desirable to-one correspondence between the levels of reactivity and the input contacts.

In addition, there is a viable way-to-one correspondence between input and output contacts of the switch speed of the load and the inputs and outputs of the switching element. Thus, in particular, the inputs of the switching element exactly match the speed of reactivity. Through the switching element as part of the switch speed of the load, thus, expressed approval of the reactance of the transformer by selecting a stage with seats branches of the choke coils.

The second task in accordance with the invention is solved by a transformer, in particular for an electric arc furnace, which correlated reactive ballast device of the above type.

In the transformer is the preferred way built an additional device for the installation of reactivity with a choke coil and switch the speed of the load.

Tert what I task in accordance with the invention is solved in an electric arc furnace, in particular, for smelting steel, to which is connected a transformer of the above type.

In the following description is explained in more detail an example implementation of the invention with reference to the drawings, in which, in schematic image shows the following:

Figure 1 - reactive ballast device with a choke coil without ferromagnetic core and switch speed load

Figure 2 - the process of switching the switching element between the position of the speed and position of the bridge in 6 separate views And F, and

Figure 3 - linear circuit electric arc furnace with transformer and reactive ballast device of the aforementioned type.

Figure 1 generally shows a reactive ballast device V with a choke coil 1 without ferromagnetic core with a free switch 2-speed load. Choke coil 1 without ferromagnetic core through the point 3 power supply connected to the current network and equipped with a number of evenly placed seats 4-way, through which flows through the choke coil 1 without ferromagnetic core current can branch out after, respectively, significance isometric partial section of the flow through the coil. In necessary case, the choke coil 1 without ferromagnetic core may be placed is to be cleansed and purified in the tank 5, which is shown here by the dotted line.

Free switch 2-speed load has a steel hull 6, the inner space 7 which is filled with an insulating medium, in particular oil. Switch 2-speed load is supplied with a certain number of input pins 8, which are connected by a wire with Seating for 4 taps choke coil 1 without a ferromagnetic core. In the inner space 7 steel 6 input pins 8 are inputs for localized there switching element 9, which is shifted variable as a whole. The output switching element 9 via the output contact 10 leads to the outside and through the network conductor 11 is connected to the electric arc furnace transformer. Due to a certain shift of the switching element to a specific input terminal 8 and the corresponding 4 exhaust closes the load circuit reactive ballast units V between point 3 power supply and the output conduit 11. Thus, corresponding to the 4 exhaust reactivity 4 choke coil 1 without ferromagnetic core available on the output conductor 11.

Figure 2 schematically shows a process of switching the switching element 9 of figure 1 between the position of the speed and position of the bridge in the switch phases a to F. using and what the considerations applying phase shift And the first explains in detail the components of the switching element, which are the same for the other switch phases b through F. For clarity, the images switch phases b through F components of the switching element 9 only in cases provided with a reference position, where it is necessary to explain the switching process.

Shown in figure 2, the switching element 9 is connected through switch 2-speed load with Seating for 4 taps choke coil 1 without a ferromagnetic core, as can be seen in figure 1. Presents two inputs 12l, 12r of the switching element 9, which in figure 1 correspond to the input contact 8 of switch 2-speed load. In the view on the drawing, the switching element 9 has a left conductive branch, or branch 13l, conductive or right branch, or branch 13r, which are, respectively, provided with a throttle reels 14l 14r and, respectively, through passages 15l, 15r of contact with the tumblers 16l, 16r is connected to node 17 branching. Node 17 branching leads to the exit 21 of the switching element 9. Accordingly, between the throttle reels 14l, 14r and places 15l, 15r contact has a cross-connection 18 with the vacuum switch 20 between the conductive branches 13l and 13r, which in places 19l, 19r connection, respectively, associated with them. Arrow S indicates the opposite direction of the current.

The switching process is evident from the individual asperuloside with And F:

And the Switching element 9 is in the position of the steps at the entrance 12l. Both branches 13l and 13r is applied to the input of 12l. Tumblers 16l and 16r are in corresponding locations 15l, 15r contact in the closed position, so that both branches 13l and 13r are under load. Choke coils 14l and 14r provide symmetrical load balancing on the branches 13l and 13r.

In - Tumbler 16r is opened, the place 15r contact, the contact is broken. Thus now the cross-connection 18 through a closed vacuum switch is under load.

With the Vacuum switch 20 is opened, the branch 13r free from load and can be shifted, the entire burden falls on the branch 13l.

D - free from the load branch 13r is shifted from input 12l to the entrance 12r.

E - the Vacuum switch 20 is closed, the cross-connection 18 and the branch 13r are once again under load, the position of the bridge is active, as is now the inputs 12l and 12r through node 17 branching install closed circuit.

F - Toggle 16r again locked in place 15r contact is again established contact. The position of the bridge instead of implementing through the cross-connection 18 is implemented through both 15l, 15r of the contact.

In a reverse sequence relative to the sequence from A to F mirror-symmetrically to it can now move the branch 13l to set the position of the stage both ve the Wei 13l and 13r at the entrance 12r.

In this way, using the bridge circuit of the switching element 9 with the formation positions of the bridge on the various inputs may be offset from the position of the stage to the position of the stage between these different inputs under load.

Figure 3 shows an electric arc furnace with the furnace transformer T and reactive ballast V device of the above type with a choke coil 1 and switch 2-speed load.

1. Reactive ballast device (V), for electric arc furnace transformer with point (3) power supply is choke-coil (1), free the switch (2) levels of load and output pin (10), and the choke coil (1) is connected to point (3) power supply, and referred to free the switch (2) speed load is supplied with a certain number of input contacts (8)are connected by a wire with the places (4) bends choke coils (1) and with the switching element (9) switch (2) levels of load, and the output switching element (9) through the output pin (10) leads to the outside and through the network conductor (11) is connected with the electric arc furnace transformer, switch (2) speed load is made with possibility of installation of reactivity choke coils (1) under load.

2. Reactive ballast device (V) according to claim 1, and the choke coil (1) is Ipanema as free, with dry insulation choke coil without a ferromagnetic core.

3. Reactive ballast device (V) according to claim 1, and the choke coil (1) is provided with a certain number of seats (4) drainage, which corresponds to a certain number of turns of the choke coil (1).

4. Reactive ballast device (V) according to claim 1, and the choke coil (1) is designed as a free, dry insulation choke coil without a ferromagnetic core, with choke coil (1) is provided with a certain number of seats (4) drainage, which corresponds to a certain number of turns of the choke coil (1).

5. Reactive ballast device (V) according to claim 1, with the switch (2) speed load includes a number of input contacts (8), at least one output pin (10) and the switching element (9), while the switching element (9) is arranged to connect at least one input pin (4) with output contact (10)and the reservoir (6) with insulating means, and a reservoir (6) is made with the possibility of placing him in a switching element (9).

6. Reactive ballast device (V) according to claim 5, and a switching element (9) contains a number of inputs (121, 12r) and at least one outlet (21), and one or each output of correlated node (17) branching, with whom which are connected, at least two branches (131, 13r) of the bridge circuit, and the branches (131, 13r), respectively, are deactivatable in the inclusion (151, 15r), and branch (131, 13r), respectively, scalable way connected with the inputs (121, 12r) and, respectively, are pairwise interconnected through a cross-connection (18) is connected with the seat (20) enable load/ in particular, the vacuum switch.

7. Reactive ballast device (V) according to claim 1, and the choke coil (1) is provided with a certain number of seats (4) allocation, and the switch (2) speed load includes a number of input contacts (8), at least one output pin (10) and the switching element (9), while the switching element (9) is arranged to connect at least one input pin (4) with output contact (10)and the reservoir (6) with insulating means, and tank (6) is made with the possibility of placing him in a switching element (9), and the number of seats (4) bends choke coils (1) coincides with the number of input contacts (8) switch (2) levels of load and, consequently, (4) connection is connected to the input pin (8).

8. Reactive ballast device (V) according to claim 1, and the choke coil (1) is provided with a certain number of seats (4) drainage, while the switching element (9) contains some of the second number of inputs (121, 12r) and at least one outlet (21), and one or each output of correlated node (17) branching, which incorporate at least two branches (131, 13r) of the bridge circuit, and the branches (131, 13r), respectively, are deactivatable in the inclusion (151, 15r), and branch (131, 13r), respectively, scalable way connected with the inputs (121, 12r) and, respectively, are pairwise interconnected through a cross-connection (18) is connected with the seat (20) turn on the load, in particular, the vacuum switch, and the number of seats (4) bends choke coils (1) coincides with the number of input contacts (8) switch (2) levels of load and, consequently, (4) connection is connected to the input pin (8).

9. Reactive ballast device (V) according to claim 7 or 8, and the input (8) and outputs (10) switch speed load unambiguously correlated with the corresponding inputs (121, 12r) and outputs (A) a switching element.

10. Transformer (T), in particular, for electric arc furnace (Of), designed to connect before him a reactive ballast device (V) according to claim 1 for installation reactivity.

11. Transformer (T) in paragraph 10, and the transformer has an optional device for installation reactivity with a choke coil and switch the speed of the load.

12. Electric arc furnace (O), in which lastnosti, for smelting steel, is connected to the transformer (T) PP or 11.



 

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