CN201829954U

CN201829954U - Complete device special for filtration and compensation of arc furnace

Info

Publication number: CN201829954U
Application number: CN2010205648836U
Authority: CN
Inventors: 童淮安; 杜小毛; 李飞龙
Original assignee: GUOWANG NANZI HOLDING (HANGZHOU) CO Ltd
Current assignee: GUOWANG NANZI HOLDING (HANGZHOU) CO Ltd
Priority date: 2010-10-16
Filing date: 2010-10-16
Publication date: 2011-05-11
Anticipated expiration: 2020-10-16

Abstract

The utility model relates to a complete device special for filtration and compensation of an arc furnace, comprising a filtering circuit branch. The complete device is characterized in that a filtering and compensating device consists of three filtering circuit branches which are respectively connected with a three-phase low-voltage bus side of an arc furnace transformer, each filtering circuit branch is formed by sequentially connecting an isolation switch and a triangular closed circuit in series, the triangular closed circuit consists of three single-phase units connected with the triangular closed circuit, each unit is formed by sequentially connecting a capacitor, a thyristor valve and a reactor in series, a lightning arrestor is arranged between the isolation switch and the triangular closed circuit, the thyristor valve of each filtering circuit branch is electrically connected with one end of a controller, and the other end of the controller is electrically connected with a low-voltage bus of the arc furnace transformer. By adopting the structure, the design principle of the filtering circuit branch is as follows: the circuit branches connected in series are utilized, the impedance of certain harmonic wave is zero, and the harmonic wave isolates a power system by a capacitance-impedance branch circuit, so that the power system is not damaged by the harmonic wave.

Description

Arc furnace filtering compensation special complete device

Technical field

The utility model belongs to filtering compensation device, is specifically related to a kind of arc furnace filtering compensation isolated plant.

Background technology

Along with the development of steel and smelting technique, increasing arc furnace equipment is put in the middle of the production, and its capacity is increasing.Because the operating characteristic of himself has caused serious day by day harmonic pollution problem, has badly influenced the quality of power supply, and is extremely urgent to its harmonic wave control.

Arc furnace generally is a three-phase type, and by special-purpose arc furnace transformer power supply, the transformer high-voltage side is generally 6.3kV, 10kV, 35kV, also has 110kV, low-pressure side to be generally volt more than 100 to more than 1,000 volts.Mainly between 2T to 100T, arc furnace work operating mode is divided into two stages, melting stage and refining period substantially to arc furnace specification commonly used at present, melting stage is owing to there being in a large number not fusant, the stove state labile, at this moment current waveform is irregular, and harmonic content is big, mainly be low-order harmonics comparatively such as 2,3,4,5,6,7, harmonic wave between containing in a large number, and follow voltage fluctuation and flickering, cause the distortion of line voltage and electric current, refining period, arc furnace was stable, and harmonic content is little.Arc furnace belongs to nonlinear-load, in the process of work, can produce high order harmonic component, and the power consumption of arc furnace is very big, the capacity of furnace transformer is from counting megavolt-ampere to tens of megavolt-amperes, smelting process branch from iron and steel, the course of work of arc furnace can be divided into three phases: melting stage, the heat of oxidation and reduction period, iron and steel is very big at the power consumption of melting stage, the power consumption of the heat of oxidation and reduction period obviously reduces, iron and steel power consumption maximum of arc furnace not only in melting stage, and in this stage avalanche makes electrode contact steel scrap to cause short circuit with furnace charge owing to the starting the arc of decline electrode, thereafter the fast lifting electrode is broken electric arc again and is caused and open circuit, produce very big electric current in during the short circuit, cause three-phase imbalance.In smelting process because the flowing of the effect of electromagnetic force and gas stream in the stove and molten steel and slag, the continuous variation in path and the arc gap degree of ionization of arc discharge are constantly changed, thereby cause that load current changes greatly, pace of change is fast, it is frequent and random to change.In electric power system, the quality index of power supply, the security reliability of operation of power networks and economy are the most basic problems, reasonably regulate power system reactive power fast, adjusting to the stable and system voltage of AC network, there is crucial meaning reasonable distribution trend and restriction power network overvoltage aspect, particularly when contiguous AC system breaks down, as not compensating the reactive power that fluctuates widely rapidly, will cause system out of control, in recent years, along with metallurgy, the develop rapidly of electric railway, such as electrical arc furnace with impact load, rolling mills etc. constantly drop into electrical network, cause power factor of electric network to descend, wave distortion, voltage fluctuation, public hazards such as Harmonic Interference.

Summary of the invention

Technical problem to be solved in the utility model is: a kind of safe and reliable, arc furnace filtering compensation isolated plant that reaction speed is fast is provided.

In order to solve the problems of the technologies described above, the utility model adopts following technical scheme:

A kind of arc furnace filtering compensation isolated plant, comprise filter branch, it is characterized in that: described filtering compensation device is made of three filter branch, every filter branch inserts furnace transformer three-phase low-voltage bus bar side respectively, described every filter branch is composed in series successively by isolating switch and triangular closed loop, the triangular closed loop is made of three single-phase unit that triangle connects, each unit is by capacitor, thyristor valve and reactor are in series successively, be provided with a lightning arrester between described isolating switch and the triangular closed loop, described every filter branch thyristor valve all is electrically connected with an end of a controller, and the other end of described controller is electrically connected with the arc furnace transformer low-voltage bus bar.

Described thyristor valve is made of two thyristor inverse parallels.

Described thyristor adopts the IXYS element of Germany.

Described capacitor is selected the filtering capacitor of the full film medium of metal for use, and described series reactor is a dry type iron core filter reactor.

Adopt said structure, the design principle of filter branch is that to utilize series arm be zero at the impedance of certain subharmonic, this subharmonic is by capacity reactance branch road diversion electric power system, make electric power system not be subjected to the harm of this subharmonic, therefore 3 branch roads described in the utility model are respectively three filter branch 2 times, 3 times, 4 times, thereby stablize its electric power system, the stable furnace transformer that makes of supply power voltage obtains the most effective utilization, and stable fusing power can be provided; Eliminate flowing of reactive current, can reduce the loss of circuit and electric substation's transformer, the system power factor also can be significantly improved, and this device has the effect of reactive power compensation in the filtering appts harmonic wave.

Description of drawings

Fig. 1 is an electrical schematic diagram of the present utility model.

Embodiment

Referring to Fig. 1, a kind of arc furnace filtering compensation isolated plant, comprise filter branch, filtering compensation device is made of three filter branch, every filter branch inserts furnace transformer three-phase low-voltage bus bar side respectively, article 3, branch road is respectively 2 times, 3 times, 4 three filter branch, corresponding 2 times 3 times, 4 times low-order harmonic, situation and reactive requirement according to the each harmonic generating capacity, optimization Simulation design through the computer dedicated program, determine each setting of bar filter branch and capacity allocation, every filter branch is composed in series successively by isolating switch 1 and triangular closed loop, the triangular closed loop is made of three single-phase unit that triangle connects, each unit is by capacitor 2, thyristor valve 3 ' and reactor 4 are in series successively, be provided with a lightning arrester 5 between isolating switch 1 and the triangular closed loop, the thyristor valve 3 ' of every filter branch all is electrically connected with an end of a controller 6, and the other end of controller 6 is electrically connected with the arc furnace transformer low-voltage bus bar.Isolating switch 1 can adopt GN12 series, characteristics are that tangible cut-off point is arranged, capacitor 2 is selected the filtering capacitor of the full film medium of metal for use, specifically can adopt AFM type filtering capacitor, adopt metalized film, the built-in explosion-protection equipment of the insulating oil of vacuum impregnation high-quality, safe and reliable, current overload ability 〉=1.5In.Capacitor long-time running under 1.1 times rated voltage, 1.3 times rated current.Reactor 4 is a dry type iron core filter reactor, can adopt tri-phase iron core filter reactor (LKSG type), does not produce electromagnetic interference, and the linearity is 1.8In, the three-phase electricity sensibility reciprocal degree of balance≤2%.The other end ground connection of lightning arrester, lightning arrester are in order to prevent operation and Lightning Over-voltage.

Thyristor valve is made of two thyristor 3 inverse parallels, and thyristor 3 adopts the IXYS element of Germany, and thyristor has the advantage of operating passing zero non-transient process, and advanced technology, perfect in shape and function, reliability height, maintenance are little.

Controller 6 is controlled thyristor valve according to the current and voltage signals of gathering, controller adopts 32 ARM microprocessor chips, its structure of controller mainly comprises: power circuit, display circuit, key circuit, the electrical measurement circuit, sample circuit and CPU, by power circuit to each other circuit supplies, electrical measurement circuit and sample circuit and CPU join, sample circuit is used to gather the current and voltage signals of transformer, and send conversion of signals to the electrical measurement circuit, the signal that the electrical measurement circuit is sent sample circuit here is handled, carry out the transmitted in both directions that signal is finished in communication with CPU, the cpu monitor operating state, the signal that the electrical measurement circuit is sent here is analyzed, logic determines, calculate, with the operating state of control device.The electrical measurement circuit adopts the special-purpose electric energy measure chip of the ADE7758 model of U.S. ANOLOG DEVICE company production.Controller, multiple functional easy to operate, autoalarm is arranged, every defencive functions such as overvoltage, overcurrent, ultraharmonics are arranged, guarantee that the product all operations uses monitoring controlling in-house operation.Operation of equipment is convenient, and safe and reliable, specifically, controller also can be selected some general purpose controllers on the market for use, such as: the controller of the JKGF series that s7-200 Programmable Logic Controller that Siemens Company produces or Hua Guan company produce.

Draw this device by top circuit structure and have following effect: 1) this device has the effect of reactive power compensation in the filtering appts harmonic wave; 2) guarantee after this device drops into that every harmonic wave index that PCC is ordered satisfies the requirement of national standard about the harmonic wave limit value; 3) examination point monthly average power factor satisfies average power factor 〉=0.95; 4) after this device drops into not with system's generation parallel resonance, promptly at resonance point under the various operational modes not under main subfrequency; 5) this device overcurrent, overvoltage security performance are checked; 6) realize technology, the safety index of this device with most economical investment; 7) grouping of this device takes into full account load change and PCC point place can easily cut-out filtering compensation branch road when not allowing idle sending, and guarantees the requirement of not overshoot of every harmonic wave index simultaneously; 8) dynamic response time is less than 100ms.

It is zero at the impedance of certain subharmonic that filter branch utilizes series arm, this subharmonic is by capacity reactance branch road diversion electric power system, make electric power system not be subjected to the harm of this subharmonic, therefore 3 branch roads described in the utility model are respectively three filter branch 2 times, 3 times, 4 times, thereby stablize its electric power system, the stable furnace transformer that makes of supply power voltage obtains the most effective utilization, and stable fusing power can be provided; Eliminate flowing of reactive current, can reduce the loss of circuit and electric substation's transformer, the system power factor also can be significantly improved, and this device has the effect of reactive power compensation in the filtering appts harmonic wave.

Claims

1. arc furnace filtering compensation special complete device, comprise filter branch, it is characterized in that: described filtering compensation device is made of three filter branch, every filter branch inserts furnace transformer three-phase low-voltage bus bar side respectively, described every filter branch is composed in series successively by isolating switch (1) and triangular closed loop, the triangular closed loop is made of three single-phase unit that triangle connects, each unit is by capacitor (2), thyristor valve (3 ') and reactor (4) are in series successively, be provided with a lightning arrester (5) between described isolating switch (1) and the triangular closed loop, the thyristor valve (3 ') of described every filter branch all is electrically connected with an end of a controller (6), and the other end of described controller (6) is electrically connected with arc furnace transformer three-phase low-voltage bus bar.

2. a kind of arc furnace filtering compensation special complete device according to claim 1 is characterized in that: described thyristor valve (3 ') is made of two thyristors (3) inverse parallel.

3. a kind of arc furnace filtering compensation special complete device according to claim 2 is characterized in that: described thyristor (3) adopts the IXYS element of Germany.

4. a kind of arc furnace filtering compensation special complete device according to claim 1 and 2, it is characterized in that: described capacitor (2) is selected the filtering capacitor of the full film medium of metal for use, and described reactor (4) is a dry type iron core filter reactor.