CN201667527U - Multifunctional selective protection module for explosion-proof switch - Google Patents

Abstract

The utility model belongs to the field of power network fault detection, relay protection and electrical safety and particularly discloses a multifunctional selective protection module for an explosion-proof switch, which comprises a zero-sequence voltage u0, zero-sequence currents i01 and i02, a multifunctional selective time-sequence discriminator ASIC (application specific integrated circuit), the direct-current detection signal UDZ for the operating value of an insulation resistor and a connected peripheral circuit. In order for the special conditions and actual requirements of a leakage protection system for the low-voltage network of mines, the multifunctional selective protection module serving the function of selective protection based on two outgoing feeders is capable of guaranteeing the quick and accurate selection of the outgoing feeders, distinguishing the three-phase symmetric leakage from single-phase leakage and separately displaying the single-phase leakage on the bus and the back-up protection for general detection. Therefore, the multifunctional selective protection module is applicable to not only general feeder switches, but also branch feeder switches.

Description

Protection module is leaked in a kind of multi-functional choosing that is used for flame-proof switch

Technical field

The utility model belongs to electric network fault detection, relaying protection and electrical safety field, and protection module is leaked in a kind of multi-functional choosing that is used for flame-proof switch that is specifically related to the not directly grounded 380V of industrial and mining enterprises of neutral point, 660V, 1140V low voltage electric network and 3300V medium voltage network.

Background technology

China's mine low-voltage leakage protection all was a non-selectivity before the eighties in 20th century; be that low voltage electric network any one generation electric leakage in exploiting field all acts on total feeding switch tripping operation by inserting the unique leak detection relay of electrical network (as JY-82, JL82 etc.), cause the low pressure full electric network to have a power failure.For this reason, 1986, China classified country's " the Seventh Five-Year Plan " tackling of key scientific and technical problems task as with " research of underground electric network leakage protection system and device ".Before and after nineteen ninety; China begins to have had down-hole low-voltage leakage protection device selectively; and be directly installed in each low-voltage explosion-proof feeding switch; this is the progress of China's coal-mine electric leakage protection technology, but the total feeding switch of working section sub station low pressure still adopts traditional additional dc power supply non-selectivity earth leakage protective.

Recent two decades has been gone over, the down-hole low-voltage leakage protection system that China's mine is made of the earth leakage protective device in the low-voltage explosion-proof feeding switch still rests on the level at the beginning of the nineties in last century, its major defect and problem have five: first, divide the earth leakage protective in the feeding switch, know-why is outmoded, function singleness, and choosing leakage accuracy rate is not high, generally do not reach 60%, exist serious multiselect, leakage choosing or mistake to select phenomenon; The second, have the leak current fault of 50% probability will lean on the ground deferred action of total leak detection protection non-selectivity in the mine low-voltage electricity grid, cause full exploiting field always to have a power failure, and the deferred action time usually at 300～500ms, directly influence the 30mAS safety value; The 3rd, mining low-voltage explosion-proof feeding switch is usually with the typhon mouth of 4 power supply power cable connections, wherein except that 2 typhon mouths pass in and out as bus, all the other 2 typhon mouths can be used separately as the outgoing of different load or different distributor points, but the function that protection does not possess differentiation two-way outgoing leak current fault is leaked in the choosing of the low pressure of existing low-voltage feeder switch; The 4th, the horizontal choosing leakage protection that has now between each minute feeding switch generally adopts the zero sequence power direction choosing to leak principle, the selective leakage protection system of Gou Chenging must be abolished the zero-sequence reactor that always uses for a long time thus, make the capacitive current of the single-phase electric leakage of low voltage electric network can not get compensation, thereby increased the possibility of the dangerous of personal electric shock injures and deaths and initiation gas explosion; The 5th; total leak detection protection in existing total feeding switch can only be done the delay " backup protection " of simple non-selectivity; in fact " three symmetrical electric leakages " protection and " protection of electric shock of the power source bus side person or single-phase electric leakage " that three-phase insulation against ground symmetry drops to dangerous values also taken in total protection of hunting leak, but existing total leak detection protection does not possess the function of differentiating these three kinds of dissimilar leak current faults.

At above-mentioned situation, the applicant is that the patent of invention " small current grounding system single-phase grounding selecting method and apparatus " of ZL02110276.7 was carried out technological innovation in 2005 based on the patent No., make progress, apply for two patents of invention again, be that the patent No. is " mine low-voltage electricity grid sequential discriminating leakage selecting method and the protector " of ZL200510042067.2 and " earthing compensation process of mine low-voltage electricity grid selective leakage protection system " that the patent No. is ZL200510044820.1, make China's mine low pressure choosing leak resist technology and pushed ahead a step, and achieved tangible results; But these two patent achievements have only solved in above-mentioned five " major defect and problems " half, promptly first and the 4th, and a part of second, all the other shortcomings more than two and problem still exist, and do not solve.

Summary of the invention

In order to solve above-mentioned five shortcomings and problem comprehensively; the utility model is on the basis of acquired three patent of invention ZL02110276.7, ZL200510042067.2 and ZL200510044820.1; provide a kind of multi-functional choosing that is used for flame-proof switch to leak protection module; the explosion-proof feeding switch of shunt that both can be used for the industrial and mineral low voltage electric network; the total feeding switch of explosion-proof type that also can be used for the industrial and mineral low voltage electric network; in addition, through suitably function expansion, also can be used for explosion-proof type unit switch and explosion-proof type load center.

For achieving the above object, the technical solution adopted in the utility model is as follows:

Residual voltage u ₀With zero-sequence current i ₀Extracting method and ZL200510042067.2 roughly the same, slightly improve; " the zero sequence first-harmonic time sequence logical discrimination " that the pick method of single-phase electric leakage adopts ZL02110276.7 to propose; In order to limit the single-phase earthing leakage current, the zero-sequence reactor dispersion compensation method that also adopts ZL200510044820.1 to propose.

Include the residual voltage u that ground warp electric capacity is taken out every straight, transformer step-down from the three-phase reactor neutral point ₀, the zero-sequence current i that takes out of the zero sequence current mutual inductor secondary circuit installed from the two-way outgoing ₀₁And i ₀₂Leak sequential discriminator ASIC with multi-functional choosing, also include insulation resistance operating value direct current detection signal U _DZ, residual voltage u ₀Be connected with filter circuit respectively after being divided into 2 groups, the signal decomposition of output is positive and negative half-wave and is connected two-way zero-sequence current i respectively with the phase-shift circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC ₀₁And i ₀₂Be connected with filter circuit respectively, the signal decomposition of output is positive and negative half-wave and is connected U with the amplitude discrimination circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC respectively _DZBe connected with ASIC; the output signal of " always examining backup protection ' ZJHB ' " of including " the single-phase electric leakage of outgoing ' XL ' ", " the single-phase electric leakage of bus ' MXLD ' ", " three symmetrical electric leakages ' SXLD ' ", leak current fault is set in the ASIC; above-mentioned signal XL, MXLD, SXLD and ZJHB are connected with the drive circuit of JSJ interface circuit and the apparent interface circuit of LED lamp respectively and show interface circuit output by JSJ interface circuit and LED lamp, and " tripping operation ' TZ ' " signal is connected with photoelectric coupled circuit and tripping operation drive circuit and exports.

The utlity model has following good effect:

(1), the utility model reference voltage U that the sequential discrimination method is required _0jIncrease to 4 by former 1; make every power frequency period can carry out 4 sequential and differentiate (only being 1 time in the past); thereby guarantee that two-way feeds out line selection and leaks protection accurately and reliably; and will shorten to operate time less than 30ms (band zero-sequence reactor compensation; allow≤80ms); guaranteed that the personnel in the pit touches the fail safe of low voltage electric network, no matter and this low voltage electric network whether have the zero-sequence reactor compensate function, no matter also zero-sequence reactor is in undercompensation or overcompensation state.

(2), the utility model possesses the choosing leakage function of two-way outgoing, thereby can give full play to the function of existing four typhon mouths of mining low-voltage explosion-proof feeding switch, allowing wherein, 2 typhon mouths are used for the power source bus turnover, two typhon mouths are used as the electric power outgoing of two loads or two distributor points in addition, and then make a feeding switch possess the effect of two feeding switchs.For example a working section sub station is if any 6 road outgoings; leak protection in order to realize choosing; if adopt conventional scheme; then need 1 total feeding switch and 6 branch feeding switches; and adopt this programme only to need a total feeding switch and 3 branch feeding switches, can directly save 3 explosion-proof feeding switchs of shunt.

(3), the utility model decomposes " the single-phase earth leakage protective of bus " come out from common " total leak detection protection "; not only making the fault point seek scope significantly dwindles; and the power source bus zone person got an electric shock or single-phase operate time of protection through the electric leakage of 1K Ω grounding through resistance shortens in the 100ms from the 300～500ms in past, this technological innovation is significant to ensure the person safety of getting an electric shock to guaranteeing the 30mAS safety value.

(4), the utility model decomposes " three symmetrical earth leakage protective " that the decline of electrical network three-phase insulation against ground horizontal symmetrical causes to come out from traditional " total leak detection protection "; avoided " total leak detection " to move after the feeding switch tripping operation, the personnel in the pit is the invalid work of trouble-shooting point blindly.Because this leak current fault belongs to dispersive leakage, do not have concrete fault point, and need analyze, judge one or more cable line the longest or that corrosion is more serious from service life according to the work on the spot experience.This technological innovation has much practical value.

(5), the utility model is real " backup protection of always hunting leak " that divides feeding switch in time not trip and caused because of the outgoing electric leakage; from traditional " total leak detection protection ", decompose to come out; help timely tracking " backup protection " inadvertent operation reason, and then improve the technical performance of backup protection.The inadvertent operation reason of backup protection for example; may be that protector oversize or inefficacy operate time is leaked in choosing along separate routes; or faulty line vacuum circuit-breaker operate time is oversize or fault arranged; or " backup protection of always hunting leak " adjusts operate time shortly partially or it reacts too sensitivity etc., can make a concrete analysis of, suit the medicine to the illness and administer.This technological innovation also is of practical significance.

Description of drawings

Fig. 1 is a principle schematic of the present utility model;

Fig. 2 is for using peripheral circuit principle wiring schematic diagram of the present utility model.

Embodiment:

Below in conjunction with the drawings and specific embodiments the utility model is described in detail:

As shown in Figure 1: include the residual voltage u that ground warp electric capacity is taken out every straight, transformer step-down from the three-phase reactor neutral point ₀, the zero-sequence current i that takes out of the zero sequence current mutual inductor secondary circuit installed from the two-way outgoing ₀₁And i ₀₂Leak sequential discriminator ASIC with multi-functional choosing, also include insulation resistance operating value direct current detection signal U _DZ, residual voltage u ₀Be connected with filter circuit respectively after being divided into 2 groups, the signal decomposition of output is positive and negative half-wave and is connected two-way zero-sequence current i respectively with the phase-shift circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC ₀₁And i ₀₂Be connected with filter circuit respectively, the signal decomposition of output is positive and negative half-wave and is connected U with the amplitude discrimination circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC respectively _DZBe connected with ASIC; the output signal of " always examining backup protection ' ZJHB ' " of including " the single-phase electric leakage of outgoing ' XL ' ", " the single-phase electric leakage of bus ' MXLD ' ", " three symmetrical electric leakages ' SXLD ' ", leak current fault is set in the ASIC; above-mentioned signal XL, MXLD, SXLD and ZJHB are connected with the drive circuit of JSJ interface circuit and the apparent interface circuit of LED lamp respectively and show interface circuit output by JSJ interface circuit and LED lamp, and " tripping operation ' TZ ' " signal is connected with photoelectric coupled circuit and tripping operation drive circuit and exports.Concrete operation principle of the present utility model is as follows:

(1), the residual voltage u that will take out every straight, transformer step-down ground warp electric capacity from the three-phase reactor neutral point ₀Be divided into 2 groups, each group is divided into positive half wave and negative half-wave two parts again, passes through " signal processing circuits " such as filtering, phase shift, shaping, optocouplers respectively and obtains 4 reference voltage square-wave signal U _0J1+, U _0J1-, U _0J2+, U _0J2-

(2), the zero sequence current signal i that will take out from the zero sequence current mutual inductor secondary circuit that the two-way outgoing is installed ₀₁And i ₀₂Be divided into positive half wave and negative half-wave two parts, and obtain square-wave signal I through " signal processing circuits " such as filtering, amplitude discrimination, shaping, optocouplers respectively ₀₁₊, I _01-, I ₀₂₊, I _02-

(3), U _DZBe to detect with traditional additional dc power supply method to obtain, " insulation resistance operating value " signal of reflection electrical network insulation against ground level.

(4), to leak sequential discriminator ASIC be core of the present utility model in multi-functional choosing, it accepts above-mentioned U _0J1+, U _0J1-, U _0J2+, U _0J2-, I ₀₁₊, I _01-, I ₀₂₊, I _02-And U _DZInput signal; these input signals are through logical operation, analysis and the judgement of ASIC inside; the fault identification result is exported; the output signal of " the single-phase electric leakage of outgoing ' XL ' ", " the single-phase leakage of bus ' MXLD ' ", " three symmetrical electric leakages ' SXLD ' " and leak current fault " always examining backup protection ' ZJHB ' " is set in the ASIC; the output signal circuit divides three the tunnel, is respectively applied for driving malfunction tripping operation, JSJ interface circuit and LED lamp and shows interface circuit.

The utility model is hereinafter to be referred as " multi-functional choosing leakage protection module ",

Fig. 2 comprises low voltage electric network main electrical scheme system and the multi-functional choosing leakage of flame-proof switch protection two large divisions.660V or 1140V low voltage electric network main electrical scheme system mainly comprise a master switch KB ₀With many branch switches such as KB ₁, KB ₂KB _nEach branch switch is (with the 2nd KB ₂Be example) comprise that again main circuit and auxiliary circuit two parts, main circuit represent with the thick black line of three-phase, KB wherein ₂Be vacuum circuit-breaker, KB ₂Contain one group of three-phase main contacts and two auxiliary contacts; KB ₂The load side main circuit is divided into two, and forms the two-way outgoing, and the head end of every road outgoing is provided with a zero sequence current mutual inductor CT respectively ₂₁, CT ₂₂Auxiliary circuit mainly comprises zero sequence current mutual inductor CT ₂₁, CT ₂₂, three-phase reactor SK ₂, zero-sequence reactor LK ₂, capacitor C ₂₀, C ₂₁And relevant connecting line.It is core with " multi-functional choosing leakage protection module " that the protection part is leaked in the multi-functional choosing of flame-proof switch, also comprises " the insulation monitoring additional dc power supply box " that place in total feeding switch, or places branch feeding switch interior " filter band "; Also to reach " liquid crystal display ", " combined network communication " etc. by " the integrated protection Single Chip Microcomputer (SCM) system " of flame-proof switch.

" multi-functional choosing leakage protection module " required residual voltage signal u of total feeding switch ₀From three-phase reactor SK ₀Neutral point take out, through C ₀Every straight coupling and transformer TC ₀Be divided into 2 groups after the step-down, each group is divided into positive half wave and negative half-wave two parts again, passes through " signal processing circuits " such as filtering, phase shift, shaping, optocouplers respectively and obtains 4 reference voltage square-wave signal U _0j1+, U _0j1-, U _0j2+, U _0j2-The back input; Required zero sequence current signal i ₀₁And i ₀₂The zero sequence current mutual inductor CT that installs from the two-way outgoing ₀₁And CT ₀₁Secondary circuit is divided into positive half wave and negative half-wave two parts after taking out, and obtains square-wave signal I through " signal processing circuits " such as filtering, amplitude discrimination, shaping, optocouplers respectively ₀₁₊, I _01-, I ₀₂₊, I _02-The back input; The detection electric current of the electrical network insulation against ground resistance that it is required is by the LK that is installed in the additional dc power supply in total feeding switch _DZEnd output is through LK ₀, SK ₀, KB ₀Auxiliary contact is to the three-phase distribution net, again through electrical network three-phase insulation against ground resistance to the earth, and then get back to the earth terminal of " additional dc power supply ", constitute insulation resistance thus and detect the loop; Action resistance value signal U _DZTake out (divider resistance does not draw) from the divider resistance that detects the loop in DC power box, deliver to the U of " multi-functional choosing leakage protection module " respectively _DZEnd.

In view of key wiring diagram shown in Figure 2, existing at present following 4 kinds of specific embodiments:

Embodiment 1:

" protection is leaked in the multi-functional choosing of flame-proof switch " comprises " protection is leaked in the required multi-functional choosing of total feeding switch " and " protection is leaked in the required multi-functional choosing of branch feeding switch "; texturally be combined as a module, so that flame-proof switch is multiple functional, agile and all-purpose.And when practical application, make a concrete analysis of, carry out function selecting, get and give up, when as the branch feeding switch, only getting the wherein choosing of two shunt outgoings leaks defencive function; And when as total feeding switch, mainly select for use " busbar grounding MXJD ", " three-phase electric leakage SXLD ", " backup protection ZJHB always hunts leak " three choosings to leak function; Feed out line selection leakage protection as for the two-way in total feeding switch and whether will use, decide on on-the-spot Main Wire Connection Scheme.

Embodiment 2:

Flame-proof switch divides mining type and factory's type, therefore should " multi-functional choosing leakage protection module " both can be used under the coal mine, and also available chemical plant and other have the place of explosive mixture, and specific implementation method is similar to above-mentioned " 1 ".

Embodiment 3:

" multi-functional choosing leakage protection module " is through suitably expansion; promptly increase by one " outgoing (multichannel) selects the stripping pattern piece "; can be used for " flame-proof type load center "; should " flame-proof type load center " 1140V and two kinds of distribution voltages of 3300V be arranged; every kind of distribution voltage has 4 to 8 road outgoings; relevant " rules " regulation should " flame-proof type load center " must be equipped with selective earth leakage protection.

Embodiment 4:

" multi-functional choosing leakage protection module " also can be used for 1140V or 3300V " flame-proof mine unit switch ", specifically implements method and above-mentioned " 3 " are similar.

In sum, protection module is leaked in the multi-functional choosing that is used for flame-proof switch that the utility model provides, defencive function is leaked in choosing with two-way outgoing, can guarantee to feed out line selection leaks rapid, accurate, can be distinguished three symmetrical electric leakages and single-phase electric leakage again, can also separately show the single-phase electric leakage on the bus and total inspection backup protection, thereby both can be used for total feeding switch, can be used for the branch feeding switch again, no matter and whether low voltage electric network have zero-sequence reactor compensation, no matter also zero-sequence reactor is in undercompensation or overcompensation state; The utility model suitably expands " feeding out line selection leaks " way, also can be used for mining explosion-proof type " unit switch " and reaches " load center ".

Claims (1)

1. protection module is leaked in a multi-functional choosing that is used for flame-proof switch, includes from the three-phase reactor neutral point ground warp electric capacity every residual voltage u straight, that the transformer step-down is taken out ₀, the zero-sequence current i that takes out of the zero sequence current mutual inductor secondary circuit installed from the two-way outgoing ₀₁And i ₀₂Leak sequential discriminator ASIC with multi-functional choosing, it is characterized in that, also include insulation resistance operating value direct current detection signal U _DZ, residual voltage u ₀Be connected with filter circuit respectively after being divided into 2 groups, the signal decomposition of output is positive and negative half-wave and is connected two-way zero-sequence current i respectively with the phase-shift circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC ₀₁And i ₀₂Be connected with filter circuit respectively, the signal decomposition of output is positive and negative half-wave and is connected U with the amplitude discrimination circuit that is connected in turn, shaping circuit, photoelectric coupled circuit and ASIC respectively _DZBe connected with ASIC; the output signal of " always examining backup protection ' ZJHB ' " of including " the single-phase electric leakage of outgoing ' XL ' ", " the single-phase electric leakage of bus ' MXLD ' ", " three symmetrical electric leakages ' SXLD ' ", leak current fault is set in the ASIC; above-mentioned signal XL, MXLD, SXLD and ZJHB are connected with the drive circuit of JSJ interface circuit and the apparent interface circuit of LED lamp respectively and show interface circuit output by JSJ interface circuit and LED lamp, and " tripping operation ' TZ ' " signal is connected with photoelectric coupled circuit and tripping operation drive circuit and exports.

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