CN102185296A - Selective electric leakage protection device and method for mine low-voltage power supply system - Google Patents
Selective electric leakage protection device and method for mine low-voltage power supply system Download PDFInfo
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- CN102185296A CN102185296A CN2011101070629A CN201110107062A CN102185296A CN 102185296 A CN102185296 A CN 102185296A CN 2011101070629 A CN2011101070629 A CN 2011101070629A CN 201110107062 A CN201110107062 A CN 201110107062A CN 102185296 A CN102185296 A CN 102185296A
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Abstract
The invention discloses a selective electric leakage protection device and method for a mine low-voltage power supply system. Four branch feed switch protecting devices and a main feed switch protecting device are respectively connected with a supervisory computer by respectively adopting a field bus; the four branch feed switch protecting devices are respectively connected with four corresponding zero-sequence current sampling and conditioning circuits; the main feed switch protecting device is respectively connected with a continuous sampling circuit of an insulation resistor, an executing mechanism control circuit, the zero-sequence voltage sampling and conditioning circuits and a display and keyboard circuit module; an additional direct-current power supply method and zero-sequence power direction line selection criterion combined selective electric leakage protection method is adopted; an electric leakage current value is measured by utilizing the additional direct-current power supply method, and an electric leakage line is judged by the judgment line selection principle of the zero-sequence power direction; and by adopting the integration of the two methods, the power-off range caused by electric leakage protection is reduced to the greatest extent so that the longitudinal selectivity of an electric leakage protection system is more reasonable and perfect.
Description
Technical field
The present invention relates to electric leakage protection technology, be applied to the low-voltage power supply system selective earth leakage protection of mine isolated neutral.
Background technology
Coal Production is mainly carried out in the down-hole, and most of supply line adopts cable power supply, because the space, down-hole is narrow and small, environment is abominable, and is dark moist, thus service cable make moist and mechanical damage all is easy to make cable that single-phase leak current fault takes place.Also just become big because of superpotential probability appears in single-phase electric leakage, add that downhole cable is moist and be vulnerable to that hard extrusion is bumped, the cable insulation situation is than poor on the ground, bears superpotential ability also with regard to variation.When the colliery power supply grid single-phase leak current fault takes place particularly during single-phase earthing, the place very easily causes arcing ground over-voltage ground connection, puncture the insulation weakness of service cable probably, cause the two phase ground short circuit and may cause gas, coal-dust explosion, even electric detonator is ignited in advance.In addition, leakage current also causes the accident of human electric shock easily, influences coal mine production safety, and the existence of long-term leakage current also can be burnt electric equipment.
The earth leakage protecting method commonly used of underground low voltage power system has additional DC source method, zero-sequence current amplitude comparison method, colony than width of cloth phase comparing method, zero sequence power direction method etc.Additional DC source method is to add an independently DC power supply in three phase network, make it to act between three phase network and the earth, measure the leak electricity detection of accident of the size variation reflection electrical network insulation against ground changes in resistance flow through the DC current values on three relatively the insulation resistances then; The zero sequence power direction method is exactly to come the failure judgement circuit by the direction of judging homopolar power.
Adopt single earth leakage protecting method because most of mine low-voltage power supply systems more,, had a strong impact on the safety in production in colliery so the phenomenon of selective earth leakage protection malfunction in the low-voltage power supply system use, tripping under China's mine at present happens occasionally.Have time-delay because the higher level discrimination protection moves simultaneously, feasible selective leakage protection device near power supply is longer operate time, so the danger that the person gets an electric shock in this scope is just high more.
Summary of the invention
The present invention is the weak point that exists for fear of above-mentioned technology, proposes a kind of low-voltage power supply system selective leakage protection device and guard method that is applied to the mine isolated neutral.
The technical scheme that selective leakage protection device of the present invention adopts is: power transmission cable connects total feeding switch protective device by dry-type transformer; The output of total feeding switch protective device connects four branch's feeding switch protective devices respectively by partial node, and four branch's feeding switch protective devices, total feeding switch protective devices connect respectively and all adopt fieldbus to connect between host computer and the three; Four branch's feeding switch protective devices connect corresponding four zero-sequence currents sampling and modulate circuit respectively; Total feeding switch protective device connects continuous sampling circuit, actuating mechanism controls circuit, residual voltage sampling and modulate circuit and the display and the keyboard circuit module of insulation resistance respectively by its different port; Total feeding switch protective device comprises digital signal processor, and each branch's feeding switch protective device has included processor.
The technical scheme that selective earth leakage protection method of the present invention adopts is to have the following steps: 1) additional DC power supply in the three phase network at total feeding switch protective device place; make it to act between three phase network and the earth, measure and to flow through three relatively insulation resistance r
∑On DC current values; 2) residual voltage sampling and modulate circuit are gathered insulation resistance r
∑On direct current sampled signal U
S, residual voltage U
0, the continuous sampling circuit 11 of insulation resistance detects insulation resistance r
∑When electrical network just often, according to formula r
∑=U*R
S/ U
S-∑ R shows the insulation situation of electrical network in real time, to detect the electric leakage accident that whether takes place; U is that DC power supply both end voltage, ∑ R are the D.C. resistance value R in parallel of the every phase coil of three-phase reactor
(L), R is equivalent resistance, the R of three-phase reactor
SBe sample resistance, R
EBe the earth resistance sum; 3) zero-sequence current sampling and modulate circuit are gathered the zero-sequence current I of four branch's feeding switch protective device place branch roads respectively
0Signal is as insulation resistance r
∑After dropping to operating value, total feeding switch protective device is with residual voltage U
0Value send to each branch's feeding switch protective device, each branch's feeding switch protective device is according to the zero-sequence current I that gathers
0Value, again in conjunction with branch road homopolar power formula P
r=I
0IU
0R-I
0RU
0IJudge, work as P
r0 be judged as fault branch, work as P
r, be judged as non-fault branch at＜0 o'clock; P
rBe homopolar power, U
0I, U
0R, I
0I, I
0RBe respectively residual voltage U
0With zero-sequence current I
0Imaginary part and real part.
The present invention's advantage compared with prior art is:
1, PROFIBUS-DP fieldbus based on the RS-485 interface is adopted in the communication of processor in the branches at different levels of the present invention feeder protection equipment.This bus has the multiple spot two-way communications capabilities, allows a plurality of processors to be connected on the same bus, has solved single transmission technology and can not satisfy the problem of carrying out on same cable of being transmitted in of data and power supply.The anti-common mode of RS-485 interface is done ability and is strengthened, and can effectively suppress the noise jamming in the long Distance Transmission, and promptly noise immunity is good.The data maximum transmission rate of this bus is 10Mbps, and transmission range can reach 1500m farthest, has satisfied the requirement of mine low-voltage power supply system, compares the bus of other interface shape, has reduced cost, has improved cost performance.
2; the selective earth leakage protection method that the present invention adopts additional dc power supply method and zero sequence power direction route selection criterion to combine; utilize the additional dc power supply method to measure the size of leakage current value; and the criterion route selection principle of passing through zero sequence power direction is judged the electric leakage circuit; these two kinds of methods comprehensively can avoid conventional method such as zero-sequence current amplitude comparison method effectively; colony can't make the drawback of effective selection to the leak current fault circuit than width of cloth phase comparing method etc.; can carry out effective route selection to leak current fault again; farthest dwindle the outage scope that causes because of earth leakage protective, truly realizing carrying out selective leak current fault; the excision of scope is arranged.Protective devices at different levels in this selective earth leakage protection system are all the wink ejector half, can realize the earth leakage protective of stepless difference, make vertical selectivity of leakage protection system more reasonable, more perfect.
3, the TMS320F28335 type digital signal processor that adopted of the total feeding switch protective device of the present invention is a 32 the TMS320C28X series Floating-point DSP controller of TI company; compare with fixed DSP in the past; the precision height of this device; cost is low; power consumption is little, performance height, peripheral hardware integrated level height; data and procedure stores amount are big, and A/D conversion is more accurate fast etc.It adopts inner 1.9V power supply, outside 3.3V power supply, thereby power consumption reduces greatly.And dominant frequency is up to 150MHz, and processing speed is fast, is that those need the ideal of floating-point operation portable product to select.This digital processing unit compare with traditional single-chip microcomputer have that the CPU operational capability is strong, response break period is short, communication interface is abundant and the characteristics such as peripheral module of enhancement mode.
4, the processor selected for use of branch of the present invention feeding switch protective device is the PIC16F877A chip that Microchip company produces, and this SCM peripheral circuit is simple, the conversion accuracy height.And its memory organization architecture is " Harvard " structure, and its program storage and data storage area are independent fully on physical space, and the bus of reading command and the bus of access data are also separated fully.Because bus is independent, reading command and accessing operation can carry out simultaneously, have improved the data traffic in the single-chip microcomputer and the operational efficiency of code greatly.
Description of drawings
Fig. 1 is the low-voltage power supply system selective leakage protection device figure that is applied to the mine isolated neutral;
Among the figure: 1. total feeding switch protective device; 2,3,4,5. branch's feeding switch protective device; 6. dry-type transformer; 7. power transmission cable; 8. fieldbus; 9. host computer; 11. the continuous sampling circuit of insulation resistance; 12. actuating mechanism controls circuit; 13. display and keyboard circuit module; 14. residual voltage sampling and modulate circuit; 21, sampling of 31,41,51. zero-sequence currents and modulate circuit; K1. partial node; K2, K3, K4, K5. output node.
Embodiment
In Fig. 1; the power transmission cable 7 of 6KV is by behind the explosion-proof dry-type transformer 6; in the outlet cable of explosion-proof dry-type transformer 6, connect total feeding switch protective device 1; the output of total feeding switch protective device 1 is divided into four tunnel low voltage power transmission circuits by partial node K1; four branch's feeding switch protective devices 2,3,4,5 are set respectively in four tunnel low voltage power transmission circuits of telling; four tunnel low voltage power transmission circuits all adopt power transmission cable 7 power supplies, and the output node of four tunnel low voltage power transmission circuits is respectively K2, K3, K4, K5.Four branch's feeding switch protective devices 2,3,4,5, total feeding switch protective devices 1 connect respectively between 9, four branches of host computer feeding switch protective device 2,3,4,5, total feeding switch protective device 1 and the host computer 9 and all adopt the PROFIBUS-DP fieldbus 8 based on RS-485 to communicate connection.Four branch's feeding switch protective devices 2,3,4,5 connect corresponding zero-sequence current sampling and modulate circuit 21,31,41,51 respectively.Total feeding switch protective device 1 connects continuous sampling circuit 11, actuating mechanism controls circuit 12, residual voltage sampling and modulate circuit 14 and the display and the keyboard circuit module 13 of insulation resistance respectively by its different port.
Total feeding switch protective device 1 includes TMS320F28335 type digital signal processor; TMS320F28335 type digital signal processor is a 32 the TMS320C28X series Floating-point DSP controller of TI company, and display is connected the interface of this digital signal processor TMS320F28335 with keyboard circuit module 13.Each branch's feeding switch protective device 2,3,4,5 has included processor; the PIC16F877A chip that processor adopting Microchip company produces; the zero-sequence current sampling is connected each processor respectively with modulate circuit 21,31,41,51, and the zero sequence current signal of sampling enters modulate circuit and handles the back input processor.
The method that earth leakage protective device shown in Figure 1 adopts additional dc power supply and zero sequence power direction route selection criterion to combine realizes earth leakage protective.Employing is carried out communication based on the PROFIBUS-DP fieldbus of RS-485 interface; the selective earth leakage protection method that adopts additional dc power supply method and zero sequence power direction route selection criterion method to combine; utilize the additional dc power supply method to measure the size of leakage current value, and judge the electric leakage circuit by the criterion route selection principle of zero sequence power direction.Comprise: total feeding switch protective device detection is set whether leaks electricity, detect the direction of homopolar power again by branch's feeding switch protective device respectively, judge the circuit that leak current fault takes place.Any time; at first total feeding switch protective device place utilizes the additional dc power supply method to measure the size of leakage current value; judge and whether leak electricity; if any electric leakage; detect the direction of homopolar power again by each branch's feeding switch protective device; branch's feeding switch protective device of faulty line obtains bus arbitration, and message is sent, by host computer record accident alarming information.Total feeding switch protective device and other each branch's feeding switch protective device operate as normal.
In the three phase network at total feeding switch protective device 1 place, add an independently DC power supply; make it to act between three phase network and the earth; measure the size variation flow through the DC current values on three relatively the insulation resistances then, reflection electrical network insulation against ground resistance r
∑Variation.Residual voltage sampling and 14 pairs of DC power supply of modulate circuit flow through three relatively insulation resistance on direct current sampled signal U
S, residual voltage U
0Gather in real time; 11 couples of insulation resistance r of the continuous sampling circuit of insulation resistance
∑Detect in real time.When electrical network just often, according to formula r
∑=U*R
S/ U
S-∑ R shows the insulation situation of electrical network in real time, so just can detect the electric leakage accident that whether takes place.Wherein, U is for independently DC power supply both end voltage, ∑ R are the D.C. resistance value R in parallel of the every phase coil of three-phase reactor
(L), R is equivalent resistance, the R of three-phase reactor
SBe sample resistance, R
EBe the earth resistance sum.
Zero-sequence current sampling and modulate circuit 21,31,41,51 gather respectively four branch's feeding switch protective devices 2,3,, the zero-sequence current I of 4,5 place branch roads
0Signal, and signal carried out data processing.As insulation resistance r
∑After dropping to operating value, total feeding switch protective device 1 is with residual voltage U
0Value send to each branch's feeding switch protective device 2,3,4,5,2,3,4,5 of each branch's feeding switch protective devices are according to the zero-sequence current I that gather
0Value, again in conjunction with branch road homopolar power formula P
r=I
0IU
0R-I
0RU
0IJudge, work as P
r0 be judged as fault branch, work as P
r＜0 o'clock, be judged as non-fault branch, and the P of fault branch
rValue is much larger than the P of non-fault branch
rValue, this criterion is accurate and reliable.Wherein, P
rBe homopolar power, U
0I, U
0R, I
0I, I
0RBe respectively residual voltage U
0With zero-sequence current I
0Imaginary part and real part.
When leak current fault takes place in partial node K1 place, after total feeding switch protective device 1 receives the block signal of each branch's feeding switch protective device 2,3,4,5, total feeding switch protective device 1 does not move in tripping operation with having time-delay, sends fault message to host computer 9 simultaneously; When leak current fault took place at arbitrary place (as arbitrary place of output node K2, K3, K4, K5) of branched line, the microprocessor TMS320F28335 at total feeding switch protective device 1 place was with residual voltage U
0Value pass to processor in each branch's feeding switch protective device 2,3,4,5, and be responsible for the calculating of route selection criterion by each processor PIC16F877A, after determining fault branch according to route selection criterion method, do not have time-delay ground and move in tripping operation, the while is sent fault message to host computer 9; If after the time-delay (150ms) that total feeding switch protective device 1 process is scheduled to; do not receive the actuating signal of branch's feeding switch protective device 2,3,4,5 as yet; then by total feeding switch protective device 1 non-selectivity move in tripping operation; thereby play the backup protection effect, send fault message to host computer 9 simultaneously.
Claims (1)
1. mine low-voltage power supply system selective leakage protection device, power transmission cable (7) connects total feeding switch protective device (1) by dry-type transformer (6), it is characterized in that: the output of total feeding switch protective device (1) connects four branch's feeding switch protective devices (2,3,4,5) respectively by partial node (K1), and four branch's feeding switch protective devices (2,3,4,5), total feeding switch protective device (1) connect respectively and all adopt fieldbus (8) connection between host computer (9) and the three; Four branch's feeding switch protective devices (2,3,4,5) connect corresponding four zero-sequence currents sampling and modulate circuit (21,31,41,51) respectively; Total feeding switch protective device (1) connects continuous sampling circuit (11), actuating mechanism controls circuit (12), residual voltage sampling and modulate circuit (14) and the display and the keyboard circuit module (13) of insulation resistance respectively by its different port; Total feeding switch protective device (1) comprises digital signal processor, and each branch's feeding switch protective device (2,3,4,5) has included processor.
2.A kind of guard method of selective leakage protection device as claimed in claim 1 is characterized in that having following steps:
1) additional DC power supply in the three phase network that total feeding switch protective device (1) is located makes it to act between three phase network and the earth, measures to flow through three relatively insulation resistance r
∑On DC current values;
2) residual voltage sampling and modulate circuit 14 are gathered insulation resistance r
∑On direct current sampled signal U
S, residual voltage U
0, the continuous sampling circuit (11) of insulation resistance detects insulation resistance r
∑When electrical network just often, according to formula r
∑=U*R
S/ U
S-∑ R shows the insulation situation of electrical network in real time, to detect the electric leakage accident that whether takes place; U is that DC power supply both end voltage, ∑ R are the D.C. resistance value R in parallel of the every phase coil of three-phase reactor
(L), R is equivalent resistance, the R of three-phase reactor
SBe sample resistance, R
EBe the earth resistance sum;
3) zero-sequence current sampling and modulate circuit (21,31,41,51) are gathered the zero-sequence current I of four branch's feeding switch protective devices (2,3,4,5) place branch road respectively
0Signal is as insulation resistance r
∑After dropping to operating value, total feeding switch protective device (1) is with residual voltage U
0Value send to each branch's feeding switch protective device (2,3,4,5), each branch's feeding switch protective device (2,3,4,5) is according to the zero-sequence current I that gathers
0Value, again in conjunction with branch road homopolar power formula P
r=I
0IU
0R-I
0RU
0IJudge, work as P
r0 be judged as fault branch, work as P
r, be judged as non-fault branch at＜0 o'clock; P
rIt is homopolar power; U
0I, U
0R, I
0I, I
0RBe respectively residual voltage U
0With zero-sequence current I
0Imaginary part and real part.
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|---|---|---|---|
| CN2011101070629A CN102185296A (en) | 2011-04-27 | 2011-04-27 | Selective electric leakage protection device and method for mine low-voltage power supply system |
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Cited By (9)
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| CN102938558A (en) * | 2012-11-26 | 2013-02-20 | 保定供电公司 | Low-voltage distribution system with leakage protection device |
| CN103972863A (en) * | 2014-04-17 | 2014-08-06 | 朱开久 | Real-time detection and control device for shunt electric leakage |
| CN104753026A (en) * | 2015-03-18 | 2015-07-01 | 胡妍 | Electricity leakage protecting system for preventing symmetric electricity leakage |
| CN104753024A (en) * | 2015-03-18 | 2015-07-01 | 胡妍 | Electricity leakage protecting method for preventing symmetric electricity leakage |
| CN105305376A (en) * | 2015-11-25 | 2016-02-03 | 国家电网公司 | Coal mine load control center selective electric leakage protection system and method |
| CN108983027A (en) * | 2018-07-26 | 2018-12-11 | 上海与德科技有限公司 | Electrical leakage detecting method, device, intelligent socket and storage medium |
| CN108983024A (en) * | 2018-07-14 | 2018-12-11 | 山东工商学院 | Mining earth leakage protective test and distant place closing device |
| CN112782529A (en) * | 2021-01-06 | 2021-05-11 | 许继集团有限公司 | Zero sequence power polarity-based line selection method and system |
| CN113922328A (en) * | 2021-09-28 | 2022-01-11 | 煤炭科学研究总院 | Method, device and equipment for underground leakage protection and storage medium |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102938558A (en) * | 2012-11-26 | 2013-02-20 | 保定供电公司 | Low-voltage distribution system with leakage protection device |
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| CN112782529A (en) * | 2021-01-06 | 2021-05-11 | 许继集团有限公司 | Zero sequence power polarity-based line selection method and system |
| CN113922328A (en) * | 2021-09-28 | 2022-01-11 | 煤炭科学研究总院 | Method, device and equipment for underground leakage protection and storage medium |
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Application publication date: 20110914 |