CN105305376A - Coal mine load control center selective electric leakage protection system and method - Google Patents
Coal mine load control center selective electric leakage protection system and method Download PDFInfo
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- CN105305376A CN105305376A CN201510830666.4A CN201510830666A CN105305376A CN 105305376 A CN105305376 A CN 105305376A CN 201510830666 A CN201510830666 A CN 201510830666A CN 105305376 A CN105305376 A CN 105305376A
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Abstract
The invention discloses a coal mine load control center selective electric leakage protection system and method and belongs to the field of three mining equipment protection techniques. The system comprises a DSP, a zero sequence signal acquisition circuit, a signal processing circuit, an insulation resistance detection circuit, an execution unit, an operation unit, a display unit, and a CAN communication unit. The electric leakage protection method protects coal mine load control center electric leakage faults by using a way combining an additional DC power method with a zero-crossing trigger method, may measure leakage current, and may accurately detect a branch with electric leakage.
Description
Technical field
The invention belongs to the large resist technology field of mining equipment three, and a kind of especially colliery the center of load control selective earth leakage protection system and method.
Background technology
Along with the high speed development of colliery fully-mechanized mining technology, the continuous increase of underground power supply used Network stretch distance, to the reliability of underground coal mine electric power system and the requirement of fail safe more and more higher.Due to downhole production humid environment, badly, often leak current fault is there is in low-voltage power supply system, if eliminating in time huge potential safety hazard can not can be there is in fault, coal-dust explosion, gas explosion, premature ignition detonator etc. such as may be caused to jeopardize the accident of safety in production, directly jeopardize the personal safety of national wealth and underground work personnel.Earth leakage protective and overcurrent protection, ground protection are listed as three protecting greatly of ensureing that coal mine downhole safety powers, are the important measures preventing the person from getting an electric shock.Selectively earth leakage protective refers to when electrical network generation leak current fault, can send fault-signal or disengagement failure branch road power supply selectively, but not faulty component works on.Current colliery the center of load control selective earth leakage protection system major part adopts based on zero-sequence current size and zero-sequence current direction protection technology; this protection in emanant supply network when the length of a certain branch road is far longer than other branch roads; more difficultly meet selective protection demand; may there is misaction in protective device, well can not complete the object of protection.
Summary of the invention
Goal of the invention:
In order to solve above-mentioned prior art Problems existing; the present invention proposes a kind of colliery the center of load control selective earth leakage protection system and method; the mode that this system adopts additional dc power supply method and zero cross fired method to combine is carried out protection to colliery the center of load control leak current fault and is detected, and can prepare to judge electric leakage branch road simultaneously.
Technical scheme:
The present invention is achieved through the following technical solutions:
A kind of colliery the center of load control selective earth leakage protection system, is characterized in that: this system comprises DSP, zero sequence signal Acquisition Circuit, signal processing circuit, insulating resistor detecting circuit, performance element, operating unit, display unit and CAN communication unit; Wherein zero sequence signal Acquisition Circuit gathers residual voltage and zero sequence current signal, and the output of zero sequence signal Acquisition Circuit is connected with the input of signal processing circuit; The output of signal processing circuit is connected with the signal capture unit of DSP; The output of insulation resistance test circuit is connected with the input end of analog signal of DSP; Performance element comprises leakage relay and release, and the control signal input of performance element is connected with the signal output part of DSP; Operating unit is extraneous control command input unit, and the output of operating unit is connected with the signal input part of DSP; The driving input of display unit is connected with the signal output part of DSP; The input of CAN communication unit is connected with the inside CAN communication module port of DSP.
Insulating resistor detecting circuit is additional dc power supply in three phase network, the anode contact resistance R3 of DC power supply, resistance R3 connects with electric capacity C2, C3 and resistance R1, three phase network is connected with resistance R1 by three-phase reactor L, and resistance R1 connects with resistance R2, resistance R2 is connected DC power supply negative terminal respectively and electric capacity C1; Three phase network is by three phase network insulation resistance r ground connection, and three phase network is by three-phase polar capacitor C
a, C
b, and C
cground connection.
Zero sequence signal Acquisition Circuit comprises residual voltage Acquisition Circuit and zero-sequence current Acquisition Circuit; Residual voltage and zero-sequence current primary signal send to the signal capture pin of DSP to feed back to the analog to digital converter ADC of DSP after light-coupled isolation, Schmidt trigger circuit shaping and resistance, electric capacity phase shift.
Residual voltage signal connects the input of optocoupler EL814 by resistance R4, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R6 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R8 with C4 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP; Zero sequence current signal connects the input of optocoupler EL814 by resistance R5, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R7 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R7 with C5 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP.
The earth leakage protecting method of a kind of colliery described above the center of load control selective earth leakage protection system, it is characterized in that: insulating resistor detecting circuit is additional dc power supply in three phase network, DSP by detect in real time three relatively electric current judge the change of three-phase insulation against ground resistance; According to the practical operation situation of electrical network, the safety value of setting insulation resistance; When the insulating resistance value detected exceeds safety value, judge leak current fault occurs, then judge concrete fault branch according to the feedback signal of zero cross fired method.
Advantage and effect:
The present invention relates to a kind of colliery the center of load control selective earth leakage protection system and method, tool has the following advantages and beneficial effect.
(1) mode adopting additional dc power supply method and zero cross fired method to combine is carried out protection to colliery the center of load control leak current fault and is detected, and can prepare to judge electric leakage branch road simultaneously.
(2) earth leakage protective of system at the total feeding switch place of Coal Mine Power Network adopts additional dc power supply principle; adopt zero cross fired method in the feeding switch place earth leakage protective of each branch road, and the CAN technology adopting antijamming capability strong realizes the data communication between point feeding switch and total feeding switch.
Accompanying drawing explanation
Fig. 1 is structural representation of the present invention.
Fig. 2 is insulating resistor detecting circuit figure.
Fig. 3 is zero sequence signal signal sampling and processing circuit diagram.
Fig. 4 is present system workflow diagram.
Fig. 5 insulation resistance overhaul flow chart.
Fig. 6 zero sequence signal collecting flowchart figure.
Wherein, 1, zero sequence signal Acquisition Circuit; 2, signal processing circuit; 3, DSP; 4, display unit; 5, operating unit; 6, performance element; 7, CAN communication unit; 8, insulating resistor detecting circuit.
Embodiment
The mode that the present invention adopts annex DC power supply method and zero cross fired method to combine is carried out protection to colliery the center of load control leak current fault and is detected; the measurement of leakage current size can not only be realized; can also prepare to judge electric leakage branch road simultaneously; the earth leakage protective of system at the total feeding switch place of Coal Mine Power Network adopts additional dc power supply principle; adopt zero cross fired method in the feeding switch place earth leakage protective of each branch road, and the CAN technology adopting antijamming capability strong realizes the data communication between point feeding switch and total feeding switch.
Be described in detail below in conjunction with the specific implementation process of accompanying drawing to patent.
Colliery the center of load control selective earth leakage protection system construction drawing as shown in Figure 1, system take DSP as core, mainly comprise DSP3, zero sequence signal Acquisition Circuit 1, signal processing circuit 2, insulating resistor detecting circuit 8, performance element 6, operating unit 5, display unit 4 and CAN communication unit 7, wherein zero sequence signal Acquisition Circuit 1 gathers residual voltage and zero sequence current signal, and the output of zero sequence signal Acquisition Circuit 1 is connected with the input of signal processing circuit 2; The output of signal processing circuit 2 is connected with the signal capture unit CAP port of DSP3; The output of insulation resistance test circuit 8 is connected with the input end of analog signal ADC of DSP3; Performance element 6 is by leakage relay and release, and the control signal input of performance element 6 is connected with the signal output part XD of DSP3; Operating unit 5 is extraneous control command input unit, and the output of operating unit 5 is connected with the signal input part GPIOA of DSP3; The driving input of display unit 4 is connected with the signal output part of DSP3; The input of CAN communication unit 7 is connected with inside CAN communication module port CANTXA and the CANRXA of DSP3.
Insulating resistor detecting circuit 8 as shown in Figure 2, adopt additional dc power supply in three phase network, the anode contact resistance R3 of DC power supply, resistance R3 connects with electric capacity C2, C3 and resistance R1, three phase network is connected with resistance R1 by three-phase reactor L, and resistance R1 connects with resistance R2, resistance R2 is connected DC power supply negative terminal respectively and electric capacity C1; Three phase network is by three phase network insulation resistance r ground connection, and three phase network is by three-phase polar capacitor C
a, C
b, and C
cground connection.
Insulating resistor detecting circuit is additional dc power supply in three phase network, DSP3 by detect in real time three relatively electric current I judge the change of three-phase insulation against ground resistance.According to the practical operation situation of electrical network, the safety value of setting insulation resistance; When the insulating resistance value detected exceeds safety value, judge leak current fault occurs, then judge concrete fault branch according to the feedback signal of zero cross fired method.Testing circuit is followed successively by: DC power supply anode, resistance R3, greatly, line insulation resistance, three phase network, three-phase reactor L, resistance R1, resistance R2 and DC power supply negative terminal.
The computing formula of electric current I:
In formula, R
lfor the every phase coil D.C. resistance of three-phase reactor; R
sfor the resistance of ground connection Shen; r
∑for three phase network total insulation resistance over the ground.R is only had in above formula
∑for variable (r
∑=r/3), so the insulation situation of electrical network can be reflected according to the change of electric current I.According to the practical operation situation of electrical network, the safety value of setting insulation resistance.When the insulating resistance value detected exceeds safety value, judge leak current fault occurs, then judge concrete fault branch according to the feedback signal of zero cross fired method.
As shown in Figure 3, zero sequence signal Acquisition Circuit comprises residual voltage Acquisition Circuit and zero-sequence current Acquisition Circuit to zero sequence signal signal sampling and processing circuit; Residual voltage and zero-sequence current primary signal send to the signal capture pin of DSP to feed back to the analog to digital converter ADC of DSP after light-coupled isolation, Schmidt trigger circuit shaping and resistance, electric capacity phase shift.
Residual voltage signal connects the input of optocoupler EL814 by resistance R4, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R6 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R8 with C4 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP.
Zero sequence current signal connects the input of optocoupler EL814 by resistance R5, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R7 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R7 with C5 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP.
Utilize the capture function of DSP, catch at the dead-center position of each residual voltage and zero-sequence current, utilize analog to digital converter to carry out synchronized sampling to the signal caught.Signal is after optocoupler EL814 isolation and Schmidt trigger 74HC37 shaping, resistance and capacitance phase-shifting circuit and inverter 74LS19 process, and feed back to the analog to digital converter of DSP, DSP carries out computing to signal and realizes zero cross fired method earth leakage protective.Residual voltage and zero-sequence current primary signal send to the signal capture pin of DSP after light-coupled isolation, Schmidt trigger circuit shaping and resistance, electric capacity phase shift.Suppose to capture the zero crossing of residual voltage in the T1 moment, the zero crossing of zero-sequence current is captured in the T2 moment, if 0.005≤T2-T1≤0.01, then the delayed residual voltage signal of zero sequence current signal 90 °-180 ° is described, realizes the judgement to concrete branch road leak current fault.
Colliery the center of load control selective earth leakage protection system adopts structured design procedures, whole system workflow is divided into several independent flow, then each flow process is linked into an organic whole.Colliery the center of load control selective earth leakage protection working-flow figure, insulation resistance testing process and zero sequence signal collecting flowchart are as shown in Figure 4, Figure 5 and Figure 6.
Claims (5)
1. a colliery the center of load control selective earth leakage protection system, is characterized in that: this system comprises DSP, zero sequence signal Acquisition Circuit, signal processing circuit, insulating resistor detecting circuit, performance element, operating unit, display unit and CAN communication unit; Wherein zero sequence signal Acquisition Circuit gathers residual voltage and zero sequence current signal, and the output of zero sequence signal Acquisition Circuit is connected with the input of signal processing circuit; The output of signal processing circuit is connected with the signal capture unit of DSP; The output of insulation resistance test circuit is connected with the input end of analog signal of DSP; Performance element comprises leakage relay and release, and the control signal input of performance element is connected with the signal output part of DSP; Operating unit is extraneous control command input unit, and the output of operating unit is connected with the signal input part of DSP; The driving input of display unit is connected with the signal output part of DSP; The input of CAN communication unit is connected with the inside CAN communication module port of DSP.
2. colliery according to claim 1 the center of load control selective earth leakage protection system, it is characterized in that: insulating resistor detecting circuit is additional dc power supply in three phase network, the anode contact resistance R3 of DC power supply, resistance R3 connects with electric capacity C2, C3 and resistance R1, three phase network is connected with resistance R1 by three-phase reactor L, and resistance R1 connects with resistance R2, resistance R2 is connected DC power supply negative terminal respectively and electric capacity C1; Three phase network is by three phase network insulation resistance r ground connection, and three phase network is by three-phase polar capacitor C
a, C
b, and C
cground connection.
3. colliery according to claim 1 the center of load control selective earth leakage protection system, is characterized in that: zero sequence signal Acquisition Circuit comprises residual voltage Acquisition Circuit and zero-sequence current Acquisition Circuit; Residual voltage and zero-sequence current primary signal send to the signal capture pin of DSP to feed back to the analog to digital converter ADC of DSP after light-coupled isolation, Schmidt trigger circuit shaping and resistance, electric capacity phase shift.
4. colliery according to claim 3 the center of load control selective earth leakage protection system, it is characterized in that: residual voltage signal connects the input of optocoupler EL814 by resistance R4, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R6 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R8 with C4 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP; Zero sequence current signal connects the input of optocoupler EL814 by resistance R5, another input end grounding of optocoupler EL814, one of optocoupler EL814 exports termination high level VCC, the input of the Schmidt trigger 74HC37 of another output difference contact resistance R7 and signal processing circuit; The output of Schmidt trigger 74HC37 is divided into two branch roads, a branch road connects the input of inverter 74LS19, another branch road is by being connected another input of inverter 74LS19 after R7 with C5 resistance capacitance phase-shift circuit in series, the output of inverter 74LS19 connects the signal capture pin of DSP.
5. the earth leakage protecting method of a colliery the center of load control selective earth leakage protection system as described in claim 1,2,3 or 4, it is characterized in that: insulating resistor detecting circuit is additional dc power supply in three phase network, DSP by detect in real time three relatively electric current judge the change of three-phase insulation against ground resistance; According to the practical operation situation of electrical network, the safety value of setting insulation resistance; When the insulating resistance value detected exceeds safety value, judge leak current fault occurs, then judge concrete fault branch according to the feedback signal of zero cross fired method.
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Cited By (1)
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Application publication date: 20160203 |