CN105629128A - Device and searching method for searching power grid undercurrent single-phase earth fault - Google Patents
Device and searching method for searching power grid undercurrent single-phase earth fault Download PDFInfo
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- CN105629128A CN105629128A CN201610025979.7A CN201610025979A CN105629128A CN 105629128 A CN105629128 A CN 105629128A CN 201610025979 A CN201610025979 A CN 201610025979A CN 105629128 A CN105629128 A CN 105629128A
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- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000012545 processing Methods 0.000 claims abstract description 33
- 230000007935 neutral effect Effects 0.000 claims description 40
- 238000004458 analytical method Methods 0.000 claims description 22
- 230000001629 suppression Effects 0.000 claims description 9
- 238000005070 sampling Methods 0.000 claims description 8
- 238000002955 isolation Methods 0.000 claims description 6
- 230000008676 import Effects 0.000 claims description 4
- 230000036772 blood pressure Effects 0.000 claims description 3
- 238000003745 diagnosis Methods 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims description 3
- 238000013480 data collection Methods 0.000 abstract 2
- 238000012216 screening Methods 0.000 abstract 1
- 238000007726 management method Methods 0.000 description 3
- 238000012790 confirmation Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 238000013024 troubleshooting Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008033 biological extinction Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
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Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/08—Locating faults in cables, transmission lines, or networks
- G01R31/081—Locating faults in cables, transmission lines, or networks according to type of conductors
- G01R31/086—Locating faults in cables, transmission lines, or networks according to type of conductors in power transmission or distribution networks, i.e. with interconnected conductors
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
- Locating Faults (AREA)
Abstract
The invention discloses a device and a searching method for searching power grid small current single-phase earthing fault, belonging to the earth fault screening field in the small current earth system. The device comprises a zero sequence CT/PT, an automatic circuit breaking control device, a control module and a circuit breaking sequence table; the zero sequence CT/PT is installed on all circuits of the small current earthing system; the automatic circuit breaking control device comprises a main control unit, a data collection and processing unit, a switch position input-output module and an external trigger module; the output terminal of the zero-sequence CT/PT is connected to the main control unit through the data collection and the processing unit; the corresponding terminal of the main control unit is in both way junction with the input terminal of the switch position; the output terminal of the external trigger module is connected to the trigger signal input terminal of the main control unit; and the main control unit is provided with a signal port for inputting the circuit breaking sequence table. The invention has advantages of accuracy, high pertinence and high safety.
Description
Technical field
The invention belongs to earth fault investigation field in small current neutral grounding system, be specifically related to a kind of device searching electrical network small area analysis singlephase earth fault and lookup method thereof.
Background technology
Data shows according to statistics, and in line fault, the fault of 70% is all earth fault, and singlephase earth fault accounts for more than the 80% of low current neutral grounding system fault. In small current neutral grounding system, single-phase earthing is a kind of common provisional fault, mostly occurs at weather moist, rainy. After there is single-phase earthing, fault phase voltage-to-ground reduces, the phase voltage rising that non-faulting is biphase, but line voltage is still symmetrical, thus does not affect the continuous power supply to user, and system can run 1��2h, and this is also the great advantage of small current neutral grounding system. If but electrical network longtime running when there is singlephase earth fault, because two phase-to-ground voltages of non-faulting raise 1.73 times, it is possible to the weak link causing insulation is breakdown, develops into phase fault, makes fault spread, affects the normal electricity consumption of user. Along with increasing of feeder line, capacitance current is also increasing, and long-play easily makes fault progression become or multipoint earthing short circuit at 2, arc grounding also can cause total system overvoltage, and then damage equipment, endanger system safety operation, so faulty line must be found in time to be excised.
At present, there be device and the lookup method thereof of the low current grounding automatic route selection of some comparative maturities in China, the Principle Method that each producer adopts is different, sum up to get up mainly to have two classes: 1. adopt the fault amount of system generation during line-to-ground fault, such as the residual voltage that bus produces, the zero-sequence current of ground path and ungrounded circuit zero-sequence current and residual voltage, than equal method, carry out analysis grounding fault and occur at which bar circuit; 2, utilize external signal input method, when system generation earth fault, adopt external equipment input signal source, and by detecting every circuit feedback signal, carry out analysis grounding fault and occur at which bar circuit. Two kinds of methods are all first select earth fault line, then send circuit warning signal and notify that dispatcher and operations staff process.
But owing to, in the complexity of earth fault, particularly small current neutral grounding system, when system capacitive current is bigger, route selection accuracy is higher, but route selection accuracy is low when capacitance current is less. When there is singlephase earth fault in the distribution of neutral by arc extinction coil grounding, ground path electricity feature shows different features according to the difference of arc suppression coil compensation mode, and there will be ground path and ungrounded circuit and there is the situation (cross such as arc suppression coil and repay a kindness under condition) of same charge feature, making multiple location design no longer applicable, line selection device for low current has exited operation all in succession. When often occurring dispatcher to pull open respective lines by route selection result because being in operation, it has been found that needing again circuit to serve after incorrect, front and back to have a power failure 3 minutes, causes the power failure that user is unnecessary.
Therefore, when there is small current system ground connection in transformer station, often to try the circuit drawing a plurality of outlet just can find out real ground connection, this just makes operator on duty assume responsibility for very big workload, also make the equipment ground time longer, have impact on the normal power supply of ungrounded circuit, reduce power supply reliability, be unfavorable for the safe operation of grid equipment.
Summary of the invention
The technical problem to be solved be to provide a kind of promptly and accurately, the high device searching electrical network small area analysis singlephase earth fault of with strong points, degree of safety and lookup method thereof.
For solving the problems referred to above, the technical solution used in the present invention is:
A kind of device searching electrical network small area analysis singlephase earth fault, its key technology is in that: it includes zero sequence CT/PT, automatically draws road to control device, control module and draw road sequence table; Described zero sequence CT/PT is installed on each circuit of small current neutral grounding system, the sampling end of described zero sequence CT/PT is connected with zero-sequence current/voltage end on each circuit of described small current neutral grounding system, and the outfan of described zero sequence CT/PT accesses the described signal input part automatically drawing road to control device; Described automatically draw road control device include main control unit, data acquisition and processing unit, position of the switch input/output module and external trigger module; The outfan of described zero sequence CT/PT is connected with main control unit through data acquisition and processing unit, the respective end of described main control unit and position of the switch input/output module are bi-directionally connected, the output of described external trigger module terminate described main control unit triggering signal input part; Described control module is installed in the neutral point place of described small current neutral grounding system, and described control module and described position of the switch input/output module are bi-directionally connected; Described main control unit is provided with described in input to draw the signal port of road sequence table.
Further, described control module be the installing of described small current neutral grounding system neutral point controllable impedance, can switching resistance or can switching capacitance in short-term in short-term.
Further, described data acquisition and processing unit include current/voltage transformer, amplifying return circuit and A/D change-over circuit; The outfan of described zero sequence CT/PT accesses the input of current/voltage transformer, and the outfan of described current/voltage transformer passes sequentially through amplifying return circuit and A/D change-over circuit output extremely described main control unit.
Further, described automatically draw road control device also include power module, described power module is connected with the power end of described main control unit.
Further, described automatically draw road control device also include input-output apparatus, described input-output apparatus includes keyboard and/or LCD MODULE, and described input-output apparatus is connected with main control unit.
Further, described in draw road sequence table to add up the single-phase small current neutral grounding of Nian Nei transformer station of each transformer station one branch, tripping operation total degree, described in draw road sequence table to be ranked up by ground connection, tripping operation total degree order from more to less; Rewrite when there is small area analysis single-phase earthing, tripping operation, update described in draw road sequence table, draw sequence table input in road automatically to draw road to control in device described in after updating.
The lookup method of a kind of device utilizing lookup electrical network small area analysis singlephase earth fault is as follows:
(1) there is low current grounding;
(2) road sequence table will be drawn to import main control unit, and described main control unit reads and draws road sequence table:
Adding up the single-phase low current grounding total degree of Nian Nei transformer station of each transformer station one branch, and road sequence table is drawn in establishment according to this, sequence table importing in Bing Jiangla road is described draws road controller automatically;
Described single-phase low current grounding total degree be ground connection, tripping operation total degree, described in draw road sequence table by ground connection, tripping operation total degree order from more to less be ranked up;
Should fill in time when there is small area analysis single-phase earthing, tripping operation, updating this and draw road sequence table (a year statistics once), carry out dynamically management, sequence table input in renewals Hou La road is drawn automatically in road control device;
(3) zero sequence CT/PT samples, the sampled signal of analyzing and processing zero sequence CT/PT;
(4) road is automatically drawn to control device carries out diagnosing whether meet operating criterion;
Diagnosing according to the described road order of drawing drawing road sequence table to determine, the diagnosis algorithm of circuit is as follows:
A, zero sequence CT/PT are installed on the section switch of each circuit, respectively in the forward and backward sampling completed each circuit zero sequence current/voltage of system generation single-phase earthing, and sampled signal is delivered to automatically draw road control device;
B, automatically draw road to control device in ground connection process, to change the line parameter circuit values such as system zero sequence impedance by controlling module, such as control the methods such as arc suppression coil little scope change compensativity, in short-term switching resistance, in short-term switching capacitance and realize the control to zero sequence loop; The time controlling module change loop generally maintains 2��3 power frequency cycles every time.
C, zero sequence loop line parameter circuit value change after, automatically draw road to control device and gather the zero-sequence current after each circuit changes again, calculate line parameter circuit value and change forward and backward each circuit zero sequence current differential �� I0, and according to zero-sequence current difference DELTA I0Each circuit is ranked up, and the circuit changing forward and backward zero-sequence current difference maximum is faulty line.
D, zero sequence CT detect zero-sequence current automatically, and the zero-sequence current data recorded is filtered, pass to data acquisition and processing unit after isolation processing; Zero sequence PT detects residual voltage automatically, and the residual voltage data recorded pass to data acquisition and processing unit after blood pressure lowering, filtering and isolation processing; Zero-sequence current and residual voltage are carried out Vector operation and process by data acquisition and processing unit, obtain the advance angle of zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current, and according to zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current advance angle judge the section that singlephase earth fault occurs; E, in isolated neutral system, when certain block switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 180��270 ��, then judge that the load side at this block switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault; In arc suppression coil earthing system, when certain section switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 90��270 ��, then judge that the load side at this section switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault.
(5) if meeting operating criterion, drawn by automatically drawing road control device to carry out examination;
(6) after examination is drawn, confirm that chopper is already off, time delay 10 seconds, wait that SCADA data refreshes;
(7) observe fault-signal whether involution, if the non-involution of signal, be back to step (3);
(8) if signal return, then terminate examination and draw.
Adopt and have the beneficial effects that produced by technique scheme:
The present invention is not by the impact of the factors such as capacitance current size, earthing type in small current neutral grounding system, can effectively differentiate out of order direction and classification, and draw road sequence table by working out importing, can according to the more circuit prioritizing selection of earth fault occurs, be effectively reduced the wrong route selection of tradition line selection device for low current, overcome that the singlephase earth fault basis for estimation that prior art exists is not accurate enough, fault discovery more not in time, troubleshooting needs manual operation, troubleshooting specific aim is poor, often result in the problems such as large-area power-cuts situation.
Accompanying drawing explanation
In order to be illustrated more clearly that the specific embodiment of the invention or technical scheme of the prior art, the accompanying drawing used required in detailed description of the invention or description of the prior art will be briefly described below, apparently, accompanying drawing in the following describes is some embodiments of the present invention, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the structured flowchart of the present invention.
Fig. 2 is the structured flowchart of data acquisition and processing unit in the present invention.
Fig. 3 is the use flow chart of the present invention.
Fig. 4 is the use flow chart automatically drawing road to control device in the present invention.
Detailed description of the invention
For making the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing 1-4 and specific embodiment, invention is carried out clear, complete description.
Embodiment as depicted in figs. 1 and 2, a kind of device searching electrical network small area analysis singlephase earth fault includes zero sequence CT/PT, automatically draws road to control device, control module and draw road sequence table; Described zero sequence CT/PT is installed on each circuit of small current neutral grounding system, the sampling end of described zero sequence CT/PT is connected with zero-sequence current/voltage end on each circuit of described small current neutral grounding system, and the outfan of described zero sequence CT/PT accesses the described signal input part automatically drawing road to control device; Described automatically draw road control device include main control unit, data acquisition and processing unit, position of the switch input/output module and external trigger module; The outfan of described zero sequence CT/PT is connected with main control unit through data acquisition and processing unit, the respective end of described main control unit and position of the switch input/output module are bi-directionally connected, the output of described external trigger module terminate described main control unit triggering signal input part; Described control module is installed in the neutral point place of described small current neutral grounding system, and described control module and described position of the switch input/output module are bi-directionally connected; Described main control unit is provided with described in input to draw the signal port of road sequence table.
Further, described control module be the installing of described small current neutral grounding system neutral point controllable impedance, can switching resistance or can switching capacitance in short-term in short-term.
Further, described data acquisition and processing unit include current/voltage transformer, amplifying return circuit and A/D change-over circuit; The outfan of described zero sequence CT/PT accesses the input of current/voltage transformer, and the outfan of described current/voltage transformer passes sequentially through amplifying return circuit and A/D change-over circuit output extremely described main control unit.
Further, described automatically draw road control device also include power module, described power module is connected with the power end of described main control unit.
Further, described automatically draw road control device also include input-output apparatus, described input-output apparatus includes keyboard and/or LCD MODULE, and described input-output apparatus is connected with main control unit.
Further, described in draw road sequence table to add up the single-phase small current neutral grounding of Nian Nei transformer station of each transformer station one branch, tripping operation total degree, described in draw road sequence table to be ranked up by ground connection, tripping operation total degree order from more to less; Rewrite when there is small area analysis single-phase earthing, tripping operation, update described in draw road sequence table, draw sequence table input in road automatically to draw road to control in device described in after updating.
As it is shown in figure 1, the operation principle of the present embodiment is as follows:
Zero sequence CT/PT that the present embodiment includes being sequentially connected with, automatically road is drawn to control device, control module and draw road sequence table. Wherein zero sequence CT/PT is installed on each circuit, completes the sampling to each circuit zero sequence current/voltage after small current neutral grounding system generation single-phase earthing, and sampled signal is delivered to and automatically draw road to control device. The described single-phase small current neutral grounding drawing road sequence table to add up Nian Nei transformer station of each transformer station one branch, tripping operation total degree, draw road sequence table to be ranked up by ground connection, tripping operation total degree order from more to less, and Bing Jiangla road sequence table imports main control unit; Should fill in time when there is small area analysis single-phase earthing, tripping operation, update described in draw road sequence table, described in draw road sequence table 1 year statistics once, carry out dynamically management, sequence table input in renewals Hou La road drawn automatically in road control device. Described automatically draw road control device include main control unit, power module, clock, keyboard, LCD MODULE, and the data acquisition being connected with main control unit respectively and processing unit, external trigger module, position of the switch input/output module, described data acquisition and processing unit receive the sampled signal of zero sequence CT/PT, and described position of the switch input/output module is connected with controlling module; Described power module is connected with all the other each modules automatically drawing road to control device respectively, to they power supplies, and presses optional 220V or the 110V input of practical situation, i.e. AC/DC universal. Described control module is installed in small current neutral grounding system neutral point, and be controlled by automatically draw road control device, receive and automatically draw road after controlling the control command sent by position of the switch input/output module in device, small current neutral grounding system zero sequence loop to be changed, and control confirmation signal is replied to by position of the switch input/output module automatically draw road control device; Automatically draw road to control after device receives control confirmation signal, complete zero sequence loop current, the sampling of voltage, calculating after disturbance by zero sequence CT/PT. When implementing, described control module can be small current neutral grounding system neutral point installing controllable impedance (such as arc suppression coil), can in short-term switching resistance or can in short-term switching capacitance (can control put into or excision exit resistance, electric capacity, to be selected go out after circuit, excised at once) etc.
Described zero sequence CT/PT and current transformer/current transformer.
As shown in Figure 2, described data acquisition and processing unit mainly include the current/voltage transformer, amplifying return circuit and the A/D modular converter that are sequentially connected with, it is digital signal that the analogue signal that described current/voltage transformer gathers when small current neutral grounding system is properly functioning enters A/D modular converter by amplifying return circuit, and is connected with the input of main control unit.
As it is shown on figure 3, the use flow process of the present invention is as follows:
(1) there is low current grounding;
(2) road sequence table will be drawn to import main control unit, and described main control unit reads and draws road sequence table:
Adding up the single-phase low current grounding total degree of Nian Nei transformer station of each transformer station one branch, and road sequence table is drawn in establishment according to this, sequence table importing in Bing Jiangla road is described draws road controller automatically;
Described single-phase low current grounding total degree be ground connection, tripping operation total degree, described in draw road sequence table by ground connection, tripping operation total degree order from more to less be ranked up;
Should fill in time when there is small area analysis single-phase earthing, tripping operation, updating this and draw road sequence table (a year statistics once), carry out dynamically management, sequence table input in renewals Hou La road is drawn automatically in road control device;
(3) zero sequence CT/PT samples, the sampled signal of analyzing and processing zero sequence CT/PT;
(4) road is automatically drawn to control device carries out diagnosing whether meet operating criterion;
Diagnosing according to the described road order of drawing drawing road sequence table to determine, the diagnosis algorithm of circuit is as follows:
A, zero sequence CT/PT are installed on the section switch of each circuit, respectively in the forward and backward sampling completed each circuit zero sequence current/voltage of system generation single-phase earthing, and sampled signal is delivered to automatically draw road control device;
B, automatically draw road to control device in ground connection process, to change the line parameter circuit values such as system zero sequence impedance by controlling module, such as control the methods such as arc suppression coil little scope change compensativity, in short-term switching resistance, in short-term switching capacitance and realize the control to zero sequence loop; The time controlling module change loop generally maintains 2��3 power frequency cycles every time.
C, zero sequence loop line parameter circuit value change after, automatically draw road to control device and gather the zero-sequence current after each circuit changes again, calculate line parameter circuit value and change forward and backward each circuit zero sequence current differential �� I0, and according to zero-sequence current difference DELTA I0Each circuit is ranked up, and the circuit changing forward and backward zero-sequence current difference maximum is faulty line.
D, zero sequence CT detect zero-sequence current automatically, and the zero-sequence current data recorded is filtered, pass to data acquisition and processing unit after isolation processing; Zero sequence PT detects residual voltage automatically, and the residual voltage data recorded pass to data acquisition and processing unit after blood pressure lowering, filtering and isolation processing; Zero-sequence current and residual voltage are carried out Vector operation and process by data acquisition and processing unit, obtain the advance angle of zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current, and according to zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current advance angle judge the section that singlephase earth fault occurs; E, in isolated neutral system, when certain block switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 180��270 ��, then judge that the load side at this block switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault; In arc suppression coil earthing system, when certain section switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 90��270 ��, then judge that the load side at this section switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault.
(5) if meeting operating criterion, drawn by automatically drawing road control device to carry out examination;
(6) after examination is drawn, confirm that chopper is already off, time delay 10 seconds, wait that SCADA data refreshes;
(7) observe fault-signal whether involution, if the non-involution of signal, be back to step (3);
(8) if signal return, then terminate examination and draw.
As shown in Figure 4, for the small current neutral grounding accident of a double-bus transformer station, specifically used flow process is as follows:
1) sequence table first is read in as currently processed item;
2) judge whether switch closes position;
3) as closed position, then step 4) is carried out; As do not closed position, next of Ze Zhila road tagmeme table is currently processed item, it is judged that whether tagmeme table is empty, if it is empty, then illustrates not find ground connection branch road, arrives step 6); If not empty, then transfer to return step 2) continue to judge;
4) selected switch, remote control disconnects, it is judged that whether signal resets;
5) as resetted, then remote control is closed, and LCD MODULE shows that this branch road goes wrong; As do not resetted, then remote control is closed, and next of Zhi La road tagmeme table is currently processed item, it is judged that whether tagmeme table is empty, if it is empty, then illustrates not find ground connection branch road, arrives step 6); If not empty, then transfer to return step 2) continue to judge;
6) leave it at that.
Last it is noted that above example is only in order to illustrate technical scheme, it is not intended to limit; Although the present invention being described in detail with reference to previous embodiment, it will be understood by those within the art that: the technical scheme described in previous embodiment still can be modified by it, or wherein portion of techniques feature is carried out equivalent replacement; And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of embodiment of the present invention technical scheme.
Claims (8)
1. the device searching electrical network small area analysis singlephase earth fault, it is characterised in that: it includes zero sequence CT/PT, automatically draws road to control device, control module and draw road sequence table; Described zero sequence CT/PT is installed on each circuit of small current neutral grounding system, the sampling end of described zero sequence CT/PT is connected with zero-sequence current/voltage end on each circuit of described small current neutral grounding system, and the outfan of described zero sequence CT/PT accesses the described signal input part automatically drawing road to control device; Described automatically draw road control device include main control unit, data acquisition and processing unit, position of the switch input/output module and external trigger module; The outfan of described zero sequence CT/PT is connected with main control unit through data acquisition and processing unit, the respective end of described main control unit and position of the switch input/output module are bi-directionally connected, the output of described external trigger module terminate described main control unit triggering signal input part; Described control module is installed in the neutral point place of described small current neutral grounding system, and described control module and described position of the switch input/output module are bi-directionally connected; Described main control unit is provided with described in input to draw the signal port of road sequence table.
2. a kind of device searching electrical network small area analysis singlephase earth fault according to claim 1, it is characterised in that: described control module be the installing of described small current neutral grounding system neutral point controllable impedance, can switching resistance or can switching capacitance in short-term in short-term.
3. a kind of device searching electrical network small area analysis singlephase earth fault according to claim 1, it is characterised in that: described data acquisition and processing unit include current/voltage transformer, amplifying return circuit and A/D change-over circuit; The outfan of described zero sequence CT/PT accesses the input of current/voltage transformer, and the outfan of described current/voltage transformer passes sequentially through amplifying return circuit and A/D change-over circuit output extremely described main control unit.
4. a kind of device searching electrical network small area analysis singlephase earth fault according to claim 1, it is characterised in that: described automatically draw road control device also include power module, described power module is connected with the power end of described main control unit.
5. a kind of device searching electrical network small area analysis singlephase earth fault according to claim 1, it is characterized in that: described automatically draw road control device also include input-output apparatus, described input-output apparatus includes keyboard and/or LCD MODULE, and described input-output apparatus is connected with main control unit.
6. a kind of device searching electrical network small area analysis singlephase earth fault according to claim 1, it is characterized in that: described in draw road sequence table to add up the single-phase small current neutral grounding of Nian Nei transformer station of each transformer station one branch, tripping operation total degree, described in draw road sequence table to be ranked up by ground connection, tripping operation total degree order from more to less; Rewrite when there is small area analysis single-phase earthing, tripping operation, update described in draw road sequence table, draw sequence table input in road automatically to draw road to control in device described in after updating.
7. utilize the lookup method of the arbitrary described a kind of device searching electrical network small area analysis singlephase earth fault of claim 1 ~ 6, it is characterised in that step is as follows:
(1) there is low current grounding;
(2) road sequence table will be drawn to import main control unit, and described main control unit reads and draws road sequence table:
Adding up the single-phase low current grounding total degree of Nian Nei transformer station of each transformer station one branch, and road sequence table is drawn in establishment according to this, sequence table importing in Bing Jiangla road is described draws road controller automatically;
Described single-phase low current grounding total degree be ground connection, tripping operation total degree, described in draw road sequence table by ground connection, tripping operation total degree order from more to less be ranked up;
Should fill in time when there is small area analysis single-phase earthing, tripping operation, updating this and draw road sequence table, carry out dynamically management, sequence table input in renewals Hou La road is drawn automatically in road control device;
(3) zero sequence CT/PT samples, the sampled signal of analyzing and processing zero sequence CT/PT;
(4) road is automatically drawn to control device carries out diagnosing whether meet operating criterion;
(5) if meeting operating criterion, drawn by automatically drawing road control device to carry out examination;
(6) after examination is drawn, confirm that chopper is already off, time delay 10 seconds, wait that SCADA data refreshes;
(7) observe fault-signal whether involution, if the non-involution of signal, be back to step (3);
(8) if signal return, then terminate examination and draw.
8. a kind of lookup method according to claim 7, it is characterised in that: it is as follows that described step (4) draws road control device to carry out diagnosing the concrete grammar whether meeting operating criterion automatically:
Diagnosing according to the described road order of drawing drawing road sequence table to determine, the diagnosis algorithm of circuit is as follows:
A, zero sequence CT/PT are installed on the section switch of each circuit, respectively in the forward and backward sampling completed each circuit zero sequence current/voltage of system generation single-phase earthing, and sampled signal is delivered to automatically draw road control device;
B, automatically draw road to control device in ground connection process, to change the line parameter circuit values such as system zero sequence impedance by controlling module, such as control the methods such as arc suppression coil little scope change compensativity, in short-term switching resistance, in short-term switching capacitance and realize the control to zero sequence loop; The time controlling module change loop generally maintains 2��3 power frequency cycles every time;
C, zero sequence loop line parameter circuit value change after, automatically draw road to control device and gather the zero-sequence current after each circuit changes again, calculate line parameter circuit value and change forward and backward each circuit zero sequence current differential �� I0, and according to zero-sequence current difference DELTA I0Each circuit is ranked up, and the circuit changing forward and backward zero-sequence current difference maximum is faulty line;
D, zero sequence CT detect zero-sequence current automatically, and the zero-sequence current data recorded is filtered, pass to data acquisition and processing unit after isolation processing; Zero sequence PT detects residual voltage automatically, and the residual voltage data recorded pass to data acquisition and processing unit after blood pressure lowering, filtering and isolation processing; Zero-sequence current and residual voltage are carried out Vector operation and process by data acquisition and processing unit, obtain the advance angle of zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current, and according to zero-sequence current, residual voltage, the advanced residual voltage of zero-sequence current advance angle judge the section that singlephase earth fault occurs; E, in isolated neutral system, when certain block switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 180��270 ��, then judge that the load side at this block switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault; In arc suppression coil earthing system, when certain section switch detect zero-sequence current more than set threshold value, residual voltage more than set threshold value time, if the advance angle of the advanced residual voltage of zero-sequence current is 90��270 ��, then judge that the load side at this section switch occurs earth fault; When the advance angle of the advanced residual voltage of zero-sequence current is 0��90 ��, then judge that the mains side at this section switch occurs earth fault.
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