CN201234133Y - Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid - Google Patents
Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid Download PDFInfo
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- CN201234133Y CN201234133Y CNU2008201138729U CN200820113872U CN201234133Y CN 201234133 Y CN201234133 Y CN 201234133Y CN U2008201138729 U CNU2008201138729 U CN U2008201138729U CN 200820113872 U CN200820113872 U CN 200820113872U CN 201234133 Y CN201234133 Y CN 201234133Y
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Abstract
The utility model discloses a protection system for eliminating single-phase grounding fault of a power grid with non-effectively grounded neutral point, which aims to eliminate the misunderstanding on determining the single-phase grounding fault of the power grid with non-effectively grounded neutral point. The protection system can reliably eliminate the faults, such as arc grounding, without being influenced by the grounding current and can reduce the grounding fault current without the needs of accurate tracking and compensation current regulation by adopting the combination of a voltage limitation method achieved by clamping the fault-phase voltage, a bypass protection method and a current compensation protection method which adopts an inductive current to compensate for a grounding capacitive current. The protection system has the advantages of high practicability, simple control and reliable protection.
Description
Technical field
The utility model relates to a kind of neutral non-effective grounding electrical network to comprehensive differentiation of single phase ground fault, the comprehensive method of protection and the Integrated Protection System thereof of elimination fault, and specifically a kind of neutral non-effective grounding electrical network is eliminated the single phase ground fault protection system.
Background technology
In electric power system, single-phase earthing is the major failure form of operation of power networks, accounts for more than 60% of full electric network total failare, and quite a few phase fault is to be developed by single phase ground fault.The reliable degree of electric power system under the identical situation of other conditions, only depends on the working method of electric power system neutral point.The earthing mode of research electric power system neutral point mainly is correctly to be familiar with and to handle the single phase ground fault problem that this is seen at most.
The type of single phase ground fault can be divided into: arc grounding, high resistance ground and metal ground connection.According to the statistics of electric power system, the single phase ground fault of the overwhelming majority is arc grounding and high resistance ground.The harm maximum of single-phase arc grounding, high resistance ground is the most common, extension as the branch in the overhead transmission line bumps, the cable insulation in the broken string, cable line makes moist, aging or the like, all present the feature of high resistance ground, and the arc grounding fault develops from high resistance earthing fault mostly also.
The earth resistance excursion of high resistance ground is big, unstable, and malfunction is the most complicated, and after earth resistance arrived to a certain degree greatly, fault signature was different from common feature, and fault message is very faint, so that become a difficult problem in protection and the route selection.So; when high resistance earthing fault takes place owing to report is arranged during the accident that protection malfunction or tripping cause: breaking to fall as transmission line causes loss of life or personal injury in cement flooring protection tripping, and broken string falls to protect tripping in the mountain and forest region and cause that fire, cable blow out or the like.Most protection product all exists erroneous judgement, malfunction or tripping to high resistance earthing protecting, and its reason is except fault message is faint, and main is the mistaken ideas that exist on the understanding.Because the voltage analysis during usually to isolated neutral system generation single-phase earthing all is to analyze by typical metal ground connection, this moment, the ground connection phase voltage was zero, the non-phase voltage that connects is upgraded to line voltage, and neutral point excursion is to earth point, and residual voltage equals the phase voltage before the opposite fault of direction.So that produce a kind of generally conclusion of approval: ground connection is the minimum phase of amplitude in the three-phase voltage mutually, the overwhelming majority is that the earth fault protection product of criterion also all is to differentiate the ground connection phase by this conclusion with voltage.In fact this is correct in the scope of earth resistance less than certain critical value, and when earth resistance during greater than this critical value, this conclusion is wrong.In other words, in the scope of high resistance ground, arrive to a certain degree when earth resistance is big, ground connection is not the minimum phase of voltage magnitude mutually.Defend tenaciously aforementioned conclusion, must cause erroneous judgement, the malfunction protected in the high resistance earthing fault.In addition, be the earth fault protection product of criterion with the electric current, zero-sequence current is very little during owing to high resistance ground, and tripping; The route selection product also therefore and can't route selection.
Arc suppression coil is modal a kind of protection equipment of eliminating single phase ground fault; it is connected between neutral point of electric network and the ground; when single phase ground fault takes place; it produces the capacity current that inductance current is offset fault; fault current is reduced in the scope of regulation, to eliminate arc grounding or to suppress other earth fault.This just requires the capacitance current of measuring system exactly, and the inductance value of accurately regulating arc suppression coil is complementary with the capacitance current that needs to offset, otherwise does not just reach the purpose of protection.
Because the trend that the capacity of transformer station has the process that substep puts in place and continues to enlarge, this just make the capacity of arc suppression coil often be in non-little be big awkward condition: little, then be operated in the undercompensation state, be easy to generate resonance during system excision circuit; Big, cause the idleness of equipment to damage easily and waste.Even the heap(ed) capacity of arc suppression coil meets the needs of current system, because the size of the capacitance current of system changes with the change of system operation mode, make the arc suppression coil measure and control device very complicated, operating difficulties, calculating and accuracy of measurement that capacitance current is changed are not enough, in actual motion, be difficult to operate in best gear, particularly cause resonance in order to avoid compensation, often make the residual flow in compensation backarc road still bigger, being still within the bounds of possibility of resume combustion after the zero passage finally causes the extinguishing arc failure.And arc suppression coil compensation only is the power frequency capacitance current, and actual electric current by earth point not only has the power frequency capacitance current, but also include a large amount of high-frequency currents and current in resistance property, the sustained combustion that only high-frequency current and current in resistance property just can pilot arcs when serious, particularly the high frequency oscillation current amplitude of cable circuit is bigger, decay is slow, so that high-frequency current still has big amplitude when the power current zero passage, can not accomplish complete blow-out.
In addition, arc suppression coil can cause neutral point displacement voltage to raise unusually, can not reduce maximum of arcing ground over-voltage or the like, and suchlike drawback so that arc suppression coil is not high at many local operational percentages, causes significant wastage, and interruption of service has report also the time.And arc suppression coil the complete sets of equipment assembly is many, cost is high, take up an area of greatly, and operation maintenance complexity, bad adaptability, along with the development of current power, the increase-volume of electrical network, many arc suppression coils are faced with superseded.
Summary of the invention
At existing single phase ground fault is differentiated have mistaken ideas, easily cause the erroneous judgement of high resistance earthing fault or fail to judge and effective protection problem can't be provided, a kind of neutral non-effective grounding electrical network of utility model is eliminated the single phase ground fault protection system.
The technical solution of the utility model is:
A kind of neutral non-effective grounding electrical network is eliminated the single phase ground fault protection system; it is characterized in that: mainly by microcomputer control device, reactor L, reactor Ln, voltage transformer TV, current transformer (CT1, CT2), four monopolar high-voltage switches (Ko, Ka; Kb Kc) forms.The power supply neutral point is connected with monopolar high-voltage switch (Ko) upper contact head, and the following contact of monopolar high-voltage switch (Ko) is connected with the end of reactor Ln, and the other end of reactor Ln passes ground connection behind the winding of current transformer CT2; The power supply three-phase bus respectively with monopolar high-voltage switch (Ka, Kb, Kc) the upper contact head of often opening main contacts separately is corresponding to link to each other, after interconnecting, their following contact links to each other with the end of reactor L, the other end of reactor L passes ground connection behind the winding of current transformer CT1, four monopolar high-voltage switch (Ko, Ka, Kb, Kc) be subjected to the control of the output switching terminal of microcomputer control device, the end points of voltage transformer TV secondary winding links to each other with the corresponding voltage input of microcomputer control device respectively, current transformer CT1, the secondary terminals (I of the secondary terminals of CT2 and system's feeder line zero sequence current mutual inductor
01..., I
0n) link to each other with the corresponding current input terminal of microcomputer control device respectively.Microcomputer control device wherein can adopt conventional microcomputer to add software and realize.
The beneficial effects of the utility model:
The utility model has disclosed the rule of isolated neutral system single phase ground fault; various features and the differentiation and the protection guard method of high resistance earthing fault have been found out; no matter how earth resistance and fault signature change, and can both accurately differentiate fault and fault mutually, implement effectively protection.
The utility model has been realized the isolated neutral system single phase ground fault is implemented FR effective protection, especially can differentiate the small-signal that is difficult to discover high resistance earthing fault, and fault is eliminated in bud.
The utility model combines the guard method of pressure limiting, bypass and the guard method of current compensation; the two advantage is separately given full play to, and the two shortcoming is separately remedied mutually, and is practical; observing and controlling is simple and reliable, has realized a kind of desirable approach of single phase ground fault of eliminating.
Description of drawings
Fig. 1 is differentiation of the present utility model and guard method flow chart.
Fig. 2 is the electric structure principle chart of protection system of the present utility model.
Fig. 3 is the theory diagram of microcomputer control system of the present utility model.
Among the figure: Ko, Ka, Kb, Kc are high-pressure vacuum switch, and TV is a voltage transformer, and CT1, CT2 are current transformer, and Ln is an arc suppression coil, L is a reactor, and XHXC is an arc suppression coil, and SXDY is a three phase mains, MX is a bus, and WCZZ is a microcomputer control device, and XHZZ is an arc-extinction device.
Embodiment
Below in conjunction with drawings and Examples this utility model is further described.
One, single phase ground fault phase method of discrimination
A kind of method of discrimination of single phase ground fault phase of neutral non-effective grounding electrical network, with reference to figure 1: when single phase ground fault takes place, be fault signature district 1 with residual voltage greater than 1/2 normal phase voltage, that declares three-phase voltage in this zone minimumly is the fault phase mutually; Equaling 1/2 normal phase voltage with residual voltage is fault signature district 2, and the phase voltage of declaring 90 ° of hysteresis residual voltages in this zone is the fault phase; Is fault signature district 3 with residual voltage less than 1/2 normal phase voltage, and declaring the inferior low of three-phase voltage in this zone is the fault phase mutually.
Two, eliminate the comprehensive method of protection of single phase ground fault
A kind of neutral non-effective grounding electrical network is eliminated the guard method of single phase ground fault; with reference to figure 1, Fig. 2; it is characterized in that: microcomputer control device is set respectively on electrical network and is used to eliminate the reactor L of fault and arc-suppression reactor Ln etc. forms protection system; zero-sequence current value when haveing with fault by three-phase voltage, the residual voltage of microcomputer control device detection of grid, carry out fault as follows and eliminate:
Microcomputer control device has detected single phase ground fault, and at first the failure judgement phase satisfies the condition in fault signature district 1 as if residual voltage, and declaring voltage minimum is the fault phase mutually; If residual voltage satisfies the condition in fault signature district 2, the voltage of declaring 90 ° of hysteresis residual voltages is the fault phase mutually; If residual voltage satisfies the condition in fault signature district 3, declare the inferior low fault phase that is mutually of voltage; If ground connection zero-sequence current value is less than 20A, protection is only finished by throw-moving back reactor L, and process is as follows: 1) microcomputer control device driving malfunction phase high-voltage switch gear closure, this is passed through reactor L ground connection mutually, to clamp down on the fault phase voltage, shift fault current, make the fault point insulation recovery, eliminate earth fault, drive this high-voltage switch gear time-delay disjunction then, withdraw from reactor L, normal if system voltage recovers, then protection is finished; 2) if fault still exists, then repeat above process, for the second time fault congenial-move back reactor L; 3) if still have fault, then be judged to the continuous earth fault, continue for the third time,, reactor L is withdrawed from until the faulty line excision at the congenial reactor L of fault.
Microcomputer control device has detected single phase ground fault, and at first the failure judgement phase satisfies the condition in fault signature district 1 as if residual voltage, and declaring voltage minimum is the fault phase mutually; If residual voltage satisfies the condition in fault signature district 2, the voltage of declaring 90 ° of hysteresis residual voltages is the fault phase mutually; If residual voltage satisfies the condition in fault signature district 3, declare the inferior low fault phase that is mutually of voltage; If ground connection zero-sequence current value is greater than 20A, protection is by throw-moving back reactor L and throwing-move back reactor Ln to finish jointly, process is as follows: 1) microcomputer control device is earlier at the congenial reactor L of fault, then drive high-voltage switch gear Ko closure, the power supply neutral point is passed through reactor Ln ground connection, the capacitance current of the inductive current compensation of ground fault that Ln produces, make it less than 20A, because L is to the pressure limiting of fault phase, the bypass effect has guaranteed not to be subjected to the influence of earth current size, single phase ground faults such as reliable elimination arc grounding, thereby, needn't accurately pursue the current compensation degree, make observing and controlling become simple to electric current, the two combination of L and Ln realizes the ideal effect of protecting; Then, reactor L is moved back in the high-voltage switch gear of fault phase time-delay disjunction; At this moment, normal if system voltage recovers, then disjunction high-voltage switch gear Ko withdraws from reactor Ln, finishes protection; 2) if fault still exists, keep reactor Ln to drop at the power supply neutral point, for the second time fault congenial-move back reactor L, 3) if still have fault, then be judged to the continuous earth fault, keep reactor Ln equally, for the third time at the congenial reactor L of fault and lasting in power supply neutral point input, until the faulty line excision, make reactor L and coil Ln withdraw from, reset again.
Three, eliminate the Integrated Protection System of single phase ground fault
A kind of neutral non-effective grounding electrical network is eliminated the Integrated Protection System of single phase ground fault; with reference to figure 2, Fig. 3; it is mainly by microcomputer control device, reactor L, reactor Ln, voltage transformer TV, current transformer (CT1; CT2), four monopolar high-voltage switch (Ko; Ka; Kb, Kc) and form.The power supply neutral point is connected with monopolar high-voltage switch (Ko) upper contact head, and the following contact of monopolar high-voltage switch (Ko) is connected with the end of reactor Ln, and the other end of reactor Ln passes ground connection behind the winding of current transformer CT2; The power supply three-phase bus respectively with monopolar high-voltage switch (Ka, Kb, Kc) the upper contact head of often opening main contacts separately is corresponding to link to each other, after interconnecting, their following contact links to each other with the end of reactor L, the other end of reactor L passes ground connection behind the winding of current transformer CT1, four monopolar high-voltage switch (Ko, Ka, Kb, Kc) be subjected to the control of the output switching terminal of microcomputer control device, the end points of voltage transformer TV secondary winding links to each other with the corresponding voltage input of microcomputer control device respectively, current transformer CT1, the secondary terminals (I of the secondary terminals of CT2 and system's feeder line zero sequence current mutual inductor
01..., I
0n) link to each other with the corresponding current input terminal of microcomputer control device respectively.
Microcomputer control device wherein can adopt conventional microcomputer to add software and be realized, its hardware is formed as shown in Figure 3.
Described high-voltage switch gear is monopolar high-voltage vacuum switch or high-tension electricity electronic switch.
Example 1.
When 6kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 2kV, and this system's normal phase voltage is 3.6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 1, therefore, can declare and minimum one be the fault phase mutually in the three-phase voltage this moment, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 2.
When 6kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 1.8kV, and this system's normal phase voltage is 3.6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 2, therefore, that phase voltage that can declare 90 ° of the residual voltages of lagging behind this moment is the fault phase, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 3.
When 6kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 1.2kV, and this system's normal phase voltage is 3.6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 3, therefore, can declare in three-phase voltage this moment time low one and be the fault phase mutually, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 4.
When 10kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 4kV, and this system's normal phase voltage is 6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 1, therefore, can declare and minimum one be the fault phase mutually in the three-phase voltage this moment, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 5.
When 10kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 3kV, and this system's normal phase voltage is 6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 2, therefore, that phase voltage that can declare 90 ° of the residual voltages of lagging behind this moment is the fault phase, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 6.
When 10kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 2kV, and this system's normal phase voltage is 6kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 3, therefore, can declare in three-phase voltage this moment time low one and be the fault phase mutually, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 7.
When 35kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 12kV, and this system's normal phase voltage is 21kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 1, therefore, can declare and minimum one be the fault phase mutually in the three-phase voltage this moment, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 8.
When 35kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 10.5kV, and this system's normal phase voltage is 21kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 2, therefore, that phase voltage that can declare 90 ° of the residual voltages of lagging behind this moment is the fault phase, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
Example 9.
When 35kV neutral non-effective grounding network system generation single-phase earthing, recording residual voltage is 9kV, and this system's normal phase voltage is 21kV, can find out by the described method of discrimination of claim 1, this single phase ground fault satisfies the condition of characteristic area 3, therefore, can declare in three-phase voltage this moment time low one and be the fault phase mutually, (ground protection can be by reactor L ground connection to drop into ground protection immediately on this phase bus, or alternate manner ground connection), if fault current less than 20A, does not then drop into reactor Ln, only finish protection by throwing-move back reactor L; If it is greater than 20A, then reactor Ln is measured current value adjustment to suitable position according to CT2, drive high-voltage switch gear Ko closure, by reactor Ln ground connection, the inductive current compensation of ground fault current that is produced by Ln is less than 20A with the power supply neutral point; For transient fault, after the above-mentioned protection time-delay several seconds, withdraw from reactor L, whether eliminate according to the system voltage failure judgement then, then withdraw from Ln if eliminate; Otherwise, keep reactor Ln in the neutral point input, make fault mutually by reactor L ground connection once more, through the several seconds time-delay, withdraw from reactor L more for the second time; If still have fault, then be judged to the continuous earth fault, still keep reactor Ln in the neutral point input, continue once more at the congenial reactor L of fault, until according to prior selection, or by artificial tripping operation disengagement failure circuit, or by device tripping operation case action disengagement failure circuit, involution reactor L and reactor Ln.
The utility model does not relate to the part prior art that maybe can adopt all same as the prior art to be realized.
Claims (1)
1, a kind of neutral non-effective grounding electrical network is eliminated the single phase ground fault protection system, it is characterized in that: mainly by microcomputer control device, reactor (L), reactor (Ln), voltage transformer (TV), current transformer (CT1, CT2), four monopolar high-voltage switch (Ko, Ka, Kb, Kc) form, the power supply neutral point is connected with monopolar high-voltage switch (Ko) upper contact head, the following contact of monopolar high-voltage switch (Ko) is connected with an end of reactor (Ln), and the other end of reactor (Ln) passes ground connection behind the winding of current transformer (CT2); The power supply three-phase bus respectively with monopolar high-voltage switch (Ka, Kb, Kc) the upper contact head of often opening main contacts separately is corresponding to link to each other, after interconnecting, their following contact links to each other with the end of reactor L, the other end of reactor (L) passes ground connection behind the winding of current transformer (CT1), four monopolar high-voltage switch (Ko, Ka, Kb, Kc) be subjected to the control of the output switching terminal of microcomputer control device, the end points of voltage transformer (TV) secondary winding links to each other with the corresponding voltage input of microcomputer control device respectively, current transformer (CT1, the secondary terminals (I of secondary terminals CT2) and system's feeder line zero sequence current mutual inductor
01..., I
0n) link to each other with the corresponding current input terminal of microcomputer control device respectively, microcomputer control device wherein can adopt conventional microcomputer to add software and realize.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008201138729U CN201234133Y (en) | 2008-01-21 | 2008-07-11 | Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid |
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| Application Number | Priority Date | Filing Date | Title |
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| CN200820031272 | 2008-01-21 | ||
| CN200820031272.8 | 2008-01-21 | ||
| CNU2008201138729U CN201234133Y (en) | 2008-01-21 | 2008-07-11 | Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid |
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| CN201234133Y true CN201234133Y (en) | 2009-05-06 |
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| CNU2008200033081U Expired - Fee Related CN201146385Y (en) | 2008-01-21 | 2008-01-29 | Apparatus for discrimination and protection of eliminating single phase ground fault of neutral point non-useful earthing electric network |
| CNU2008201138729U Expired - Fee Related CN201234133Y (en) | 2008-01-21 | 2008-07-11 | Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid |
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| CNU2008200033081U Expired - Fee Related CN201146385Y (en) | 2008-01-21 | 2008-01-29 | Apparatus for discrimination and protection of eliminating single phase ground fault of neutral point non-useful earthing electric network |
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| CN (2) | CN201146385Y (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101340086B (en) * | 2008-01-21 | 2010-04-21 | 孙嘉宁 | Single-phase grounding fault determining, protecting method and system of neutral-point uneffective earthed electric grid |
| CN102623985A (en) * | 2012-01-17 | 2012-08-01 | 合肥凯高电气设备有限公司 | Novel comprehensive grounding protection and route selection device for medium-voltage power distribution system |
| CN102969696A (en) * | 2012-11-14 | 2013-03-13 | 国家电网公司 | Power system relay protection treatment method |
| CN103050963A (en) * | 2011-10-14 | 2013-04-17 | 安徽一天电气技术有限公司 | Arc extinguish device capable of avoiding direct grounding arc extinguish and overvoltage resetting, and working method thereof |
| CN103050962A (en) * | 2011-10-14 | 2013-04-17 | 安徽一天电气技术有限公司 | Grounding transfer current detection compensation device and working method thereof |
| CN106329509A (en) * | 2015-06-18 | 2017-01-11 | 上海金艺检测技术有限公司 | Small current fault line selection protection system of power grid isolated neutral system |
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| CN102005741A (en) * | 2010-10-29 | 2011-04-06 | 华北电力大学 | Distribution network line single phase earthing fault diagnosis and isolation method and device |
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2008
- 2008-01-29 CN CNU2008200033081U patent/CN201146385Y/en not_active Expired - Fee Related
- 2008-07-11 CN CNU2008201138729U patent/CN201234133Y/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101340086B (en) * | 2008-01-21 | 2010-04-21 | 孙嘉宁 | Single-phase grounding fault determining, protecting method and system of neutral-point uneffective earthed electric grid |
| CN103050963A (en) * | 2011-10-14 | 2013-04-17 | 安徽一天电气技术有限公司 | Arc extinguish device capable of avoiding direct grounding arc extinguish and overvoltage resetting, and working method thereof |
| CN103050962A (en) * | 2011-10-14 | 2013-04-17 | 安徽一天电气技术有限公司 | Grounding transfer current detection compensation device and working method thereof |
| CN102623985A (en) * | 2012-01-17 | 2012-08-01 | 合肥凯高电气设备有限公司 | Novel comprehensive grounding protection and route selection device for medium-voltage power distribution system |
| CN102969696A (en) * | 2012-11-14 | 2013-03-13 | 国家电网公司 | Power system relay protection treatment method |
| CN106329509A (en) * | 2015-06-18 | 2017-01-11 | 上海金艺检测技术有限公司 | Small current fault line selection protection system of power grid isolated neutral system |
| CN106329509B (en) * | 2015-06-18 | 2019-09-13 | 上海金艺检测技术有限公司 | The small current earthing wire-selecting of neutral point of electric network isolated neutral system protects system |
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Assignee: GUANGZHOU NINGZHI ELECTRIC POWER SCIENCE & TECHNOLOGY CO., LTD. Assignor: Sun Jianing|Luo Zhizhao Contract record no.: 2010440000539 Denomination of utility model: Protection system for eliminating single phase earthing failure by neutral-point uneffect earthed electric grid Granted publication date: 20090506 License type: Exclusive License Record date: 20100521 |
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