CN2296087Y

CN2296087Y - Automatic aligning arc blast device

Info

Publication number: CN2296087Y
Application number: CN 96208863
Authority: CN
Inventors: 李健生; 欧阳勋
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-04-04
Filing date: 1996-04-04
Publication date: 1998-10-28
Anticipated expiration: 2006-04-04

Abstract

The utility model relates to an automatic aligning arc-suppression device, which is used for an ungrounded electric network of a neutral point. A winding of arc-suppression coils is in a classifying and adjustable type; one end of the winding of the arc-suppression coils is connected with the neutral point of a transformer, and the other end is grounded through a resistor. Phase voltage of some phase which is led out from a bus bar PT is input to a residual flow monitor, one path of the voltage which is led out from a secondary measurement winding of an arc-suppression ring is input to the residual flow monitor while the other path is input to a voltage relay, and an output signal of the residual flow monitor is sent to a tuner. The output of the tuner is connected with a loaded tapped switch, and the output of the voltage relay is connected with a contactor. The automatic aligning arc-suppression device can make an electric network lie in an optimal compensating state at any time; arc suppression is efficiently conducted; over voltage is suppressed, and reliable power supply of the electric network can be ensured.

Description

The self-tuning arc-extinguishing device

The utility model is the electrical network that is used for isolated neutral, belongs to electrical technology field.

Adopt the isolated neutral mode at China 5～10KV urban power distribution network and the station service electrical system overwhelming majority.In recent years, because the continuous development of electrical network, use cable more and more in the urban distribution network, capacitance current increases very fast thereupon in the electrical network, therefore when single phase ground fault takes place, earth point electric arc forms intermittent electric arc, spread all over whole network and long-term arc grounding overvoltage thereby produce, its peak can reach 3.5 times of phase voltage, make the insulation breakdown of building full phase, cause 2 ground short circuits, cause " baked wheaten cake is operated " accident of supply line's tripping operation or substation bus bar, if earth point occurs in substation bus bar, and capacitance current is when big, because the diffusion effect of electric arc, even overvoltage is very low, also can cause " baked wheaten cake operate accident ", seriously threaten the safe and stable operation of electric power system.According to statistics, the isolated neutral electrical network, the arc grounding overvoltage accounts for 77.8% of whole overvoltage accidents.Be to cause the electrical network can not be to the main cause of the reliable power supply of user.In order to address this problem, must take to reduce the measure of earth point residual flow, be about to the earth point electric current, compensate to less than 10A.Because the switching of circuit in service is frequent, system capacitive current is changeable, and with traditional power failure, manual mode, the arc-extinction device of adjusting will compensate to the earth point residual flow below a certain numerical value, is impossible fully.In recent years, all at the arc-extinction device of research automatic tuning, learn from reported in literature both at home and abroad that certain structures was too complicated, optional equipment is many, and cost is expensive, the requirement that technical performance can not be up to state standards, and operation stability and reliability are low.

Goal of the invention of the present utility model is, design a kind of novel self-tuning arc-extinguishing device, can be automatically with the variation of combining system capacitive current, the inductance value of regulating arc suppression coil makes electrical network all be in the The optimal compensation state at any time, residual flow is controlled at below the numerical value of rules requirement, it is simple in structure, and control stabilization is reliable.

In order to realize the foregoing invention purpose, this self-tuning arc-extinguishing device of inventor's design is by grounding transformer, arc suppression coil, and resistor and control system are formed.It is characterized in that grounding transformer is a full symmetrical configuration, the winding of arc suppression coil is that classification is adjustable, a termination transformer neutral point of arc suppression coil, other end termination resistor, resistor other end ground connection.Control system is: draw a certain phase phase voltage signal from bus PT, input residual flow watch-dog is measured winding extraction voltage signal from the secondary of arc suppression coil, and one the tunnel also imports the residual flow watch-dog, one road input voltage relay.The output signal of residual flow watch-dog is sent into tuner.Tuner output is connected to on-load shunting switch to regulate the tap of arc suppression coil, adjusts inductive current.Voltage relay output connects the short circuit of control resistor and input with contactor.

The utility model has the advantages that: the acquisition controlling signal need not increase auxiliary equipment basically, and is simple in structure, and cost is low.Transformer, arc suppression coil, the design of resistor is to adopt to divide body structure, and is flexible and convenient to use, can move out of doors.The arc suppression coil electric current is to adopt turn-adjusting, vibrates for a short time, and noise is low.Adopt the intelligence control system of microprocessor, had the software of careful design and part more, precise control, fast, reliable and stable, antijamming capability is strong.This device can make electrical network always be in the The optimal compensation state automatically with combining the building-out capacitor electric current, and promptly the residual flow minimum of earth point has suppressed overvoltage effectively, thereby has guaranteed the safe operation of electrical network.

Accompanying drawing 1 is a self-tuning arc-extinguishing device wiring schematic diagram: 1, grounding transformer; 2, arc suppression coil; 3, resistor; 4, on load tap changer; 5, contactor; 6, residual flow watch-dog; 7, tuner; 8, voltage relay.

Accompanying drawing 2; The control system panel layout; Accompanying drawing 3; The tuner line assumption diagram

Accompanying drawing 4: voltage relay line assumption diagram; Accompanying drawing 5: residual flow watch-dog action block diagram

Accompanying drawing 6: residual flow watch-dog flow chart

In conjunction with the accompanying drawings embodiment of the utility model is described in detail

Grounding transformer 1, its effect are to draw neutral point of electric network, and arc suppression coil 2 is installed.Its class of insulation is identical with the rated voltage of using point, and is all insulation.Three phase windings are Z type symmetrical structure, and under the single-phase earthing situation, it is comprehensive, and preface impedance is very little in addition, less demanding in dress with 3% of the arc suppression coil maximum current tap resistance value of capacity.Its winding is totally 6 joints, adorns two joints on every stem stem, and being connected into the Z type is meander configuration (seeing attached 1 figure).Its iron core is to adopt mitre three column types.

Grounding transformer 1 also can have secondary winding, but dual-purpose station transformer, and standing has ± 5% range of regulation with transformer, so just the station is united two into one with transformer and grounding transformer, thereby has saved investment, has also reduced the area occupied of equipment fabricating yard.

Arc suppression coil 2 its design features are secured core air gaps, vibrate for a short time, and noise is low, and the coil windings number of turn is that classification is adjustable, and the utility model adopts 9 grades of adjustings to 6～10KV level, and the 35KV level is adopted 7 grades of adjustings.Its advantage can guarantee that offset current is sinusoidal waveform, helps extinguishing of electric arc.This arc suppression coil 2 is used in combination with on load tap changer 4, can realize online automatic tuning, but on load tap changer 4 on-loads switch 20000 not maintenance.Arc suppression coil 2 band secondary winding, purpose is to gather neutral point displacement voltage signal, input control system.

Resistor 3 is to be serially connected in arc suppression coil 2 earth terminals, and its major function is to strengthen the system damping rate, prevents resonance series, makes resonant earthed system can be in overcompensation and undercompensation operational mode, and the neutral point of electric network displacement voltage guarantees to be lower than 0.15V _ψ(V _ψBe phase voltage).Resistor 3 inserts when normal operation and transient earthing fault, and by short circuit, the short circuit of resistor 3 and input are finished by contactor 5 by control system during system generation permanent earth fault.Contactor 5 is to be contained in the casing of resistance box, but in the fuel tank outside.Resistance is to be immersed in the fuel tank, is to form with special alloy filament winding system, and resistance is 10 ohm.Resistor 3 is by through-current capability examination, and logical 5A can continuous service, passes through 3 seconds of extinguisher 2 rated current of being connected, and maximum temperature is less than 600 ℃.Resistance box requires withstand voltage 2KV/lmin.The arc suppression coil 2 of different capabilities, the resistance of the resistor 3 of being joined is constant, but thermal capacity is different with size of current, and all to reach the technology indication of above-mentioned through-current capability.

Control system is mainly by, residual flow watch-dog 6, and tuner 7 and voltage relay 8 are formed.

Residual flow watch-dog 6, it is the intelligence control system that adopts microprocessor, according to system capacitive current actual measurement situation, artificial 6 one the predetermined value A of residual flow watch-dog that give earlier, the control range of this predetermined value is A+ Δ A＜A＜A-Δ A, residual flow watch-dog 6 is constantly gathered two electric weight, one is that the phase voltage signal gathered from bus PT (any mutually can) is as benchmark, another amount is the neutral point displacement voltage signal of gathering from the secondary winding of arc suppression coil 2, two amounts are carried out the phase angle computing relatively, when its number is A+ Δ A greater than the predetermined value upper limit, residual flow watch-dog 6, send instruction on load tap changer 4 with the parted hair of extinguisher 2 to downward modulation, to strengthen inductive current.When number enters predetermined range, just stop regulating.When number was A-Δ A less than the predetermined value lower limit, residual flow watch-dog 6 sent instruction and gives tuner 7, instruction on load tap changer 4 with the parted hair of arc suppression coil 2 to rise, reduce inductive current, when number enters the predetermined value district, just stop regulating the automatic tuning of electrical network when normal operation that Here it is.When system takes place instantaneous or discontinuity is single-phase when being connected on fault, residual flow watch-dog 6 can not send action command to tuner 7, have only when permanent single-phase earthing takes place electrical network, rapid change will take place in the voltage signal from electrical network, residual flow watch-dog 6 will promptly withdraw from the automatic tuning state automatically, and be in the state that electrical network is monitored.Neutral point displacement voltage raise and surpassed 50 volts this moment, and voltage relay 8 sends instruction and closes a floodgate for contactor 5, makes resistor 3 short circuits.This moment electrical network electric capacity (C _A+ C _B+ C _C) in parallel with arc suppression coil, form the shunt-resonant circuit, apply phase voltage.Electrical network single-phase earthing one footpath disappears, and residual flow watch-dog 6 is got back to the automatic tuning state again.Contactor 5 disconnects, and resistor 3 puts into operation again, and electrical network changes normal operating condition again over to, arc suppression coil 2 and resistor 3 and electrical network electric capacity (C _A+ C _B+ C _C) be the resonance series loop.

Tuner 7, its major function are to accept the instruction of residual flow watch-dog, and realization upgrades on load tap changer 4 and reduces inductive current, and the increase inductive current lowers category.Residual flow watch-dog 6, tuner 7 and voltage relay 8 etc. is installed in the wall-hanging control cubicle together, and is connected with private cable between the on load tap changer of arc suppression coil 2 bodies.Tuner 7 can record the number of operations of on-load shunting switch 4 automatically, and decision should not overhauled.When on load tap changer 4 is in upper and lower two limit tap positions, can also guarantee its direction beyond the limit do not move.Can also clearly demonstrate shunting switch gear of living in, therefore can learn the electric current of arc suppression coil 2.

The utility model automatic tuning is to have used phased principle in a word, has promptly utilized the intrinsic asymmetrical voltage of distribution system, and the variation of phase angle realizes the closed-loop adjustment of system capacitive current between the residual voltage of formation and the bus phase voltage.These the complete sets of equipment, neutral point displacement voltage is no more than 15% of specified phase voltage in the time of guaranteeing that electrical network normally moves, and is general all less than 10% of specified phase voltage.The linear flow Ir of fault point under the single-phase earthing situation: to capacity is that (rated current is 50A～100A) for the arc suppression coil of 600KVA, can guarantee 0＜Ir＜10A, to capacity be 300KVA (arc suppression coil of rated current 25A～50A) can guarantee 0＜Ir＜5A, to capacity be 212KVA (rated current is that 17.5A～35A) arc suppression coil can guarantee 0＜Ir＜3A.

The utility model is in the linked network trial run of 10KV system, transformer by dress is ZW-360/10, arc suppression coil is 10 ohm for the ARN-360/10 resistor, on load tap changer be 9 grades adjustable, with the residual flow watch-dog of control system, tuner and voltage relay etc. is pressed accompanying drawing 1 and is connected, since dropping into operation, this electrical network was once gone through single-phase transient earthing, discontinuity earth fault, and arc-extinction device all can correct extinguishing arc.Facts have proved that the utility model has reached the regulation of designing requirement and national standard fully, can realize the automatic tuning of resonant earthed system, reach extinguishing arc and suppress the purpose that overvoltage reached and improved the power distribution network power supply reliability with it.

Claims

1, a kind of self-tuning arc-extinguishing device is by grounding transformer, arc suppression coil, and resistance and control system are formed; It is characterized in that grounding transformer (1) is a full symmetrical configuration, the winding of arc suppression coil (2) is that classification is adjustable, a termination transformer neutral point of extinguishing arc line (2), other end termination resistor (3), resistor (3) ground connection; Draw a certain phase phase voltage signal from bus PT, input residual flow watch-dog (6) is measured winding extraction voltage signal, one road P from the secondary of arc suppression coil (2) ₁P ₂Input residual flow watch-dog (6), one road P ₁P ₂Input voltage relay (8); The output signal of residual flow watch-dog (6) is sent into tuner (7); The output of tuner (7) is connected to on-load shunting switch (4); The output of voltage relay (8) connects with contactor (5).