CN2205077Y

CN2205077Y - Arc eliminator

Info

Publication number: CN2205077Y
Application number: CN 94245938
Authority: CN
Inventors: 周配明
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-11-23
Filing date: 1994-11-23
Publication date: 1995-08-09
Anticipated expiration: 2004-11-23

Abstract

The utility model relates to a neutral point earthing device of an electric network. An antihunt impedor, which is formed by connection of a linear resistor and a nonlinear inductor in parallel, is connected in series with a neutral point inductor of the existing arc suppression coil or arc suppression transformers, and the nonlinear inductor is formed by winding coils around a glass-jade alloy ring used as a magnet conducting core body. The utility model can not only achieve the functions of existing arc suppression equipment, but also can avoid the tuning syntony completely. The utility model can be run at overcompensation or undercompensation, and can be also run at full compensation.

Description

Arc eliminator

The utility model relates to a kind of power network neutral ground equipment, especially a kind of anti-humorous compensating arc distinction device.

In the 3-60 kv grid, its neutral point can improve the electric power netting safe running level through extinguishing arc equipment ground.The extinguishing arc equipment that adopts is arc suppression coil and arc suppression transformer at present.When the inductive reactance xl value of the compensating inductance L that the capacitive reactance Xc value of electrical network three-phase ground capacitance C and extinguishing arc equipment insert is close, under the effect of neutral point asymmetrical voltage, can constitute resonance tuning, the lighter causes that neutral point displacement voltage surpasses 15% of phase voltage value, make operation undesired, weight person causes the neutral point displacement overvoltage, makes a phase or two phase-to-ground voltages surpass the maximum line magnitude of voltage that allows, and causes the accident.Disconnection fault particularly taking place, the Uo value is enlarged markedly, can cause serious neutral point displacement overvoltage.For safety, stipulate that common compensating arc distinction equipment should adjust in overcompensation operation, thereby make and adjust inconveniently, increase the weight of operation and adjust burden, and the neutral point displacement overvoltage that can not avoid disconnection fault to cause fully.Existing compensating arc distinction equipment does not have anti-resonance tuning characteristic.

The purpose of this utility model provides a kind of safety allowance extinguishing arc equipment of avoiding resonance tuning fully, but its overcompensation or undercompensation operation also allow full compensation operation.

Scheme of the present utility model is: a kind of anti-humorous arc suppression coil, comprise the arc suppression coil that links to each other with neutral point of electric network, and difference is that arc suppression coil is connected in series by the linear resistance anti-humorous impedance that constitutes in parallel with nonlinear inductance, this nonlinear inductance is by glass

Alloy hoop winds with coil as magnetic conductive core and constitutes.

Another scheme of the present utility model is: a kind of anti-humorous arc suppression transformer, comprise the arc suppression transformer that connects the electrical network three-phase, this arc suppression transformer is made of Z-shaped wiring transformer and neutral point inductance, difference is that arc suppression transformer is connected in series by the linear resistance anti-humorous impedance that constitutes in parallel with nonlinear inductance, and this nonlinear inductance is by glass

Alloy hoop winds with coil as magnetic conductive core and constitutes.

The utility model is with existing arc suppression coil or the anti-humorous impedance of arc suppression transformer serial connection, its nonlinear inductance has high excitation induction reactance and fast saturated performance, make it both have the compensating arc distinction function, has good anti-humorous characteristic again, anomaly or the accident that can avoid causing because of resonance tuning under normal operation or the disconnection fault take place, it can move under overcompensation or undercompensation, can compensate operation entirely again, adjusts flexible, safety.

Fig. 1 prevents humorous arc suppression coil circuit diagram.

Fig. 2 prevents humorous arc suppression transformer circuit diagram.

Fig. 3 nonlinear inductance V-I characteristic for example.

Fig. 4 adjusts anti-humorous arc suppression transformer circuit diagram automatically.

In Fig. 1, Fig. 2 wiring, Lo is an arc suppression coil, and To is an arc suppression transformer, and Lm is the nonlinear inductance with high excitation induction reactance and fast saturated performance, and Rm is a linear resistance.Lm system glass

Alloy hoop is made magnetic conductive core, winds with coil to make.Fig. 3 is the V-I characteristic of a kind of Lm, and V, I all are unit with the effective value, and initial saturation voltage is 180V, and V is 180V and following, is in undersaturated condition, excitation induction reactance height, and the I value is not more than 5-10mA; V is 183V, and I is 0.5A, has fast saturated performance; V is 215V, and I is 50A, and it is very little promptly to be in the equivalent induction reactance value of degree of depth when saturated.

The operation of anti-humorous compensating arc distinction device, the compensating arc distinction function when anti-humorous characteristic under the normal operation and action, following design example specifies.Certain 10 kv grid inserts the anti-humorous compensating arc distinction device as Fig. 1 or Fig. 2 wiring, and offset current is adjusted in maximum parted hair 50A, and unbalanced earth fault capacitance current Ic also is 50A, full compensation operation down; The V-I characteristic of Lm in the anti-humorous impedance as shown in Figure 3, Rm value 500 Ω.Operation of power networks phase voltage V

Be 10.5/

\sqrt{3}

KV equals 6062V.Because of the V-I characteristic of Lm is 215V in the V value of I value 50A,, be 117 Ω so the XL value of offset current 50A is calculated by (6062-215)/50; The Xc value of Ic value 50A is calculated by 6062/50, is 121.24 Ω.Normal operation down, because of Uo value less than 180V, the excitation induction reactance height of Lm, much larger than Rm value, neutral point is real be that Rm value is got the value greater than XL, can guarantee to avoid fully resonance tuning through XL and Rm series connection ground connection, has well normally to move and prevents humorous characteristic.During action, electrical network is the single-phase earthing state, and neutral point voltage amplitude instantaneous value is

\sqrt{2}

* 6062V, the corresponding offset current and the amplitude instantaneous value of Ic electric current are all

\sqrt{2}

* 50A, so fault point aftercurrent idle component instantaneous value is zero, the fault point aftercurrent idle component instantaneous value of other different neutral point voltage instantaneous value correspondences is respectively:

\sqrt{2}

* 5000V is 0.4A;

\sqrt{2}

* 4000V is 0.76A;

\sqrt{2}

* 3000V is 1.0A;

\sqrt{2}

* 2000V is 1.5A;

\sqrt{2}

* 1000V is 1.8A;

\sqrt{2}

* 500V is 2.0A;

\sqrt{2}

* 180V is 2.1A.Find out that thus fault point aftercurrent idle component maximum instantaneous value compensates to being not more than 2.1A, illustrates that compensate function is good.In addition, behind the single-phase earthing arc extinction, capacitance energy storage on the three-phase ground capacitance C is through the Zm of XL and series connection oscillation due to discharge, produce the free voltage of attenuated oscillation, though this voltage between the short-term of the low instantaneous value voltage of zero cross near in, owing to Lm enters undersaturated condition oscillation due to discharge is blocked, but it is little to the free oscillation voltage frequency influence, still can reduce the recovery voltage behind the arc extinction of fault point, make electric arc be difficult for restriking, effectively bring into play arc eliminator.

The operation of anti-humorous compensating arc distinction device is well prevented under the normal operation the humorous characteristic except that having, and prevents that in addition disconnection fault from causing superpotential another the well anti-humorous characteristic of neutral point displacement.Disconnection fault takes place will make Uo enlarge markedly, when Uo greater than the initial saturation voltage of Lm, when constituting resonance tuning again, the anti-humorous effect of anti-humorous impedance Z m reduces greatly, but at this moment anti-humorous impedance Z m still can play the effect that restriction neutral point displacement overvoltage raises, reach and prevent the neutral point displacement overvoltage, avoid disconnection fault to cause accident.When Uo greater than the initial saturation voltage of Lm, the effect that anti-humorous impedance Z m restriction neutral point displacement voltage raises depends on the ratio of Uo and the initial saturation voltage of Lm, this ratio is more little, and is big by total harmonic current percentage value of Zm, its restriction effect is just greatly.Because of the 3-60KV electrical network is many feeders power supply grid, a feedback line generation disconnection fault makes Uo be up to 0.18U

Simultaneously constitute resonance tuning again, its probability of occurrence will be very little.When the Uo value is 0.18U

, the initial saturation voltage of Lm is 0.03U , Xc equals XL and constitutes under the complete resonance tuning, and the total harmonic current by Zm will be greater than 10% of fundamental current, and therefore can calculate neutral point displacement voltage will be unlikely above 0.54U

, a maximum phase-to-ground voltage will be not more than 1.6U

, electrical network is not had harm; Xc constitutes incomplete resonance tuning greater than XL, and when for overcompensation 5%, a maximum phase-to-ground voltage will be not more than 1.3U When being undercompensation 5%, a maximum phase-to-ground voltage will be not more than 1.35U

Certain 10 kv grid, the whole network Ic value 35A, connect feeder line on the bus many times overhead wire outlets and terminal three-phase three core high-voltage cables that connect are arranged, wherein one time Ic value reaches 12A, one broken string and when being subjected to the disconnection fault on electric side joint ground in the broken string place mutually takes place when the overhead wire of this time goes out line segment, because the alternate electric capacity of terminal stube cable equals 1/2nd of electric capacity relatively, makes the Uo value rise to 0.18U , make the whole network Ic value constant again simultaneously, at this moment, if the logical compensating arc distinction equipment of installing one Daepori is 40.3A even offset current is adjusted, overcompensation reaches 15%, when above-mentioned disconnection fault takes place, the extinguishing arc device power will be pressed surpass U And make two phase-to-ground voltages all above line voltage, and the serious threat power grid security, therefore the generation that can cause the accident must limit offset current and adjust in being not less than 42A, and safety guarantee is just arranged, and like this, not only adjusts dumbly, and the fault point aftercurrent is also bigger.If anti-humorous compensating arc distinction equipment of installing, press numerical value the most separately near the selected offset current of Ic value 35A, but not only overcompensation operation, also can move by undercompensation, also allow full compensation operation, adjust flexibly safety again, also can make the fault point aftercurrent little, when above-mentioned disconnection fault takes place when, the unlikely 1.6U that surpasses of its maximum that causes one phase-to-ground voltage

, do not constitute power grid security threatened.

Anti-humorous arc suppression transformer shown in Figure 4, the primary coil of step-down transformer Tm is in parallel with neutral point inductance L o, be connected to the secondary coil that is connected to step-down transformer behind the gate-controlled switch K2-K11 serial connection low pressure inductance L2-L11 of cyclelog P, the side that pays of output pressure limiting transformer Ts meets program automatic controller P, meet the former side of output pressure limiting transformer behind two groups of capacitance series, and be connected on the nonlinear inductance Lm behind these two groups of capacitance series third harmonic voltage sources by gate-controlled switch control.

Under the normal operation, Lm is unsaturated, has high value inductance, and simultaneously, getting Rm is high value, makes the Zm value higher.Because the Zm value is higher, therefore the triple-frequency harmonics power supply can be pressed U3 inject the loop of compensating inductance L and electrical network three-phase ground capacitance C series connection, and in series loop, additionally seal in the power frequency tuned impedance that C, C ' electric capacity and C11 and L11 compose in parallel, make it to constitute the tuning series loop of the triple harmonic current that is not subjected to the Uo voltage influence.It is tuning that C11 and L11 constitute power frequency in parallel, and making its triple-frequency harmonics impedance is not high numerical value, but its power frequency impedance value should be very high, to limit the electric current that Uo voltage produces under the normal operation in L, C series loop, avoids it to influence automatic control.Fig. 4 design has 11 separately of automatic control adjustment, as gets offset current for to transfer to 50A from 20A, can be designed to 1 fen head current 20A, 2 fens head current 23A ..., 11 fens head current 50A.K2-K11 is big electric current contact gate-controlled switch among the figure, and 1 separately down, and K2-K11 disconnects entirely; 2 separately down, the K2 closure 11 separately down, and K2-K11 is all closed.S2-S11 and S2 '-S11 ' is the little current switch contact of relaying protection, and 1 separately down, and S2-S11 and S2 '-S11 ' all disconnects; 2 separately down, S2 and S2 ' closure 11 separately down, and S2-S11 and S2 '-S11 ' is all closed.As when running under the 2 parted hair 23A, adjust C1, C2 value in parallel and C1 ', C2 ' parallel connection value, make it to satisfy following requirement, when the Ic value was 23A, Ts output voltage U s should be 100V; Reduce to 20.5A and following when the Ic value, Us should reduce to 80V and following, and all the other program control are restarted in the under-voltage protection action in the start-up routine automatic controller P, with K2, S2, S2 ' disconnection, transfers to 1 operation down separately automatically; When the Ic value rises to 25.5A and when above, Us should rise to 120V and more than, all the other program control are restarted in the overvoltage protection action in the start-up routine automatic controller P, with K3, S3, S3 ' closure, transfer to 3 operations separately automatically.Automatic control adjustment action is identical separately for other.Like this, the Ic value is faded in the 52.5A scope by 17.5A, and self controllable adjustment compensation makes fault point aftercurrent idle component be not more than 2.5A, can finely satisfy service requirement.When the electrical network single-phase earthing or other reason that the Lm of anti-humorous impedance Z m is taken place is saturated, Us voltage will significantly reduce, so the design of program automatic controller P should be got rid of at Lm the malfunction adjustment takes place to cause when saturated.In addition, the Ts transformer is the output transformer with pressure limiting characteristic, when Us voltage during greater than 160V, deboost is raise again, with defence program automatic controller P.

Claims

1, a kind of anti-humorous arc suppression coil comprises the arc suppression coil that links to each other with neutral point of electric network, it is characterized in that the arc suppression coil serial connection by the linear resistance anti-humorous impedance that constitutes in parallel with nonlinear inductance, and this nonlinear inductance is by glass Alloy hoop winds with coil as magnetic conductive core and constitutes.

2, by the described anti-humorous arc suppression coil of claim 1, the primary coil that it is characterized in that step-down transformer is in parallel with arc suppression coil, be connected to the secondary coil that is connected to step-down transformer behind the gate-controlled switch serial connection low pressure inductance of cyclelog, the side that pays of output pressure limiting transformer connects the program automatic controller, meet the former side of output pressure limiting transformer behind two groups of capacitance series, and be connected on the nonlinear inductance behind these two groups of capacitance series third harmonic voltage sources by gate-controlled switch control.

3, a kind of anti-humorous arc suppression transformer, comprise the arc suppression transformer that connects the electrical network three-phase, this arc suppression transformer is made of Z-shaped wiring transformer and neutral point inductance, it is characterized in that the arc suppression transformer serial connection by the linear resistance anti-humorous impedance that constitutes in parallel with nonlinear inductance, and this nonlinear inductance is by glass

Alloy hoop winds with coil as magnetic conductive core and constitutes.

4, by the described anti-humorous arc suppression transformer of claim 3, the primary coil that it is characterized in that step-down transformer is in parallel with the neutral point inductance, be connected to the secondary coil that is connected to step-down transformer behind the gate-controlled switch serial connection low pressure inductance of cyclelog, the side that pays of output pressure limiting transformer connects the program automatic controller, meet the former side of output pressure limiting transformer behind two groups of capacitance series, and be connected on the nonlinear inductance behind these two groups of capacitance series third harmonic voltage sources by gate-controlled switch control.