CN101075738A - System for removing damp resistance discharging secondary arc-eliminating coil and its resonance - Google Patents

Abstract

A resonance eliminating method for the secondary side of an arc extinction wire includes the steps as: 1)add a secondary winding on the arc extinction wire; 2)link buffer resistance to the secondary winding and adjustable silicon trigger circuit; 3)under normal running, the adjustable silicon is conducting and the arc extinction wire runs around resonance point, and the resistance restrains neutral point voltage increase. When the system links to earth, the neutral point voltage excesses the limitation and monitored by voltage transformer which makes the adjustable silicon triggers the control circuit and shut off resistance circuit.

Description

Damping resistance is put the elimination system resonance method of arc suppression coil secondary side

Technical field

What the present invention relates to is a kind of method of technical field of electricity, specifically is the elimination system resonance method that a kind of damping resistance is put the arc suppression coil secondary side.

Background technology

Arc suppression coil is widely used as the compensating element, when system's generation single phase ground fault.Present widely used turn-adjusting arc suppression coil operates near the resonance point at ordinary times, must install damping resistance additional and prevent direct-to-ground capacitance generation resonance in arc suppression coil and the network system, and the neutral point voltage of system is limited in the safe operation scope.

Find through literature search prior art, the document of " high voltage technique " 2005 the 5th phases: " arc suppression coil installs the operating analysis behind the damping resistance additional ", this article is mentioned: domestic widely used turn-adjusting arc suppression coil, its damping resistance is to be connected in the primary circuit, can effectively suppress neutral point displacement voltage when normal operation, the short circuit damping resistance is realized The optimal compensation when earth fault takes place.Arc suppression coil primary side installing damping resistance has played significant effect to the safe operation of electrical network, but this mode has also been brought unsafe factor to system: 1. because damping resistance is the primary equipment of system, the switching control of operating experience proof damping resistance should not be controlled by secondary and realize, optimum control type is to utilize ohmically voltage to control automatically, if it is improper that resistance is selected, or the degree of unbalance of system itself is big, ground connection becomes that tap is improper, phase shortage, broken string, and system's generation three-phase imbalance problem takes place to cause easily when ground connection disappears.2. when earth fault took place, if damping resistance can not be in time cut, the inductive current that has arc suppression coil compensation flow through, and damping resistance may be burnt, and finally causes arc suppression coil out of service, causes great harm to system.3. damping resistance operates in the primary system, equipment and and protective value require to improve, the cost of product increases.

Summary of the invention

The present invention is directed to deficiency of the prior art, propose a kind of damping resistance and put the elimination system resonance method of arc suppression coil secondary side, make it on existing arc suppression coil, increase a secondary winding, to originally be installed in the damping resistance of arc suppression coil primary side, change on the secondary winding that is connected on increase.Damping resistance changes parallel way into by series connection, and damping resistance input coefficient during operate as normal is realized damping function, and after ground connection was taken place, the damping resistance automatic disconnection had improved the fail safe and the reliability of system.

The present invention is achieved by the following technical solutions, may further comprise the steps:

1. on arc suppression coil, increase a secondary winding;

2. damping resistance is connected on the secondary winding that arc suppression coil increases, and is going here and there the controllable silicon trigger control circuit on this loop;

3. under system's normal running (operation) conditions, the controllable silicon conducting, damping resistance puts into operation, this moment, preset arc suppression coil operated near the resonance point, and damping resistance plays the effect that neutral point voltage raises that suppresses, when ground connection is taken place in system, the voltage of system neutral raises and has exceeded set point, voltage transformer (PT) detects the voltage condition of neutral point, by voltage relay control controllable silicon trigger control circuit, disconnects the damping resistance loop voluntarily.

Constituting of described controllable silicon trigger control circuit: the branch road parallel connection that branch road that bidirectional triode thyristor SCR1, capacitor C 3, diode D1 compose in parallel and bidirectional triode thyristor SCR2, capacitor C 4, diode D2 compose in parallel, voltage relay YJ and the two ends that are connected on silicon controlled control end G1, G2 after intermediate relay ZJ is in parallel, the secondary that wire resistor R01 and two series arms that capacitor C 1, wire resistor R02 and capacitor C 2 are formed are attempted by arc suppression coil respectively is around, two-phase silicon controlled in parallel two ends.Under system's normal running (operation) conditions, voltage relay YJ conducting wherein, intermediate relay ZJ disconnects, the bidirectional triode thyristor conducting, damping resistance R puts into operation; When system's generation earth fault, voltage relay YJ disconnects, and bidirectional triode thyristor SCR1-2 disconnects, and damping resistance R is out of service; After ground connection disappeared, artificial control intermediate relay ZJ made the intermediate relay ZJ closure, bidirectional triode thyristor SCR1-2 conducting, and voltage relay YJ conducting thereupon, damping resistance R puts into operation, and intermediate relay ZJ disconnects; Two series arms that wire resistor R01 and capacitor C 1, wire resistor R02 and capacitor C 2 are formed provide protection for bidirectional triode thyristor.

The present invention be directed to and operate near a solution that causes the too high shortcoming of neutral point voltage the resonance point and propose under the preset arc suppression coil normal condition.The present invention is placed on the secondary side of arc suppression coil with damping resistance, has solved and has been placed on existing problem of primary side and danger, has improved the fail safe and the reliability of system.Being placed on the primary side Device for eliminating harmonic with damping resistance compares; it is required withstand voltage lower with protection class that damping resistance is put secondary side equipment; reduced equipment cost (having reduced by 30%); and be easy to control; success rate 100% in experimentation; improve reliability, also made simultaneously damping resistance put the fault type that arc suppression coil that primary side takes place can not in time put into operation and be reduced to 0, improved the fail safe of system.

Description of drawings

Fig. 1 system principle circuit diagram of the present invention;

Fig. 2 is a controllable silicon trigger control circuit theory diagram of the present invention.

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are elaborated: present embodiment is being to implement under the prerequisite with the technical solution of the present invention, provided detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

The realization of arc suppression coil harmonic elimination method of slight is as shown in Figure 1: U0 is the unbalance voltage of system, C is the direct-to-ground capacitance of network system, L is the arc suppression coil of band secondary winding, PT is the voltage transformer that is used for measuring neutral point voltage, R is for eliminating the damping resistance of primary system resonance, and controllable silicon trigger control circuit and damping resistance, arc suppression coil secondary side are formed series loop; Under system's normal running (operation) conditions, controllable silicon in the controllable silicon trigger control circuit is conducting, damping resistance R puts into operation, although arc suppression coil operates near the resonance point in the primary circuit, because putting into operation of damping resistance, the neutral point voltage of system is controlled in the safe range of setting, guarantees the safe and reliable operation of electrical network; When system's generation earth fault, the voltage of neutral point raises rapidly, and the status signal of voltage passes to the controllable silicon trigger control circuit by voltage transformer pt, the automatic disconnection controllable silicon, damping resistance is cut, the capacitance current in the then effective bucking-out system of arc suppression coil; After ground connection disappears, by control controllable silicon trigger control circuit, make the controllable silicon conducting, damping resistance puts into operation, continues to play the effect of eliminating primary circuit resonance.

The selection principle of damping resistance should satisfy the requirement of system safety operation, should guarantee when promptly maximum unbalance voltage occurring in system that the voltage of the neutral point of arc suppression coil system is not higher than the permissible value of GB regulation.

Can get the voltage U of arc suppression coil neutral point by systematic schematic diagram _NCalculate as the formula (1):

The system circuit impedance is as the formula (2):

$\frac{j{X}_{L}R}{R+j{X}_L}-j{X}_C=\frac{X_L^{2}R+j(R^2{X}_L-R^2{X}_C-X_L^2{X}_C)}{R^2+X_L^2}---\left(2\right)$

When system's generation resonance

$R^2{X}_L=R^2{X}_C+X_L^2{X}_C---\left(3\right)$

Promptly

$X_C=\frac{R^2{X}_L}{R^2+{\mathrm{<figure-callout\; id="2"\; label="X\; L"\; filenames="A20071004196500082.png"\; state="\{\{state\}\}">X</figure-callout>}}_L^{}}$

GB stipulates that the neutral point voltage of system is not higher than system's phase voltage of 15%:

U _N＜0.15U _φ (4)

Can get by following formula

$\frac{\mathrm{\&epsiv;}{U}_{\mathrm{\&phi;}}}{\frac{X_L^2\mathrm{<figure-callout\; id="2"\; label="R\; R"\; filenames="A20071004196500082.png"\; state="\{\{state\}\}">R</figure-callout>}}{R^{}}}\&CenterDot;\frac{j{X}_L}{R+j{X}_L}R<{\mathrm{\&lambda;U}}_{\mathrm{\&phi;}}---\left(5\right)$

Wherein ε is the degree of asymmetry of system voltage, and its maximum is 1.5%, if following formula is all set up under any condition, needs damping resistance R to meet the following conditions:

$R<\sqrt{99}{X}_L---\left(6\right)$

X wherein _LMinimum reactance value for arc suppression coil.

The formation of controllable silicon trigger control circuit as shown in Figure 2 in the secondary circuit: R is that damping resistance, SCR1-2 are that bidirectional triode thyristor, D1-2 are that diode, C1-4 are that electric capacity, R01-2 are that wire resistor, RD are that voltage relay, ZJ are auxiliary relay for protection fuse, YJ.The arc suppression coil secondary winding forms series loop with damping resistance, two-phase controllable silicon in parallel; The branch road parallel connection that branch road that bidirectional triode thyristor SCR1, capacitor C 3, diode D1 compose in parallel and bidirectional triode thyristor SCR2, capacitor C 4, diode D2 compose in parallel, voltage relay YJ and the two ends that are connected on silicon controlled control end G1, G2 after intermediate relay ZJ is in parallel, the secondary that wire resistor R01 and two series arms that capacitor C 1, wire resistor R02 and capacitor C 2 are formed are attempted by arc suppression coil respectively is around, two-phase silicon controlled in parallel two ends.

Under system's normal running (operation) conditions, voltage relay YJ conducting, intermediate relay ZJ disconnects, the bidirectional triode thyristor conducting, damping resistance R puts into operation; When system's generation earth fault, voltage relay YJ disconnects, and bidirectional triode thyristor SCR1-2 disconnects, and damping resistance R is out of service; After ground connection disappeared, artificial control intermediate relay ZJ made the intermediate relay ZJ closure, bidirectional triode thyristor SCR1-2 conducting, and voltage relay YJ conducting thereupon, damping resistance R puts into operation, and intermediate relay ZJ disconnects; Two series arms that wire resistor R01 and capacitor C 1, wire resistor R02 and capacitor C 2 are formed provide protection for bidirectional triode thyristor.

According to above design; through actual verification; putting the primary side Device for eliminating harmonic with damping resistance compares; it is required withstand voltage lower with protection class that damping resistance is put secondary side equipment, reduced equipment cost (having reduced by 30%), and be easy to control; success rate 100% in experimentation; improve reliability, also made simultaneously damping resistance put the fault type that arc suppression coil that primary side takes place can not put into operation and be reduced to 0, improved the fail safe of system.

More than for describing in detail, its technical scheme of eliminating three-phase imbalance principle and secondary circuit control principle is preferred embodiment of the present invention.

Claims (4)

1, a kind of damping resistance is put the elimination system resonance method of arc suppression coil secondary side, it is characterized in that, may further comprise the steps:

1. on arc suppression coil, increase a secondary winding;

2. damping resistance is connected on the secondary winding of arc suppression coil, and is going here and there the controllable silicon trigger control circuit on this loop;

3. under system's normal running (operation) conditions, the controllable silicon conducting, damping resistance puts into operation, this moment, preset arc suppression coil operated near the resonance point, and damping resistance suppresses neutral point voltage and raises, when ground connection is taken place in system, the voltage of system neutral raises and has exceeded set point, voltage transformer detects the voltage condition of neutral point, by voltage relay control controllable silicon trigger control circuit, disconnects the damping resistance loop voluntarily.

2, damping resistance according to claim 1 is put the elimination system resonance method of arc suppression coil secondary side, it is characterized in that, described controllable silicon trigger control circuit, it constitutes: bidirectional triode thyristor SCR1, capacitor C 3, branch road that diode D1 composes in parallel and bidirectional triode thyristor SCR2, capacitor C 4, the branch road parallel connection that diode D2 composes in parallel, voltage relay YJ be connected on silicon controlled control end G1 after intermediate relay ZJ is in parallel, the two ends of G2, wire resistor R01 and capacitor C 1, the secondary that two series arms that wire resistor R02 and capacitor C 2 formed are attempted by arc suppression coil respectively around, two-phase silicon controlled in parallel two ends.

3, damping resistance according to claim 2 is put the elimination system resonance method of arc suppression coil secondary side, it is characterized in that, described controllable silicon trigger control circuit is under system's normal running (operation) conditions, voltage relay YJ conducting wherein, intermediate relay ZJ disconnects, the bidirectional triode thyristor conducting, damping resistance R puts into operation; When system's generation earth fault, voltage relay YJ disconnects, and bidirectional triode thyristor SCR1-2 disconnects, and damping resistance R is out of service; After ground connection disappeared, artificial control intermediate relay ZJ made the intermediate relay ZJ closure, bidirectional triode thyristor SCR1-2 conducting, and voltage relay YJ conducting thereupon, damping resistance R puts into operation, and intermediate relay ZJ disconnects; Two series arms that wire resistor R01 and capacitor C 1, wire resistor R02 and capacitor C 2 are formed provide protection for bidirectional triode thyristor.

4, the elimination system resonance method of putting the arc suppression coil secondary side according to claim 1 or 3 described damping resistances is characterized in that described damping resistance R meets the following conditions: $R<\sqrt{99}{X}_L,$

X wherein _LMinimum reactance value for arc suppression coil.

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