CN101593969A - Utilize residual voltage of breaker port to realize the method for station-to-station error prevention - Google Patents

Abstract

A kind of method of utilizing residual voltage of breaker port to realize station-to-station error prevention provides a kind of method that realizes station-to-station error prevention, make in the line between or circuit opposite end when earth point is arranged, can have technological means to prevent misoperation.This method is utilized the fracture electric capacity and the relation of the dividing potential drop between the line mutual-ground capacitor of circuit breaker, differentiates this circuit by the port residual voltage of protection measure and control device or other isolated plants detection circuit breaker and whether has earth point; The port residual voltage is zero when on the circuit earth point being arranged, and the port residual voltage is not greater than zero when having earth point on the circuit.The port residual voltage is zero when on the circuit earth point being arranged, and port residual voltage value is not 0.1V～1.0V when having earth point on the circuit.

Description

Utilize residual voltage of breaker port to realize the method for station-to-station error prevention

Technical field

The present invention relates to a kind of power automation field, particularly the electric power system five-preventing system.

Background technology

In the electrical production,, avoid the generation of all kinds of misoperation faults, must implement anti-misoperation locking and linked groups's management means for guaranteeing the safe operation of transformer station.Though the safe operation of system is always attached great importance in electric power system, annual always generation has caused many unnecessary loss and casualties because of all kinds of accidents that electric misoperation causes.In the different locking of form, the simplest padlock is arranged, and the anti-misoperation locking in the mechanical lock, electric loop lock, micro_computer five_proof system, automated system etc.

Anti-misoperation locking (being called for short " five is anti-") is meant:

1, prevents to divide by mistake, close circuit breaker;

2, prevent the on-load branch, close isolating switch;

3, prevent charged extension (closing) earth connection (ground connection disconnecting link);

4, prevent to be with earth connection (ground connection disconnecting link) to close circuit breaker (isolating switch);

5, prevent mistakenly entering charged chamber.

At present 1,2,3,5 in anti-can be solved preferably by existing five-preventing system at five, be with earth connection (ground connection disconnecting link) to close circuit breaker at the 4th prevent, existing five-preventing system can solve preferably to the earth connection of this side, but then powerless to the earth connection in the middle of offside and the circuit.That is to say and when the ground connection disconnecting link of offside closes, also the circuit breaker of this side can be closed, thereby cause the generation of accident by existing five-preventing system.

Summary of the invention

Technical problem: the purpose of this invention is to provide a kind of method of utilizing residual voltage of breaker port to realize station-to-station error prevention, when there was earth point between solution in the line or opposite end, the existing insurmountable problem of five-preventing system reached the effect that realizes the station-to-station error prevention operation.

Technical scheme: the present invention utilizes residual voltage of breaker port to realize the method for station-to-station error prevention, utilize the fracture electric capacity and the relation of the dividing potential drop between the line mutual-ground capacitor of circuit breaker, differentiate this circuit by the port residual voltage of protection measure and control device or other isolated plants detection circuit breaker and whether have earth point; The port residual voltage is zero when on the circuit earth point being arranged, and the port residual voltage is not greater than zero when having earth point on the circuit.The port residual voltage is zero when on the circuit earth point being arranged, and port residual voltage value is not 0.1V～1.0V when having earth point on the circuit.

Or the definite value of the port residual voltage of circuit breaker is set to 0.2V, promptly shows there is not earth point on the circuit during greater than 0.2V when the port residual voltage, and circuit can put into operation; When the port residual voltage shows that earth point is arranged on the circuit during less than 0.2V, need forbid that circuit puts into operation.

Beneficial effect: a kind of method that realizes station-to-station error prevention is provided, make in the line between or circuit opposite end when earth point is arranged, can have technological means to prevent misoperation.

Description of drawings

Fig. 1: the circuit wiring schematic diagram,

Fig. 2: the equivalent circuit diagram when M side stand-by heat, the maintenance of N side,

Fig. 3 circuit M side stand-by heat, the equivalent circuit diagram during N side cold standby,

Equivalent circuit diagram during Fig. 4 circuit both sides stand-by heats.

Embodiment

Circuit breaker for double break mouth and multi-break, because the equalizing capacitance of circuit breaker and the existence of line mutual-ground capacitor, (the ground connection disconnecting link is opened when being in stand-by heat in the M side, bus, circuit isolation switch close, circuit breaker is opened) and the N side when being in inspecting state (the ground connection disconnecting link closes, and isolation switch, circuit breaker are opened) equivalent circuit diagram as shown in Figure 2; If can cause above-mentioned said accident during M side breaker closing this moment, and existing five-preventing system can't work.If the equivalent circuit diagram when the circuit both sides all are in hot stand-by duty as shown in Figure 3.

220kV circuit (LGJQ-300) parameter:

Z ₁＝0.108+j0.41957Ω/km

C ₁＝0.0061366μF/km

Then to the 220kV circuit of 100km,

Line impedance: Z _L=10.8+j41.957 Ω

Direct-to-ground capacitance: $C_{L1}=C_{L2}=\frac{100\×0.0061366}{2}=0.30683\mathrm{\μF}$

Earth impedance: $\frac{1}{\mathrm{j\ω}{C}_{L1}}=\frac{1}{j{\mathrm{\ωC}}_{12}}=\frac{1}{j314*0.30683*{10}^{-6}}=-j10379.4\mathrm{\Ω}$

Generally, the fracture electric capacity of the SF6 circuit breaker of 220kV double break mouth is 2000pF, then:

The fracture impedance: $\frac{1}{\mathrm{j\ωC}1}=\frac{1}{j314*2000*{10}^{-12}}=-j1592356.7\mathrm{\Ω}$

Busbar voltage is 100V (secondary side).

The voltage that protection measure and control device installation place P is ordered

$U_P=\frac{\frac{\frac{1}{\mathrm{j\ϖ}{C}_{L1}}\×Z_L}{\frac{1}{\mathrm{j\ω}{C}_{L1}}+Z_L}}{\frac{\frac{1}{\mathrm{j\ω}{C}_{L1}}\×Z_L}{\frac{1}{\mathrm{j\ω}{C}_{L1}}+Z_L}+\frac{1}{\mathrm{j\ω}{C}_1}}\×U_M---\left(1\right)$

Because: $Z_L<<\left|\frac{1}{\mathrm{j\&omega;}{C}_{l1}}\right|$ $\left|\frac{1}{\mathrm{j\&omega;}{C}_{L1}}\right|<<\left|\frac{1}{\mathrm{j\&omega;C}1}\right|$

So formula (1) can be reduced to:

$U_P=\frac{Z_L}{\frac{1}{\mathrm{j\&omega;C}1}}\&times;U_M---\left(2\right)$

M side stand-by heat then, during the maintenance of N side, the residual voltage that protection installation place P is ordered is very little, is about 0.0027V.If earth point is near more apart from the M side, voltage is more little; But the drift of protection measure and control device is all greater than this value, so as long as on the circuit earth point is arranged, the voltage that P is ordered all is zero.

$U_P=\frac{\frac{\frac{1}{\mathrm{j\&omega;}{C}_{L1}}\&times;(Z_L+\frac{1}{\mathrm{j\&omega;}{C}_{L2}})}{\frac{1}{\mathrm{j\&omega;}{C}_{L1}}+Z_L+\frac{1}{\mathrm{j\&omega;}{C}_{L2}}}}{\frac{\frac{1}{\mathrm{j\&omega;}{C}_{L1}}\&times;(Z_L+\frac{1}{\mathrm{j\&omega;}{C}_{L2}})}{\frac{1}{\mathrm{j\&omega;}{C}_{L1}}+Z_L+\frac{1}{\mathrm{j\&omega;}{C}_{L2}}}+\frac{1}{\mathrm{j\&omega;}{C}_1}}\&times;U_M---\left(3\right)$

Formula (3) can be reduced to:

$U_P=\frac{\frac{1}{j2\&times;\mathrm{\&omega;}{C}_{L1}}}{\frac{1}{\mathrm{j\&omega;}{C}_1}}\&times;U_M---\left(4\right)$

Then when M side stand-by heat, N side cold standby, the residual voltage that protection installation place P is ordered is about 0.33V.

The fracture capacitance size of supposing circuit two ends circuit breaker is identical, and the both sides voltage swing equates and homophase, then can calculate the residual voltage of protecting installation place P to order and be about 0.66V (twice and a side stand-by heat, the residual voltage during the opposite side cold standby).

The present invention utilizes the method for residual voltage of breaker port realization station-to-station error prevention to utilize the fracture electric capacity and the relation of the dividing potential drop between the line mutual-ground capacitor of circuit breaker, differentiates this circuit by the port residual voltage of protection measure and control device or other isolated plants detection circuit breaker and whether has earth point; The port residual voltage is zero when on the circuit earth point being arranged, and the port residual voltage is not greater than zero when having earth point on the circuit.The port residual voltage is zero when on the circuit earth point being arranged, and port residual voltage value is not 0.1V～1.0V when having earth point on the circuit.

As above-mentioned criterion:

When on the circuit earth point being arranged, the detected voltage in protection installation place is zero; And when the protection installation side is in stand-by heat and does not simultaneously have earth point on the circuit, can detect voltage greater than 0.3V.Therefore can be implemented by following method:

1) revise the no pressing lock criterion of inspection in the protection measure and control device:

Existing criterion is generally: voltage is less than 30% rated voltage

Criterion changes into: voltage is less than 30% rated voltage and greater than Uzd (Uzd is a setting value, as 0.2V)

2) by the differentiation to residual voltage of breaker port, output contact is given five-preventing system.

Claims (3)

1, a kind of method of utilizing residual voltage of breaker port to realize station-to-station error prevention, it is characterized in that utilizing the fracture electric capacity and the relation of the dividing potential drop between the line mutual-ground capacitor of circuit breaker, differentiate this circuit by the port residual voltage of protection measure and control device or other isolated plants detection circuit breaker and whether have earth point; The port residual voltage is zero when on the circuit earth point being arranged, and the port residual voltage is not greater than zero when having earth point on the circuit.

2, the method for utilizing residual voltage of breaker port to realize station-to-station error prevention according to claim 1, the port residual voltage is zero when it is characterized in that on the circuit earth point being arranged, port residual voltage value is not 0.1V～1.0V when having earth point on the circuit.

3, the method for utilizing residual voltage of breaker port to realize station-to-station error prevention according to claim 1, the definite value that it is characterized in that the port residual voltage of circuit breaker is set to 0.2V, promptly show there is not earth point on the circuit during greater than 0.2V when the port residual voltage, circuit can put into operation; When the port residual voltage shows that earth point is arranged on the circuit during less than 0.2V, need forbid that circuit puts into operation.

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