SU476575A1 - Line modeling device - Google Patents

Description

one

The invention relates to the field of creating models of a line for testing the breaking capacity of switches in the mode of a non-deleted short circuit (short-circuit) on simulation installations equipped with percussion generators and on network test benches.

In the known devices, when testing switches without shunting resistances in the disconnection mode of unclipped short circuits, a number of line model circuits containing at least four reactors and four capacitors are used.

Known models contain a significant number of reactive elements - reactors and capacitors. The shape of the curve of the restoring voltage (with an unreleased short-circuit) differs noticeably in the initial part from a linearly increasing one. In addition, since the coefficient exceeds the amplitude of the restoring voltage on the known models is 1.9 (calculated value), and when tested in the mode of unreleased short circuit. this coefficient should be 1.6, then the additional inductance is used in the known device.

The aim of the invention is to simplify the device and improve the accuracy of the simulation.

The proposed device is different in that

that it contains an additional resistor. The first and second reactors are connected in series, and a shunt circuit consisting of a third reactor connected in series, a second capacitor, and an additional resistor are connected in parallel with the second reactor.

This reduces the number of used reactors and capacitors, provides a fairly accurate approximation of the shape of the first ascending part of the recovery voltage curve to a linearly increasing one, and also directly provides the normalized value of the amplitude excess voltage recovery coefficient corresponding to real lines.

FIG. 1 and 2 shows the proposed device.

Reactors 1 and 2 connected in series are connected to the output terminals of the device. In parallel with the second reactor, a shunt circuit is connected from a series-connected third reactor 3, a capacitor 4, and an additional resistor 5. In addition, veggie from a resistor 6 and a capacitor 7 are connected to the output terminals.

A device for simulating a line in a test circuit is placed in series with a generator 8, an auxiliary switch 9, an inductive circuit 10 and a test switch 11. A capacitor 12 is used to regulate the curve of the restoring voltage from the network side.

Such a test setup corresponds to the actual disconnection conditions of an unreleased short circuit on the line in the high-voltage network, and the proposed model of the line replaces the actual short-circuited line of the appropriate length in the test circuit.

The test begins by turning on the auxiliary switch 9 (Fig. 2) with the contacts of the test switch 11 closed. A short circuit current flows in the circuit and is switched off by the switch 11. After the arc 11 of the switch 11 is extinguished, the voltage from the generator 8 is restored on the capacitor 12, and On the model side of the line, the voltage is restored (in the transient process), which is close enough to correspond to the normalized curves for testing in the disconnected mode of unresolved short circuits.

The branch of the resistor 6 and the capacitor 7 is located directly near the test switch, for example in the test chamber. The remaining elements of the model can be located in another room and connected to the specified branch with the inductance LTJI. Then the inductance of the reactor 1 Z-1 is taken to be equal to the inductance of the Lb, i.e. Li Li.

In this case, the remaining parameters of the model can be, for example, determined from the following ratios, which provide a fairly good approximation of the initial part of the recovery voltage curve to a linearly increasing, and the amplitude excess factor is 1.6.

L, -L, 1z (1 -IJ (0.351 - 1.351ZJ,

0.349

/, 0.458 (

:

La + l-li

C, 0.160, / ,,

L is the inductance of the reactor 1; La is the inductance of the reactor 2; LZ - reactor inductance 3; LUI - women's productivity; RI is the resistance of the resistor 6;

 resistance of resistor 5; GI - capacitor capacitance 7; GZ is the capacitance of the capacitor 4, and all parameters are given in relative units with respect to the characteristic impedance, inductance and capacitance of the simulated short-circuited line.

As can be seen from the expression for / -z with Lm

- 0,26, inductance z 0 and reactor

1.351

3 can be disabled. Consequently, when the inductance value of the Lb, smaller than the limit value (for example, 26), a model can be applied in which only one reactor 2 must be designed for the total current.

With an inductance of LUI equal to or greater than the limiting value (for example, / ,, 26), a model can be applied in which the parameters (in relative units), for example, are equal to Li 0.26, L2 0.74, C2 0.472, / 2 0.339 , Ci 0.160,, and reactor 3 is disabled.

If the inductance of the splitting is, then its part (w-Lj) is used as part of the inductance LZ and to obtain the required magnitude of inductance, a reactor with corresponding inductance is included in series with this part, i.e. in this case only one reactor designed for full current .

Compared to the known line modeling device, in the proposed device, the number of actually installed reactors and capacitors is reduced by no less than two times.

Subject invention

A line modeling device comprising capacitors, reactors and a resistor connected in series with the first capacitor, characterized in that, in order to simplify the device and increase the modeling accuracy, it contains an additional resistor, the first and second reactors are connected in series and parallel to the second reactor a shunt circuit of a third reactor connected in series, a second capacitor, and an additional resistor.

±: 7

Line model

gears - / --- 1