SU920933A1 - Device for physical simulating of short-circuiting current - Google Patents

Description

(54) DEVICE FOR PHYSICAL MODELING OF SHORT CIRCUIT CURRENT

This invention relates to electrical engineering, namely, relay relay.

Methods are known that make it possible to obtain the most reliable results on the behavior of relay protection devices by field tests, short circuit experiences in the energy system, as well as using shock generators and according to operating data 1. However, such methods are not economical and testing relay protection devices by simulating processes in power systems.

At present, a setup containing, among other things, two electrodes is being assembled for physical simulation of a short-circuit current through an arc. A thin wire is placed between these electrodes and voltage is applied. The wire burns out and an arc arises. The disadvantages of this installation are that it is not possible to regulate the phase of the arc and it is necessary to have a rather large supply voltage of the installation. In addition, significant inconvenience arises from the need to observe npaJBHi

Safety measures associated with the presence of open flame and high current between the electrodes.

. A device for physical simulation of a short-circuit current containing a laboratory: an autotransformer, the primary winding of which is connected to an alternating current network, is known; a series circuit is connected to the secondary winding, you- complete in the form of a phase-switching unit, linear inductance, resistance and primary winding of the current transformer, to the secondary, the secondary winding of which is connected to the relay protection unit 2.

However, this device does not simulate a current during a short circuit through an electric arc.

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The purpose of the invention is to expand the functionality of the device by simulating a current during short circuits through an electric arc.

Claims (2)

The goal is achieved by the fact that. a device for physical modeling of a short-circuit current, containing a laboratory autotransformer, the primary winding of which is connected to a variable current supply network, a secondary circuit connected to the secondary winding, made in the form of a phase-switching unit, linear resistance inductance and primary winding of the current transformer, to the secondary winding of which the relay protection unit is connected, a key element, a semiconductor bridge, a zener diode included in one diagonal floor are additionally introduced conductive bridge to whose other diagonal subkey key element included in said series circuit between the output terminals of the current transformer primary winding and the secondary winding of the autotransformer laboratory. The drawing is a schematic diagram of the proposed device. A device for a physical model of a short-circuit current contains a laboratory autotransformer 1, the primary winding of which is connected to an AC network, a secondary circuit connected to the secondary winding, disconnected in the form of a phase-switching unit 2, a linear inductive 3, an active resistance 4, and the primary winding of a current transformer 5, the secondary winding of which is connected to the relay protection unit b, a semiconductor bridge, made on the diodes 7, in one. Well, the diagonal of which is on the Zener diode 8, the key diagonal is connected to its other diagonal, oh. element 9, included in the specified serial circuit between the output terminals of the primary winding of the current transformer 5 and the secondary winding of the laboratory autotransformer 1. The device works as follows. When the key element 9 is open, the equation of the process in the model is E –Sanlujt -v) l. | J- + (1) where is the voltage across the zener diode L is the inductance of the model; R is the active resistance of the model; GG is the amplitude of the voltage across the secondary winding of the laboratory autotransformer 1; H - the initial phase of the short circuit, set by the installation on the phase switching unit; LU is the angular frequency of the voltage. The equation of the process in the network when a short-circuit through the arc is similar to (1) only L and R should be understood respectively as an inductance K is the resistance of the loop of a short circuit, the voltage on the arc weakly depends on the current and can constant, i.e. as well as the voltage at the zener diode. Introduce the ratio of the voltage drop across the arc to the amplitude of the supply voltage dr- | A «1 This network ratio depends on the voltage drop across the arc, however, in the model it is more convenient to change E and rearrange L and R, for which the autotransformer and variables are used L and R. In the closed state of the key element 9 in equation (1), we should put and on-O / a, so the device models the current in the network with series-connected L and R, i.e. metal short circuit current, or short circuit through transient contact resistance (increase R). The proposed device allows to simulate a short-circuit current through an arc. Apparatus of the Invention A device for physically modeling a short-circuit current containing a laboratory autotransformer, the primary winding of which is connected to an AC network, is connected to the secondary winding by a series circuit made in the form of a phase-switching unit, linear inductance, active resistance and primary winding of a current transformer, to the secondary winding relay protection unit is connected, which is tricky so that, in order to extend the functionality by simulating In the event of a short circuit through an electric arc, a key element, a semiconductor bridge, a zener diode included in one diagonal of a semiconductor bridge are additionally introduced, to the other diagonal of which is connected a key element included in the specified series between the current transformer primary and laboratory secondary windings autotransformer. Sources of information accepted attention in the examination 1. A. Maykonar. Arc closures on power lines. Energie, 1965. 2. Kuzhenov S.L. et al. On methods of reproducing primary processes for testing relay protection devices. Lime in higher educational institutions. Electromechanics, 1978, 9.