SU132704A1 - Elliptical Directional Resistance Relay - Google Patents

Description

Elliptic characteristic directional resistance relays are known. They contain voltage and current transformers connected to the line voltage and the current difference of the two phases, a bridge circuit comparing semiconductors to the secondary windings of transformers, and a null indicator on semiconductor triodes. The disadvantages of such relays are the complexity of the relay circuit and the difficulty of adjusting the axes of the elliptical characteristic of the relay.

In the described relay, these disadvantages are eliminated by using the output stage on the triode, which provides a time delay equal to one double-period current period, which is released. RC circuit included at the output of the comparison circuit.

The prinpa scheme of the described relay is shown in the drawing.

Voltage transformer / switched on. Line voltage. The current transformer 2 is provided with two primary windings connected to the phase phase buses to which transformer 7 is connected. Transformer 5 is used as a memory unit. Voltages proportional to the linear voltage and current differences. Vuh phases, taken from the secondary windings of transformers / and 2, are fed to the comparison circuit formed by two bridges 5 and 7, in the arms of which are used semiconductor diodes. The output of the comparison circuits is connected to an RC circuit, which is formed by a resistance of 8 and a capacitance of 9. The double frequency voltage, the loopable signal, is fed to the input of a null indicator, made on semiconductor triodes 10, 11, 12 and 13.

When a positive voltage is applied to the input, the triode 11 is unlocked, and the triode 12 is closed, with the result that the capacitance 14 begins to charge. Permanent charge time selected

№ 132704 -2

so that after 11 -1.2 ms the triode J3 is unlocked and the voltage is applied to the polarized relay 15.

Adjusting the constant charge of the capacitor 14 is made by changing the resistance value 16. When the positive signal is removed, the triodes 10 and 12 are unlocked again, and the triode 11 is locked, and the capacitance 14 is instantly discharged, after which the triode 13 is locked - Due to the rapid discharge After the voltage is removed from the input of the zero indicator, the capacitor 14 instantly disappears the voltage at its output. If several positive pulses with a duration of 7-8 msec are applied to the input of the null indicator, then if there is at least a small interval between them, the voltage at the output of the null indicator He does not appear.

The selection of the delay time for tripping the output triode 13 of the nullindicator equal to one period of the doubled frequency current obtained at the RC output of the circuit formed by resistance 8 and capacitor .9, simplifies the relay circuit, since the elliptical response characteristic is obtained by comparing the two (linear voltage and voltage, proportional difference of currents), rather than three electrical quantities. Adjusting the ratio of the axes of the elliptical response characteristic of the relay is carried out by selecting the capacitance value of 9 RC circuits.

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Claims (2)

1. A directional resistance relay with: a flip-flop characteristic containing voltage transformers and currents connected to the line voltage and current differences of the two phases, a bridge comparison circuit on semiconductors connected to the secondary windings of the transformers, and null indicators on semiconductor triodes, different By the fact that, in order to simplify the relay circuit and facilitate the adjustment of the axes of the elliptical characteristic, the output triode in the null indicator has a response time delay equal to one current period twice hydrochloric frequency of bodily RC circuit included in the output of the comparison circuit. 2. Use of a variable capacitor in the device according to claim 1 for adjusting the axes of the elliptical characteristic.