SU561248A1 - Power direction relays - Google Patents

Description

(54) POWER DIRECTION RELAY

one

The invention relates to the protection of electrical installations and is used, in particular, to protect thyristor converters with power supply to the control system from a common network, in which, if the auxiliary voltage disappears, it can be fed by other consumers.

A device responsive to a change in the direction of power in a network, containing current and voltage sensors, a matching circuit, reacting and operating organs, is known. The disadvantage of this device is inertia.

. The closest in technical essence and the achieved result to the invention is a power direction relay containing current and voltage sensors, coincidence circuits, reacting and executive units 2. The disadvantage of this relay is also inertia.

The purpose of the invention is to increase speed.

This is achieved by the fact that the relay is equipped with a single-resistor comparison circuits connected between the sensors and the inputs of the coincidence circuits.

The drawing shows a power direction relay diagram. Voltage sensor 1 is connected via dividing diodes 2 and 3 to resistors 4, 5 and parts of the matching circuit 6. Current sensor 7 through dividing diodes 8, 9 is connected to resistors 10, 11 and the second part of the matching circuit 6. Diode resistor Comparison 12 and the coincidence circuit are made according to: push-pull circuits, which provide operation in both positive and negative half-waves of controlled voltage and current. The output of the scheme coincides denich 6 through the reacting threshold body 13 is connected to the executive body 14.

Claims (2)

. Voltage sensors 1 and current 7 are set up so that, with a positive half of the voltage applied to the operative diode 2, a negative half current is applied to the coupling 8 and vice versa. Similarly, the signal must be phased; supplied to the remote diode 3, 9. The voltage from voltage pins 1 and current 7 is compared with the voltage drop across resistors 5, 4, 10, 11 from the current flowing through the current limiting resistors 15, 16 and rhyodes 17, 18 and 19, .20. Comparison voltage is chosen greater than the maximum voltage at the time of coincidence of the polarity of the measured voltage and current at the minimum phase shift. Diodes 21, 22 combine the signals at the input of the reacting body 13 from the corresponding channel of the coincidence circuit. When the voltage from the voltage drop sensor on the resistor 4 is exceeded, the diode 19 closes, If c. this instant of time to the separation diode 8 is applied a negative half-wave current; the output at the output of the coincidence circuit does not change the signal. If, at the moment when the separation diode 2 is open, an excess current is applied to the separation diode 8, the diode 20 is also closed at the output of the coincidence circuit 6. A signal whose duration is equal to the duration of the current and voltage phase coincides. the coincidence of the phases includes the threshold reacting body 13 and the executive body 14. The relay circuit operates in the same way in the next half-wave voltage. The introduction of nonlinear elements that provide a dead zone at the input of the reacting body, and the absence of inertial elements at the relay output, allows to increase the speed while ensuring a given noise immunity. Claims of the invention Power direction relays containing current and voltage sensors, coincidence circuits, responsive and executive units, characterized in that, in order to improve speed, they are equipped with diode-like comparison circuits connected between the sensors and the inputs of the coincidence circuits. Sources of information taken into account in the examination: 1, the book The Use of Semiconductors in Relay Protection and System Automation, M., 1962, Higher School, pp. 99-100, fig. 4-6. 2. Book of Nadezhdin V, B, and others. Static relays in relay protection, Science, Ld, 19b, p. 99, fig. Zh 1 V IG-O