SU1522342A1 - Apparatus for protective disconnector in insulated-neutral power network - Google Patents

Abstract

This invention relates to electrical engineering and is intended to protect electrical networks when earth faults are detected. The purpose of the invention is to reduce the active power consumed by the device and to increase the reliability of its operation. If a single-phase leakage or leakage occurs through a symmetrical insulation resistance, the leakage current creates a voltage drop across resistor 3. The target, consisting of a capacitor 8 and a resistor 9, causes the voltage drop across resistor 3 to average. When the voltage on the capacitor 8 reaches the voltage of the transistor 6 unlocking, the transistor opens along the following circuit: plus capacitor 8, emitter of transistor 6, first base of transistor 6, anode of LED of thyristor optocoupler 7, cathode of LED, minus of capacitor 8 passes current, opens opistron thyristor the pair 7, the capacitor 10 is discharged to the breaking coil 4 of the circuit breaker 5, the switch is turned off. 1 il.

Description

The invention relates to electrical engineering, in particular to power protection devices, and is intended for the protective disconnection of a three-phase network at a voltage of up to 100 V with an insulated neutral with single-phase locking to the ground.

The purpose of the invention is to reduce the active power consumed by the device and to increase the reliability of its operation,

The drawing is a schematic diagram of the device for the purpose of shutdown.

The device for protective disconnection contains a source of operating voltage 1, the input of which is connected to the terminals for connection to the mains phases and connected according to the scheme D. Larionov reacting body 2, the input of which is connected in parallel with the leakage current sensor 3 and in the form of a resistor between; u connection to the som source voltage. The output of the reacting organ 2 is connected in series with the disconnecting coil 4 of the automatic switch 5, the first base of the unijunction transistor 6 is connected to the anode of the LED of the thyristor optocoupler 7, the cathode of the LED is connected to the negative source i of the operating voltage, the first BEJ-water of the capacitor 8 and the first brood leakage current sensor 3, second base

with the plus of this source, the eater of the unijunction transistor 6 is connected i to the second terminal of the capacitor 8 and I via a resistor 9 to the second terminal of the leakage current sensor 3,

with

0

5 5 o

0

five

unlocking transistor 6, the transistor opens along the circuit: plus the end of the 8 torus, the emitter of transistor 6, trans} behind the base of transistor 6, the anode of the LED of the thyristor optro1 and 7, the cathode of the LED, the minus of the capacitor 8 - current flows, the thyristor of the optocourier pair 7, the capacitor 10 discharged to the tripping coil 4 of the circuit breaker 5, the circuit breaker trips.

The capacitor 13 serves as a c; 1 increase in the noise immunity of the electrical circuit during wiring / disconnection of consumers with their own capacitance relative to the earth (electric motors, cables). Since the bias current of transistor 6 is very small (less than 1 mA), the source 1 with no leakage consumes small active power.

Claims (1)

The absence of an electromagnetic relay significantly increases the operational reliability of the device. Therefore, the proposed device increases the level of electrical safety and reliability of the power supply. Device for protective disconnection in the network with insulated neutral, Containing a source of operating voltage, the input of which is connected to terminals for connection to the phases of the network, a reactive body, the input of which is connected in parallel to the leakage current sensor between the terminal for connection to ground and minus of the source of operating voltage, the output of the reacting organ is connected to the switch. The device is turned off by an automatic reel, in the following way, In the initial state, when the circuit breaker is turned on, a voltage appears at the output of the source i. This voltage is applied to the transition of the first base. - the second base of the transistor 6 - the transistor is closed, the thyristor of the optocoupler pair 7 is closed, the capacitor 10 through the resistor 11, the valves 12 are charged to the magnitude of amplitude voltage -50 by the anode of the thyristor back-up LED. If a single-phase leak or leakage occurs through a symmetrical insulation resistance, the leakage current creates a voltage drop across the resistor, distinguished by that, in order to reduce the active power consumed by the device and increase its reliability, the reactive augap is made on a single junction transistor and thyristor oltron with a tmM resistor and a capacitor, with the first base of the single junction transistor with :. united the throne, the cathode of the LED is connected to the omn source of operating voltage, with the first capacitor lead and the first lead of the leakage current sensor