RU18807U1 - HUMAN PROTECTION DEVICE FOR ELECTRIC SHOCK - Google Patents

Abstract

1. Device for protecting a person from electric shock, comprising interconnected overcurrent protection device, leakage current sensor, amplification and comparison device, load, characterized in that it is equipped with a power element connected in parallel to the output terminals of the overcurrent protection device. 2. The device according to claim 1, characterized in that it is equipped with a current limiter connected in series with the power element.

Description

Device for protecting a person from electric shock

The utility model relates to safety, designed to protect a person from electric shock and can be used in various installations, buildings and structures.

A device for protective shutdown in a three-phase electric network with an isolated neutral containing a power source, a measuring unit made on a transistor, the input of which is connected to a source of direct current and pulse reference currents, and the output of the specified unit, shunted by an electronic key, is connected via a capacitor to an actuator connected to the circuit breaker, shunted by the first diode, turned on in accordance with the specified power source, while The additional body is made in the form of a double-winding relay, one of the windings of which is shunted by a newly introduced capacitor, connected in series with a second diode connected in opposite to the power source, and connected in parallel with the first diode, and the other winding is connected to an additional source of constant reference voltage (see. S. USSR No. 815829, class.

The disadvantage of this device is the low efficiency of protecting a person from electric shock.

A device for protective shutdown in an alternating current network, comprising a leakage sensor, the output of which is connected to the input of the first signal converter, the output of which is connected through the first differentiating block to the input of the pulse shaper, the output of which is connected to the actuator through the prohibition block, the control input of the block prohibition is connected to the output of the prohibition pulse forming unit, the input of which is connected to the output of the second signal converter through the second differentiating unit, input One of which is connected to the output of the load current sensor, while a phase-synchronization pulse generator with input terminals is additionally inserted into it for connecting to the network wires, the output of which is connected to the synchronization inputs of the first and second signal converters, which are made in the form of phase-sensitive rectifiers (see. .s. USSR No. 1359842, class HO2H / 1b).

The disadvantage of this device is the design complexity, low reliability of protecting a person from electric shock.

The closest in technical essence and the achieved positive effect and adopted by the authors for the prototype is a residual current device containing interconnected overcurrent protection device, leakage current sensor, amplification and comparison device, load, (see Technical Specifications TU 16-92 IZhTSh. 656111.085 TU).

The disadvantage of this device is that when the circuit breakers containing special coils of independent trip units are turned off, the damage energy stored in the load (in capacitors, transformers, etc.) continues to affect a person.

The technical result that can be achieved using the proposed device for protecting a person from electric shock is to increase the level of electrical safety by reducing the time and magnitude of the current flowing through a person by shunting by a high-speed power, for example, a semiconductor element or with a current limiter connected in series with it, and the energy of human damage accumulated in the load after the network is disconnected by the overload current protection device is dissipated mainly on a load and a power element or on a load, a power element with a current limiter connected in series with it, and not on a person.

The technical result is achieved using a known device for protecting a person from electric shock, comprising interconnected overcurrent protection device, leakage current sensor, amplification and comparison device, load, while it is equipped with a power element connected in parallel to the output terminals of the overload current protection device .

The device is equipped with a current limiter connected in series with the power element, if the total resistance of the electrical circuits does not provide a current limitation to the maximum allowable value through the power element.

The electrical energy of the load is transmitted to the power element by means of food connected to the current limiter.

In FIG. 1 shows a block diagram of a device for protecting a person from electric shock, without a current limiter.

In FIG. 2 shows a block diagram of a device for protecting a person from electric shock with a current limiter.

In FIG. Figure 3 shows the waveform of the voltage at a load of 1 kΩ (approximate human resistance) over time of a device for protecting a person from electric shock without a current limiter (see Fig. 1).

In FIG. Figure 4 shows the waveform of the voltage at a load of 1 kΩ (approximate human resistance) over time of a device for protecting a person from electric shock with a current limiter (see Fig. 2).

The device for protecting a person from electric shock includes interconnected overcurrent protection device 1, for example, a circuit breaker, leakage current sensor 2, for example, a differential current transformer whose primary windings are connected between the overcurrent protection device 1 and

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load 3, the secondary winding of the leakage current sensor 2 is connected to the input of the amplification and comparison device 4, the output of which is connected to the input of the power element 5, the latter is connected by power leads parallel to the output terminals of the overcurrent protection device 1 (see Fig. 1), or power the element 5 connected in series with the current limiter 6 is connected in parallel with the output terminals of the overcurrent protection device 1 (see Fig. 2).

The device for protecting a person from electric shock consists in the fact that when a person touches live parts or a violation of the insulation resistance in the load circuits 3, a person is shunted by a power, for example, semiconductor element 5.

The principle of operation of a device for protecting a person from electric shock is as follows.

After turning on the overload current protection device 1, for example, a circuit breaker, the mains voltage through the leakage current sensor 2, for example, a differential current transformer, is applied to load 3, which contains, for example, in addition to active resistance, capacitance, inductance, electric motor, etc. P.

If there is no load circuit 3 (after the leakage current sensor 2), the earth leakage resistance, i.e. there is no human touch on the current-carrying conductors and the insulation resistance of the electrical circuits corresponds to the established norm, a signal is sent from the leakage current sensor 2 to the amplification and comparison device 4, which does not generate a signal to the power element 5, the latter is in the off state.

When a person touches current-carrying load circuits 3 or

in cases of violation of the insulation resistance in the electrical circuits of the load 3, the leakage current sensor 2 generates a signal that is amplified by the amplification and comparison device 4 and is supplied to the power element 5,

the latter is switched on with or without a current limiter 6 connected in series, parallel to the output terminals of the current protection device, overload 1, thereby shunting the person. After switching on the power element 5, the switching on time of which is tens of microseconds (μs), the voltage on a person decreases to the magnitude of the voltage drop on the power element 5 or on the power element 5 and the current limiter 6, while the device is protected by an overload current of 1 more that did not disconnect the load 3 and person from the network. In FIG. Figure 3 shows the waveform on a resistor with a resistance of 1 kOhm (equivalent to human resistance).

At 18 milliseconds (ms), the power element 5 turned on and the voltage on the “person decreased from 10 to 15 V, with the touch occurring several hundred microseconds before the power element 5 was turned on. FIG. Figure 4 shows the waveform on the same resistor in the device, in which a current limiter 6, a resistor with a resistance of about 0.2 ohms, is connected in series with the power element 5. For 9 ms, the power element 5 turned on and the voltage on the person decreased from 305 V to 40 V. In both experiments, the voltage on the person decreased to a safe value. The time a person is under voltage is determined by the speed of the leakage current sensor 2, amplification and comparison device 4, and power element 5. After disconnecting the “person and load 3 from the network, the device is protected by overload current 1, the person’s damage energy stored in load 3 will be mainly to bypass a person through a power element 5 or a power element 5 with a current limiter 6 connected in series with it. The power element 5 and the current limiter 6 are selected from the condition of a quick and reliable shutdown of a person stroystvom current overload protection 1 from a supply voltage while maintaining their health.

In the proposed device for protecting a person from electric shock, a power element 5 and a current limiter 6, the equivalent resistance of which is an order of magnitude less than the resistance of the load 3 and several orders of magnitude less than the resistance of a person (approximately 1 kOhm), are still shunting the person while the overload current protection device 1 is on, thereby reducing the time spent by a person under the full voltage of the network, since it is divided in proportion to the total resistance of the circuit from the power source (generators, transformers) to current restrictor 6 and the resistance of the restrictor.

After the network is disconnected by the overload current protection device 1, the energy of human damage accumulated in the load circuit 3 is mainly dissipated not by the person, but by the load 3 and the power element 5 (see Fig. 1) or on the load 3, the power element 5 and a current limiter 6 connected in series with the power element 5 (see Fig. 2). This provides a higher level of electrical safety for a person, and the speed is determined by the leakage current sensor 2, the amplification and comparison device 4 and the power element 5. Structurally, the device Human shields against electric shock accomplished by block-functional principle and consists of two modules:

-module 1 - overload current protection device 1;

-module 2 - leakage current sensor 2, amplification and comparison device 4, power element 5 with current limiter 6 or without current limiter 6.

This design allows module 2 to be used both on newly created facilities and on existing facilities, without dismantling previously installed overcurrent protection devices. 6

-increasing the level of electrical safety by reducing the time and magnitude of the current flowing through a person by shunting it with a quick-acting power element or a power element with a series-connected current limiter;

-simplification of the design, due to the modular design;

-Small dimensions;

-relatively cheap cost of the device;

-the ability to interface with almost all protection devices for overload current;

-the ability to install the module both on newly created facilities and on existing facilities without dismantling previously installed protection devices for overload current.

Authors: // Zaitsev N.I.

-Zaitsev Yu.N.

Chemerkin G.I.

/ yr P

Claims (2)

1. Device for protecting a person from electric shock, comprising interconnected overcurrent protection device, leakage current sensor, amplification and comparison device, load, characterized in that it is equipped with a power element connected in parallel to the output terminals of the overcurrent protection device. 2. The device according to claim 1, characterized in that it is equipped with a current limiter connected in series with the power element.