SU1691917A1 - Method of protection of worker against affects of electric current in network with insulated neutral - Google Patents

Abstract

This invention relates to safety precautions, is intended to protect a person from electric shock, and can be used primarily in mine electrical networks with an insulated neutral transformer. The purpose of the invention is to increase the speed and level of electrical safety by reducing the capacitive leakage current by splitting the network into separate sections. The way to protect a person from electric shock is that, at the same time as the network is turned off, the leakage breaker disconnects all switched branches. 2 Il.

Description

This invention relates to safety precautions, is intended to protect a person from electric shock, and can be used primarily in mine electrical networks with an insulated neutral transformer.

There is a known method of protecting a person against electric shock, which consists in disconnecting the network if a person accidentally touches someone who is in charge of a group automatic switch on a signal from a leakage relay. After disconnecting the group circuit breaker to reduce the current through the person caused by the emf of the rotating electric motors, the capacitive leakage currents are statically compensated.

It is also known a technical solution based on the operation of a network-wide leakage relay in case of an emergency, the signal from which is sent to all switched branches.

In this case, the network is divided into separate connections.

The disadvantage of this method is that the signal to disconnect the group circuit breaker from the mains leakage relay comes with a time delay, creating the possibility of selective shutdown (which is not always appropriate for the technological cycle), as well as reducing electrical safety.

The known method, by its technical nature, is closest to the invention, according to which a person is protected by disconnecting the network containing switched taps with a grouped automatic switch, generating a disconnect signal from the leakage relay and compensating for capacitive leakage currents using compensating droplets whose conductivity varies depending on network capacity.

However, the effectiveness of reducing capacitive leakage currents is limited by nisp

with

sk y

Yu

VI

koi good quality of the contour of zero succession.

I pjib of the invention increase in bypass and disinfection by reducing the capacitive current of the duck due to the fragmentation of the network into separate sections. The goal is to achieve that in the well-known method of man from electrical shock in a network with an isolated neutral containing switched branches by disconnecting the network with a leakage current group switch, mono-speeds also disable all switched branches

Figure 1 shows the principal electric power supply sham of the switch of the local network with a group of automatic switches in FIG. diagrams of change of the currents flowing by a person in time.

The device, in which the method is implemented, contains an automagical group switch 1 and switched on i branching including mine magnetic starters 2 4, switching mine current collectors 5-7 and capacitances 0-10 of commutative branches.

The method of protection against defeat by a pleururic current is that simultaneously with the disconnection of the network, the group switch 1 turns off all switched branches.

A disconnect signal is generated from the leakage relay 11 when a person touches the supply side.

Paoola devices illustrated by diagrams (phi 2)

When a person touches the 12th current, the leakage relay 11 is triggered after a time ti, which causes the shutdown of the automatic group switch 1 to stop, KOI disconnects the network after a time ta. Turning off the switch 1, the current through the person 1 is reduced by the exponential law (curve Q) and when the voltage decreases due to the electromotive voltage of the rotating electrode gels, to P, 5 Um, a sharp decrease in time tj occurs as the comaglite minders Young starters 2 4 op G | 1O last. As a result, this current through the person 12 is determined only by the capacitance H of the discharge from the current collector 5, which is the electric motor (capacitive i and 9, 10 with current collectors 6 7 are turned off by the trigger 3 4). Such a change in current

through the person 52 in time occurs when the miner magnetic actuators 2-4 have coils of magnetic flux on the transient current. When pp p m kan / necks of eiitromagnets n / scagelrm 2 4 but with a constant current, the latter are switched off when the voltage drops to 0.2 L, the process is changing, the current changes somewhat (curve R), i.e. shutdown starters

0 2-4 occurs through time ti + t / j.

As can be seen from Fig. 2, the amount of electrical energy released in the human body is 12 (the area bounded by the abscissa and ordinal axis and the curves of changes in the current Q and R),

5 has a significant value, that is, the level of electrical zigzagness is not high enough. According to the proposed method, when a person touches 12 g., The current-carrying part (Fig. 1) reps 11 of the leakage forms a signal

0 off at the same time on the switch

1 and miner starters 2-4 as a result

Moreover, the current through person 12 through time ti

(own response time of relay 11

Claims (1)

leakage) and the time t2 (off time of the switch 1 and starters) decreases sharply from the value of / (with automatic compensation of capacitance) or IB (with static compensation to 1c according to an exponential law with a constant time sampling of an electric motor (curve S), as a result of which the branch capacitance is small, as the length of the cable 5 line is limited by the conditions of the motor start and greater than 300 m, a current of 1s is significantly less than a current of 1d, and this is due to the total capacity of all the branches. The amount of electricity released in human body 2 (area, coordinate axis and S curve) is significantly reduced. 5Ways to protect a person about g defeat electric current in the network with insulated neutral, containing switched branches, consisting in switching off the network with a group switch 0 for leakage current, which is so that in order to increase speed and electrical safety level by reducing the capacitive leakage current by splitting the network into separate parts, simultaneously with 5 disconnecting the network with a group switch and disconnecting all switched branches eight // 7Т C (mA) lpt / 9.1 h tfa)