Electrified barriers with non-contact operating principle

Electrified barriers of non-contact principle of action.

Dmitry Nikolaevich Udintsev,
Candidate of Technical Sciences

The modern market of special equipment needs not only detection and control means, but also means of influencing the detected object.

Electrified barriers with a rich history are proposed to be used as one of such means.

The proposed article examines the operating principle of an electrified barrier of a non-contact principle with a biological object.

In recent years, the gap between the development of detection means and means of impact (defeat) on the detected object has become increasingly obvious. This is due to a number of reasons.

One ​​of them is the difficulty in regulating the degree of impact on a biological object (BO) by various means, which increases the likelihood of a fatal outcome as a result of such impact.

Considering that the latter is not desirable, many means remain unclaimed.

Another reason is the quite fair restrictions imposed by legislation.

One ​​of the means of influence that does not have these drawbacks is electrified barriers (EB). Many have been familiar with the simplest types of EB, such as electric fences and electric shocks, for quite a long time.

The operating principle of EB is shown in the simplest single-pole diagram (Fig. 1).

1 – source of electric energy;
2 – cable network;
3 – linear part;
4 – grounding conductor.

Fig. 1. Schematic diagram of a single-pole electrified fence

In general, the EZ includes the following main elements: a source of electrical energy; a cable network; a linear part; a grounding conductor. One of the terminals of the source of electrical energy (SEE) of this simple EZ is grounded, the other is connected to the linear part. The object of influence, having touched the linear part with any part of the body, is exposed to phase voltage.

The first mention of the combat use of EZ dates back to the time of the defense of the Port Arthur fortress during the Russo-Japanese War at the beginning of the century.

For example, during the fourth assault on the night of November 26, 1904, the Japanese lost 780 soldiers killed, 150 of whom were burned on the electric fence.

This EF included:

• a linear part of the EF in the form of copper uninsulated wire, fixed on wooden poles of various heights through porcelain insulators;
• a source of energy, which was the central power station, located in the rear and having a generator of 3000 V;
• transformer to supply power to each of the four sections of the linear part. This transformer was installed near the power station and transmitted voltage to other transformers located near the linear part. They increased this voltage to 3000 V and supplied power to their sections. This installation made it possible not to use high-voltage cables to supply power to the linear part.

During the First World War, the same type of barriers were used as during the Russo-Japanese War. In addition, special types of barriers were developed — the Vulcan network, the low-lying Spotykach. Attempts were made to electrify strips of land and throw out electrified cables using grenade launchers and mortars.

Throughout the century, large-scale development and improvement of barriers was carried out.

As a result, modern barriers in service with the Russian army have a number of positive differences from the first models, such as:

• low energy consumption, ability to operate from a low-power energy source;
• ability to fairly accurately regulate the degree of impact on a biological object at the level of damaging and repelling effects, relatively small dimensions, allowing to reduce transportation costs, reduce deployment time;
• ease of maintenance and operation;
• low cost compared to other types of engineering barriers.

However, not everything is so simple.

Just as in ancient times the invention of the sword was followed by the invention of the shield, so the invention of the EZ was followed by the development of means and methods for overcoming and neutralizing them. Even at the time of the emergence of the EZ, a method of short-circuiting the linear part with metal poles was known. In this case, not only did a section of the EZ appear that could be overcome, but energy consumption also increased significantly.

During the Second World War, special kits were used to make passages and overcome EZs.

Many problems have always arisen due to the corpses of enemy soldiers left on the line after unsuccessful attacks. They created a mode close to a short circuit. Due to the above, there is currently a need to develop an EZ for which the currently known methods and means of overcoming are not a “shield”.

In addition, the development of EB that affects the enemy contactlessly, at a distance, is relevant. Work on creating such a barrier is being carried out at the Military Engineering University.

The principle of operation of a contactless electrified barrier (BEZ) is based on the phenomenon of voltage resonance. This phenomenon, widely known in electrical engineering, is remarkable in that in a circuit containing series-connected resistance, inductance, and capacitance, in resonance mode, the voltage on the reactive elements significantly exceeds the voltage generated by the IEE.

The bio-object, which is a conductor, although not ideal, and the conductive linear part (CL) are nothing more than capacitor plates separated by a dielectric layer (air). Thus, the capacitor in this circuit is the BO – air – CL system.

The calculated electrical circuit of the effect of the BEZ on the BO is shown in Fig. 2. The characteristics of the elements of the calculated electrical circuit of the effect of the BEZ on the bio-object are given in the table.

E – a source of electric power that generates harmonic oscillations of the required voltage and frequency;
L – an inductor coil connected in series with a linear conductor;
RL– active resistance of the inductor coil;
Слч-бо– capacitance between the LC and the internal conductive tissues of the body BO;
Rlch-bo – resistance between the LC and the internal conductive tissues of the body BO;
Rvn – internal resistance of the body BO;
Сбо-зь – capacitance between the internal conductive tissues of the body BO and the ground;
Rбо-зь – resistance between the internal conductive tissues of the body BO and the ground (includes the resistance of the external integuments (skin) of the BO and shoes (for humans)).

Fig. 2. Calculated electrical circuit of the impact of a contactless electrified barrier on a biological object.

Table: Characteristics of elements of the calculated electrical circuit of the impact of a contactless electrified barrier on a biological object

It is obvious from the equivalent circuit that by changing the values ​​of inductance, capacitance or frequency, the phenomenon of voltage resonance can be achieved.

An experiment conducted in laboratory conditions confirmed the operability of the installation.

When using a low-power low-voltage harmonic oscillation generator (Uout Ј 15 V, f=0 – 200 Hz), a bare conductor, which is the LP, was fed through the inductance L.

The subjects of the research, who did not even feel the effect of voltage on them when directly touching the generator outputs, noted the effect at the level of sensations when they were at a certain distance from the LC.

As the conducted research has shown, this barrier, in addition to the possibility of remote action, has another advantage over the traditional EZ: when short-circuiting the linear part to the ground, the effect of not increasing but decreasing the current in the LC is observed.

This is due to the fact that when the capacitance C is shunted, the system leaves the resonance mode, as a result of which the reactive and intrinsic equivalent resistance increase, and the current and power consumption decrease.

It is advisable to use this effect to register an attempt to overcome the EZ.

With an isolated LF, an attempt to short-circuit only leads to an increase in the system's capacitance and, therefore, the need to adjust it to the resonance mode.

The proposed barrier will be able to operate in several modes:

1. When operating in the security mode, the contactless electrified fence functions as a security alarm;

2. In the security-repellent mode, when an intruder approaches, a signal about a violation is sent to the control panel, and the intruder is affected without causing a lethal outcome;

3. In the security-defeating mode, a signal is also sent to the control panel, but the intruder receives a lethal effect;

4. In the repulsive mode, the intruder is affected enough to discourage him from going further, but not enough to cause a lethal outcome;

5. Any attempt to overcome in the defeat mode will result in a lethal outcome.

Based on the possible operating modes, the areas of application of the contactless electrified barrier are obvious.

The first through third modes are advisable to use when the service personnel are constantly at the control panel.

For example: guarding the state border, guarding important state facilities, guarding buildings and premises.

The fourth and fifth are designed for use without the constant presence of personnel.

According to preliminary estimates, the energy consumption of the BEZ, developed according to this principle, will be no more than 4 kW per 1 km in the defeat mode, and up to 100 W in the standby mode, with a significant advantage over existing models in terms of weight and size.

A very simple, affordable and easy-to-install LC will significantly reduce the costs of equipping the open borders of Russia after the collapse of the USSR.

A simple and reliable BEZ kit can become a reliable means of protecting both the personnel of law enforcement agencies in areas armed conflicts, as well as agricultural pastures.