Help, anti-theft for copper and aluminium cables
It protects the cables of concentration trunk of field panels, alarms manholes of cable pipelines and accesses to technical rooms.

Problem

Just type "Theft of Copper of Photovoltaic systems" on any search engine, to run into an endless list of articles documenting every day raids of this metal, also known as "red gold". The extensive damage caused by the theft of copper or aluminium conductors, it is necessary to add the costs of replacement and PV system downtime. The most affected are the trunks where the copper wires connect the photovoltaic field panels to the inverter input. They are copper cables with a section up to 300 mm2, where pass currents up to 200A and voltages of 900V.

The theft attempt of copper cables at night, when the photovoltaic system is not working, up to now it cannot be possible to report because in absence of voltage in the electrical lines, there was no way of noticing the cut down.

Solution

HELP is the 1st anti-theft in the World that offers total protection: of the electric cables in copper and aluminium, of the manholes of cable pipelines openings and of the technical areas. Taking advantage on innovative patented system, first it reports the opening attempt of the manholes and then, in case one of the cables of the trunk concentration strings is disconnected or truncated, the system will send an alarm.

Example of Application

Each HELP control unit is able to protect up to 4 concentration trunks, for a total of 8 cables and two lines dedicated to alarm of the manholes of cable pipelines and the accesses of technical areas.

Operation

HELP indicates any opening attempts of the manholes or other access to cable pipelines and simultaneously controls the presence of the cables 2 ways: during the day measures the current flow generated by the photovoltaic modules; during the night it generates a series of pulses on the cables and through TAHELP-TX device the energy is transferred by electromagnetic induction to the cable arriving to the field panel where DC LOOP device is located that closes the circuit, the impulse retraces the cable back up to TAHELP-RX device. Here, still by electromagnetic induction, it is transformed into current pulse and detected by HELP which measures it and compares the values with those stored during the installation phase.

In case DC LOOP device is removed or short circuited, or even just one of the two trunk cables is cut off, or if the length is altered by a bridge, HELP detects a difference between the control signal and the value stored during the calibration phase and the alarm is generated.

System Composition

• HELP control unit, which is placed near the inverter and, therefore, in a safe area. Help may protect up to 4 trunks (4 connections of field panels-inverter), and thus 8 cable lines, as well as two dedicated lines for the protection of the manholes or the accesses to technical areas.

For each trunk (couple of copper cables-field panel) are needed:

• TX device Cod.AF1.TAHELP-TX

• RX device Cod.AF1.TAHELP-RX

• two DC LOOP, one installed at the input of field panel, the other on the inverter input. The connection is made in a quick and safe way by cables with Multicontact connectors at the input of the field panel modules. Tampering or removal of this device causes the alarm. Code AF1.DCLOOP.

• Proximity sensors on the manholes (optional)..

Autocalibration

HELP, to fit the length and characteristics of the cables, which varies from system to system, performs an autocalibration procedure during the installation phase in order to adjust power and frequency of the pulse energy of each individual channel.

High security level

There is no electrical contact between the sensors and cables to be protected. The device has an insulation of 4kV compared to the cables.

How the anti-theft communicates

HELP has an RS485 port with ModBus communication protocol, for remote monitoring; is also available a relay with changeover contact, programmable in its functionality and timing. You can monitor the system remotely through a monitoring software that is able to e-mail alarm status, from a virtually unlimited HELP-AC devices.

Example of an inverter with an input that brings together 4 trunks

Typical installation