I.Relevant standards and specifications for cable selection

1. DL / t5044-2004 electric power industry standard of the people's Republic of China

2. Gb50217 code for design of cables in Power Engineering

II.Main technical requirements

1. Two core cables should be used for DC power supply circuit, and single core cables can be used when necessary.

2. PVC insulated cables should not be used in places with high temperature above 100 ℃ or low temperature below - 20 ℃.

3. When directly buried cables are laid, steel strip armored cables shall be used when the cables bear large pressure or are in danger of mechanical damage.

4. The temperature of the cable core under the action of the maximum working current shall not exceed the allowable value determined according to the service life of the cable.

5. Determine the ambient temperature of the continuous allowable current carrying capacity of the cable. If the cable is laid in the air or cable trench, the average value of the daily maximum temperature in the hottest month shall be taken.

III.The selection of cable route shall comply with the following provisions.

1. Avoid the cable from mechanical external force, overheating, corrosion and other hazards.

2. Make the cable shorter under the condition of meeting the safety requirements.

3. Convenient for laying and maintenance.

4. Avoid the place to be excavated for construction. The parts of the cable that change up, down, left and right in any laying mode and all path conditions shall meet the requirements of the allowable bending radius of the cable.

IV.Cable types, characteristics and laying methods of photovoltaic power generation system

1. Photovoltaic special cable

The cables from the string to the combiner box generally use the special photovoltaic cable pv1-f1 * 4mm2. The structure of photovoltaic cable is simple. The polyolefin insulation material used has excellent heat resistance, cold resistance, oil resistance and ultraviolet resistance. It can be used under harsh environmental conditions and has certain mechanical strength.

2. Power cable

1) Steel tape armored flame retardant crosslinked cable zrc-yjv22

Widely used in: connecting cables from combiner box to DC cabinet, DC cabinet to inverter, inverter to transformer, transformer to power distribution device, and connecting cables from power distribution device to power grid.

2) Power cable nh-vv

Nh-vv copper core PVC insulated PVC sheathed fire-resistant power cable.

3. Control cable

Zrc-kvvp copper core PVC insulated PVC sheathed braided shielded control cable. It is applicable to control, monitoring circuit and protection circuit with AC rated voltage of 450 / 750V and below.

4. Communication cable

1) Djyvrp2-22 polyethylene insulated PVC sheathed copper wire braided shielded armored computer special flexible cable is suitable for electronic computers and automatic connecting cables with high anti-interference requirements for rated voltage of 500V and below.

2) RVVP copper core PVC insulated PVC sheathed insulated shielded flexible cable RVVP, also known as electrical connection anti-interference flexible cable, is a communication cable suitable for anti-interference, safe and efficient data transmission such as alarm and security.

5. RF cable

Solid core polyethylene insulated PVC sheathed RF coaxial cable SYV.