How to correctly select the special cable for photovoltaic power generation system?
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 electric power engineering cable design specification, ii. Main technical requirements 1. DC power supply circuit should adopt two-core cable, and single-core cable can be used when necessary. 2, high temperature above 100 ℃ or low temperature- PVC insulated cables are not suitable for places below 20℃. 3, directly buried cable laying, when the cable is under great pressure or there is a danger of mechanical damage, the application of steel armored cable. 4. The cable core temperature 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 highest temperature on the hottest day should be taken. Three, the choice of cable path should comply with the following provisions 1, to 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, easy to lay, maintenance. 4. Avoid the place where the construction will be excavated. The cable should meet the requirements of the allowable bending radius of the cable in any laying method and the upper, lower, left and right parts of all path conditions. 4. Types, characteristics and laying methods of cables in photovoltaic power generation system 1. Cables connected to bus box by photovoltaic special cable group are generally used with photovoltaic special cable pv1-F1 * 4mm2. Photovoltaic cable has a simple structure, and the polyolefin insulation material used by it has excellent heat resistance, cold resistance, oil resistance and ultraviolet resistance, 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 is widely used in: Bus box to DC cabinet, DC cabinet to Inverter, inverter to transformer, transformer to distribution equipment connection cable, distribution equipment to the grid connection cable. 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 suitable for 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 connection 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 alarm, security and other anti-interference, safe and efficient data transmission. 5. Radio frequency cable solid core polyethylene insulated PVC sheathed radio frequency coaxial cable SYV.