In the past 10 years, photovoltaic cables have gone through mainstream standards such as VDE-AR-E 2283-4 / 2 PFG 1169 / EN50618 / IEC62930 / UL4703, excluding some national standards issued by individual countries. At present, in addition to the countries and regions that use the American standard UL4703, the EN50618 standard is the most widely used. However, as the cost of photovoltaic systems is getting lower year by year, the competition for components is becoming increasingly fierce. TUV Rheinland’s 2 PFG 2642 aluminum alloy cable standard was officially launched. The standard covers 10 square meters to 400 square meters. Below 10 square meters, refer to the relevant requirements of EN50616, combined with the characteristics of aluminum alloy conductors, and related tests and certificate issuance are also attached.
Can aluminum alloy conductors replace the current tinned copper conductors? Is there a security problem? This is what all junction box factories and photovoltaic system installers care about.
In fact, all the focus is on the electrochemistry between copper and aluminum anyway. There is a potential difference between anode copper and cathode aluminum, forming a structure similar to a PN junction under certain conditions. The aluminum electrons move to the copper pole, forming a potential difference between the copper and aluminum, and the electrochemical reaction occurs from this. An important condition for the formation of an electrochemical reaction is the electrolyte. There are gaps between copper and aluminum, and water molecules in the air exist in the gaps. Therefore, the conditions for the electrochemical reaction are met.
If the positive and negative electrodes are connected externally, the electrochemistry will continue until the activity on the electrodes is gradually lost, a new balance is formed, and no external discharge is required, and the chemical reaction basically stops. This is the same as the principle of the battery, the battery will not deplete the plate before finally stopping the energy output.
There are mature copper-aluminum transition terminals for the transition of copper and aluminum materials. Copper-aluminum transition terminals have been used for decades. Why hasn't the copper-aluminum transition terminals been exhausted due to electrochemical reactions? This is based on two reasons. One is that the contact surface of the copper-aluminum transition terminal is completely isolated from the air, and the contact surface does not have the reaction conditions. The second is that even if the exposed surface forms a battery-like reaction, the aluminum material is very active in the air. The alumina prevents further corrosion of aluminum.
Therefore, there is no technical risk in choosing pure aluminum or aluminum alloy materials as conductors for aluminum alloy photovoltaic cables above 10mm2. Since the cable insulation material is consistent with EN50618 and other standards, as long as the feasibility of the conductor resistance or current-carrying capacity is considered. (See Table8.2 for reference table of current carrying capacity from 10mm2 to 400mm2)
Cables of more than 10 square meters are mainly used in photovoltaic systems to complete the connection from the combiner box to the inverter, replacing the embarrassing situation of using YVJ or YJLV cables in the past. Because YJV is usually used for communication and is not suitable for direct sunlight. The construction had to adopt bridge protection. Photovoltaic cables can be used in direct sunlight. Except for the large-size photovoltaic cables between the combiner box and the inverter, the new standard aluminum alloy cables can be used, so can the solar cell modules and the photovoltaic cables from the solar cell modules to the combiner box or inverter use the 2 PFG 2642 standard? Of aluminum alloy photovoltaic cables? Below I will make a simple interpretation of this standard.
2 Article 1 of the scope of the PFG 2642 standard specifies flexible aluminum or aluminum alloy conductors other than Class 1 or Class 2 and not specified in IEC60228. This standard serves as a certification guide. That is, TUV according to 2 PFG 2642 can make relevant certifications for non-category 1, category II aluminum alloy conductor photovoltaic cables according to user requirements.
In addition to aluminum alloy photovoltaic cables for ground photovoltaic systems, aluminum alloy flexible conductors can also be used for photovoltaic cables in the solar junction box, and the flexible photovoltaic cables between the solar cell string and the inverter in the photovoltaic system. Specifically, pure aluminum, aluminum alloy, and coated conductors can be selected, and the conductor composition will be specified by the user.