The global application of photovoltaic voltage 1500V PV system has begun to be popularized on a large scale.The economy of scale and innovations in the area of system technology, which are leading to a reduction of the levalized cost of energy (LoCE), are among the main drivers behind this development . Moreover, a shift in DC system voltage from 1000 V to 1500 V can be observed in utility-scale systems . The implementation of this increased operation voltage started from the low power class with its string- and residential inverters in the past, now followed by the megawatt (MW) classes of the solar central inverter. Nowadays the operation voltage of 1500 V is the established standard for all the different power classes in the solar application area.
Advantages of 1500V voltage standard
Compared with the traditional 1000V PV system, the 1500V PV system can increase the series number of photovoltaic modules by about 1.5 times, from the original 24 blocks / string to 34 blocks / string, so the cable cost can be reduced by about 1 / 3, the number of combiner boxes can be reduced by 1 / 3, and the cost of cables and combiner boxes can be reduced .At the same time, the increase in the number of components in series further reduces the cost of support, pile foundation and construction and installation, and saves another 0.05 yuan / watt. In addition, the reduction of parallel network and the loss of AC / DC PV system are also recessive cost reduction.
Challenge of 1500V voltage standard
1500V PV system voltage will reduce electrical safety and reliability, and increase PID and other risks. Therefore, the production of 1500V photovoltaic modules mainly considers the factors affecting the reliability and safety of modules such as backplane partial discharge, electrical connector and electrical insulation. The difficulty is mainly in the selection of materials. For example, enterprises should choose junction boxes, backplanes and connectors with better quality and stricter requirements.
The 1500V PV system voltage has higher requirements for the inverter, mainly considering the problems such as insulation, electrical clearance and breakdown discharge after voltage rise. Therefore, the inverter needs to adopt more complex topology design, power devices with higher voltage level and DC switchgear.
After the voltage level rises to 1500V, the requirements for the safety performance of the PV system are higher. DC and AC are different, and there is no zero crossing. Once there is leakage, it will cause major accidents. Therefore, choosing a suitable 1500V DC switch is very important to improve the safety of the whole PV system.
Prospect of 1500V voltage standard
It is reported that the trial standard for 1500V modules launched by the International Electrotechnical Commission (IEC) will transition to a mandatory standard in the near future. In the future, 1500V will become a new industry standard. 1500V has made a qualitative leap compared with 1000V PV system voltage, which means that photovoltaic modules and parts must meet much higher technical and quality requirements than existing standards.
How to select pv DC switch?
Photovoltaic DC switch is an important protective device in the application of photovoltaic PV system, which directly affects the safe and reliable operation of photovoltaic PV system. This will affect the stable power generation and income of the whole photovoltaic PV system, especially in the DC 1500V photovoltaic PV system, to ensure the safe, stable and reliable operation of the photovoltaic PV system, and the importance of selecting an appropriate DC switch in the process of operation, maintenance, installation and commissioning of the safety maintenance PV system will be self-evident.
Germany, the Netherlands and other countries require the inverter manufacturer's trademark to be equipped with a built-in DC switch. Britain, India, Australia and other countries require that the photovoltaic PV system must be equipped with an external DC switch.
As a new technical concept, 1500V PV system voltage at DC side requires the joint participation and cooperation of inverter, cable and other component manufacturers. Among them, DC switch is the most important component to ensure the safety of photovoltaic PV system, and its working current and voltage will also affect the PV system selection. The voltage and current of the DC switch are determined by the series voltage and parallel current of the photovoltaic array to be disconnected. Therefore, in the PV system selection, it is necessary to confirm the PV system current and voltage first, and then select the appropriate photovoltaic DC switch. The voltage of general photovoltaic PV system may reach 1000V, or will reach 1500V in the future. The current to be disconnected varies according to the brand and power of components and whether the connection mode of photovoltaic PV system is multi series parallel connection or multi series independent connection (multi-channel MPPT).
Since 1500V PV system voltage design will become the mainstream trend, DC switching voltage design needs to be paid attention to in PV system selection in the future. The DC switches of the safety appliances are all in line with the design of 1500V photovoltaic PV system. For more information, please contact us.