01What is a photovoltaic cable?   Photovoltaic cables are mainly used to connect solar panels and various solar system equipment, and are the basis of supporting electrical equipment in solar systems. The basic structure of photovoltaic cables consists of conductors, insulation layers, and sheaths.   Photovoltaic cables are divided into DC cables and AC cables: Photovoltaic DC cables are mainly used for connection between modules, parallel connection between strings and between strings and DC distribution boxes (combiner boxes), and between DC distribution boxes and inverters. Photovoltaic AC cables are mainly used for connection between inverters and low-voltage distribution systems, connection between low-voltage distribution systems and transformers, and connection between transformers and power grids or users.   Photovoltaic cables need to withstand long-term erosion from natural conditions such as wind and rain, day and night exposure, frost, snow, ice, and ultraviolet rays. Therefore, they need to have characteristics such as ozone resistance, UV resistance, acid and alkali resistance, high temperature resistance, severe cold resistance, dent resistance, halogen-free, flame retardant, and compatibility with standard connectors and connection systems. The service life can generally reach more than 25 years.   02What is a bidirectional meter?   A bidirectional meter refers to a bidirectional meter, which is a meter that can measure electricity consumption and power generation.   In a solar system, both power and electric energy have directions. From the perspective of electricity consumption, power consumption is counted as positive power or positive electric energy, and power generation is counted as negative power or negative electric energy. The meter can read the positive and reverse electric energy through the display screen and store the electric energy data. The reason for installing a bidirectional meter in a household solar system is that the electricity generated by photovoltaics cannot be consumed by all users, and the remaining electric energy needs to be transmitted to the power grid, and the meter needs to measure a number; When solar power generation cannot meet user needs, it is necessary to use the power of the power grid, which requires another number to be measured. Ordinary single meters cannot meet this requirement, so it is necessary to use smart meters with bidirectional metering functions.