DC and AC disconnector is an important part of the installation of solar panel system, AC disconnector is mainly to separate the solar panel system from the grid, often between the inverter and the meter, DC disconnector is a device to isolate part of the circuit, when reaching the trigger conditions will be directly blocked the power supply of the solar panel.
(1) DC disconnector consists of movable contacts and a fixed contact, when the circuit power exceeds the expected value, the movable contact will automatically open to cut off the circuit, mainly through the introduction of electric arc to cut off the current, and is only applied to DC circuit.
(2) AC disconnector, is a movable contact and a solenoid ring, when the current is too large will produce a magnetic field to make the movable contact open to cut off the circuit, the use of alternating current cyclic changes in the current over the zero point to break the circuit, applicable to AC circuits.
(1) safety, DC and AC disconnectors are for the use of solar energy system safety considerations, not only and grid-connected solar energy system, off-grid solar energy system also need DC disconnectors, AC disconnectors are to prevent the occurrence of accidents can be disconnected from the grid in time, the grid contains a huge amount of electricity is the biggest difficulty in the accident.
(2) Regulations, all solar energy system installation will be equipped with DC and AC disconnectors, some countries and regions have different norms but in general there are clear installation specifications for DC and AC disconnectors for solar energy systems.
(3) Prevent power feedback, for public utilities need to be disconnected from the PV power generation system during power outages for maintenance, during power outages the power of the solar system may be fed back into the grid, causing harm to the maintenance staff, but also to facilitate the maintenance staff to check whether the PV power generation system is disconnected. Ensure the flow of electricity between the solar system and the grid.
Empty and easy to access, obvious markings outside the house, for DC and AC disconnectors main role is to facilitate the active disconnection of the various parts of the circuit connection, in the firefighters to control the PV fire need to quickly shut down the connection of the power grid, so the DC and AC disconnectors are often installed in the outdoor walls, and there must be obvious markings to facilitate the search.
DC disconnect is to block the solar panels for the inverter to deliver DC power, and the capacity of the inverter and solar panels related to the provisions of the inverter output and the building or structure between the disconnecting device circuit conductor according to the value of the inverter’s output quota to determine the size of the AC current disconnect needs to be the same specifications with the inverter, for example, the photovoltaic system’s voltage is 800 volts and current of 150A then you need to choose the 920 volts and 188 amps of DC disconnect. and 188A DC disconnector voltage reserve 15% current reserve 25% to prevent the high intensity of the sun at noon power generation caused by high malicious disconnection, but the choice of disconnectors can not be too high to short-circuit accidents can not be disconnected in a timely manner.
Yes, the replacement of the disconnector can ensure the overall safety of the solar system, but the replacement of the disconnector must ensure that there is no voltage in the circuit, the high voltage in the solar system will cause great harm, in addition to replacing the same specifications with the old, do not just modify the cause of security risks.
Photovoltaic system is a separate circuit system, the use of disconnectors can also facilitate maintenance, photovoltaic solar panels and other parts of the encounter need to replace the inspection can be temporarily opened disconnectors to ensure the safety of the entire circuit, speeding up the speed and simplicity of maintenance.
DC and AC disconnector is an important part of the solar energy system, on the face of natural disasters can effectively prevent the second electrocution danger, is the fastest means of prevention and control of rescue workers facing the electric leakage, is a strong safety guarantee, is necessary to install.
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