China Solar Circuit Breaker PV CIRCUIT BREAKER MRL7-63 What is a photovoltaic circuit breaker? How to select photovoltaic switch? What is a photovoltaic circuit breaker? Photovoltaic circuit breaker can also be called photovoltaic switch. The reliability and stability of photovoltaic DC switch is not only related to the safe and reliable operation of photovoltaic distribution system, but also related to the stable power generation and income of photovoltaic industry. Main problems of photovoltaic DC switch 1. Contact high impedance causes overheating or even fire; 2. The switch cannot be turned off normally, and the switch handle remains in the «off» state; 3. Incomplete cut-off, causing sparks; 4. Because the allowable working current is too small, it is easy to cause overheating and damage or even shape deformation of the switch arc extinguishing chamber. How to select photovoltaic DC switch? 1. Determine the system voltage The maximum allowable voltage of the selected DC switch shall meet the voltage requirements of the photovoltaic system. Common are 600V and 1000V. Generally, the maximum system voltage connected to single-phase inverter is 600V, and the maximum system voltage of three-phase series or power station inverter is 1000V. 2. Determine the number of independent battery strings If the built-in DC switch is integrated in the inverter, it is related to the number of independent MPPT of the inverter. Common inverters are single channel MPPT and dual channel MPPT. There are also a few grid connected inverters with three channel MPPT on the market. Generally, the inverter with power level of 1kw-3kw is designed as single channel MPPT; 3kw-30kw are two-way MPPT, and a few companies also have three-way MPPT inverters: large inverters above 100kW are generally input into one-way MPPT after confluence through combiner box. The number of independent mppts of the inverter determines the number of independent pass sections of the selected built-in DC switch. If it is an external DC switch, it may be related to the designed system networking. You can choose an external DC switch with multiple strings of battery boards on and off or an external DC switch with only one string of battery boards on and off. 3. Determine the voltage and current of the battery string If you have a better understanding of the structure of the photovoltaic inverter, especially when the inverter manufacturer selects the built-in DC switch, in order to effectively save the overall cost of the inverter, you can select it by studying the DC voltage and current curve in and out of the inverter, so as to ensure that the selected DC switch curve envelops the DC switch and current curve input by the inverter under various weather environments and temperatures. 4. Analyze the use environment and installation mode The working temperature, protection and fire rating are determined according to the environment. Generally, the DC switch with good quality can work stably at — 40 掳 to 60 掳. The protection grade of common external DC switch is IP65. After the installation of built-in DC switch, the whole machine can pass IP65. The fire rating is generally shell or body material UL94V-0 and handle UL94V-2. Installation methods include panel installation, base installation, single hole installation, etc. 5. Determine the specific model If the above 1-4 conditions are met, the specific model needs to be selected from the preferred brands. Generally, the specifications of specific models are segmented by current, and it is difficult to find a fully matched DC switch. Generally, a certain margin is reserved to select a DC switch higher than the specifications calculated theoretically. Common are 16a, 25a and 32A. MEANRAY Electric (MRL7 Series) have 40a, 50a, 63a, 600V or 1000V rated voltage levels. SPECITICATIONO ItemDC MCB CodeMRL7-63 Pole1P2P3P4P Voltage250V DC550V DC800V DC1200V DC Current1A,3A,6A,10A,16A,20A,32A,40,50A,63A StandardIEC/EN 60947-2, VC8036, SANS556-1 Breaking Capacity6KA,10KA Characteristic CurveB,C,D Working Temperature"-5掳«to +40掳 Protection DegreeIP20 Electrical lifeMore than 8000times Mechanical lifeMore than 2000times Dimension(W)X(H)X(D)18X80X7136X80X7154X80X7172X80X71 Installation35MM DIN RAIL AccessoryYES Installation Altitude鈮?000M WORKSHOPChina Solar Circuit Breaker website: