How to calculate the rated output voltage of solar panels

- Jan 18, 2019-

A solar panel is a device that converts solar radiation directly or indirectly into electrical energy by photoelectric effect or photochemical effect by absorbing sunlight. The main material of most solar panels is “silicon”. Solar panels are greener products that are more energy efficient and environmentally friendly. Today, I will tell you two ways to know about the rated voltage.

 

Method one:

 

(1) Rated output voltage

 

The PV inverter should be able to output a constant voltage value within the allowable fluctuation range of the specified input DC voltage. For medium and small independent light fast power stations, the general transmission radius is less than 2km. The inverter output voltage is single-phase 220V and three-phase 380V. It is no longer boosted and delivered to the user. The voltage fluctuation range is as follows.

 

1 When operating in steady state, the voltage fluctuation range does not exceed +5% of the rated value;

 

2 When there is an impact load, the voltage fluctuation range does not exceed 10% of the rated value;

 

3 In normal operation, the three-phase electrical imbalance of the inverter output does not exceed 8%;

 

4 output voltage sine wave distortion requirements are generally less than 3%:

 

5 The frequency fluctuation of the output AC voltage should be within 1%, and the output voltage frequency specified in GB/T 19064-2003 should be between 49~51Hz.

 

(2) Rated output power

 

Rated output power is the product of the rated output voltage of the inverter and the rated output current when the load power factor is 1, in kV.A,

 

(3) Overload capability

 

The overload capability is the time required for the inverter to continue to operate under the rated output power conditions. The standard is as follows:

 

1 When the input voltage and output power are rated, the stepper should be able to work continuously for more than 4 hours;

 

2 When the input voltage and output power are 125% of the rated value, it should be able to work continuously for more than 1 min;

 

3 When the input voltage and output power are 150% of the rated value, it should be able to work continuously for more than 10s.

 

(4) Rated DC input voltage and range

 

The rated DC input voltage refers to the DC voltage value of the input inverter in the photovoltaic power generation system. The input voltage of small power inverters is generally 12V, 24V, 48V, and medium and high power inverters usually have 110V, 220V, 500V and so on.

 

Since the voltage of the energy storage battery pack of the independent photovoltaic power generation system is changed, the inverter should be able to satisfy the change of the input current and voltage within a certain range without affecting the change of the output voltage. Usually, the value is 90%~120%. .

 

(5) Protection function

 

The inverter should have the following main protection functions. To ensure safe and reliable operation of photovoltaic power generation system: 1 overvoltage, undervoltage protection 2 overcurrent protection, 3 short circuit protection; 4 reverse connection protection; 5 lightning protection grounding protection.

 

Method Two:

 

(1) Inverter efficiency

 

Inverter efficiency represents its own power loss. Generally, the efficiency of the converter can be required according to the following standards. The inverter with a capacity of 1001000 kW should have an efficiency of 96% - 98% or more. The inverter with a capacity of 10 to I00 kW should have an efficiency of 90% to 93%. : For a transformer with a capacity of 1~10kW, the efficiency should be 85%~90% or more. The inverter with a capacity of 0.1~1kW should have an efficiency of 80%~85%.

 

It should be noted that the efficiency referred to herein refers to the efficiency achieved by the reverser under full load conditions, and the good quality retrospective is also more efficient under light load.

 

(2) Rated output voltage

 

The PV inverter should be able to output a constant voltage value within the allowable fluctuation range of the specified input DC voltage. For medium and small independent light fast power stations, the general transmission power is less than 2km, and the output voltage of the inverter is single-phase 220V and three-phase 380V. It is no longer open to the user, and the voltage fluctuation range is as follows.

 

1 When operating in steady state, the passive range of voltage does not exceed +5% of the rated value; 2 in the case of impact load, the voltage fluctuation range does not exceed 10% of the rated value; 3 in normal operation, the output of the inverter Three-phase electromedical unbalance does not exceed 8%, 4 output voltage sine wave distortion requirements are generally small dry 3%: 5 output AC voltage frequency fluctuation should be within 1%, GB/T 10064-2003 specified output voltage frequency Should be between 49~51Hz,

 

(3) Rated output power

 

Rated output power is the product of the rated output voltage of the inverter and the rated output current when the load power factor is 1, in kV.A,

 

(4) Overload capability

 

The overload capability is the time required for the inverter to work continuously under the rated output power. The standard is as follows: 1. when the input voltage and output power are rated, the converter should be able to work continuously for more than 4 hours, 2. input voltage when the output power is 125% of the rated value, it should be able to work continuously for more than 1 min. When the input voltage and output power are 150% of the rated value, it should be able to work continuously for more than 10 s.

 

(5) Set the DC input voltage and range

 

The rated DC input voltage refers to the DC voltage value of the input channel transformer in the photovoltaic power generation system. Low-power inverter input voltage is generally 12V, 24V, 48V, medium and high-power inverters usually have 110V, 220V, 500V and so on.

 

Since the voltage of the first battery pack of the independent photovoltaic power generation system is changed, the inverter should be able to meet the change of the input current and voltage within a certain range without affecting the change of the output voltage. Usually, the value is 90%~ 120%.

 

(6) Protection function

 

The speed changer should have the following main protection functions. To ensure safe and reliable operation of photovoltaic power generation system: 1 overvoltage, undervoltage protection 4 overcurrent protection, 3 short circuit protection; 1 reverse connection protection; 5 lightning protection grounding protection.

 

More info about solar panels, two methods of rated voltage, which one do you prefer?