2021 is coming to an end, this year, the photovoltaic industry in the whole county to advance, in the double control of energy consumption charge, as of October this year, the domestic photovoltaic installed 29.3GW, year-on-year growth of 26%.
Pv is in the stage of high quality development, and the quality of power station is the top priority. Xiao Gu summarized the atypical questions sent by everyone in the background in 2021 and their solutions, hoping to help you.
Device Parameter Class
1. What does access to different MPPT mean? What are the conditions for access?
A: Cluster inverters usually have more than 2 channels of MPPT, and each MPPT usually has 1 or more clusters. Each MPPT is independent and has the ability to track and control the changes of output voltage and current. The biggest advantage is that the array always maintains the working state of maximum output, which is referred to as maximum power point tracking. Access different MPPT in case of multiple orientations, shadows, inconsistent string lengths, and inconsistent angles.
2. There is error in two sets of MPPT and two open circuit voltages. Is MPPT tracking high voltage or low voltage?
A: In the case of parallel voltage mismatch, the MPPT maximum power tracking points are different, and the low voltage will pull down the high voltage, affecting the overall output power.
3. How much is the rated voltage of the inverter?
A: Theoretically close to the maximum voltage of MPPT.
4. Does the maximum DC working current 25/25ADV marked on the inverter mean that each MPPT can have 25A working current? Can we get 50A in total?
A: The maximum input current of each MPPT is 25A. If each MPPT has two strings, the maximum input current of each string is 12.5a. If there is a string, the current of the string is less than 25A.
5, different power components must not be connected in series? Or that the power gap is not large under the situation can be series? How much power difference can series?
A: We do not recommend this, because the power of the component is different, the operating current is different, in series, the whole string will follow the smallest component current. The greater the difference in power, the greater the difference in current.
6. What is the difference between the maximum short-circuit current and the maximum input current?
Answer: the maximum allowable current measured by positive and negative electrode short-circuit is the maximum short-circuit current, and the maximum working current refers to the maximum output current value allowed to work in series.
7. Can the dc input of the inverter be calculated according to the rated voltage of the component?
Answer: It can be calculated in accordance with the provisions of GB50797, the design specification for photovoltaic power stations. It needs to be calculated according to the open-circuit voltage of components (the maximum number of connected components in each string) and the operating voltage of components (the MPPT efficiency of the inverter). Specific can be decided according to the actual situation.
System Design
1. Do you need to change the inverter if you want to change the power station to self-use surplus electricity for Internet access?
Answer: More than electricity or full Internet access is mainly to see and dot is in the front or back end of the load, and the inverter has no relationship, do not need to change the inverter. If you have applied for full Internet access before, you need to apply for surplus Internet access from the power supply company again.
2. Can the south slope and the north slope share an inverter?
A: One inverter can be shared. The premise is that components of different slopes need to be put into different MPPT, and the number and orientation of each channel components under the same MPPT should be kept consistent.
3, 30kW inverter can be matched with 35kW components?
Answer: The maximum input power of 30kW inverter GW30K-MT is 39kW, which can be connected to 35kW components. The specific amount of overallocation needs to be designed according to the actual situation of the project.
4, each group of voltage is not over, power will be over? For example, the 15kW inverter uses three MPPT channels, each channel of 5kW.
A: In general, the design of components will exceed the power rating of the inverter, and the voltage will not exceed the maximum system voltage of the inverter. 15KW inverter, if it is 3-channel MPPT, can be designed as 2 series, or 3 series, which can be designed to exceed the power rating of 15KW.
5. How much circuit breaker does 50kW inverter use?
A: The maximum output current of 50kW inverter is 80A, and the circuit breaker can be designed as 80A * 1.25 times of value, and 100A is selected.
6, 20kW inverter 380V with how much air switch?
Answer: when the overload of 20kW system is 1.1 times, the maximum ac output power is 22kW. The corresponding current is 22/1.732 * 0.4 = 31.8A. The circuit breaker is usually selected according to the rated current 1.25 times. That is, the rated current of about 40A can be switched on.
7. Can the 25kW SMT inverter match the 50.02Hz grid frequency?
A: Yes. The inverter has a certain ability to tolerate abnormal system frequency, and can operate in accordance with the provisions within the frequency range of the power grid. The frequency setting range is between 48.5HZ-50.5Hz.
8. Can 1kW182 components really generate 1500 KWH electricity in a year?
A: It can be done. It can be divided into two situations: 1. In resource areas with annual equivalent utilization hours more than 1500 hours; 2. In resource areas with annual equivalent utilization hours less than 1500 hours, tracking supports or other auxiliary technologies can be used.
9. How much lithium battery can the 10kW ET energy storage inverter connect? Does it come with a lithium battery?
Answer: The battery of 10kW ET energy storage inverter needs to be selected. The maximum capacity of Lynx S equipped with Goodway battery is 20kWh.
10. Do you have any suggestions on lightning protection for the whole system?
Answer: The lightning protection of the system includes direct lightning and inductive lightning. Direct lightning can form grounding device through metal frame of photovoltaic module, bracket and metal object of original building structure. Inductive lightning can be connected by equipotential, magnetic shielding and installation of SPD.
11. If the distributed photovoltaic power station is built together with the 4G and 5G transmission base stations of China Mobile (there is no reflection), will the power generation be affected? Is it going to get worse?
A: Because of the special nature of base stations, they need to be built on high ground. Photovoltaic power generation is one of many complementary ways to power base station equipment. There are many factors affecting the power generation of photovoltaic power station, including its own design: component orientation, Angle, line loss, spacing, etc., and external aspects: shadow, etc. Base station is a load for photovoltaic power station, which does not affect the power generation. Even if the load is not done, it does not affect the power generation.
The photovoltaic power station is not the highest point, but the lightning rod at the top of the base station is the highest point, and the lightning rod will lead the lightning load underground. The photovoltaic power station together with the base station will not actively initiate lightning, but conduct lightning protection through grounding, SPD and other ways.
12. How much influence does the Angle of component and horizontal plane have on power generation efficiency?
Answer: Different latitude and longitude regions have different effects on power generation efficiency. Take Jinan as an example (due south orientation, under the same conditions, 30 degrees is the best inclination Angle, without loss of power generation). For example, if the component inclination Angle is 50 degrees, the power generation loss is 4%; When the inclination Angle is 40 degrees, the power generation loss is 0.9%. When the inclination Angle is 20 degrees, the power generation loss is 1.3%. The dip Angle is 10 degrees and the power generation loss is 4.6%.
