Design and introduction of 10kW household energy storage system in Pakistan

(1) Customer's electricity demand and lighting situation

The customer is a villa user in Pakistan. The main electrical equipment is air conditioning, refrigerator, TV, kitchen equipment, lighting, etc. The total load power is 6kW, and the daily electricity consumption is about 30 degrees, including about 20 degrees during the day and 10 degrees at night. The installation site of the project has good lighting conditions, the annual effective utilization hours are 1200 hours, and the average daily peak sunshine is 4.2 hours, which is more suitable for photovoltaic installation.

(2) Equipment type selection

 Household energy storage has two schemes: DC coupling and AC coupling. According to the characteristics of users, the proportion of photovoltaic self-use is large, and the system is newly installed, so the integrated system with DC coupling and battery energy storage is selected. According to the load power of the user, the inverter is designed with one control inverter integrated machine, and the output power is three-phase 10kW.

The component power should be confirmed based on the user's daily electricity consumption. The average daily electricity consumption of users is 30 degrees per day, the local peak sunshine is 4.2 hours, and the efficiency of the off-grid system is about 0.85. Therefore, the design adopts 18540W single crystal components with a capacity of 9.72kW, which can generate 40 degrees of electricity per day and give users about 32 degrees without loss, which can basically meet the needs of customers. The inverter has two sets of strings, supporting up to 13kW component access, and has 30% expansion space. The battery capacity is determined according to the electricity consumption when the user has no light. The photovoltaic power generation can be used directly to the load without power storage during the day. The user consumes 10 degrees every night, and the design uses 2.56 degrees of lithium batteries, and the total power is 10.24 degrees.

(3) Electrical scheme design

The components are 18 pieces, which are connected to the inverter, and the battery pack, load and power grid are connected to the corresponding circuit switch respectively.

(4) Electrical function debugging

In order to adapt to different occasions, and the off-grid energy storage inverter has been designed with a lot of functions, before the application, to set up according to the actual requirements of the user. Choose the grid connection mode or off-grid mode first, if it is the grid connection mode, then choose the battery charging mode, is photovoltaic first or city power first, or city power is only bypass, not charging; Internet access mode can choose the photovoltaic power generation spontaneous surplus storage and photovoltaic power generation spontaneous surplus online; the peak and valley price difference is large.