Views: 0 Author: Site Editor Publish Time: 2024-06-29 Origin: Site
Unlike large-scale energy storage peak-shaving and frequency-regulating power stations, the main purpose of industrial and commercial energy storage systems is to use the peak-valley price difference of the power grid to achieve investment returns. The main load is to meet the power demand of industry and commerce itself, maximize photovoltaic power generation for self-use, or arbitrage through peak-valley price difference. The system is mainly composed of photovoltaic modules, photovoltaic storage integrated machine, battery pack, load, etc. When there is light, the photovoltaic module array converts solar energy into electrical energy, supplies power to the load through the photovoltaic storage integrated machine, and can also charge the battery pack at the same time; when there is no light, the battery pack supplies power to the load through the integrated machine. The main application scenarios are office buildings, shopping malls, industrial and commercial parks, island microgrids, villages, and large households.
01 Photovoltaic storage integrated machine
Its function is to regulate and control the power generated by solar cell modules and convert it into sinusoidal AC power.
02 Battery pack
Its main task is to store energy, ensure energy balance and energy supply stability, and ensure load power demand at night or on rainy days.
03 AC distribution cabinet
It mainly shuts down and protects the AC output side.
04 Smart Energy Manager SEM
It realizes communication interconnection with the integrated photovoltaic storage machine, smart meter, and battery. It has dry contacts to control the oil machine externally. It can be connected to the customer's emergency stop, fire protection, security and other systems to achieve complex system linkage requirements.
05 Photovoltaic module
The main part of the solar power supply system, its function is to convert the solar radiation energy into DC power.
WIT Industrial and Commercial Photovoltaic Storage Application Scenario Solution System Diagram
WIT Off-island Microgrid Application Scenario Solution System Diagram
Design principles of industrial and commercial energy storage system
01. Load type and power determine the selection of integrated photovoltaic storage machine
Loads are generally divided into inductive loads and resistive loads. Central air conditioners, compressors, cranes and other loads with motors are inductive loads. The starting power of the motor is 3-5 times the rated power. In the early design stage, when the equipment is off-grid, the starting power of these loads should generally be taken into account. The output power of the inverter should be greater than the power of the load. For monitoring stations, communication stations and other strict occasions, the output power is the sum of all load powers. However, in this energy storage system, the WIT series (currently 50K/63K/75K/100K, 4 power ranges) has a strong load capacity, supports motor loads and 100% three-phase unbalanced loads, and can be overloaded by 110% for a long time.
02. Confirm the power of the component based on the daily power consumption
The design principle of the component is to meet the daily power consumption of the load under average weather conditions, that is, the annual power generation of the solar cell component must be equal to the annual power consumption of the load. Because the weather conditions are lower and higher than the average, the design of the solar cell component basically meets the needs of the worst season for sunlight, that is, the battery can be fully charged every day in the worst season for sunlight. The power generation of the component cannot be completely converted into electricity consumption. The efficiency of the controller, the loss of the machine and the loss of the battery pack must also be considered. The battery pack will also have a loss of 10-15% during the charging and discharging process. The available power of the energy storage system = total power of the component * average hours of solar power generation * controller efficiency * battery pack efficiency.
03. Design capacity of storage battery
The task of the battery pack is to ensure the normal power consumption of the system load when the solar radiation is insufficient. The capacity of the battery pack can be designed according to the actual situation. Three points should be paid attention to during design: the voltage of the battery pack should reach the voltage of the photovoltaic storage system (the operating voltage range of the WIT series battery is 600-1000V (under 3P3W conditions) / 680-1000V (under 3P4W conditions)); the amount of electricity stored in the battery pack should meet the user's requirements (energy time shifting, peak-valley arbitrage, etc.); when off-grid operation is required, consider the backup power situation on rainy days.
04. EMS solution
Like large-scale energy storage systems, industrial and commercial energy storage systems also include energy management systems (EMS). Growatt's EMS solution is SEM (Smart Energy Manager), which uses lithium batteries as energy storage devices. Through local and remote EMS management systems, it completes the balance and optimization of power supply and power demand between the power grid, batteries, integrated machines, and loads. It can also use dry contacts to easily access other types of equipment, bringing application value in peak and valley power consumption and power safety. The EMS of industrial and commercial energy storage systems is also different from large energy storage power stations. Usually, there is no need to consider the needs of grid dispatching. It mainly provides power for local areas and only needs to have energy management and automatic switching within the local area network.
Summary
"Photovoltaic + energy storage" industrial and commercial energy storage is currently the most reliable and most promising application, and it is also the most likely distributed photovoltaic solution to be applied on a large scale. In places with high electricity prices and large peak and valley price differences, reasonable design can achieve high investment returns. (Growatt)
