In the photovoltaic power generation system, through the scientific and reasonable application of energy storage devices, the power changes caused by fluctuations during the actual operation of the photovoltaic power generation system can be effectively reduced, the power changes can be reduced, and the impact on the power grid and load can also be reduced. This ensures that the photovoltaic system can achieve a smooth transition even in the off-grid state, and effectively improves the operation quality of the power supply system. However, in the actual setting process, the energy storage unit can be set up using valve-regulated sealed lead-acid batteries. Based on the analysis of the operating characteristics of the photovoltaic power generation system itself, the operating advantages of the energy storage unit under different operating states are based on this. Establish a complete charging control system and discharge control system, and use targeted management measures to verify their effectiveness.
Composition of photovoltaic grid-connected power generation system
The photovoltaic grid-connected power generation system is mainly composed of relay protection devices, photovoltaic arrays, inverters, energy storage devices, and maximum power point tracking devices. In order to ensure that the voltage and current are at the same frequency, the most basic link in the entire photovoltaic system is the photovoltaic array, which can be used to convert solar energy into electrical energy, and then the battery cells are installed in series and parallel on the bracket according to the actual needs of voltage and current. However, the array of photovoltaic cells has a very strong nonlinear characteristic, mainly because it is affected by multiple factors such as load illumination and temperature during the power output process. The maximum power point tracking device can ensure that the battery array always maintains the maximum output power and ensures that the efficient use of photovoltaic energy can be truly realized. The energy storage device mainly regulates and controls the electrical energy in the photovoltaic system, stores sufficient electrical energy during the illumination process, and releases the stored electrical energy when needed, which can effectively regulate the power supply balance state and the output state of the power supply. The inverter is mainly for the effective connection between the photovoltaic power generation system and the power grid. Through the inverter and transformer, direct current can be converted into alternating current that can be used by people. It is also an important part of the entire power generation system. Photovoltaic power generation systems also have some very typical characteristics, that is, they are affected by external factors such as temperature and light, which will affect the output power, resulting in unstable power generation and lack of controllability. The cost of the entire photovoltaic system is very high. Therefore, maximizing the absorption and utilization of solar energy and controlling operating costs are the key issues that relevant staff need to solve. Only by effectively improving the active power of the photovoltaic power generation system and fundamentally improving the utilization rate of solar energy can the grid-connected voltage of the system be ensured to be consistent with the grid-connected voltage.
Application of energy storage technology in photovoltaic grid-connected power generation
1 Power peak load regulation
The most direct purpose of power peak regulation is to meet the concentrated and high-power electricity demand during peak hours, and to effectively control the load of the power grid to the maximum extent. The energy storage device can store the electricity generated by the photovoltaic system according to the actual operation of the power grid when the load is relatively low, and then release it during the peak period of electricity consumption, thereby ensuring the output of the peak power of the power grid and the reliability of the power supply system.
2 Load response
In the actual operation of the power system, in order to ensure the effectiveness of the power grid operation and minimize the probability of accidents, some high-power loads are usually adjusted automatically. When the load is high, different parts of the power grid usually operate alternately, so that the operation of the power grid during peak hours can meet people’s actual needs and ensure the stability of power supply. When using photovoltaic energy storage systems, power users can maximize the stability of user power supply. However, in this process, relevant staff should also focus on the connection between energy storage power stations and power grids in the load response system. It is necessary to ensure that at least one communication line can operate normally. Only in this way can high-power equipment be avoided to the greatest extent and the response requirements of the load can be truly met. The use of load response technology in photovoltaic power generation systems can reduce the probability of failures during system operation by alternating the effective selection of different power grids. The use of compliance response technology can adjust high-power loads accordingly to ensure stable operation within the critical value range. Under the premise of ensuring the quality of power supply, it can also minimize the adverse effects on the stable operation of the power grid when adjusting the power supply, ensure the safe and stable operation of the power system, and maximize the stability of power supply.
3 Smoothing out power fluctuations
The energy source of photovoltaic power generation system is solar energy, and photovoltaic power generation system cannot generate electricity at night. By using energy storage devices and relevant control strategies, the output of photovoltaic power generation system can be tracked, electric energy can be absorbed when the output is at its peak, and electric energy can be released when the output is at its lowest, thereby maintaining the smoothness of output power and making the prediction of photovoltaic power generation output more accurate. From the existing research results, it can be seen that battery energy storage system has a significant effect on smoothing the output fluctuation of photovoltaic power generation system.
4 Increase the ability to absorb solar energy
The northwest of my country is rich in solar energy resources and is a Class I region for the distribution of solar energy resources in my country. However, the northwest is a sparsely populated plateau area in my country, with low population density and small population. At the same time, the industry in the northwest is relatively backward compared with other regions. Therefore, the load pressure in the northwest is much smaller than that in North China, Central China, South China and other regions. Therefore, in the northwest region with a high photovoltaic penetration rate, due to the mismatch between power generation and load, the phenomenon of abandonment often occurs, causing huge losses and negative effects. At this time, the energy storage system is applied to auxiliary services such as peak and frequency regulation in the power system. Through the unified dispatch of the energy management system and combined with the automatic control system of the photovoltaic power station, the charging and discharging time and number of the energy storage system can be controlled, which can reduce the abandonment of light on the power generation side, increase the absorption capacity of solar energy, improve energy utilization, and bring good economic benefits.
5 Improve power supply reliability
The energy storage system can play a role in shaving peak loads and filling valleys. During peak load periods, the energy storage system can convert its stored energy into electrical energy and inject it into the power grid. During low load periods, the energy storage system can absorb excess electrical energy in the power grid and convert it into the energy form corresponding to the energy storage device for storage, balancing the power level of the power grid by shaving peak loads and filling valleys. At the same time, the energy storage system can play a backup power supply role.
6 Improve power quality
Due to the influence of factors such as weather, temperature, and component inclination, the output power of the photovoltaic power generation system will change, resulting in unstable power generation, increasing the difficulty of power generation prediction, and affecting the harmonics fed into the power grid. In addition, as the intensity of solar radiation changes, the photovoltaic power generation power will have a certain impact on the load characteristics in the power grid flow. After the photovoltaic power generation system is connected to the power grid, it will affect the direction of the power grid flow, the existing power grid dispatching, and the planned operation mode, increasing the difficulty of power grid dispatching and control. When a large number of photovoltaic power generation systems are connected to the power grid, the voltage fluctuation will be aggravated, causing the frequent operation of the voltage regulator, and the power quality of the power grid will be reduced. When the energy storage is connected to the photovoltaic power generation system, the corresponding energy conversion system controls the charging and discharging of the energy storage device, which can achieve the purpose of peak regulation of the power grid and effectively control the power generation of the photovoltaic power generation system. In addition, the access of the energy storage device can suppress the change of the power grid flow direction, increase the stability of the power grid, and thus improve the power quality of the photovoltaic power generation system after it is connected to the power grid.
7 Microgrid
For the power transmission system, microgrid connection is the main trend of future development. The use of microgrids can fundamentally improve the reliability of power supply. If the microgrid is separated from the entire power system, that is, the microgrid is in an isolated operation state, it can independently meet the power supply needs of the power load. In this case, the photovoltaic power generation system is used to form a microgrid, which can also play its own role and ensure that the power supply of the entire system is safer and more reliable.
Conclusion
In summary, in photovoltaic power generation systems, the application of energy storage technology will involve all aspects. Enterprises should also adapt to the needs of the rapid development of the times, make full use of advanced Internet technologies, properly handle the application conditions and specific influencing factors of energy storage technology, try to eliminate the impact of the external environment, and effectively improve the company’s energy storage management level. Through effective incentive mechanisms, establish a sound talent management system, strictly follow the principles of adapting measures to local conditions and overall planning, and establish a safer and more reliable photovoltaic grid-connected power generation system to provide people with more stable electricity.
