In solar photovoltaic power generation systems, the electrical energy generated by photovoltaic panels is usually direct current with a relatively low voltage level, which cannot directly meet the requirements of the power grid or the needs of long-distance transmission. At this time, transformers work in conjunction with inverters to play an important role in power conversion. The inverter first converts the direct current generated by the photovoltaic panels into alternating current, and then the transformer steps up the voltage. For example, in some large centralized photovoltaic power plants, the voltage output by the photovoltaic array may be only a few hundred volts. Through step-up transformers, the voltage can be increased to 10 kV, 35 kV or even higher. This can not only effectively reduce the power loss on the transmission lines but also improve the efficiency and distance of power transmission, enabling solar power generation to be integrated into the power grid on a large scale and realizing the effective integration and utilization of power resources.
Wind power generation systems also rely on transformers to achieve efficient power conversion. The voltage and frequency of the electrical energy generated by wind turbines fluctuate with changes in wind speed. First, the transformer steps up the voltage output by the wind turbine, and then, combined with power electronic converters, the frequency and voltage of the electrical energy are accurately adjusted to meet the grid connection standards. For example, in large offshore wind turbine generators, the electrical energy generated is stepped up from the relatively low generation voltage to about 35 kV by the box-type transformer, and then further stepped up to 220 kV or even higher by the main transformer in the offshore booster station, so that the electrical energy can be stably transmitted to the onshore power grid, ensuring the efficient development and utilization of wind energy resources.
The grid connection of new energy power generation is a key link in realizing its power value, and transformers play a vital role in it. Whether it is a solar power station or a wind farm, specific
transformers are required to adjust their own electrical energy parameters to be consistent with those of the power grid when connecting to the grid.
For distributed photovoltaic power generation systems, small
step-up transformers are usually used to step up the low-voltage alternating current generated by photovoltaic panels to 10 kV or 35 kV before connecting to the local distribution grid. This grid connection method can make full use of the existing structure of the distribution grid, realize the local consumption of solar power, and reduce the loss and cost in the power transmission process. For large-scale centralized new energy power generation bases, large-capacity and high-voltage step-up transformers are needed to step up the electrical energy to ultra-high voltage or ultra-high-voltage direct current levels for long-distance and large-capacity transmission of electrical energy to load centers or the main power grid. For example, in large wind power bases in northwest China, a series of step-up transformers are used to step up the wind power to 750 kV or even higher voltage levels and then transmit it to areas with high electricity demand such as the eastern coastal areas, effectively solving the imbalance between energy resources and energy demand in different regions and promoting the optimal allocation of energy resources across the country.
New energy power generation is characterized by intermittency and volatility. The introduction of energy storage systems can effectively alleviate this problem, and transformers play a bridging and regulating role in the energy interaction between energy storage systems and the power grid.
When the energy storage system is charging, the transformer can step down the electrical energy of the grid to a voltage level suitable for energy storage devices to charge the energy storage batteries or other energy storage media. For example, in some lithium-ion battery energy storage systems, the high-voltage electricity of the grid is converted into low-voltage direct current by a step-down transformer to meet the charging requirements of the battery pack. When new energy generation is insufficient or during peak electricity consumption periods, the energy storage system discharges, and the transformer steps up the electrical energy output by the energy storage devices and converts it into alternating current that meets the requirements of the power grid and feeds it back to the grid, playing a role in peak shaving, valley filling, and stabilizing the voltage and frequency of the power grid. In addition, in some integrated energy systems that include multiple energy storage technologies and new energy power generation forms, transformers can flexibly convert and distribute electrical energy according to the voltage levels, power capacities and other parameters of different energy storage devices and power generation units, realizing the efficient and coordinated operation of the entire system.
With the continuous expansion of the new energy industry, a series of new challenges have been posed to transformer technology and capacity.
In terms of technology, the complexity and variability of new energy power generation require transformers to have a higher level of intelligence. For example, they should be able to monitor the voltage, frequency, phase and other parameters of the power grid in real time and automatically adjust their own operating states to adapt to the intermittency and volatility of new energy power generation and improve the stability and power quality of the power grid. Meanwhile, in order to reduce the energy consumption of transformers themselves, the research and development of new energy-saving transformer technologies are urgently needed, such as adopting new magnetic materials and optimizing the winding structure of transformers to improve the energy efficiency ratio of transformers.
In terms of capacity, with the continuous expansion of the scale of new energy power generation, especially the construction of large offshore wind farms and centralized photovoltaic power plants, larger-capacity transformers are needed to meet the requirements of voltage stepping up and power transmission. This requires transformer manufacturing enterprises to continuously improve their manufacturing processes and technological levels and develop transformer products with higher voltage levels and larger capacities. For example, developing large-capacity converter transformers suitable for ultra-high-voltage direct current transmission to meet the requirements of long-distance and large-capacity new energy power transmission.
To cope with these challenges, the transformer industry should strengthen in-depth cooperation and collaborative innovation with the new energy industry. On the one hand, increase investment in transformer technology research and development, establish a joint research and development mechanism among industry, academia and research institutions, and jointly overcome technical difficulties. On the other hand, according to the characteristics and requirements of new energy power systems, formulate unified transformer technology standards and norms to promote the standardization and serialization development of transformer products, improve the universality and compatibility of products, and provide more reliable transformer equipment support for the stable and efficient operation of new energy power systems.
In conclusion, transformers play a crucial role in new energy power systems, running through all aspects of new energy power generation, grid connection, energy storage systems and the entire power transmission and distribution. Facing the new challenges brought by the development of the new energy industry, continuously promoting technological innovation and progress of transformers and improving their capacity and performance are the keys to realizing the large-scale and efficient utilization of new energy power and building a sustainable energy system.
