Huawei's unique energy storage array

According to a recent report released by the International Energy Agency, in order to achieve the climate goals of all countries and ensure energy security, the world will need to add or replace 80 million kilometers of power grids by 2040 and make major changes in the way power grids are operated and regulated.

It can be seen that as the scale of global renewable energy grid connection becomes larger and larger, the improvement of grid support capacity becomes more and more important. However, in addition to replacing the grid, you can also think about the solution from another angle, and microgrid is one of them. At present, the application scope of microgrid is mainly in smaller areas such as parks and islands. If you imagine that you want to build a new city with 28,000 square kilometers in the endless desert, with one million people coming and going and living, without access to the large grid, and only relying on photovoltaic power generation for power supply, then what do you imagine its power supply method and power supply facilities?

The first thing people think of is: How can we have stable power supply without grid support?

But now there really is such a scenario, and there really is such a company that has solved this problem through unprecedented technical solutions.

This project is Saudi Arabia's "Red Sea New City" project. Located in western Saudi Arabia, the project is a key project in Saudi Arabia's "Vision 2030". The biggest highlight of the city construction is that all electricity supply comes from new energy.

As the world's first GW-level independent microgrid project powered by 100% renewable energy, the Saudi Red Sea 400MW photovoltaic and 1.3GWh microgrid energy storage systems all use Huawei's intelligent photovoltaic storage solution.

The latest issue of "Bits and Watts", a high-tech video column launched by Huawei Digital Energy, introduced this GWh-level "new energy microgrid" that has sprung up in the desert, and detailed the unique technical tool for the successful construction of the microgrid - virtual synchronous machine technology.

Brand new column, brand new output

BIT and WATT were "two-dimensionalized" in the show, appearing as two mechanical figures, representing digital technology and energy technology respectively.

In the field of digital technology, Huawei is a leader that is "far ahead". After entering the energy business, it has achieved outstanding results in multiple projects and fields with its profound "BIT+WATT" technical advantages. Recently, Huawei Digital Energy launched the "Bits and Watts" video column. Scientists in Huawei's ICT, power electronics and other fields, with their understanding and insight into technology, brought professional and in-depth scientific views to the program to help the public understand the real uses of digital energy black technology.

Not only that, Huawei has rich digital energy practices. In "Bits and Watts", Huawei scientists openly share the pitfalls Huawei has encountered on the "front line" and the direct experience it has accumulated, in order to help more companies accurately grasp the changes and trends in the energy and digital fields, and allow practitioners and ordinary audiences to find their own connection with change from more specific cases and realities.

Of course, we can’t just talk about the “pitfalls” we have encountered, we must also “Versailles” from time to time. In this episode, Huawei invited senior expert Dr. She Hongwu to focus on introducing the technical weapon used in the Saudi Red Sea project: virtual synchronous machine technology.

The new energy model behind the grand project

Dr. She Hongwu first introduced the basic meaning of "100% photovoltaic energy storage" in Honghai New City: 100% use of photovoltaic power generation during the day to charge the energy storage equipment at the same time, and completely use the discharge of the energy storage system to provide power at night.

Because there is no access to Saudi Arabia's large power grid, it is equivalent to building a very complete power grid from 0 to 1, and its energy storage scale reaches 1.3GWh. This is not only a first-of-its-kind project in Saudi Arabia, but also a first in the world. To a certain extent, it also represents a new generation-storage-use model for future human society.

Since it covers multiple cross-domain technologies, the corresponding standards and key technologies are still blank internationally. Huawei has relied on its long-term and large-scale R&D investment to carry out special efforts in technologies such as grid-based energy storage and achieved fruitful results, which have been fully applied in this project.

In addition to the extremely pioneering significance of the technology, Saudi Arabia's topography also adds difficulties to technology research and development. The highest temperature in the Red Sea region of the Middle East in summer exceeds 50°C, and the project site is only 100 meters away from the sea. In an environment of high temperature, high humidity, high salt fog, and wind and sand, how to ensure the available capacity, operating life, transportation, construction, operation and maintenance of the energy storage system is also one of the challenges. Huawei's intelligent string energy storage equipment has achieved IP55 protection capability and C5 level corrosion resistance, and the distributed temperature control design can ensure stable operation in high temperature scenarios.

Problem: The big power grid disappears

The Red Sea has plenty of sunshine, so there is no pressure on photovoltaic power generation. However, how to ensure a stable supply of electricity is a huge challenge faced by project participants.

The voltage and frequency are the most closely related to residents in the daily power supply system. If the voltage is unstable and the range of variation is too large, it will not only affect the operation of the power grid equipment, but also seriously damage household appliances and lines. In more serious cases, it will cause fires and threaten personal safety. Unstable frequency will also damage electrical equipment and even cause power outages, affecting the stability of the power system.

It is not particularly difficult for traditional power grids to achieve voltage and frequency stability, because the power grid system uses synchronous generators to generate electricity, controls the frequency of the grid through speed regulators, and controls the voltage through exciters, thereby providing users with stable power supply.

At present, grid-following energy storage systems have been adopted in many power generation projects and power supply systems, but these energy storage systems only play an auxiliary role in the stability of the power grid, because the stable operation of the large power grid is mainly supported by synchronous generators. The energy storage system is based on energy storage inverters to realize the charging and discharging between energy storage batteries and the power grid. Each energy storage inverter follows the frequency and voltage of the large power grid. It only needs to control its own output current to complete the auxiliary function of improving the stability of the power grid.

However, in the Red Sea project, the energy storage system does not have a fixed frequency and voltage to follow, and the large power grid is completely drained. The diesel generators are only used for emergency backup, which means that the energy storage system becomes the bearer of the grid stability task and must be able to maintain stable operation of the grid under various steady-state and transient fault conditions.

Stable! Voltage and frequency!

Huawei was born for research and development. Faced with this extremely difficult problem, Huawei pioneered the development of Virtual Synchronous Generator (VSG) technology, which allows each power storage converter (PCS) to simulate the operation mode of a traditional synchronous generator, using a virtual speed regulator to control the frequency of the power grid and a virtual exciter to control the voltage of the power grid.

More than a thousand! Not far from the coast of the Red Sea, the moon-white energy storage system stands upright, forming a magnificent square array. It is the energy storage converters in it that support the stable operation of the Red Sea microgrid.

While building a stable power grid, it can also achieve off-grid continuous fault ride-through under 100% new energy microgrid and support GW-level black start of the entire network, enabling minute-level power recovery and effectively avoiding power outage losses. At the same time, in view of the frequent sudden demand for on-site transformers and the impact current generated by the start and stop of impact loads such as motors, which may cause the risk of power grid collapse, through the advanced grid-forming energy storage algorithm, without over-allocation of PCS, it supports the switching of 100% energy storage rated capacity transformers to ensure stable power supply for the entire network.

Of course, this is not just a theoretical effect, but an effect that has been proven in the Red Sea project. In order to achieve no deviation in practice, Huawei built the world's largest 8.8 MW PV-storage off-grid laboratory, which was fully verified before product delivery through three phases of rigorous testing: full digital simulation, semi-physical simulation, and 8.8 MW prototype laboratory. At the same time, the expert team was stationed at the Saudi Red Sea site to solve various difficult and complicated problems encountered on site as soon as possible.

At the SNEC Energy Storage Exhibition on November 3, Huawei participated in the world's largest microgrid photovoltaic storage project in the Saudi Red Sea with a capacity of 1.3GWh, which won the "Energy Storage Technology Excellence Award". This award also included recognition for the groundbreaking virtual synchronous generator technology.