With the rise of strategic level, the development of global energy Internet ushered in significant opportunities. Building a global energy Internet can transform the traditional way of using energy and meet global electricity demand in a clean and green way.

To build a global energy Internet, we need to first land on technology and equipment. Nanrui Group Co., Ltd. vigorously strengthens the global energy Internet frontier technology research and major equipment development, fully supports the application of new technologies and new project pilot, has achieved a series of breakthrough results.

Building a strong and reliable UHV power grid

Uhv plays an important role in the global energy Internet strategy. The goal of State Grid Corporation is to establish "strong communication and direct" UHV power grid, and the major technology and equipment supporting its development is the top priority in the global energy Internet construction.

Recently, Purui Engineering Co., LTD., a subsidiary of Nanrui Group, formed a consortium with Nanrui Jibao Electric Co., LTD., and successfully won the bid for all converter valve equipment of Shanghai Miao-Linyi UHVDC project. The project is the world's first 6250A UHVDC power transmission project, increasing the transmission capacity from 8 million kilowatts to 10 million kilowatts for the first time.

As the core equipment of UHV DC power transmission, UHV converter valve is the core unit of AC-DC power conversion. Multiple sets of converter valves can be triggered according to the program to realize the control and regulation of converter voltage, current and power. Valve involves power electronics, power system, transmission and distribution engineering, automatic control and other more than ten professional, the technical difficulty is huge.

At present, Nanrui Group has signed a framework agreement on technology transfer with the State Grid Smart Grid Research Institute, established a whole-process cooperation mechanism for technology research and development, project implementation, and market development, and established a good cooperative relationship in the development and engineering application of converter valves. Based on this, Puri Engineering is undertaking more and more practical engineering applications. Nanrui Jibao Electric Co., LTD., through independent research and development, has conquered the key technologies of UHV converter valve, and gradually carried out practical engineering application.

Uhv converter valve is a major equipment for UHV direct current transmission. The world's first 1100 kV controllable shunt reactor is a representative of UHV AC major equipment developed by Nanrui. Controllable shunt reactor is a new type of flexible AC transmission system technology, which can flexibly adjust its reactive power output capacity according to the operation mode of the system. It is one of the important equipment to ensure the safe, efficient and economic operation of UHV power grid. At present, this equipment has passed the Chinese Society of Electrical Engineering product technical identification, which indicates that China has mastered the core technology completely. Recently, Nanrui Group is carrying out the world's first 1100 kV controllable shunt reactor equipment calibration, debugging and other post-stage work, to prepare for the equipment to be put into engineering application.

Make smart grid more secure and stable

On February 2, the three scientific and technological research teams of power grid stability, dispatching and lightning strike warning of Nanrui Group passed the evaluation of the first batch of scientific and technological research teams of State Grid Corporation, and the grades were excellent, good and excellent respectively. The stable team ranked first in all 15 teams.

With the rapid development of UHV AC-DC power grid and large-scale development of clean energy, the operation characteristics of power grid have undergone profound changes. Ac and DC, transmission and receiving end interact with each other, and the continuous application of distributed energy, electric vehicles and other power electronic equipment make the power grid system more complex, posing new challenges to the security and stability of power grid.

Based on the application of the original technology and equipment, the company will build a batch of phase regulating units to solve the reactive power and voltage problems of the power grid. "The phase-modulated unit is actually a generator, but it does not produce active power, only reactive power. The construction of the camera is one thing, but the operational control of the camera is quite another. These units will be included in the control scope of the safety and stability control system, and we will carry out in-depth research and application." Researcher Dr. Li Wei said.

At present, the main means of power grid security and stability control technology is to maintain the stability of the power grid through scientific arrangement of the operation mode of the dispatching system, cutting machine and cutting load, which is the prevention control and emergency control of the power grid. In the future, in the case of extreme emergencies in the power grid, such as war and snow disaster, the cooperation of the system and the device can make the power grid quickly restore power supply. At present, Nanrui Group has planned the layout in this field, and the power grid will fully realize the self-healing function.

Surrounding the smart grid protection and control operation, south group success last year approved construction of state key laboratory, the relay protection, security and stability, intelligent dispatching and substation automation in areas such as research, to solve the large-scale ac/dc hybrid, new energy access and given new environment, such as power grid fault fast processing, security and stability of coordinate control and other technical problems, To provide three lines of defense for the safe and stable operation of the power grid.

No matter day or night, in the State Key Laboratory of Smart Grid Protection and Operation Control, the pace of scientific and technological breakthroughs has never stopped. The products developed from here are continuously moving towards engineering applications.

Increase clean energy penetration

Recently, Nanrui light Volt R & D team is preparing for the virtual synchronous machine type test, after the completion of the demonstration application. By changing a series of core algorithms, the equipment virtual the traditional inverter into a generator set, so that the new energy power plant has the function of participating in the power grid frequency modulation.

After 10 years of virtual synchronization technology development, there have been a variety of different schools of technology, but most of them are in the stage of laboratory research. The self-synchronous virtual synchronous machine technology developed by Nanrui Group overcomes the shortcomings of various domestic and foreign technical schemes in connection with the grid, and successfully applied for the 863 project in this direction on behalf of the company. At present, basic theoretical research and core equipment development have been completed.

A large number of clean energy is connected, and its volatility affects the security and stability of power grid. The virtual synchronous machine has the function of frequency modulation, which improves the friendliness of wind power and photovoltaic power generation.

Virtual synchronous machine technology has a broad application prospect, and can achieve frequency modulation in a short time on the basis of current source access of new energy. Through the gradual demonstration, the new energy primary frequency and pressure control, secondary frequency and pressure control, system damping control technology. In the medium and long term application, this technology can be gradually applied to distributed new energy access control, and in the long term, it can be applied to power electronic interface load equipment, such as electric vehicle charge and discharge control.

At present, Nanrui Group has developed a series of products and complete solutions including photovoltaic inverters, wind power converters, energy storage converters and self-synchronous voltage inverters with virtual synchronous machine characteristics. The power levels cover various application scenarios such as large-scale grid-connected and distributed photovoltaic, wind power and energy storage power stations, and microgrids.

Under the background of "two alternatives" strategy, in addition to the virtual synchronous machine technology, south group of large-scale emergency control, micro power grid as a whole new energy solutions, such as international leading technology, constant support clean energy higher permeability and clean power structure, toward a "a" clean energy using resolutely.

We will vigorously promote the development of a global energy Internet

In January this year, Nanrui Group established the Global Energy Internet Research Center, which is responsible for supporting the energy strategic research and planning of the company and Nanrui Group, organizing basic forward-looking technology pre-research and major key core technology research, widely carrying out technical communication and cooperation, and participating in standard formulation.

"The global energy Internet is achieved one step at a time. The power grid covers from countries and regions to the whole world, which puts forward new requirements for technology and equipment, and its realization must rely on technology driven and equipment support." Nanrui Group technology department head Li Ning said.

In the next step, Nanrui Group will focus on the development of complete sets of high-voltage and high-capacity flexible DC transmission equipment, UHV DC transmission converter valve and control and protection system and products, as well as high-voltage and high-capacity flexible DC circuit breaker, UHV unified power flow controller (UPFC) and other products to meet the needs of global energy Internet flexible power transmission.

South group which correspond to technical research, is Internet related industry development, promote the global energy and stronger uhv dc transmission industry, formed the conventional dc transmission and flexible HVDC overall solution, and a new generation of flexible HVDC overall solution, do big energy-saving environmental protection industry, do big distributed energy grid and energy storage business.

The ultimate goal of the global energy Internet is to connect across borders and continents. Following the internationalization pace of State Grid Corporation, Nanrui Group has spared no effort in accelerating the promotion of UHV technology "going global". At present, Nanrui Group is fully supporting the company's Beautiful Mountain Phase II in Brazil, Pakistan DC and Mongolia coal power transfer projects. At the same time, Nanrui Group also actively participates in international organizations to strengthen the revision of international standards. Taking the opportunity of launching the new Working group proposal of "Suggestions on Systematic Framework Design of Power System Stability Control" in CIGRE, Nanrui Group will strengthen the international standard output of technologies in the advantages of power grid stability control and other fields. It provides support for the company to lead the discourse power of international standards, promote internationalization strategy and accelerate the construction of global energy Internet.

Source: State Grid News

Original author: Yuan Zhongwei

Responsible Editor: Wang Xiaoyan

Nanrui Engineering/Design

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