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WHAT ARE THE GAPS BETWEEN CHINA’S POWER DISTRIBUTION NETWORK CONSTRUCTION AND DEVELOPED COUNTRIES IN THE WORLD?

2022-09-11141 have been browsing

Analysis of the development status of high-voltage switchgear in 2018 Production growth and market concentration gradually increased

 

1. GIS production hit a new high

 

In 2016, the country produced a total of 19205 GIS (gas-insulated metal-enclosed switchgear) with voltage levels of 126kV and above, and the compound growth rate from 2009 to 2016 was 7.03%. From the perspective of subdivided products, during the “Twelfth Five-Year Plan” period, the output of 550kV GIS increased rapidly. According to the preliminary statistics of the Prospective Industry Research Institute, the output of GIS with a voltage level of 126KV and above in 2017 exceeded the 21,000 interval mark, reaching about 21,433 intervals.

 

Chart 1: GIS output of 126kV and above voltage level from 2009 to 2017 (unit: interval)

 

Source: Compiled by Qianzhan Industry Research Institute

 

From the current practice, GIS has the characteristics of safety and reliability, flexible configuration, strong environmental adaptability, long maintenance period and convenient installation. At present, in the 63-500kV power system in our country, the application of GIS has been quite extensive.

 

From the perspective of the competition pattern, the number of GIS manufacturers in my country is increasing, including state-owned enterprises, joint ventures, and private enterprises. But in general, Xi’an Xikai High Voltage Electric Co., Ltd., Henan Pinggao Electric Co., Ltd., and New Northeast Electric (Shenyang) High Voltage Switchgear Co., Ltd. occupy the main market share, and these three companies have the ability to produce 1100kV voltage level Ability.

 

1. The rapid development of distributed photovoltaics has become the main force of distributed energy

 

Compared with the traditional “centralized” energy utilization, “distributed” energy refers to a comprehensive energy utilization system built near the user’s load center rather than long-distance transmission, covering power generation, cogeneration, storage Various forms of energy and energy management systems, such as household solar power generation systems or household wall-mounted gas heating systems are common distributed energy sources. The early distributed energy was developed on the basis of the combined heat and power system (CHP), and then the distributed energy system gradually expanded to the multiple energy types of cooling, heating, electricity and steam on the user side (CCHP) systems and renewable energy generation systems.

 

As my country continues to promote the structural reform of the energy supply side and promote the transformation of energy development from extensive to quality and efficiency improvement, distributed energy such as photovoltaics, natural gas, wind power, biomass energy, and geothermal energy has become my country’s response to climate change. An important part of ensuring energy security.

 

Natural gas distributed energy developed earlier. According to the forward-looking “2018-2023 China Distributed Energy Industry Business Model Innovation and Investment Prospect Forecast Analysis Report”, in 2016, the national cumulative installed capacity of natural gas distributed power generation was 12 million kilowatts, less than 2% of the country’s total installed capacity. , there is a big gap from the “Guiding Opinions on the Development of Natural Gas Distributed Energy” that the installed capacity will reach 50 million kilowatts by 2020.

 

In recent years, my country’s distributed photovoltaics have experienced explosive growth. The “Annual Development Report of China’s Clean Energy Industry” shows that in 2017, my country’s photovoltaic power generation installed capacity continued to maintain rapid growth, with an additional installed capacity of 53.06 GW, ranking first in the world for five consecutive years, a year-on-year increase of 53.6%. Among them, distributed photovoltaics increased by 19.44 GW, a year-on-year increase of 3.7 times. As of the end of 2017, the cumulative installed capacity of photovoltaic power generation nationwide reached 130 GW, of which 100.59 GW of photovoltaic power plants and 29.66 GW of distributed photovoltaics.

 

Compared with distributed photovoltaics, the development of distributed wind power is relatively slow. Industry experts said that due to many institutional and mechanism problems, there is still very little decentralized wind power. However, referring to developed countries, it is basically distributed. Only when it is combined with the user side and the demand side can there be hope in the future. China’s wind power may not have any hope if decentralized wind power does not work. In 2018, the current situation of wind power distribution network at home and abroad, especially the gap between my country’s distribution network and the international advanced level, I personally think that the construction of a world-class distribution network in my country needs to consider the following aspects:

 

1. Macroscopic comparison of society and economy. The development status of society and economy directly reflects and guides the planning and construction of distribution network. Some comprehensive data on my country’s new-type urbanization construction and per capita annual domestic electricity consumption show that my country’s urbanization and electrification level has a large space. Correspondingly, the planning, construction and large-scale development of urban distribution network still have great potential.

 

2. Power supply reliability. Taking 2014 as an example, the average power supply reliability rate of 10kV users in my country was 99.940%, and the average power outage time was 5.22 hours per household. Among them, the average power supply reliability rate of urban (city center + urban area + town) users is 99.971%, and the average annual power outage time is 2.59 hours/household; the average power supply reliability rate of rural users is 99.935%, and the annual average power outage time is 5.72 hours/household .

 

Compared with the international advanced level, in 2011, the reliability rate of power supply in Singapore reached 99.999941%, and the average power outage time was 0.31 minutes; in 2009, the reliability rate of power supply in Tokyo, Japan reached 99.999619%, and the average power outage time was 2 minutes.

 

It can be seen from this that there is a lot of room and pressure to improve the reliability of power supply in my country.

 

3. Distribution network structure. The structure of distribution network determines the reliability and flexibility of network operation. In this regard, different countries have developed different design methods.

 

Taking the urban distribution network as an example, the Paris urban cable network adopts the three-ring network T-connection or the double-ring network T-connection method; the London cable network adopts the multi-branch and multi-connection connection method; the Tokyo 22kV cable network adopts the main line backup line, ring, point The 6kV overhead network adopts the multi-segment and multi-connection method, and the cable network adopts the multi-segment and multi-connection method; the Singapore cable network adopts the “petal type”, that is, the ring network closed wiring.

 

Although the specific topology is different, the basic trend of foreign advanced grid structures is to develop in a “dumbbell shape”.

 

At present, the high-voltage distribution network in Beijing in my country is similar to the international advanced distribution network, mainly in ring network and radial operation (ie “hand-in-hand” grid structure). , the network wiring mode is complex, and it is difficult to form a standardization.

 

In addition, the insulation rate of 10 (20) kV urban grid overhead lines at the advanced foreign level is as high as 80%, while the domestic current is only 22.4%. Therefore, in terms of upgrading the distribution network structure, a major task at present is to learn from the advanced level of foreign countries and make adjustments in line with the actual local development.

 

Specifically, for the first-tier cities, strive to build a network architecture with both reliability and flexibility, fully realize the double-sided power supply and ring network structure, strengthen the connection rate of medium-voltage lines, and improve the load transfer capacity; for other cities and towns, combined with For the development of local economy and load, firstly solve the problem of insufficient N-1 capacity of high-voltage distribution network and the problem of “single-line single-transformation”, and gradually improve the problems of insufficient segmentation of medium-voltage distribution network and insufficient line connection; rural areas should first improve the problem of power supply radius.

 

4. The automation level of distribution network. In 2014, the overall coverage of distribution network automation within the State Grid Corporation of China was 20%, and the coverage of smart meters was 60%. The automation coverage rate in Japan is almost 100%, and in France it is 90%.

 

As far as the actual situation is concerned, some first-tier cities in my country have initially achieved a considerable and controllable distribution network, while other areas lack the ability to monitor and automate operations, and there is still potential and tasks for substantial improvement.

 

Specifically, in terms of infrastructure construction, first-tier cities should focus on improving the construction of medium and low voltage optical fibers and other communication networks; other regions should strengthen the construction of high and medium voltage communication infrastructure, and cooperate with the appropriate development of different levels of automation equipment.

 

5. Distribution network asset management. The integration of new and old equipment and new and old technology networks in the distribution network is the physical carrier of the future comprehensive energy system, and an indispensable cornerstone and support for the construction of smart grids and energy Internet.

 

Therefore, a comprehensive and systematic grasp of the health level of existing distribution network equipment and networks should be the starting point for lean and efficient management of distribution network assets.

 

From the perspective of foreign development history, when the growth of economy and electricity load is basically stable, the guarantee for distribution network enterprises to realize social responsibility, reasonably manage and control the power grid, and improve profitability is asset management technology.

 

How to utilize the existing equipment and network efficiently and effectively is one of the two major directions of the International Large Grid Organization. In particular, with the retirement of experienced engineers and technicians, there is a gap in talents and a lack of inheritance, and the inheritance of rich first-hand experience and professional knowledge is in crisis, which has aroused global attention, especially the high vigilance of Western developed countries.

 

Taking the UK distribution network as an example, since the 1970s, the UK has tried to scientifically manage a large number of assets in the distribution network, and the asset management system it developed even predates the IPv4-based Internet technology.

 

At present, after long-term practice, the British distribution network has formed a lot of advanced experience in technical specifications, software and hardware platform development and application. Comparatively speaking, the concept and technology of domestic asset management started relatively late. Asset management technology and level still need to be greatly improved.

 

In view of the characteristics of large quantity and wide range of distribution equipment, relatively low unit price, and complex and changeable distribution network structure, it is necessary to deepen the research and development of asset management theory/application system that adapts to my country’s national conditions and distribution network management and control methods as soon as possible, and conduct in-depth pilot projects. work, and then promote the application of beneficial programs.

 

State Grid Corporation of China also launched the international benchmarking of distribution network assets last year, and I myself have also participated in some work as an expert. I think it is especially necessary to change the concept and deeply understand that scientific and intelligent asset management is an effective way to improve quality and efficiency. Asset management is not a simple management work, but a systematic and comprehensive discipline that integrates various theories, technologies and experiences while coordinating technology, economics and management, and an art of balancing cost, performance and risk.

 

In the future, the integrated energy Internet will also put forward higher requirements for asset management of distribution network. Technologies in the direction of energy information physical systems, big data, deep machine learning and artificial intelligence applications will provide scientific and practical methods and tools for asset management. .

 

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