The future development trend of smart grid

Q: What do you think is the future development mode of smart grid? In the process of "smart grid" construction, what are the differences between China and developed countries in the construction of smart devices?

You Yimin: Digitalization and informationization must be the focus of smart grid development in the future. At present, each country has different focuses on smart grids:

The United States is mainly to get rid of dependence on European oil resources, solve the aging of grid equipment, and respond to the needs of power users. On the one hand, the average American has the highest carbon emissions in the world. On the other hand, the United States is the world’s major energy consumer and the world’s largest oil importer. From the perspective of the US’s own energy security and environmental protection, the United States needs to vigorously promote new energy sources. In addition, the U.S. launch of new energy is to rebuild the energy industry revolution, especially after the economic crisis of 2009. In addition, the U.S. power grid is relatively aging. This move is also aimed at resolving the contradiction between the increasingly aging power grid equipment and users' increasing demands for power supply reliability and power quality, ensuring the ability of the grid to recover from disasters, preventing attacks by terrorists and reducing the occurrence of Human error and other risks. Finally, the United States wants to apply information and digitalization to the smart grid. At the same time, I also believe that the most important development model of the smart grid in the future is digitalization and informationization.

Europe is designed to meet the needs of more efficient, flexible, environmentally friendly, and trans-European electricity markets. The energy policies of European countries have placed more emphasis on the protection of environmental protection and the development of renewable energy, especially the development of renewable energy sources such as wind power, solar energy and bioenergy. The policies of the European Union and related countries are more encouraging than the United States in supporting, advocating low-carbon power generation, renewable energy power, and efficient energy use, reducing the emission of carbides and protecting the environment. The competitive pressure from the open electricity market will increase user satisfaction, increase operational efficiency, reduce electricity prices, strengthen interaction with customers, and build the power grid into an interactive service network between operators and users. European users also place higher demands on power supply reliability and power quality. The drive of modern new technologies has also enabled Europe to develop smart grids.

China's smart grid is much more complicated. The development of smart grids is mainly due to the uneven distribution of energy resources and the rapid growth of the load. In addition, the main source of power supply structure is coal, with insufficient adjustment capability, and energy conservation and emission reduction have become the focus of attention. Reduce carbon emissions, protect the environment, and accept large-scale renewable energy such as wind power. Satisfy the rapidly increasing load demand and accelerate the construction and transformation of the power grid. Increase the investment in the power grid, especially the distribution network. The construction of the West-to-East power transmission channel will be strengthened to increase cross-regional interconnection of the power grid and solve the problem of insufficient peak-shaving capacity. Improve power supply reliability and power quality. So I think that China is also a strategic issue of renewable energy and meets rapidly increasing load requirements. At present, the power grid is the most conservative industry, so the future development space must be very large.

Q: Just now you mentioned that different countries have different focuses on the development of smart grids. What is the difference between China and other countries in the direction of selecting electric power equipment while building a smart grid?

You Yimin: The entire smart grid is a concept. The specific equipment is still in the construction phase. The United States, Europe, and some companies such as ABB and Ormazabal have begun such attempts. The digitization, informatization, and some sensing technologies just mentioned have begun to be applied to switchgear. ABB produced eVD4 on the basis of VD4, and Ormazabal also produced one, mainly decentralized smart units, and put it underground into the equipment, replacing some of the hard elements in the original mechanical equipment, as well as digitization, information, and The application of sensor technology, especially sensor technology. I think the equipment in the future will definitely develop in this direction. Just mentioned a few medium-voltage equipment, high-voltage equipment development is not so fast. In terms of high-voltage products, one of the products under the 6271-3 standard is introduced. That is, all control modules are put into institutions and digital information is used from the agency side. This is also mentioned in the Supplementary Provisions of the State Grid Corporation of China for Newly-Designed Substations in 2011, which will reduce the number of circuit breakers, auxiliary auxiliary contacts and auxiliary relays. Preferably, the circuit breaker cancels the control box, and the circuit breaker operation box control loop can be integrally integrated with the main body sub-closing and closing control loop, eliminating some redundant secondary loops and improving the working reliability of the circuit breaker's control mechanism. Is the future direction of development, 6271-3 standard also clear its development model.

Question: Can you tell us about China's development of smart substation core, key links, and difficulties that need to be overcome at this stage?

You Yimin: The smart substation adopts advanced, reliable, integrated, low-carbon, and environmentally-friendly smart devices. It takes the digitization of the entire station information, networking of communication platforms, and standardization of information sharing as the basic requirements. It automatically completes information collection, measurement, control, protection, and measurement. Monitoring and other basic functions, and supporting advanced substations such as real-time power grid automatic control, intelligent adjustment, on-line analysis and decision making, and cooperative interaction, as required. Smart substations have three parts: one is the digitization and informationization of substations, one is smart primary equipment, and the other is advanced application. Advanced applications are a icing on the cake, and the real key to the harder core is the smart primary device. The reliability of some devices and some manufacturers still have some problems. For example, the reliability of some electronic transformers is still relatively high. The problems with such reliability are mainly environmental resistance. The key to achieving reliability and environmental resistance is the design and manufacture of devices. Because the original control unit is mainly controlled, the environment on the primary side is now worse than the original one. At present, there are many problems in smart substations, so there should be a slower progress and more improvement.

Q: For the smart grid to achieve breakthrough development, what kind of support should the country give to the policy?

You Yimin: At present, the state gives more policy support to the system. Actually, our disparity is still in equipment, and equipment and devices are the core of the system. There are indeed great differences between our products and the products of big international companies, including R&D and manufacturing. Not only manufacturing, but also R&D. Currently, R&D is still in the stage of following other people and lacks the level of independent innovation. I think the country should invest more in innovation in installations and equipment. I think it might be a good idea to invest in this kind of traditional product. At present, the domestic control and protection of this block is better, no less than foreign. The three companies Nanrui, Nanzi and Sifang accounted for about 70% of the entire market in terms of control and protection. This is mainly due to the control and protection of domestic data, the service is relatively good, the flexibility is relatively high, and the price is not high, so it is difficult to enter abroad. Chinese market. However, the manufacture of a single device does not work, such as switching transformers and other foreign countries still have a gap.

Q: How to improve the domestic competitiveness of smart power equipment?

You Yimin: First of all, there is no doubt that it is from digitization and intelligence. Second, it is to improve product reliability. Again, this is the visual aspect of the product. Personally think that the application of visualization in medium-voltage products is still very limited. The medium-voltage products themselves have higher reliability and the price is relatively cheap. Too complicated to go in suits is a bit top-heavy. So in terms of visibility, different products hold different perspectives.

Electric appliance industry: The development of smart grid will bring about the integration of primary and secondary equipment systems. This will break the market structure of existing equipment manufacturers. What kind of new situation do you think will bring?

You Yimin: The smart grid enables the integration of primary and secondary devices. The primary equipment is upgraded to intelligent power equipment, and the secondary equipment is upgraded to an intelligent control unit. This is definitely a revolutionary change. It makes no distinction between primary and secondary equipment quality inspections. In the future, the primary equipment contains secondary equipment. The function of the secondary equipment is transferred to the primary equipment and is integrated into a more integrated unit. There is also a mutual restriction between the primary equipment and the secondary equipment. Traditional R&D and manufacturing patterns where primary and secondary equipment are directly isolated from each other will be broken, which means that the entire market for equipment manufacturing will be broken. At present, I feel that primary and secondary equipment are too separated, which is related to our previous industrial layout. Companies such as ABB and Siemens have once and twice converged equipment, and domestic products are separated. This mode of division is definitely unreasonable and will surely be broken in the future. Many primary and secondary equipment companies now merge with each other. For example, Nanzi and ABB have the intention to cooperate and integrate ABB's primary equipment with the South from the second. According to what I have come across, the design concepts of primary and secondary equipment are very different and it is difficult to integrate them. The integrated design is definitely a concept of integration, so in the future, one or two companies will have to carry out deep-level integration, or mergers and reorganizations. Primary and secondary devices are interactive and restrict each other's relationships. In the future, we must create a “you have me, I have you” equipment, and now smart primary equipment can not do this, so it requires multiple debugging, mainly caused by the separation of the first and second equipment. .

Q: Do you think it is possible that the secondary device will evolve into a plug-and-play plug-in?

You Yimin: Personally, I do not agree with this idea. Because the primary and secondary equipment are inseparable, like the car's steering wheel and wheels. The primary and secondary equipments should be a fusion. It must be a fusion design to achieve a perfect product. As mentioned earlier, the secondary components should be placed in the organization. How can this be plug and play? This idea may be based on the user's point of view, just as the previous switch and switchgear were bought two, but this kind of cooperation will certainly have a variety of problems in the future. It is impossible to separate the transformer body and its merging unit of the protection MU. Both of them need to be debugged together to call it a product, and each cannot be used universally. Plug and Play is bound to be an isolated, isolated design, not a fusion. Now that medium voltage is very obvious, the smart module of a mechanism box replaces the original auxiliary switch, some hard contacts, some relays and other control originals, and it is integrated with the panel design to form a very beautiful mechanism box, and plug and play. There is no way to achieve this.

Q: Can you combine specific examples and talk about how the combination of practicality and economy can be achieved in the new substation design in 2011?

You Yimin: In the “Supplementary Regulations for the State Grid Corporation of China's New Substation Design in 2011,” it was clearly pointed out that electronic voltage sensors can be used for voltage levels of 110kv and above, and conventional sensors can also be used. I think it should be based on different products. For 66kv and below voltage grades, if the switchgear monitoring and control decentralization is adopted in the user's switchgear, the conventional transformer should be adopted. I think this is not absolute and can be determined according to the product conditions. If outdoor open-distribution devices are used to protect the monitoring and control arrangement, conventional sensors can be used, as well as electronic transformers. It is recommended to cancel the horizontal electrical interlocking and locking of the local cross-section and reduce the number of circuit breakers, auxiliary auxiliary contacts and auxiliary relays. When the equipment is equipped with conditions, the control circuit of the circuit breaker operating box can be integrated with the main body sub-closing control circuit, and the redundant secondary circuit can be eliminated to improve the working reliability of the circuit breaker control mechanism. The integration unit and intelligent terminal hardware are integrated. For 110kv substations, line protection, measurement and control units can be integrated. It embodies the concept of integration and advancement. In fact, now the cost of electronic transformers is higher than that of traditional transformers, mainly because it contains some electronic devices, but in the future, its hard cost is definitely lower than that of traditional transformers, and it takes up a small amount of space. This transformer is definitely Is the direction of development. Nowadays, electronic transformers contain many technologies. In the future, as technology advances, prices will naturally decrease. Electronic transformers are small in size and use less resources. There are few cores and coils (copper and iron), and the electronic components will become cheaper. Copper and iron are more and more expensive. This trend is for sure. Therefore, the price of electronic transformers will certainly decline in the future. This must be the direction of development.

There is the concept that I just mentioned that the circuit and the body circuit of the circuit breaker operation box are integrated and integrated, that is, the control unit is devolved into the organization. This mainly reflects the concept of integration and advancement. For example, some 110,000-volt stations can integrate the entire hardware of the merging unit, intelligent terminal, and measurement and control protection. This way, the power supply is enough. The GIS Bureau's measurement of the amount of discharge is based on the pre-embedded sensor model, which uses a portable PD measurement instrument to measure the economy. Such a station requires only one measuring instrument. The cost of the embedded sensor itself is not high, and the amount of change in the partial discharge is not bad under normal circumstances. For example, the insulation, copper, etc. will not be removed until the medium-voltage switchgear exceeds the standard for one year. Slowly eroding away, this situation does not necessarily have to be monitored in real time. For example, once a portable sensor is measured once a month, I think this is also a way for the State Grid to achieve practical economics without losing reliability. . The new stations built in 2011 are basically this model. Mechanical features are basically installed. It is cheaper than partial discharge. Mechanical characteristics need to switch to measure, then install online, as long as the action can be measured data, and partial discharge can not move, as long as the substation is running, can be monitored at any time, so that you can use portable without online monitoring.

Question: The transmission grid is relatively stable, and the distribution grid is more complex. Therefore, the development of smart grids should pay more attention to the distribution grid. Do you agree with this statement?

You Yimin: In the future, smart grids will have to solve several problems at home: First, the issue of access to renewable energy, and second, the problem of inefficient use of the grid itself. The access to renewable energy and the users are on the side of the distribution network. Therefore, it is useless to transmit power without distribution. Smart distribution network is a relatively large and complex piece, and relatively difficult to do. I have previously been discussing that there is no good standard and model. I think the most important thing is that there is no good product. Recently, many people in the industry have devoted some energy to the distribution network intelligence and made efforts in the distribution network products. From the aspect of distribution network system, this is the focus of attention, and I think there will be some breakthroughs in this aspect. The equipment is integrated, which makes the product simple, reliable, and easy to use. Distribution network has just started to do, not many implementation, is still in the discussion stage, but the prospects are broad; in terms of distribution network equipment manufacturers, but also in the level will be mixed, this will lead to more problems, the need to continue to explore and Improvement; From the standard level, distribution network application is relatively small, so it has not risen to a certain standard, and has not formed a certain system to guide applications. The distribution network itself is more complex and it is difficult to form standards. Now mainly to talk about the self-healing ability of the distribution network, the removal of faults, etc., this difficulty is relatively large, the difficulty is mainly reflected in the network reconstruction.