Yang Yong (Zhejiang Electric Power Test Institute, Hangzhou 310014, China) promoted the role of insurance. It is pointed out that in order to control the pollution of the power industry to the environment, in addition to increasing scientific and technological progress and financial investment in power supply, technological progress in the field of power transmission and distribution will also have a positive impact on China's power environmental protection cause. As a basic industry of the national economy, the power industry has achieved tremendous development under the circumstance of increasing investment in the country, and the installed capacity of thermal power continues to grow rapidly. At the same time, the emissions of harmful gases such as C2, S2 and NOx from coal-fired power plants are also synchronized, which has become the main source of air pollution in China. According to relevant information, if not controlled, it is expected that by the end of 2000, the emission of S2 from coal-fired power plants will reach the first place in China. This will bring about a series of environmental disasters such as large-scale acid rain and accelerated climate warming. In response to the severe air pollution situation, the state has increased its control. On April 3, 2000, the National People's Congress passed a new air pollution prevention and control law, which imposed stricter restrictions on the emission of harmful gases from coal-fired power plants. Therefore, in the future, the development of China's power industry must put environmental pollution prevention and control in a prominent position, and increase investment in power environmental protection. In addition to measures such as expanding the installation of desulfurization units in coal-fired power plants, developing large-scale supercritical units, shutting down small thermal power plants, and implementing clean coal power generation technologies, such as measures to control the use of power sources and reduce harmful emissions, power transmission and distribution technologies Progress will also have a positive impact on power environmental protection. 1 Minimize power grid loss China's power grid, especially the urban and rural distribution network, is weak, and the power loss of transmission and distribution systems is quite high. The average line loss rate of the power grid managed by the national power sector is around 8%. The loss of the power grid, the total line loss rate is about 15%, and the transmission and distribution line loss rate of developed countries has been reduced from about 10% in 1960 to 5%~8 %. It can be seen that it is compared with industrial developed countries. Compared, the line loss rate of China's power grid is quite high. The electrical energy provided for the loss adds to the pollution of the atmospheric environment. Therefore, optimizing the operation of the transmission and distribution system not only improves the economics of the operation of the power system, but also reduces the power generation capacity occupied by the loss of the power transmission and distribution system, thereby indirectly reducing the emission of harmful gases such as C2 and S2. . 1.1 Vigorously promote energy-saving transformers Transformers are indispensable power equipment in power transmission, and are also the largest operating equipment in transmission and distribution systems. Their losses account for about 10% of total power generation, accounting for line losses in transmission and distribution systems. 50%. With the advancement of transmission and distribution technology, the loss of transformers has been declining. In 1998, the state had clearly stated that it required the elimination of high-loss old transformers and replaced them with low-loss, energy-saving S9 transformers. In recent years, foreign countries have begun to promote the application of energy-saving amorphous alloy distribution transformers. This type of transformer replaces cold-rolled silicon steel sheets with amorphous alloys, which greatly reduces the no-load loss. The prototypes of the 160, 200, 315, and 500kVA prototypes of the transformer factory of Shangchang, Foshan, and Baobian show that the no-load loss of the amorphous alloy transformer is about 75% lower than that of the S9 transformer. In foreign countries, it has been put into production. There are millions of amorphous transformers on the Internet in the United States, and more than 3,000 units have been put into operation in China. The distribution transformer has a large amount of coverage. If the amorphous transformer is fully promoted, the consumption reduction effect will be very significant. According to statistics, more than 200,000 distribution transformers are produced nationwide each year. If replaced by amorphous transformers, the reduced loss is equivalent to a small amount of CO2 emission to the atmosphere of 1.3 million tons, SO22.3 million tons, and NOx1040t. Therefore, the amorphous transformer is It is called a green power plant without a generator. The price of an amorphous transformer is about 1.3 times that of the S9 transformer, but the estimated purchase cost can be recovered from the saved electricity cost in about 3 years. Therefore, in order to rationally utilize resources and protect the ecological environment, efforts should be made to promote the application of amorphous transformers. 1.2 Other measures to reduce line loss Transmission and distribution systems, especially in urban and rural distribution networks, have large line loss rates, which are related to low investment in power grid construction, aging facilities and backward management. As far as China's current situation is concerned, the potential for reducing line losses is quite large. The main measures are: actively carry out scientific and technological innovation, speed up the implementation of distribution network automation, adjust and optimize the power flow of the distribution network through the control of the ring network load switch; through the control of the capacitor and the load distribution transformer with load regulation, realize the whole The reactive power/voltage control of the distribution network ultimately achieves the goal of reducing network losses. Strengthen electricity management, resolutely block measurement loopholes, and effectively prevent and combat electricity theft. Actively develop anti-stealing technology to improve and perfect the user's metering device to achieve accurate metering and anti-stealing function. Implement load monitoring and remote meter reading. Replace the thin wire, balance the three-phase load, add reactive compensation, and improve the power factor of the user. At present, the natural power factor of domestic household appliances is only about 0.7. At the same time, small industrial and commercial users connected to low-voltage power grids have no power factor assessment and means of detecting power factors. This is an important reason for the loss of line losses in low-voltage power grids. 2 Impact of technological progress of power transmission system on environmental protection 2.1 Construction of ultra-high voltage lines to create conditions for the transportation of clean energy In the national development strategy of the western region, actively develop western hydropower resources and realize the transmission of power from west to east. Replacing the eastern coal-fired power plants with cheap, clean and pollution-free western hydropower has far-reaching impact on China's environmental protection cause. A number of large-scale and extra-large hydropower bases under construction in the Xiluodu, Xiangjiaba hub project and western planning in the western region of China have installed capacity of several GW and tens of GW or more, and the distance to the east is more than 1000km. The transmission of this power to the eastern load center is not only to meet the needs of electricity use, but also the need for environmental protection. The existing 500kV voltage transmission line (economic transmission capacity 1GW, transmission distance 300 ~ 500km) has been difficult to meet this requirement. In addition to the use of high-voltage direct current transmission, the exchange of UHV transmission as the backbone of the West-East Power Transmission should be one of the main considerations. Taking a line with a transmission capacity of 10 GW of 1 000 km as an example, the comparison of the number of circuits under different transmission voltages and the width of the occupied corridor is shown in Table 1. As can be seen from Table 1, the number of circuits using UHV transmission is greatly reduced. In terms of line cost, the cost of a 750kV line is 500kV. The cost of a 90% 1000kV line is only 500kV. The cost is 1000kV. The transmission loss is 1/2 of 750kV, which is 1/5 of 50CkV. It can be seen that UHV transmission is used. It has a great advantage in terms of line occupancy corridor width, cost or operating cost. From a global perspective, 750kV transmission has more than 20 years of operating experience, and the technology is relatively mature. During the "10th Five-Year Plan" period, China will first construct a 75CkV UHV transmission line in the Northwest Power Grid, and the research work of UHV transmission with a voltage level of 1 000kV should be gradually developed. UHV transmission can save land resources and route corridors, better realize the strategic goal of power transmission from west to east, and effectively solve the environmental pollution problem in the load center in eastern China. Table 1 Comparison of different AC transmission voltages under the loop and occupied corridors. The transmission voltage/kV loops occupy the corridor width/m. The power transmission distance is 100Ckm. The transmission capacity is 10GW/. 2.2 Actively develop the high-voltage direct current transmission technology High-voltage direct current transmission (HVDC) commercial The operation has been nearly 50 years old. With the development of power electronics, computers, optical fiber and other technologies, the advantages of HVDC in long-distance large-capacity transmission are more obvious. Compared with AC transmission, line loss can be reduced by more than 50%. As HVDC transmission technology has matured, it will play an important role in the transmission of power from the west to the east and reducing the pollution of coal-fired power plants in the east. In order to protect the environment, we should vigorously develop renewable and non-polluting energy sources, such as runoff small hydropower, wind power, tidal power, solar power, geothermal power, etc., and gradually increase their proportion in power generation. However, these power supplies tend to have small capacity, unstable operating conditions, and large losses in AC transmission. In recent years, light-duty direct current transmission technology using high-power gate-off thyristors has emerged, which overcomes the limitation that the conventional HVDC receiving end must provide sufficient reactive power, and is particularly suitable for connecting small and dispersed power sources to large power grids. See the basic composition. Using light-duty direct current transmission technology, these non-polluting renewable power sources, fuel cells with low greenhouse gas emissions, and micro-gas turbines can be connected to the large power grid to fully utilize these environmentally-friendly energy sources and increase their energy consumption. The proportion in China will reduce the power generation of coal-fired power plants and further reduce air pollution. Main wiring diagram of light-duty direct current transmission system China has gained valuable experience in the digestion and absorption, operation and maintenance of equipment through the construction of Zhejiang Zhoushan submarine direct current transmission project composed of domestically produced equipment and the introduction of 500kV Geyinan HVDC transmission project. . At present, the single pole of the Tianshiguang project with a capacity of 1800MW taxi 500kV has been put into operation, and the DC transmission project of the Three Gorges and Changzhou is also under construction. However, compared with the international advanced level, there is still a big gap in the manufacture of DC transmission equipment, and there are not many DC transmission projects actually put into operation. This requires more efforts in equipment manufacturing, design, operation, etc., to expand the application range of DC transmission. 2.3 The role of flexible AC transmission technology in environmental protection In order to improve the static stability of the grid under fault conditions, the power system has to maintain 15%~20% of the accident reserve capacity during normal operation; the transmission line is limited by the natural transmission power. However, the transportation capacity cannot be further improved, and the addition of the line corridor will have an impact on the environment; the environmental protection requires the load center to be far away from the power supply, but the load center lacks the support of reactive power and voltage, and the transient voltage instability is more prominent; the existing transmission system circulation The existence of power often causes power circulation and power backflow, which will lead to a large loss of power transmission and transmission capacity of the transmission system; large grid interconnection can reduce the power reserve capacity, but the problem of security and stability becomes more prominent as the interconnection of the system expands. , limiting the size of the connected grid. It is more difficult to solve these problems related to power environmental protection by traditional control methods. The emergence of FACTS technology based on power electronics technology has made it possible to solve these problems. For example, the main component of FACTS controllable series capacitor compensator (TCSC), through thyristor control, can smoothly adjust the reactance value of the series compensation device of the transmission line in a considerable range, so as to improve the stability of the power system and expand the transmission of the transmission line. Power, flexible control of the power flow of the grid, and so on. Another example is the line parallel compensator using a FACTS technology, a static varactor (STATCOM), which maintains the stability of the line voltage by exchanging reactive power with the system. The effect is similar to that of a camera, but there is no rotating part, and the response speed is Extremely fast, it is an effective tool to suppress system voltage fluctuations and improve system stability, especially voltage stability. The Unified Power Flow Controller (UPFC) combines the functions of series compensation to control line voltage, impedance, and phase to achieve control of power flow, damped oscillations, and improved system stability. China's application of FACTS technology has also made considerable progress. The 2CMvarSTATCOM jointly developed by Henan Electric Power Bureau and Tsinghua University has been successfully put into operation. The TCSC application research of the ongoing Northeast Yiyifeng and Huadong Yangyihuai 50CkV transmission lines has also made great progress. From the point of view of power environmental protection, the STATCOM device adopts FACTS technology, which can improve the transmission capacity of the West-East Power Transmission, reduce the transmission lines, expand the scale of the interconnection network, and reduce the standby for the system to maintain stability. The power supply capacity reduces the power loss of the power grid and improves the stability of the load away from the power supply, which is beneficial to the protection of the environment. 3Strengthen the energy storage capacity of the power grid and reduce the standby unit of the system. With the rapid development of the national economy, the improvement of people's living standards and the rapid popularization of household appliances, the peak-to-valley difference of the power grid is getting larger and larger, and the coal power as the main power source of the power grid The peaking capacity of the power plant is not good. To this end, the grid has to expand the power capacity, as the system peaking and accident emergency standby unit capacity can account for 10% to 15% of the total capacity, the large range of unit load changes also increase coal consumption, aggravating the coal-fired power plant Atmospheric pollution. Therefore, strengthening the peaking capacity of the system is not only the need for power grid peaking and valley filling, accident standby and economic operation, but also the need to reduce the environmental pollution of coal-fired power plants. Pumped storage is the main means to strengthen the energy storage capacity of the grid. In recent years, China's pumped storage power station construction has developed rapidly. The world's largest capacity 2.4 million kW Guangzhou pumped storage power station, 1.8 million kW Zhejiang Wuhuangping pumped storage power station and 800,000 kW Beijing Ming Tombs A number of large and medium-sized pumped-storage power stations, such as pumped-storage power stations, have been put into operation, so that a group of thermal power units that originally served as peak-shaving tasks can be decommissioned, correspondingly reducing the spare capacity of the power grid, and the environmental benefits brought to society are obvious. China has built about 5.57 million kW of pumped-storage power stations, accounting for 1.9% of the national installed capacity of power generation, accounting for 5% of the capacity of pumped-storage power plants built and under construction in the world, with a small proportion. There are many pumped and storage resources available in China, and this valuable resource should be rationally developed and utilized as soon as possible. Especially in the southeast coastal areas, it is both the center of load and the strict control area of ​​environmental protection. It is even more necessary to speed up the construction of pumped storage power stations to optimize Power structure to protect the environment. In addition to pumped storage power stations, the development of superconducting reservers using superconducting technology has also made great breakthroughs. A typical superconducting energy storage system can be seen. Under normal circumstances, the electrical energy of the power grid is converted into direct current by a high-power electronic converter, and a superconducting coil is injected to establish a magnetic field, which is stored in the magnetic field in the form of electromagnetic energy, and converts the electromagnetic energy into alternating current energy when the energy is released, and the energy thereof The release rate is very fast, usually only a few ms. Because the DC resistance of the superconducting coil is almost zero, the storage of this energy will not be lossy, the conversion efficiency is as high as 95%. In contrast, the conversion efficiency of pumped storage Only around 70%. Therefore, compared with other energy storage modes such as pumped storage, battery storage, and flywheel energy storage, superconducting energy storage has the characteristics of high speed, high conversion efficiency, and no restrictions on the construction site. Peak power has great potential for development. Now, the development of superconducting energy storage has entered the practical stage of engineering. In the United States, small superconducting energy storage devices have been put into operation. Some major industrial countries in the world have invested a lot of money to actively carry out research on superconducting technology with great enthusiasm. China should also strengthen scientific and technological research in this area so that it can improve Environmental services. 4 Conclusion Power environmental protection issues have become increasingly prominent. Environmental pollution has become a limiting factor for the sustainable development of China's power industry. In addition to increasing scientific and technological progress and capital investment in power supply, it actively develops and applies energy-saving transmission and distribution in the field of power transmission and distribution. Advanced power system technologies such as equipment, FACTS technology, high-voltage direct current transmission technology, and grid energy storage technology will undoubtedly greatly reduce the loss of the power grid, reduce the peak load capacity and accident reserve capacity of the power grid, promote the use of renewable energy, and ensure the cheap west. Clean water and electricity sources are continuously sent to the eastern load center, thereby reducing the demand for coal-fired power generation, reducing the total amount of harmful gas emissions from coal-fired power plants and better protecting the environment. natural wood watch dial, mosaic wood watch dial, Handmade Wooden dial , Solid Wooden Dial , Spliced Wood Dial SHENZHEN ORINO WATCH CO.,LTD , https://www.orinowatch.com