The large-scale camera group in the DC UHV transmission project has achieved innovation in electromagnetic and mechanical performance indicators, cooling structure forms, and auxiliary machine system requirements. The operation of large-scale camera can fully exert the dynamic reactive support in the AC-DC hybrid power grid, improve the safety and stability of the power grid, improve the power factor of the power grid, maintain the voltage level of the power grid, and ensure the efficient and safe operation of the green UHV power grid. . 1 What are the functions of the sync camera? To achieve stable operation of the power system, not only requires real-time balance of active power, but also requires balance in reactive power. The most widely used reactive power compensation device in power systems is a synchronous generator. The synchronous generator set needs to adjust the active and reactive power generated according to the load change. However, the synchronous generator reactive power adjustment capability is affected by the factory voltage and static stability, and cannot meet the increasing demand for reactive power regulation. In order to stabilize the operating voltage of the power grid, capacitors and reactors are installed in the substation where the reactive power is contradictory, and the reactive power is adjusted by switching capacitors and reactors. However, the reactive power adjustment of capacitors and reactors is discontinuous, and most of them are only applicable to the steady-state operating conditions of the power grid. When the system operation is greatly disturbed and the bus voltage of the hub station such as the converter station fluctuates greatly, the traditional static reactive power compensation device such as capacitors and reactors cannot provide the dynamic reactive power compensation that meets the needs. At this time, the voltage instability problem occurs. , endangering the stability of the system. With the development of power electronics technology, new dynamic reactive power compensation devices, static var compensator (SVC) and static synchronous compensator (STATCOM), have emerged. Synchronous camera, also known as synchronous compensator, is a synchronous motor with special operating status. When running, the active power is close to zero, and it can provide or absorb reactive power to balance the reactive power of the grid. As a rotating reactive power generation device, the two-way dynamic reactive power adjustment capability has unique advantages for improving the short-circuit ratio of the receiving AC network and enhancing the strength and flexibility of the power grid. In the case that the DC system is blocked due to a fault, the camera can enter the phase-in operation state to absorb a large amount of excess reactive power due to the DC load, thereby suppressing the system voltage rise and improving the voltage level. When the DC system needs voltage support for normal operation, it can provide dynamic reactive power support for the AC grid in the late phase operation state. The strong excitation support voltage and system stability can be achieved when the fault voltage drops at the near end of the AC grid, which wins valuable time for the fault. Therefore, as a reliable two-way (phase-in, late-phase) dynamic reactive power generation device, the camera has been closely watched by the power industry because of its unique large-capacity dynamic reactive output characteristics and overload capability. The camera is economical and has a long service life of about 30 years. Compared with other reactive power compensation devices, it has a strong advantage. 2 What is the application of the large camera? In recent years, with the large-scale construction of UHV and long-distance DC transmission projects, the power grid structure has undergone major changes, forming a pattern of large power grid, long-distance transmission, and UHV AC-DC high-mixing. The ability requirements are more stringent. In order to ensure the safe and stable operation of the power system, the system must be equipped with sufficient dynamic reactive spare capacity. After the installation of a new large-capacity camera, it can effectively improve the DC transmission capacity of the transmission network and increase the proportion of new energy consumption. For the UHV DC high-power feeding area and the DC multi-infeed area, install at the receiving end grid. Adjusting the camera can effectively improve the system voltage stability and resistance to reactive power, ensuring safe and stable operation of the power grid. The traditional synchronous camera has a relatively small capacity. Very few large-capacity cameras also face the disadvantages of single cooling mode, complicated operation and maintenance, and high failure rate. The new large-capacity camera not only has a capacity of 300 megabytes, but also optimizes the design and cools it. The method is more diversified, and there are both a simple air cooling method and a dual water internal cooling method with certain operating experience. In order to alleviate the voltage problems caused by AC and DC faults and the failure of DC commutation, in September 2015, State Grid Corporation researched and deployed the application of the camera in the power grid, using the large-capacity two-way reactive power adjustment capability and dynamic reactive power of the camera. The output features improve the support capacity of the UHV DC grid and promote the development and safety and stability of the UHV grid. The first batch of 7 UHV DC projects in Jiuquan-Hunan, Zalut-Qingzhou, Ximeng-Taizhou, Shanghai Temple-Linyi, Jinbei-Nanjing, Zhundong-Hainan, Yazhong-Nanchang, etc. The station is equipped with 21 sets of 300-mega-scale large-scale camera. The first batch of camera sets involved 10 converter stations in 8 provinces (Zalut, Ximeng, Jiuquan, Yazhong, Xiangtan, Linyi, Taizhou, Nanjing, Nanchang, Weinan). After engineering feasibility study, prototype concept design, engineering preliminary design, main equipment bidding, camera construction, camera relocation supervision, joint debugging in the end of the dual-water internal cooling camera factory, air cooling camera manufacturing Joint debugging in the factory, etc. In the first batch of camera engineering projects, the camera adjustment project of Zalut converter station was completed and put into operation in December 2017. The Xiangtan station camera project was completed and put into operation in January 2018, Taizhou and Tin. The camera projects of the League, Linyi and Weinan are scheduled to be put into operation this year. In addition, the construction of the second batch of UHV DC converter stations, such as Zhengping, Fengxian, Jinhua and Chaidamu, is also being carried out in an orderly manner, thus achieving wide application in the national large power grid and becoming active. A standing dynamic reactive power support device. 3 Gansu Jiuquan Camera Project Jiuquan ±800 kV converter station is located in Hedong Township, Guazhou County, Gansu Province. It is the starting point of Jiuquan-Hunan ±800 kV UHV DC transmission project. The camera station is located close to the north side of the Jiuquan ±800 kV converter station site, and two 300-megabit cameras are built. Each camera is connected to a 750 kV AC system through a 360 MVA transformer. The camera project started construction in August 2016 and was built in parallel with the converter station. At present, the system commissioning has been completed, and the system commissioning work was started on July 23. The two camera images are symmetrically arranged and share the rotor maintenance space. The main building is made of reinforced concrete structure with ventilation system. The operating level is 4.5 meters high. Electrical main wiring: The unit wiring is connected to the 750 kV GIS power distribution unit of the converter station, and the circuit breaker outlet is not separately set. Station power wiring: no separate station change, converter station unified consideration. The starting device SFC is separately connected to the external power supply of the station, and the common load is connected to the power supply in the station. In-camera cooling system: The stator and rotor are air cooled. The external cooling system uses a closed circulating water cooling system with an auxiliary closed cooling tower. Water supply system: The fire water and living water of the camera station are uniformly considered by the converter station. The water for the camera station is connected by the water supply pipe T outside the southwest side of the converter station. Large-size transportation: The stator is installed in the infrastructure stage, and the installation and maintenance are not considered in the operation phase. The rotor is installed and repaired in consideration of the operation stage. The stator rotors are delivered at designated locations within the station. Two sets of SFCs are equipped with two sets of SFCs. The camera lubricating oil system is equipped with a storage tank, an AC/DC lubricating oil pump, and an AC/DC top-shaft oil pump. 4Jiangsu Taizhou Camera Project In July 2018, the ±800 kV UHV Taizhou Converter Station installed a synchronous camera to complete the non-full phase test, marking the successful completion of the first new generation of dual-water internal cooling camera project in East China Power Grid. Taizhou ±800 kV converter station is located in Nanshe Village, Doutou Town, Xinghua City, north of Taizhou City, Jiangsu Province. It is the end point of Ximeng-Taizhou ±800 kV UHV DC transmission project. The camera station is combined with the converter station to share the inbound road. The camera project is located next to the southwest side of the converter station and is located on the south side of the 500 kV power distribution unit of the converter station. The camera station is equipped with two 300-megabit cameras, each of which is connected to a 500 kV AC system via a 350 MVA transformer. The two camera images are symmetrically arranged and share the rotor maintenance space. The camera group is wired using the “Camera-Transformer Group†unit. The camera station power system is powered by four 10 kV power supplies provided by the converter station. The core is air cooled and the stator and rotor are water cooled. The external cooling system uses an open circulating water cooling system with a forced draft cooling tower. The water source of the fire water indoor fire hydrant system, the outdoor fire hydrant system and the water spray system of the camera station is supplied by the fire pump room of the converter station, the outdoor fire pipe network of the camera is connected with the outdoor fire pipe network of the converter station, and the integrated pump of the converter station is shared. Fire pump and fire voltage regulator system. The stator is installed in the infrastructure stage, and the installation and overhaul are not considered in the operation phase, and the rotor is installed and overhauled in consideration of the operation phase. ã€link】 The "New Grid Reader" consists of four volumes, each of which consists of 3 to 6 National Grid Corporation's scientific and technological innovation practices. The content of this edition comes from "New Equipment for Power Grid Reader", State Grid Jiangsu Electric Power Co., Ltd. Electric Power Research Institute, State Grid Hubei Electric Power Co., Ltd. Electric Power Research Institute, State Grid Corporation DC Construction Branch, State Grid Jiangsu Provincial Electric Power Co., Ltd. maintenance branch, Jie Bing, Cui Yibo, Qi Feng, Liu Yidan contributed to this article.
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What are the functions of synchronous camera in DC UHV transmission project?