Electrical Equipment Protection of Lianzhou Power Plant Desulfurization System Luo Yong (Guangdong Electric Power Test Institute, Guangzhou 510600, China) briefly introduced the protection system of electrical equipment for desulfurization system of Lianzhou Power Plant, and discussed the key issues and solutions for the calculation of the calculation. . Lianzhou Power Plant Desulfurization System, the first desulfurization system in Guangdong Province, was introduced by the limestone-gypsum wet desulfurization technology of Austrian AE Company. The company is fully responsible for the whole process of design, selection and equipment production, installation and commissioning. . Guangdong Electric Power Test Institute is responsible for the calculation and adjustment of the protection of electrical equipment. From AE's design ideas for electrical systems, it can be seen that the reliability of power supply and electrical equipment is particularly important for the entire desulfurization system. This article will explain the requirements and calculations of the desulfurization system for electrical equipment protection according to the design ideas of the electrical system. 1 system wiring and interlock protection function Lianzhou power plant desulfurization once system. The 6kV desulfurization section is connected to the IA section of No. 1 machine and the A section bus of No. 2 through circuit breakers 671B and 672B, respectively, and is connected with two circulating pumps and one oxidation fan, and passes through No. 1 or No. 2 desulfurization transformer to 380V. Power supply for the desulfurization section and the security section. A spare diesel generator set is connected to the security section. Normally, 6kVlA and A segments are respectively sent to circuit breakers 671B and 672B, and the 6kV desulfurization section is powered by only one of the circuits (such as the 671B circuit). When the 6kVlA segment suddenly switches to the spare segment, its low-voltage protection has a 1s delay to avoid the switching time of 0.5s. When the circuit fails or the switching fails, after 28s (test data), the desulfurization automatic control system (DCS) will automatically switch to another circuit (such as 672B circuit). When the whole plant is out of power and the high-voltage starting standby transformer loses power, the desulfurization system security section also has an emergency start of the diesel generator to ensure the safe operation of the desulfurization equipment. 2 The principle of setting calculations is based on the principle of overall calculation, focusing on the overall protection effect, and does not focus on the protection effect of a certain set of relay protection. It is also preferable to improve the protection effect of the overall protection by reducing the protection effect of a certain protection device. A tuning scheme has different protection effects due to different methods of setting and matching. Therefore, how to obtain an optimal setting plan will be the research topic of engineering and technical personnel engaged in relay protection setting calculation work, which is a problem of setting techniques. After continuous practice, if you can use various tuning principles and know the operating characteristics of the protected power system, you can do it - oxidation fan § cycle 循 1 cycle pump in Lianzhou power plant desulfurization primary system 3 tuning calculation considerations Factors and cooperation between the protection systems The protection of the system uses the MLPR-11C line protection equipment manufactured by Zhuhai Wanlida Electric Equipment Co., Ltd., MTPR-11C type transformer protection device and MMPR-11C type motor protection device. The setting calculation of the protection is carried out according to the principles in the design manual and according to the actual wiring and protection configuration. It can be seen that it is necessary to carefully study the quick-break and over-current protection setting principles of circuit breakers 671B and 672B. The factors considered are not mentioned in various materials and manuals. This is a typical design of AE companies in Austria and other countries. After many discussions with AE company electrical experts, since the two circuits of circuit breakers 671B and 672B are single-sided power supply, the two circuit breakers cannot be used as line protection, and should be used as protection for 6 kV bus and transformer, 6 kV motor. Backup protection. 3.1 Quick-break protection The quick-break protection considerations include: a) the maximum value of the three-phase short-circuit current of the low-voltage side of the transformer should be avoided; b) when the 6kV working section is abnormally powered down, when switching to the standby section or switching to another 6kV working section In the short pause process, the starting current /d2 of the two transformer inrush current Idi and the three 6kV motors should be avoided at the same time, and the final setting current Id takes the maximum of the above two. 11.16A, the sensitivity coefficient Kim is tested according to the busbar two-phase short circuit in the minimum operation mode, Km=2.82, which meets the requirements of the design procedure manual (Km>2). 3.2 Over-current protection Over-current protection considerations are based on the current rating of two transformers and three 6kV motors. Calculation result: Id=4. 57A, the sensitivity coefficient is tested according to the two-phase short circuit of the low-voltage side of the transformer in the minimum operation mode, Km=1.63, which meets the requirements of the design procedure manual (Kd 5). According to the squirrel-cage motor, the no-load starting current duration is 5s, and considering that if three 6kV motors are started at the same time, the starting current reaches 487A, which is greater than 457A. Therefore, the action delay of the overcurrent protection takes 6s. As for other protection, Can be calculated according to the conventional setting. 4 Conclusion Lianzhou Power Plant Desulfurization System During the trial operation, several sudden power failures occurred in the 6kV working section, but when switching to the spare section automatically or switching to another 6kV working section, both transformers can be avoided at the same time. Magnetizing inrush current and starting current of three 6kV motors. It shows that the electrical system is designed reliably, the calculation is correct, and the safe operation of the desulfurization system is guaranteed. : Luo Yong (1963 -), male, Guangdong Xingning people, power system automation engineer, mainly engaged in relay protection debugging and automatic device development work. (Continued from page 51) Receive a good signal from the other party's antenna. The half power angle of a 3 m diameter parabolic antenna is 08°, and the half power angle of a 2 m diameter parabolic antenna is 1. 51.2 m diameter parabolic antenna has a half power angle of 3°. Therefore, the vertical position of the antenna can be treated as the initial pitch angle of the antenna, so that the four independent variable angles of the two antennas are reduced to a two-variable system with only a horizontal azimuth angle, indicating that the weight line method is simpler than the traditional theodolite method. 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