1 Overview The installed capacity of the first phase of the Zhongzhou Aluminum Plant thermal power plant is three 130t/h medium temperature medium pressure boilers and three 6MW back pressure steam turbine generator sets. If two boilers are running, there is still rich steam. In order to give full play to the intrinsic potential of Zhongzhou Aluminum Plant and the favorable conditions in technological transformation, a C12-3.43/0.49 extraction steam condensing turbine generator set was added in 1999.
At present, the main electrical connection line of the Zhongzhou Aluminum Plant and the status quo is that the 110 kW Ximu and Dongmu sections of the Hanzhong West Section of the East Hanwang Regional Substation in Jiaozuo District are respectively operated with 1, 2 main transformers, and the main 6.3 kW system is divided into I, segments and spares. Busbar, I section is connected to two 6MW generators, the section is connected to a 6MW generator, the new 12MW generator (4 generator, 4F) access section, the step-up transformer is still 31.MVA. 2 Short-circuit current Calculate the addition of a 12MW generator on the segment busbar. The main transformer 2B is calculated according to the current situation of 31.5MVA, and the calculation result is as follows: 4F circuit internal three-phase short circuit, short circuit current through the circuit breaker: 3F short circuit inside the 3F circuit, short circuit current through the circuit breaker: I, the three-phase short-circuit current on the segment bus is less than the segment (the short-circuit current value when taking 0.06s, is the opening time of the circuit breaker < 3 generator breaker Technical Analysis The generator breaker currently used by the Zhongzhou Aluminum Plant's own thermal power station is the SN4-10G/5000 type oil-less circuit breaker. Its maximum short-circuit breaking current is 58kA. According to the initial calculation, the maximum short-circuit current is 0.2s. It is 56kA and less than 58kA, which can meet the requirements of use.
In the preliminary design provided by the original research institute, it is recommended to use LN-18 type sulphur hexafluoride generator breaker. The main performance parameters are: maximum voltage 18kV, rated current 6.3~8kA, rated short-circuit breaking current 6380kA, mechanical life 5000 Second, the hydraulic operation, the opening time is less than 40ms, fully meet the requirements of use. However, the price of the LN-18 type sulphur hexafluoride circuit breaker is about 600,000 yuan, which is about 23 times higher than the SN4-10G/5000 type oil-less circuit breaker. The one-time investment is too large; and because it is a single piece of equipment, spare parts It is difficult to organize, which will inevitably lead to an increase in stocks and a waste of funds.
After multi-party analysis, consultation and demonstration, the ZN65A-12/T4000-63 vacuum circuit breaker produced by a factory in Beijing was selected. The main performance parameters are as follows: rated voltage is 12kV, rated short-circuit breaking current is 63kA, rated short circuit The combined current (peak) is 160kA, and the rated short-circuit breaking current is 8 times (8 times for domestic arc chamber and 20 times for Siemens arc chamber), the opening time is 30~60ms, and the mechanical life is 10000 times. Its performance is better than LN-18 circuit breaker, fully meet the requirements of use; and the price is relatively moderate, the price of the circuit breaker of Guoguang Arc Chamber is about 150,000 ,, and the price of imported Siemens arc-breaker circuit breaker is only 250,000 yuan. Left and right, the price of the same oil circuit breaker is equivalent. In addition, the vacuum circuit breaker has a small volume, a small amount of civil works, and basically does not use embedded parts, and the one-time investment is small.
Therefore, the 4 generator breaker uses the ZN65A-12/T4000-63 vacuum circuit breaker.
4 Economic Analysis of Generator Circuit Breakers The Zhongzhou Aluminum Plant currently has three generators, all of which use SN4-10G/5000 type oil-less circuit breakers. They have been in operation since they were put into production in 1993. With the passage of time, the defects of the oil-less circuit breakers are gradually exposed. The oil-less circuit breakers usually have to be disassembled and inspected at least once in one year of operation. At least 46 hours after the operation, the power-off check is required. After each severe short-circuit fault is cut off. Also need to open the inspection. When dismantling, it takes about 5 people to complete the inspection, and 400kg of oil is replaced each time. The labor and materials cost for each dismantling inspection is about 10,000 yuan. The closing time of the oil-less circuit breaker is also long, and sometimes the closing is not in place. If it is not timely, a serious accident of burning the generator will occur. In addition, the closing coil is often burnt out, and it takes 8,000 yuan to purchase a closing coil. In this way, the annual maintenance and maintenance costs are about 50,000 yuan.
4 The generator selected ZN65A-12/T4000-63 vacuum circuit breaker, which has been running for nearly one year, has been in good condition and has never been checked. According to the instructions, the circuit breaker is maintained once after 10 years of use or 1000 times of operation. The last time the lubricating oil is tightened and the screws of each part are tightened. The vacuum interrupter is used for 20 years or the short-circuit current specified in the technical parameters is reached. After the number of breaks, it is necessary to replace the arc extinguishing chamber, and the annual maintenance and maintenance costs are basically eliminated. In addition, it can also reduce the loss of power generation caused by the shutdown of the circuit breaker maintenance operation (less operation lh, calculated according to 0.4kWh, that is, loss of 48,000 yuan). Therefore, the ZN65A-12/T4000-63 type vacuum circuit breaker has fewer advantages in terms of technology and economics.
At present, the three small oil circuit breakers SN4-10-G/5000 of Zhongzhou Aluminum Factory have all been replaced with ZN65A-12/T4000-63 vacuum circuit breakers.
弋Oriental. Power Engineering Power Design Manual. Beijing: Water Power Press, 1989. Wang Suying. Factory common electrical equipment manual. Beijing: China Electric Power Press, 1997. (Continued from page 45) transmits information to the programmable controller. Set the Valueref. Part REF1 is the data defined by DAT(I).
According to the process parameters of the 1450 bending correction, the PC elements are programmed, and then debugged in the order of compiling, connecting, locking, downloading, saving, online, unlocking, and the like.
2C200H setting and programming 2.1 message board COM06 setting 2.2 programming 2.3 protocol content table 2 protocol sequence communication sequence control response time, s send no scan reception no scan table 3 send, receive set single step command repeat number send information receive information response send send And receiving is receiving, sending and receiving is table 4 sending, receiving content information name check code data content sending information list receiving information list Note: slave address; decimal 16, write multiple registers; decimal 100, starting from register 100, That is, starting from 4101; decimal 30, write 30; decimal 60, 60 bytes. Read register; start at 4100; decimal 30, write 30. (W(DM2061), 8) Put the response of the register into consecutive 8 bytes starting from DM2061. (W(DM2031), 8) Put the response of the read register into consecutive 60 bytes starting from DM2031.
3 Conclusion For more than half a year, the entire 1450 straight line straightening machine production line is in good condition, indicating that the AC80 controller and the C200H programmable controller PLC communicate with Modbus protocol, the system is stable and reliable, and it is an ideal system. communication.
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