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Problems existing in electrical design of auxiliary engine oil station of thermal power plant and reconstruction methods

2021-09-03

Abstract: With the development of Chinese economy, the demand for energy increases gradually, the output of electric power energy has a very important role in people's production and life, in the production of thermal power plant, including secondary fans, fans and turbofans and other related auxiliary machines in the actual operation, often appear obstacles, which is not conducive to the improvement of production efficiency. In order to solve this problem, it is very important to carry out corresponding lubrication to improve its reliability and ensure the normal operation of the fan. Therefore, this paper analyzes the problems existing in the electrical design of auxiliary oil station of thermal power plant and the transformation methods, analyzes the problems existing in the electrical design, and puts forward corresponding solutions, so as to improve the operation efficiency of auxiliary equipment of thermal power plant and improve the output benefit.


Key words: thermal power plant; Auxiliary oil station; Electrical design

In the normal operation of the thermal power plant, the auxiliary equipment used has a variety, so the effective protection of these equipment has a positive significance for the safe operation of the thermal power plant, which mainly includes condensate pumps, circulating pumps and induced draft fans. In these auxiliary equipment, the condensate pump and circulating water pump and other equipment will have a fault trip, in this case the unit's action will image the load reduction state, so the failure of the operation will cause the unit trip. In addition, in the auxiliary equipment, there are oil station equipment such as induced draft fans, supply fans, etc., and the failure of the oil station will directly lead to the outage of the auxiliary equipment, so the load and safety of the unit will be affected accordingly. The thermal power plant attaches great importance to the safe operation of auxiliary equipment, and it has positive significance to the stability of equipment operation by reforming related equipment.


First, analysis of power supply problems of auxiliary equipment oil station

In many auxiliary equipment, there are two power supplies for the corresponding equipment such as the supply fan and the induced draft fan. These two power supplies mainly come from the security section and the boiler MCC section. The power supply exists in a cross-matching way, and they are both spare [1]. There are two oil pumps and corresponding heaters in each auxiliary oil station equipment, and the power supply mainly comes from the lower bus bar of the power switching device in the control box. In the case of failure and tripping, the power supply system will maintain normal state, and the standby oil pump will be started, and the auxiliary machine can achieve normal operation. When the working power supply of the oil station fails, the double-throw switch will automatically switch, transfer to another power supply, start the oil pump, and ensure the normal operation of the auxiliary machine.

The main risks in normal operation are that the two power supplies of the oil station cannot be switched, and in the actual switching process, there is an instant loss of power, which will lead to an instant shutdown of the oil pump, and then start the standby pump. The heater power supply of the oil station is mainly taken from the lower port of the power switching device. In actual operation, the heater has a high probability of failure, so it often produces grounding phenomenon. When the switch rejection occurs, the power supply of the control box of the oil station will be shut down, the two oil pumps will be shut down, and the auxiliary equipment will trip [2].

In the actual operation process, the equipment using the same control power supply mainly has two oil pumps, heaters and thermal control power supply, the control loop grounding situation in the control box, or the loop is loose, the control power will lose power, resulting in the two oil pumps out, and then the auxiliary equipment will trip. The main control mode in the local control box of the oil station can select the corresponding switch SAI, and then the control form of the oil pump and heater can be converted into a remote or local control, which will cause the control power loss in the actual switching process, and the actual operation, the influence of human factors, will also cause the two oil pumps to stop running. The auxiliary equipment has tripping risk.

In addition, the volume of the control box is relatively small, and its internal control components are more, so the auxiliary equipment is grounded, and the external environment is not good, it will lead to the failure of the electrical equipment, and lead to the problem of dual power switch, resulting in the two oil pumps stop running, and the auxiliary equipment has the risk of tripping. In addition, the maintenance of auxiliary equipment is not timely, which will also cause the risk of tripping. Because the control loop used by this equipment is a public power supply and the volume of the control box is small, the internal devices are relatively tight. When an oil pump trips, the control power will stop running during the actual maintenance process, resulting in tripping risks for auxiliary equipment [3].


Ii. Analysis of reform measures

The main transformation measure for the power supply of the oil station is to carry out dual power supply to achieve automatic switching, which can ensure that the local control box of the oil station can achieve power supply for all equipment, and the power cable in the use process, due to its length, often produce the corresponding fault problem, for the upper level of the power supply lacks the corresponding stability. When the power supply and cable fault of the upper level is generated, the standby oil pump can be used to run, and the fault treatment can be carried out in time. During the processing, there is no standby oil pump, and the safety of the auxiliary machine operation will be greatly reduced. However, after the use of dual power supply, in the case of the upper power supply or cable failure, the device will automatically switch the standby power supply, and the use of the oil pump will still maintain one operation and one backup, so as to improve the stability and safety of the operation of auxiliary equipment [4].

With the gradual optimization of the layout of the thermal power plant, its structure is gradually improved, therefore, the use distance between the security power supply and the auxiliary equipment is gradually shortened, which is for different production processes and on-site construction are carried out corresponding management to improve, and the oil station power supply and cable failure rate gradually decreased. In the distribution room, the security power supply environment is higher, and different security segments have different power supplies, which can realize automatic switching and greatly improve the stability of the power supply. In the traditional design, there are many hidden dangers, so it is necessary to improve the stability of the auxiliary oil station system. After that, special control forms are mainly used to separate the power loop and the control loop, so as to improve the stability of the oil station operation.

The transformation of thermal control power supply is mainly divided into two power supplies, and then the two oil pump switches are obtained at the upper port. After the power conversion device, DC power supply is provided to achieve switching. In case of oil pump power failure, the thermal control power supply will not be affected, and the circuit normalization of the standby oil pump is guaranteed [5].


In SUMMARY:

The control box of the fan oil station is cancelled, the oil pump is switched, the stability of the fan operation is improved, and the problems are checked and effective measures are taken to solve them, so as to improve the effectiveness of the equipment operation. In the process of fan operation, the oil pump chain signal is difficult to connect, there is no need to check the relay problem, through the corresponding equipment to find the chain logic conditions, according to the cause of its failure, the implementation of effective solution. This method can simplify the work content of the staff, improve the work efficiency and reduce the operation risk.


References:
[1] KONG Xianghua. Reliability Analysis and Transformation of Power Supply of important auxiliary oil Station in thermal power Plant [J]. Shenhua Technology, 2018, 016(002):43-44,51.
[2] Ma Hui, Li Feng, Yang Rui. Analysis of Problems in Secondary Circuit of Power Plant Relay Protection and Improvement Measures [J]. Commodities and Quality, 2017, 000(047):86.
[3] JIANG Qiuhua. Technical Improvement of control loop of boiler air preheater in Qiandong Power Plant [J]. Shandong Industrial Technology, 2016(13):179-179.
[4] TIAN Yang. Research on the reconstruction of Automatic oil circuit [J]. Architectural Engineering Technology and Design, 2018, 000(024):4197.
[5] LIANG Yongshu, Xu Yien, Yin Xinhua. Research on existing problems and renovation plan of cooling water system of generator set in Xiantan Power Plant [J]. Guangdong Water Resources and Hydropower, 2016(8):52-55.

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