Analysis of 300MW Generating Set Coordination Control Technology Han Zhihong (Shanxi Sunshine Power Co., Ltd., Pingding 045200, Shanxi, China) The advantages and disadvantages of coordinated control and the problems that restrict the coordinated control, analyzes the abnormal working conditions that occur during operation, and takes them more concretely. The measures for rectification have been taken out, and proceeding from reality, the proposals or solutions to the problems have been elaborated.
1994 The original principle of engineering 4 large (study thermal dynamics professional a:drumalElectronicPublish dust constant Us should be specified in a range. H through the operation summary i,. N negative 1 system introduction Shanxi Sunshine Power Co., Ltd. 300MW generating unit coordination control system It has been gradually implemented since 1998 and has been in operation for more than 3 years. With the unit from operation to stable operation, the primary equipments of various specialties such as machines, electric furnaces, heat, etc. have undergone relatively comprehensive improvement and rectification, achieving relatively reliable results. From the original 50% to the current 100%, the protection input rate reaches 100%, the unit is controlled within 180MW~300MW load, CCS (Coordinated Control) is realized, and even AGC (Scheduling Control) is implemented, greatly improving system automation. The degree has reduced the labor intensity of the workers, greatly improved the efficiency of the power plant and the production of safe and civilized production. However, in terms of coordinated control technology, it is still influenced and restricted by many factors. Many problems have appeared during its use, even It has threatened the safety of the crew and caused many anomalies, obstacles or even accidents to occur. Adjust control technology for some discussion.
2 Problems during Operation and Suggestions for Corrective Actions 2.1 Maladjustment characteristics of coal mills The double inlet and double outlet coal mills are the pulverizing systems for the No. 1 and No. 2 furnaces of the Sunshine Power Generation Corporation. Each furnace is equipped with 4 mills. Positive pressure blowing type, grinding force adjustment is carried out by the load adjustment flap operation. In the case of manual operation, the operator can make artificial adjustments according to the coal amount and the pressure of the mill barrel, but under the coordinated control, the adjustment characteristics of the individual coal mills are bad and different. When it is put into coordination, there will be the phenomenon of individual adjustment of each table mill. As a result, the deviation of A, B, C, D 4 mill parameters will be serious. Some of the mill air has exceeded the protection setting, and the coal supply is greater than 50t/h. (Stipulate less than 40t/h) and some mill primary air volume is obviously lower, cylinder pressure is lower than 3kPa, powder out is obviously difficult, especially during lifting load, dynamic adjustment is even more inappropriate and this will cause part of the grinding block. , Part of the mill is idling without powder, so that the combustion deteriorates. Even if the fire is not adjusted, it will result in both safety and economic consequences. According to the coordinated control input conditions, any coal mill load control system will be automatically put into operation and the primary air volume will be ground. The signal is normal. However, due to the fact that the primary equipment cannot be accurately operated during the actual operation, the tracking is slow or over-tuned, which results in difficulty in the coordination of inputs. It can be seen from the above that it is necessary to first solve the adjustment characteristics of the coal mill and make great efforts in the primary equipment reform. , To achieve the synchronization of the performance of the four mills and excellent only this can create the conditions for the normal work of the coordination system, in order to ensure the safety and economic benefits of the power plant enterprises double harvest 2.2 The impact of the unit load set value and load rise rate in the coordinated control operation On the unit, the first step in carrying out load lifting is the load setting. This operation is manually intervened by the operator. If there is slight negligence, for example, 250 MW is changed to 25 MW when the set value is changed, the unit will dump the original load. At 25 MW, a load shedding accident has occurred, causing a large loss. This is a wrong instruction and leads to serious consequences. In order to prevent this from happening, in addition to enhancing the quality of the operators and the responsibility for safety, consideration should also be given to coordinating settings such as using more than 20 MW of instructions to block without executing, that is to say, the coordinated control only accepts less than 20MW (including 20MW) instructions, this will be foolproof, so as to avoid unnecessary losses. Load rise and fall rate refers to the rate of change of the load, the unit is MW / min, the set value of the unit load rise and fall of Sunlight Power Generation Company 6MW/min Practice proved that the load For the determination of the lift rate, the lift rate cannot be affected by the following factors: It can be seen that only the operator can change the load lift rate to adapt to the requirements of variable operating conditions according to the actual situation. 2MW/min~/min, otherwise it will cause the parameter to fluctuate violently, and may cause various accidents. 2.3 Track adjustment characteristics of the machine side adjustment and the main engine thrust pad working conditions In the coordination control, the machine side adjustment door moves according to the pressure curve, Maintaining the pressure in front of the door to meet the specified value is based on this design concept and it is indeed possible to ensure steaming. Parameters, especially the main steam pressure qualified. However, when the load is high, especially at full load of 300 MW, due to the furnace side adjustment is not very accurate, or even inaccurate, resulting in overshoot, so that the pressure immediately before the door exceeds the maximum 17. 4MPa, this will make the unit Bypassing the system to operate, and the phenomenon of overloading the unit, poses a great threat to the unit's safety. To prevent this from happening, in addition to the coordination ability of the relevant professional, consider that the pressure curve set by the host to adjust the gate tracking should be smooth, so that the door control action will become more advanced, so that the pressure will not increase to the limit, resulting in consequences. The turbines produced by the Dongfang Steam Turbine Plant used by Sunlight Power Generation Co., Ltd. do not require the load of the thrust pad work to suddenly rise suddenly, and the pressure change should be stable. If the fluctuation is severe, there may be the possibility of burning the tiles and cause malignant accidents. As far as possible, consider the smooth transition of the parameter curve to protect the normal operation of the host device.
2.4 Definition of the load area and the method of coordinating investment and retreat Sunlight Power Company's 300 MW unit has a wide load area and is a power plant with peak load adjustment capability. According to the manufacturer's regulations and practices, it is proved that each auxiliary machine operates well from 300MW to 180MW, and the coordinated control system is suitable for this interval. If it is lower than 180MW, not only the water level and the combustion are difficult to control, but also the auxiliary machines, especially the coal mill, the primary fan, and the induced draft fan, cannot be normally adjusted, which causes the coordination and control to be disordered and may cause accidents. Therefore, the general sunshine company coordinated the control of the adaptive load. The area should be between 180MW and 300MW. In the event of an abnormal situation, timely exit from the coordination is an important link to ensure the safety of the unit, but the exit should strictly abide by the regulations. Firstly, the fuel master will be withdrawn, the air supply will be automatically followed, the coal mill will be automatically withdrawn, and the boiler main control will be automatically tripped, so that the furnace side combustion system will no longer be controlled by the coordination instructions and will be stabilized under one working condition. Then release the automatic turbine, manually intervene in the pressure adjustment, carefully check the status of the fixed-sliding pressure switch, correct calorific value, etc., especially when the pressure near the 300MW load of the unit is high, the solution coordination shall be executed urgently, and manual intervention shall be provided. The unit is stable. If the condition of tight stop is firmly implemented, it shall not be robbed. 2.5 Principles to be followed in typical fault handling. When an auxiliary engine fails before the unit has a RUNBACK test, the operating personnel removes the coordinated control system and manually intervenes to keep the unit stable. If the RUNBACK test is completed, it should be adjusted by the coordinated control system.
3 mills running, 1 mill brake, coordination should be cut to follow the machine, boiler control instructions down to 180MW, pressure set value changes to a certain rate of 14MPa, and fuel injection to help 2 sets of blower operation, 1 blower out After the gate, coordinate the machine to follow the way. If the unit is running 3 mills, the 3 mills will reduce the load at the same time. If 4 mills are running, the mill will jump to D. The other 3 mills will reduce the load at the same time. The value is 200MW, and the pressure setting is 14. The feedwater pump and the blower during the operation of the primary fan shall automatically exit the coordination system and the fuel master control system. The operator shall manually intervene to complete other operations. When the various accidents are processed, the system is stable. , Reach the coordination system control when the operating conditions are met.
3 Conclusion The No. 1 and No. 2 units of Sunshine Power Generation Co., Ltd. have now used a coordinated control system. The mutual coordination ability between the furnace and the boiler is obviously higher than the manual state, and the unit efficiency has been shown out. Because the coordinated control strictly follows the set curve, Parameter control is in place to ensure the safe operation of the unit. Although the benefits are obvious, there are still a lot of unsatisfactory aspects in the actual operation. It also requires a large number of employees and professionals to jointly solve and conclude a more mature coordinated control method.
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