Based on the dynamic vibration absorber method, analysis on abnormal vibration of vertical condensate pump motor and vibration reduction measures are carried out. According to the vibration characteristics of the condensate pump motor, the design method of power vibration absorption is studied theoretically, and the power vibration absorber is developed and designed and applied to the actual unit. The results show that, the dynamic balancing method has certain limitations in alleviating the vibration exceedance of the condensate pump motor during varying frequency operation, and cannot reduce the vibration amplitude of the condensate pump motor in both directions at the same time. The mass participating in the vibration of the condensate pump system shows a growing change with the increasing additional mass, and the first-order vibration mass at the top of the condensate pump motor is about 6 000 kg (X direction) and 7 000 kg (Y direction). With mass ratio of 2%, 5% and 10%, the maximum vibration amplitude in X direction is reduced by 80%, 83% and 86%, and the maximum vibration amplitude in Y direction is reduced by 68%, 77% and 83%. The dynamic vibration absorber device effectively reduces the vibration in both directions, and the actual reduction of vibration in X and Y directions is about 53% and 66% during the whole frequency operation period. The vibration control method based on the dynamic vibration absorber of the condensate pump motor has an excellent vibration reduction effect.

In view of the frequent failure of power generation equipment under the background of frequent deep peak regulation, flexible operation, energy saving and consumption reduction of thermal power units, a coal mill fault warning method based on multiple state estimation-analytic hierarchy process is proposed. Firstly, based on the characteristic parameters of coal mill Spearman correlation analysis for dimension reduction, equidistant sampling method is used to extract some samples from a large number of coal mill history data memory matrix, after normalization, memory matrix is formed. Then, multi-state estimation algorithm is adopted to calculate the corresponding memory estimated vector according to the memory matrix and the observation vector. The characteristic parameters are given different weights by using analytic hierarchy process (AHP), and the fusion similarity between the observed vector and the estimated vector is calculated, and the fault warning of coal mill is carried out based on the adaptive threshold method. Finally, the actual fault data of a roller medium speed coal mill is taken as an example to verify the effectiveness of the method. The results show that, this method has less misalarm rate and false alarm rate for coal mill fault warning, which can reduce the actual fault probability of coal mill to a certain extent.

As the proportion of new energy power generation continues to increase, the stability of grid frequency is severely challenged, and the role of conventional thermal power units in grid frequency regulation has become increasingly prominent. However, the adjustment rate and accuracy of some thermal power units are difficult to meet the demand of grid load fluctuations. Therefore, a response performance optimization strategy for flywheel-thermal power system automatic generation control based on load forecasting was proposed. Firstly, the load is predicted, using the tree-based pipeline optimization tool TPOT library to automatically machine learning to match and train the load regression prediction model, and the automatic generation control day-ahead planned value is introduced into the training data to reduce the prediction error. Then, according to the load prediction value and the current flywheel system, with the optimization goal of minimizing the regulation rate of thermal power units, the flywheel energy storage system is acted firstly in load distribution, and the state of charge of the flywheel is adjusted meanwhile. Finally, a simulation experiment is carried out based on the actual operation data of a power plant in Hubei, and the experimental results prove that the proposed method can effectively improve the frequency modulation performance of thermal power units.

The main-auxiliary combined indirect dry cooling system has attracted attention from the industry in recent years, while few scholars at home and abroad have conducted studies on its flow and heat transfer performances. In order to investigate the transport characteristics of the main-auxiliary combined indirect dry cooling system under different configurations, this paper establishes six physical models of the combined indirect dry cooling systems with the double-layer/single-layer main and auxiliary radiators. And then the cooling performances are analyzed and compared using the commercial software FLUENT. The results show that, the construction has obviously higher impacts on the auxiliary cooling system than the main one, meanwhile the air mass flow rate presents larger difference than the heat rejection; In absence of wind, the main-auxiliary combined cooling system with double-layer heat exchanger arrangement, has better cooling performance than that with the single layer heat exchanger arrangement, and case A possesses the best cooling performance; Under crosswind effects, case C has highest cooling capability of the auxiliary cooling system, while the behavior of its main cooling system should also be considered before the engineering selection. This research may provide some theoretical guidelines for the engineering design and application of the main-auxiliary combined natural draft dry cooling system.

In order to realize the cold end optimization of direct air-cooled units, a cold end operation optimization method of air-cooled units is proposed based on the historical operation data of units and combined with data mining and deep learning algorithm. Firstly, the obtained historical operation data are screened in steady state and divided into working conditions. Combined with the Gaussian mixture model algorithm, the back pressure reference interval of the unit under multiple working conditions is determined. Then, the Spearman coefficient method is used to select the characteristic variables, and the back pressure prediction model of the direct air cooling unit is constructed in combination with the gated circulation unit. The back pressure optimization suggestions and early warning information are given by comparing the back pressure reference interval with the back pressure prediction value. Finally, the method is applied to a subcritical 300 MW air-cooled condensing steam unit. The results show that the back pressure optimization method proposed in this paper can give effective back pressure early warning information and realize optimal operation of cold end of the air-cooled unit.

"Three-renovation" (energy-saving renovation, flexibility renovations and heating renovations) of coal-fired power is an effective measure for clean and low carbon utilization of coal. The paper analyzes current energy efficiency, flexibility and heating situation of coal-fired power, and researches the policy requirement, implementation progress and expected effect of "Three-renovation". In terms of technical difficulty, energy saving renovation is the most difficult, followed by flexibility and heat supply. It is anticipated that the coal consumption for power supply will be decreased to about 297 g/(kW·h), the additional peak regulation capacity will be over 40 GW and the heating scope will be further expanded. In view of the problems such as large coal power loss, difficult technical transformation of some types, hidden safety risks of equipment under low load operation, unanticipated input and output of renovation, and small financial support of renovation, this paper puts forward measures and suggestions to promote the "Three-renovation" from the perspectives of policy, technology, standards and market.

The existing GIS disconnector contact state evaluation method is based on the single state characteristic quantity, the reliability of the evaluation result is low, and it is easy to misjudge and erroneous judgment. So a method of GIS disconnector contact state evaluation based on multi-feature fusion was presented. The multi state quantity comprehensive detection experimental platform of 220 kV GIS disconnector was built. And the relationships between the GIS disconnector shell temperature signal, shell vibration signal, partial discharge signal and the contact state of the disconnector were experimentally studied. On this basis, the temperature rise of GIS disconnector shell, the amplitude of shell vibration signal and the discharge amplitude of partial discharge UHF signal were taken as the state characteristic quantities of disconnector, and the contact state evaluation model of disconnector based on support vector machine was established. The test results show that the accuracy of GIS disconnector contact state evaluation method based on multi-feature fusion is the highest, can reach 92.92%.

A field test of paper mill sludge and coal co-firing was conducted on a 600 MW unit boiler to explore the effect of mix-firing sludge on the formation and emission of dioxins (PCDD/Fs). Under the conditions with and without sludge co-firing, flue gas samples at the inlet and outlet of drying-charring machine, the inlet of selective catalytic reduction (SCR) equipment, the outlet of air preheater and chimney as well as solid samples including raw sludge, dried and partly charred sludge, slag and fly ash were collected, and the PCDD/Fs were analyzed by a high-resolution gas chromatograph combined with high-resolution mass spectrometer. The obtained results indicated that, co-firing sludge (accounted for about 1% (weight percent) of pulverized coal) did not result in the formation of PCDD/Fs via high-temperature gas-phase homogeneous formation mechanism and medium- and low-temperature catalytic formation mechanism, and did not increase the emission of PCDD/Fs to atmosphere. The international toxic equivalence quantity (I-TEQ) concentrations of 6 chimney gas samples collected under the condition with sludge co-firing were in the range of 0.008~0.013 ng/m³ (average value: 0.010 ng/m³), which did not significantly differ from that (0.008~0.015 ng/m³, average value: 0.012 ng/m³) of the 6 chimney gas samples collected under the condition without sludge co-firing. It was found that, a small quantity of PCDD/Fs was formed during sludge drying-charring process. The newly-formed and original PCDD/Fs in sludge could be completely destroyed by high temperature in coal combustor. The SCR catalyst induced the catalytic degradation of PCDD/Fs, especially the highly-chlorinated dioxins. The concentration of the PCDD/Fs in fly ash samples were lower than 0.2 ng/m³, indicating its resource utilization could not pose dioxin pollution risk to ambient environment.

Combined heat and power (CHP) units are affected by the output fluctuation of large-scale operating conditions, resulting in poor overall control quality of power generation load-extraction steam flow-throttle pressure in the turbine-boiler coordinated control system. To solve this problem, a multi-condition adaptive control method based on multi-agent deep deterministic policy gradient (MA-DDPG) is proposed. Firstly, according to the nonlinear dynamic mechanism of the unit, multiple operating condition sub-models considering the changes of state parameters are established, and the optimal operating condition sub-model is obtained by the integral function switching mechanism. For the multi-loop complex control requirements of the coordinated control system, a multi-agent synchronous operation mechanism is proposed, and the reward function is designed with the coordinated control objectives of rapid response, stable heating and safe operation. Finally, by training the agent to interact with the environment, the multi-loop gains are continuously adjusted online to achieve multi-condition adaptive control. Simulation results show that, compared with the conventional control method, the proposed method can effectively improve the load response rate under wide range operating conditions, and ensure the stability of heating.

A mathematical model of subcritical organic Rankine cycle (ORC) system is established for the flue gas waste heat of 120~150 ℃. Firstly, the thermal performance and economic performance of the system are analyzed at different heat source temperatures by taking R245fa as an example. Then, a multi-objective optimization study is conducted for six pure working fluids based on NSGA-Ⅱ algorithm. At last, working fluid selection and performance analysis of the ORC system with various heat source temperatures are carried out by TOPSIS method and gray correlation analysis. The results show that, in the temperature range of this study, the increase of superheat degree and evaporator pinch point temperature difference is not conducive to improve the system performance. The optimal working fluids are varied at different heat source temperatures, when the heat source temperature is 120 ℃, R601 has the best thermal performance, R245fa has the best economic performance and R1233zd has the best overall performance. The increase of heat source temperature is beneficial to improve the economic performance of the system. The optimal evaporation temperature of each working fluid increases with the heat source temperature. The gray correlation analysis indicates that the comprehensive performance of all six working fluids improves with the heat source temperature.