The continuous penetration of internet technology into industrial control field has given rise to conceptual systems such as Industry 4.0 and Industrial Internet. Consequently, power plants are evolving towards digitization and informatization, with the intelligence and complexity of field-controlled objects increasing steadily. Control functions of conventional distributed control systems (DCS) are gradually becoming inadequate to meet these new demands. To enhance the maturity level of intelligent manufacturing in China, it is essential to strengthen the core computational control functions of DCS. In response, a novel collaborative control platform is proposed based on software-defined principles. This platform decouples the software and hardware of conventional DCS using software-defined concepts, reconstructs the control and configuration functions on the host computer, and designs and develops a dual-redundant computing engine and configuration and debugging tools. Additionally, protection mechanisms are established to ensure the operational security of the platform and the security of third-party data. This platform inherits the conventional configuration and control functions of conventional DCS while additionally supporting the implementation of various advanced intelligent algorithms. In terms of application, it can both enhance the control performance of conventional DCS and serve as an independent product providing high-quality computing services for other control systems. Consequently, it can be widely applied to various process control scenarios, offering users a reliable, efficient, flexible and cost-effective production control solution. Moreover, it provides an optional platform foundation for the future integration of cutting-edge computer technologies such as artificial intelligence and big data into DCS.

The safe and stable operation of submarine oil-filled cables is critical, but the internal dodecylbenzene (DDB) insulating oil is subject to rapid pyrolysis and gas production at localized high temperatures due to thermal faults. Against this issue, the pyrolysis and gas production processes of dodecylbenzene insulating oil are investigated based on reactive molecular dynamics simulations (ReaxFF-MD) and thermogravimetric-infrared spectroscopy (TG-IR) experiments. The pyrolysis simulation results show that, the initial cracking reaction of the dodecylbenzene molecule is mainly the breaking of C—C bond to produce long-chain macromolecules, and then the gradual pyrolysis produces small alkyl radicals and olefinic molecules, and the DDB will eventually be pyrolyzed to the short-chain alkylbenzene molecules with the side chains of ·C₂H₅, ·CH₃ and ·C₃H₇ groups. The main characteristic gases during pyrolysis are C₂H₄, H₂, and CH₄, which are the same as the results of IR experiments, and the main reaction mechanisms for the generation of the characteristic gases are: (i) the breaking of the C—C bond at the β-position, the hydrogenation reaction, and the dehydrogenation reaction; (ii) the attack of -H radicals to the H atoms on other radicals; and (iii) the reaction of the methyl radicals (·CH₃) with the free hydrogen (·H) radicals, respectively. The kinetic results show that the activation energies of the TG experiment and ReaxFF-MD are 86.606 kJ/mol as well as 99.867 kJ/mol, respectively, and the similar activation energies further validate the reasonableness of the simulation results. The study conclusion provides theoretical support for deep understanding of the cracking and gas production mechanism of dodecylbenzene insulating oil.

In order to enhance the wind power consumption rate, achieve the goal of energy and power carbon peak and carbon neutral, with the goal of the lowest comprehensive cost of the power system, a new energy power system low carbon economic optimization method is proposed to establish the source and load side of the planning model. Firstly, on the source side of thermal power units, low-carbon transformation is performed, and a solution memory and flue gas bypass system is set up to make the unit become a liquid storage carbon capture unit, and dispatchable resources of photovoltaic power plant (concentrating solar power, CSP) and storage battery is introduced to coordinated with wind power. Then, on the load side, the price and incentive-type demand response resources are used for peak shaving and valley filling, and adjusting the users’ power consumption behaviors and power consumption. Finally, four cases are verified, and the results show that, the decarbonization of the power system from both the source and load sides can help promote wind power consumption, increase the share of renewable energy generation, enhance the low-carbon performance of the system, and save costs.

This paper focuses on aggregating decentralized demand-side resources through virtual power plants (VPPs) to enhance the peak load management capability in the construction of new electric power systems. The research centers on the core issue of “load-based” virtual power plants participating in power source planning. It investigates the modeling methods for the adjustable potential of virtual power plants, including electric vehicles, air conditioning loads, and industrial loads. Moreover, the paper delineates the economic and operational technical constraints of virtual power plants in power source planning and constructs a power source planning model that accounts for VPPs. Considering the prediction errors of renewable energy and the characterization errors of the VPPs’ response potential, the paper utilizes interval optimization theory to reformulate the model into an interval planning model and completes the deterministic transformation of the model through interval order relations and interval possibility. The rationality of the proposed power source planning method is verified through a case study. The results show that the proposed method can effectively aggregate VPP resources, significantly enhancing the system’s peak load management capability. The constructed interval planning model can effectively handle forecast errors, ensuring the reliability of planning. This method provides an economically feasible solution for the transformation of the source-load structure in new electric power systems. It is evident that the aggregation and optimized dispatch of VPPs can significantly enhance the flexibility and reliability of the power system.

In order to solve the problems of waste heat utilization, carbon capture and liquid natural gas (LNG) cold energy utilization of solid oxide batteries fueled by methane, a new type of combined cooling, heating and power system was established. The system includes the improved recompression supercritical mixed working fluid Brayton cycle, the transcritical CO₂ heat recovery Rankine cycle and the secondary mixed working fluid organic Rankine cycle. The thermodynamic analysis, equipment exergy analysis, economic cost analysis of the circulation system, and the multi-objective optimization of the system by using the genetic algorithm in MATLAB. The results show that, increasing P1, T16 and the mass fraction of R14 in the second-stage Rankine cycle can improve the network, thermal efficiency, and exergy efficiency of the system, and reduce the average unit cost. P1 is the pressure at inlet the expander in the compressed supercritical mixed working fluid Brayton cycle, T16 is the inlet temperature of the expander in the transcritical CO₂ regenerative Rankine cycle. Under the optimal working conditions, the thermal efficiency, exergy efficiency and average unit cost of the system are 64.70%, 47.85% and 24.20 dollars/GJ.

Aiming at the case of large frequency fluctuation in natural gas unit black start project, combining with the gas black start system and the waveform diagram during static frequency convertor (SFC) startup, the failure phenomenon is described in detail and the specific cause of the failure is analyzed. On the basis of considering the slow response speed of diesel generator unit, a super capacitor-assisted black start frequency modulation (FM) strategy is proposed. The SFC power is divided into base power and frequency fluctuation power, among which the base power is borne by the diesel generator unit to ensure stable operation of the system, and the frequency fluctuation power is quickly responded by the supercapacitor to suppress the frequency fluctuation effectively. Through the black start experiment of a 4F gas unit, the strategy not only effectively reduces the frequency fluctuation during the black start process, but also avoids the overcurrent fault during ramp-up and load-change phase, thus the reliability and safety of black start of the gas unit is improved.

The requirements of over limit evaluation and measuring points layout of vibration/swing in hydropower units in industry standards and national standards are compared. The layout of vibration/swing measurement points on the project site is also described. It is found that the standards related to evaluation and the ones related to measuring points arrangement are inconsistent or unclear with the engineering site, such as vibration evaluation boundary conditions, evaluation criteria, evaluation working conditions and measuring points arrangement. Analysis shows that all the differences between the standards appear in vibration evaluation and measuring points arrangement for fixed parts, and the provisions on radial vibration (swing) of the unit shafting are relatively unified. Inconsistencies in all standards are not conducive to broad-spectrum application, and are prone to ambiguity and disagreement. The phenomenon that the evaluation standard is inconsistent with the measuring points standard, is not conducive to on-site comprehensive vibration evaluation of large or giant units. All the standard evaluation criteria lack the consideration of weight coefficient of amplitude exceeding the limit and cumulative duration, which is not conducive to the development of vibration fault and condition based maintenance, and data accumulation in the new role of hydropower units. The conclusion is expected to provide analytical help and reference for the practitioners of vibration standard compilation, installation and acceptance, operation management and scientific research and test of hydropower units.

To investigate the microstructural and mechanical properties of 1 000 MPa grade ultra-high strength steel submerged arc welding welded joints for hydroelectric engineering, the microstructure of different regions of the welded joint was characterized using scanning electron microscopy (SEM). Mechanical properties of the welded joint were determined through tensile testing, impact testing, and bending testing. The results reveals that, the weld metal of the root pass and fill passes is composed of columnar, dendritic, and equiaxed grains, with a microstructure dominated by acicular ferrite and a small amount of granular bainite. The heat-affected zone (HAZ) exhibits multiple typical regions, including a critical coarse grain zone and a coarse grain zone near the fusion line along the thickness direction. Away from the weld, fine grain zones and critical zones are observed, with a microstructure primarily consisting of granular bainite, M-A constituents, and lath martensite. The weld metal of the cap pass exhibits typical columnar grains with a microstructure primarily composed of acicular ferrite. The HAZ of the cap pass includes coarse grain, fine grain, critical, and subcritical zones. Due to the absence of subsequent welding passes, no critical coarse grain zone is formed, and the microstructure is primarily composed of lath martensite, granular bainite, and M-A constituents. The average tensile strength of the welded joint reaches 980 MPa grade, the low-temperature impact absorption energy of the weld zone and the HAZ at –40 ℃ is 118.7 J and 149.3 J (at T/4), 67.0 J and 154.0 J (at T/2), respectively. No cracks appear in the lateral bending.

Reliability model is the foundation of reliability analysis. Conventional reliability modeling takes the entire system as the research object, and uses all fault data to fit the distribution function of the system, estimate parameters, and optimize the model, thus to determine the distribution type and distribution function of the system, and then to calculate the reliability indicators of the system. Wind turbine is a typical complex electromechanical system, with different functions, structures, and fault forms of each subsystem. It is obviously inappropriate to use one distribution function to determine the fault distribution of the entire system. Therefore, based on the collected and sorted fault data of wind turbines, the distribution function optimization-based reliability modeling and analysis technology of wind turbines is proposed. By applying the commonly used exponential distribution, normal distribution, log-normal distribution, Weibull distribution and gamma distribution, the distribution function fitting, parameter estimation and goodness of fit analysis of the fault interval of each subsystem of wind turbines are carried out, and the distribution function and subsystem reliability function of the fault interval time of each subsystem are determined. On this basis, a Copula connection function is used to establish the reliability function model for wind turbines, taking into account the fault correlation between subsystems. Moreover, an example analysis is conducted on the fault data of an offshore wind turbine, which verifies the feasibility of the proposed method.

The two basic structures and working principles of open type heat source towers, as well as the technology of gas-liquid heat and mass exchange inside the tower are introduced. It systematically summarizes the structural components, antifreeze fluids, heat and mass transfer characteristics, and the current research status, with a focus on the research hotspots and major advancements in the development of antifreeze fluids and the heat and mass transfer processes of the open type heat source tower. Although the open type heat source tower technology still has disadvantages such as insufficient safety and environmental protection of antifreeze, corrosiveness and toxicity, unstable regeneration technology, and high energy consumption, it has a large heat exchange intensity, high heat recovery efficiency, simple structure, and low maintenance cost. It has broad application prospects in the field of building heating. In the future, open type heat source tower technology will develop towards a more efficient, stable, safe, environmentally friendly, energy-saving and low-carbon direction, and build a better green and low-carbon heating system.