南方(以广东起步)电力现货市场“月结算”试运行关键监测指标及市场力分析

在我国电力现货市场建设加快发展的形势下,对已实施的双轨制现货市场进行市场监测是保证电力市场持续推进的关键环节。产业组织理论中的结构-行为-绩效(structure-conduct-performance,SCP)模型能够提供一个既深入结合具体实例,又有系统逻辑体系的产业分析框架。因此基于SCP框架,从市场结构、市场行为、市场绩效3个角度提出了适应中国特色双轨制现货市场的评价体系,并结合南方(以广东起步)电力现货市场2021年5月试运行数据,充分挖掘了市场主体行为及市场出清结果的规律特点及深层次原因,有效防范市场运营风险。最后,提出了推动南方区域电力市场建设、加快东西部间网架建设、加强市场力监测等建议,以期为中国电力现货市场发展提供借鉴。

全国电力现货市场试运行分析与新能源发电企业的应对建议

2017年8月28日,国家发展和改革委员会、国家能源局联合发布了《关于开展电力现货市场建设试点工作的通知》,并选择8个地区作为电力现货市场第1批试点市场;截至2019年9月,我国首批电力现货市场全部完成结算试运行。在对全国首批电力现货市场的模拟试运行和结算试运行情况展开全面调研的基础上,分析了电力现货市场对新能源发电企业产生的影响,指出了电力现货市场当前运行过程中存在的问题,并向新能源发电企业提出了几点应对建议。

山西电力现货市场中长期与现货衔接问题及对策

中长期交易与现货市场的衔接是现货市场建设需要考虑的关键要素之一。山西发用两侧均参与的集中式现货市场已在各类典型电网运行方式下经过多次结算试运行。文章对山西在市场化中长期交易与现货市场衔接方面存在的问题进行了深入分析,指出尽快建立容量补偿机制、开展适应现货市场的中长期分时段交易是解决问题的关键。最后结合现货结算试运行设计了一种新的中长期分时段交易机制,包括交易方式、交易周期、合同分解、风险控制等内容。

广东发电企业应对电力现货市场发展分析

随着电力市场化改革的不断深入,广东省电力现货市场规则自 2018 年 8 月 30 日发布征求意见稿,9 月 11 日进入了模拟运行阶段,2019 年 5 月 15-16 日、6 月 20-23 日、10 月 21-27 日,南方(以广东起步)电力现货市场分别进行了 2 天、4 天和一周现货结算试运行。本文根据当前广东电力现货交易规则,结合广东省电力系统概况以及开展的试结算等情况,分析当前现货市场试结算以及发电企业应对现货市场发展的思考。

Upper bound analytical solution for surrounding rock pressure of shallow unsymmetrical loading tunnels

By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.

Design on the Coal Management System for Small and Medium Enterprises

According to the analysis of the problem of contract management, financial settlement and placement of coal trucks in coal business, a study is made on the coal management system. This system combines B/S and C/S together, and it also uses three-tire application of ASP.NET which sets up a business subsystem based on functional module management in vehicle. Additionally, MFC solves the problems in weighing management systems. This system goes with unit testing, integration testing, and system testing, and the whole process realizes an effective monitoring from coal trucks applying for delivery, checking in, and weighing to checking out. Besides, it also secures precise and accurate weighing data, and deals with the new coming coal contract in a faster way. The real project indicates this system wins a very good reputation and it is worthy of spreading in a broader context.

Research of the test generation algorithm based on search state dominance for combinational circuit

On the basis of EST (Equivalent STate hashing) algorithm, this paper researches a kind of test generation algorithm based on search state dominance for combinational circuit. According to the dominance relation of the E-frontier (evaluation frontier), we can prove that this algorithm can terminate unnecessary searching step of test pattern earlier than the EST algorithm through some examples, so this algorithm can reduce the time of test generation. The test patterns calculated can detect faults given through simulation.

Experimental Study on the Resistance of a Transport Ship Navigating in Level Ice

This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist （1989） for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.

Experimental and numerical analysis of submerged floating tunnel

As a new type of structure which has never been built, submerged floating tunnel was studied mainly by numerical simulations. To further study the seismic response of a submerged floating tunnel, the first model experiment of submerged floating tunnel （SFT） under the earthquake was carried out on the unique underwater shaking table in China. The experimental results show that vertical excitation induces larger response than horizontal and different inclination degrees of the tether also cause different seismic responses. Subsequently, based on the fluid-structure interaction theory, the corresponding numerical model is established. And comparing the numerical results with the experimental results, those of shaking table test. Numerical model adopted is effective for it is shown that the numerical results are basically identical with dynamic response of SFT.

Optimization of Bow Shape for a Non Ballast Water Ship

In this research,a commercial CFD code ＂Fluent＂ was applied to optimization of bulbous bow shape for a non ballast water ships（NBS）.The ship was developed at the Laboratory of the authors in Osaka Prefecture University,Japan.At first,accuracy of the CFD code was validated by comparing the CFD results with experimental results at towing tank of Osaka Prefecture University.In the optimizing process,the resistances acting on ships in calm water and in regular head waves were defined as the object function.Following features of bulbous bow shapes were considered as design parameters： volume of bulbous bow,height of its volume center,angle of bow bottom,and length of bulbous bow.When referring to the computed results given by the CFD like resistance,pressure and wave pattern made by ships in calm water and in waves,an optimal bow shape for ships was discovered by comparing the results in the series of bow shapes.In the computation on waves,the ship is in fully captured condition because shorter waves,λ/Lpp 0.6,are assumed.

Mobile robot path planning based on adaptive bacterial foraging algorithm

The utilization of biomimicry of bacterial foraging strategy was considered to develop an adaptive control strategy for mobile robot, and a bacterial foraging approach was proposed for robot path planning. In the proposed model, robot that mimics the behavior of bacteria is able to determine an optimal collision-free path between a start and a target point in the environment surrounded by obstacles. In the simulation, two test scenarios of static environment with different number obstacles were adopted to evaluate the performance of the proposed method. Simulation results show that the robot which reflects the bacterial foraging behavior can adapt to complex environments in the planned trajectories with both satisfactory accuracy and stability.

Internal heat transfer coefficients in microporous media with rarefaction effects

The internal heat transfer of different gases in microporous media was investigated experimentally and numerically.The experimental test section had a sintered bronze porous media with average particle diameters from 11 μm to 225 μm.The Knudsen numbers at the average inlet and outlet pressures of each test section varied from 0.0006 to 0.13 with porosities from 0.16 to 0.38.The particle-to-fluid heat transfer coefficients of air,CO 2 and helium in the microporous media were determined experimentally.The results show that the Nusselt numbers for the internal heat transfer in the microporous media decrease with decreasing the particle diameter,d p,and increasing Knudsen number for the same Reynolds number.For Kn>0.01,the rarefaction affects the internal heat transfer in the microporous media.A Nusselt number correlation was developed that includes the influence of rarefaction.The computational fluid dynamics(CFD) numerical simulation was carried out to do the pore scale simulation of internal heat transfer in the microporous media considering the rarefaction effect.Pore scale three-dimensional numerical simulations were also used to predict the particle-to-fluid heat transfer coefficients.The numerical results without slip-flow and temperature jump effects for Kn<0.01 corresponded well with the experimental data.The numerical results with slip-flow and temperature jump effects for 0.01<Kn<0.13 are lower than the numerical results without rarefaction effects,but closer to the experimental data.The numerical results with rarefaction effects can accurately simulate the unsteady heat transfer in the microporous media.

Application of Non-Detective Techniques Traditional Masonry Structures

Study on the non-destructive detection techniques and damage identification method is of great importance in protecting and rehabilitating the ancient architectural structure. In order to identify the location and the grade of structural damages, a multi-point microtremor measurement is performed on carved brick screen walls at Songjiang area in Shanghai, and the observed dynamic parameters （natural frequencies and natural modal） are obtained. On the other hand, the dynamic parameters of the original structure are calculated by finite-elementmethod （FEM）. Normalizing tile observed and calculated parameters on unified physical quantity, the damages are located by the variation on vibration modal, and the grade of structural damages is quantitatively evaluated by stiffness losses based on the variation on vibration modal.

DETECTING COMMUNITY STRUCTURE： FROM PARSIMONY TO WEIGHTED PARSIMONY

Community detection has attracted a great deal of attention in recent years. A parsimony criterion for detecting this structure means that as minimal as possible number of inserted and deleted edges is needed when we make the network considered become a disjoint union of cliques. However, many small groups of nodes are obtained by directly using this criterion to some networks especially for sparse ones. In this paper we propose a weighted parsimony model in which a weight coefficient is introduced to balance the inserted and deleted edges to ensure the obtained subgraphs to be reasonable communities. Some benchmark testing examples are used to validate the effectiveness of the proposed method. It is interesting that the weight here can be determined only by the topological features of the network. Meanwhile we make some comparison of our model with maximizing modularity Q and modularity density D on some of the benchmark networks, although sometimes too many or a little less numbers of communities are obtained with Q or D, a proper number of communities are detected with the weighted model. All the computational results confirm its capability for community detection for the small or middle size networks.