Currently, few studies have conducted theoretical derivation and parameter calculation on the voltage, current and other electrical parameters of wind farms during offshore DC cable faults. This paper focuses on the transient evolution and short-circuit analytical calculation of WFMMC in the flexible DC system when three-phase short-circuit ground faults occur on offshore AC collection lines of offshore wind farms. The operating conditions for offshore DC cable fault tests are merely summarized and briefly described.

The intersection of physics-based vision and deep learning presents an exciting frontier for advancing computer vision technologies. By leveraging the principles of physics to inform and enhance deep learning models, we can develop more robust and accurate vision systems. Physics-based vision aims to invert the processes to recover scene properties such as shape, reflectance, light distribution, and medium properties from images. In recent years, deep learning has shown promising improvements for various vision tasks, and when combined with physics-based vision, these approaches can enhance the robustness and accuracy of vision systems. This technical report summarizes the outcomes of the Physics-Based Vision Meets Deep Learning (PBDL) 2024 challenge, held in CVPR 2024 workshop. The challenge consisted of eight tracks, focusing on Low-Light Enhancement and Detection as well as High Dynamic Range (HDR) Imaging. This report details the objectives, methodologies, and results of each track, highlighting the top-performing solutions and their innovative approaches.

With the continuous improvement of our country’s education level, the electrical design of teaching buildings has been paid more and more attention. If the safety measures of building facilities are not perfect, once there is a safety problem, it will inevitably bring irreparable huge losses to the personal safety of students and teachers and the property safety of the school. At the same time, taking into account school expenses, economy, energy saving is also a part that cannot be ignored, which requires full consideration of safety, environmental protection and other factors in the process of electrical system design.This paper mainly studies the electrical design of the teaching building, on the basis of strict compliance with national standards and norms, taking into account safety, economy, energy saving and other design factors, independently designed the power supply and distribution system, lighting system, lightning protection system, to ensure the safe operation of building electrical facilities and energy saving operation.

As the penetration rate of distributed power sources in the distribution network gradually increases, this article proposes an improved interval coordinated voltage control strategy based on second-order cone programming theory to address the impact of system active power loss on voltage and voltage exceeding limits. The proposed regulation strategy is validated in the IEEE33 node model, demonstrating its effectiveness.

With the continuous development of power electronic devices and science and technology, cables and rectifiers, inverters, DC transmission equipment, and other nonlinear loads have been widely used in power systems. However, this causes harmonic pollution and large capacitive reactive power, which can affect the safe and stable operation of the power system. Based on the analysis of the reasons for the use of static var generator in the power grid and the existing conditions of even harmonic, the impedance analysis method was used to analyze the abnormal noise event of a transformer in a substation. Firstly, the equivalent impedance model diagram is drawn by the equivalent circuit method, and the equivalent impedance value of the system is calculated. A number of harmonic amplifications and the positions of the resonance point are calculated by MATLAB software. Secondly, the correctness of the above theoretical analysis is verified by field test and simulation model built in ETAP software. Finally, because of the abnormal noise of the transformer in a substation caused by harmonic amplification, three harmonic suppression measures are given.

As one of the most prominent power quality problems in the power system, voltage transients threaten the use of many electrical and electronic devices. The rapid and accurate location of voltage drop sources can better define the responsibility between the power supply and the customer. It can also provide a reliable basis for future grid development planning. In this paper, a random forest model is set up to extract data from several electrical characteristics of voltage transients according to the classical voltage transient location method, which is used as training and test samples to input into the random forest model to achieve the upstream and downstream location of voltage transient sources. The random forest model is more accurate than the single decision tree model and the traditional upstream and downstream voltage drop location method. It is possible to determine which of the traditional judgments is more important under this model.

With the wide application of wind farms VSC-HVDC, the protection of its transmission lines is also become a popular research topic. Through the analysis of the fault characteristics of the outgoing line of the wind farms VSC-HVDC, the fault characteristics of the single-pole grounding fault, the bipolar short-circuit fault and the AC side fault of the sending-end converter of the DC transmission line are studied. According to the difference of the fault characteristics, the corresponding protection scheme is configured for the fault of the outgoing line, and then the PSCAD/EMTDC simulation platform is used to carry out the simulation verification of the fault. Through the comparison and analysis of the simulation results, the feasibility of the protection scheme is verified.

With the structural reform of China’s power system, a large number of new energy sources have been connected to the existing power grid causing impact on the power grid, resulting in a decrease in the stability of the power grid. A more scientific method of comprehensive power quality assessment is needed, and this paper proposes a comprehensive power quality assessment model based on unsupervised learning ideas to eliminate the influence of subjective weights on the comprehensive evaluation results. Firstly, the data characteristics of the power quality indicators are analyzed by factor analysis, and then the main factor analysis method is used to extract the comprehensive evaluation indicators, and the K-means clustering method is used to classify them, and finally the fuzzy comprehensive evaluation method is used to complete the comprehensive evaluation of power quality. The feasibility of the method is verified by taking the test data of three substations in Yancheng City, Jiangsu Province as an example.

In recent years, with the application of new technologies in industrial production, the large-scale use of sensitive power equipment, users have higher requirements for electric power quality. Voltage sag as a serious problem affecting power quality, has attracted more and more attention. After a voltage sag occurs, identifying the source of the voltage sag can better determine the responsibility of power suppliers and consumers for power quality issues, effectively resolve disputes between the two parties, and improve economic benefits. This paper proceeds as follows: it is based on the technology of voltage dip source location. The dual power supply network model is established, and the simulation of voltage dip source location is carried out by MATLAB simulation software, and its applicability and advantages and disadvantages are summarized. Finally, an improvement scheme was proposed to improve the positioning accuracy of the voltage dip source.

Brushless doubly-fed motor is a new type of motor that has attracted much attention in recent years, which has two sets of stator windings and one set of rotor windings, and the two sets of stator windings are known as the power winding and the control winding, respectively. In this paper, based on reviewing various domestic and foreign literatures, the basic structure and operation principle of brushless doubly-fed generator are firstly analysed and several operation modes of brushless doubly-fed motor are discussed. Then we select the appropriate coordinate transformation matrix, transform the mathematical model of the three-phase stationary coordinate system of the brushless doubly-fed motor to the dq rotating coordinate system, and build the simulation control system by using the MATLAB tool, and finally prove that the vector control system of the brushless doubly-fed motor has a good dynamic and static characteristic through the study of the output dynamic simulation curves.

为明确柴达木盆地西部地区新生界微生物碳酸盐岩微观结构及主要造岩矿物的成因机理,本文利用岩芯观察、薄片分析、扫描电镜及电子探针分析等实验测试方法,对南翼山地区上油砂山组微生物碳酸盐岩微观结构、矿物特征差异性及矿化作用开展研究.分析认为南翼山地区上油砂山组发育厚层泥晶碳酸盐岩,单层厚度3～5 m;局部发育薄层微生物碳酸盐岩,单层厚度以30～50 cm为主,单层最大厚度2 m.微生物碳酸盐岩类型以凝块石为主、局部发育叠层石,二者混合共生,通过扫描电镜在微生物碳酸盐岩中发现了大量钙化的细胞外聚合物(EPS)组构与少量微生物化石,为湖相微生物碳酸盐岩的形成提供了生物学证据.研究结果表明:①微生物碳酸盐岩主要矿物类型为方解石,微观组构复杂、类型多样,包括球粒、团粒、菱面体以及片状结构等.球粒粒径分布范围50～80 nm.团粒由若干纳米级球粒聚合黏结形成,粒径为几微米至几十微米.片状方解石往往大小不等、形态各异,粒径通常为1～10μm.②发现大量钙化EPS组构及疑似微体化石,包括球状、杆状及丝状体.杆状体微生物化石直径约0.4 μm,长0.5～1 μm.丝状体微生物化石直径约0.3～0.5 μm,长1～2μm.③方解石矿物的形成主要以有机矿化作用(或微生物诱导矿化作用)为主、生物矿化作用次之,其中,球粒方解石主要为有机矿化作用控制(或微生物诱导)形成.杆状和丝状体化石保持了微生物的形貌特征,分析认为可能由生物矿化作用控制形成.④凝块石中的球粒、卵球袋及团块的形成,可能由微生物膜及其所封闭的微生物菌落钙化形成,分析认为此类矿物可能与有机矿化作用具有相关性.

High-quality power should be a sinusoidal waveform with a constant frequency and voltage standard, but the use of modern equipment, including semiconductor switchgear, ferromagnetic saturated equipment, arc-type equipment, and other diverse load types, as well as access to new energy sources and large-scale application of direct-current transmission, has led to widespread harmonic problems. Harmonics injected into the power grid produce amplification in the process of transmission, which seriously reduces the power quality. In the paper, on the basis of analysing the transmission characteristics of harmonics through power components, an equivalent impedance model is built for the abnormal amplification of harmonic voltages actually occurring, the harmonic voltage transmission relationship is analysed by MATLAB simulation software to confirm the cause of harmonic voltage amplification, and the correctness of the above analysis is verified by using ETAP software simulation. Finally, a harmonic suppression scheme is proposed to reduce the harmonic voltage distortion rate.

为解决光伏在并网过程中功率波动的问题,首先根据国标设置功率波动的死区限值,然后对光伏控制系统进行理论分析,并且选取测试过程中功率波动较大的光伏数据,采用自适应指数移动平均算法对其优化,最后在MAT-LAB中搭建仿真模型,验证光伏和储能系统能够将超出死区的功率控制在一定范围内,同时维持系统电压的稳定.

为了解决云端机器学习在成本、延迟、可靠性、隐私等方面的问题,运用微型机器学习(Tiny Machine Learning,TinyML)技术,利用TensorFlow机器学习平台,实现了语音数据集的导入、预处理并通过短时傅里叶变换生成频谱图和分类;在PC端构建深度学习网络,对频谱图进行机器学习训练,对模型进行验证和评估;将评估性能良好的模型进行转化,生成适合微控制器运行的TFLite模型文件,实现语音关键词在微控制端的采集、推断、识别,并驱动控制小车行进.

Capacitive voltage transformers (CVTs), as the main voltage detection devices in the power grid, can accurately measure power frequency voltage, but CVT’s measurement of harmonic voltage will pass errors, resulting in CVT cannot accurately monitor the harmonic voltage in the power grid. Based on the current status of CVT, this paper studies the structure of CVT and the harmonic voltage transfer characteristics of CVT, and analyzes the frequency characteristic curve of CVT by using MATLAB simulation. Based on the study of the CVT frequency characteristic curve, this paper proposes a method of series voltage divider capacitor C3 at the ground terminal of CVT low voltage capacitance to indirectly measure the harmonic voltage on the primary side of CVT and verifies the accuracy of this method. Finally, this paper presents a preliminary design scheme for the series capacitor voltage division method.

克拉苏致密砂岩气藏位于中国塔里木盆地库车坳陷克拉苏构造带,已探明天然气地质储量超万亿立方米,已成为中国石油塔里木油田天然气上产的主要战场.由于目的 层埋藏深度大、构造复杂、断裂发育、储层致密、温度压力高、水体复杂,高效开发面临极大挑战.为了提高致密砂岩气藏最终采收率,在深化气藏地质及动态特征研究的基础上,深入分析了影响致密气藏采收率的影响因素,并建立了与该区气藏特征相匹配的开发对策体系,大幅提升了气藏的采收率.研究结果表明:①气藏可分为冲起式弱边底水、冲起式有限边底水、叠瓦断片式弱边水、叠瓦断片式有限边水和叠瓦断片式强边底水等五种类型;②非均匀水侵是影响气藏采收率的最主要因素,水侵规律与地质特征和开发参数密切相关;③针对气藏不同特征提出了差异化的布井方式、井网井型、储层改造方式、采气速度、防水控水等一系列开发技术对策.研究结论认为,采用新的开发对策后,新近投产气藏出现无明显不均衡水侵,气藏采收率较早期投产气藏可提高10％～15％,为全球其他地区超深致密砂岩气藏的高效开发提供了宝贵的开发经验和借鉴.

In the context of power market reform, the comprehensive evaluation of power quality is extremely important for the effective governance of power grids and the reasonable formulation of power prices. The paper proposed a method based on classification combined weighting and for the first time integrated with blind number measurement in order to solve the problems of strong subjectivity, inaccurate results and complex methods in comprehensive power quality evaluation. In the weights section, the subjective weights were calculated by combining load classification and an improved analytic hierarchy process. Then, the objective weights were calculated by the modified entropy weighting method. Finally, the combined weights were obtained by the Lagrange multiplier method. The introduction of load classification enabled the whole method to be more objective. In the evaluation part of the model, blind number theory was applied to modify the data reducing errors caused by data fluctuations. This was followed by a measurement using a curvilinear uncertain function to better distinguish between similar evaluation points. Once the measurements were completed, evaluation grades and scores were obtained. The correctness, objectivity and accuracy of the method were verified by analysis and comparison of practical examples.

The influence of traditional distributed photovoltaic grid-connected on the voltage is based on the three-phase balance state of the system, but with the development of society, more and more unbalanced loads are connected to the power grid, which makes the system in three-phase unbalanced state for a long time. Based on this, this paper considers the long-term unbalance of the system caused by the asymmetric load, and the system voltage changes in this state. Then, the change of negative sequence voltage is analyzed by the symmetrical component method, and the system is analyzed by the unbalanced power flow method in the ETAP software. The influence of distributed photovoltaic grid connection on bus node voltage under single-phase load access is studied by this paper. The results show that when the distributed photovoltaic is connected to the unbalanced system, the voltage value of each bus node of the system can be effectively improved, but the degree of influence on the system imbalance needs to be draw corresponding conclusions according to the difference of photovoltaic disconnection and load capacity.

由于人工经验选取的局限性,难以获取决定模型重构精度的最优网络参数是目前使用深度学习方法在自动历史拟合中对油藏地质模型进行降维时的难点之一.针对此问题,通过将深度自编码器与粒子群优化算法相互结合实现最佳网络架构的自动搜索,并以此构建一种基于集合数据同化和神经网络架构自动搜索的油藏自动历史拟合方法.分别对一个二维河流相油藏渗透率场分布模型以及SPE-10单层油藏数值模型应用该方法,并与单一的自动历史拟合方法进行对比验证.结果表明,经优化后自动搜索出最优神经网络构架的自动历史拟合方法要比优化前及单一的自动历史拟合方法能够更准确地提取出油藏数值模型的地质特征.

中国石油天然气集团有限公司(简称中国石油)非常规油气已经初步实现了规模化动用,但相比于其丰富的资源量,其产量仍具有极大的提升潜力.文章系统梳理了中国石油非常规油气"十三五"勘探开发进展,展望"十四五"发展趋势,分析了非常规油气效益开发所面临的主要挑战及关键问题,并在此基础上提出推动中国石油非常规油气高效开发的对策.研究结果表明:(1)"十三五"期间,以非常规油气为代表的低品位资源逐渐成为中国石油勘探开发的主体;(2)"十四五"期间,非常规油气产量占比将进一步提升,重点区域产能有望实现快速增长;(3)非常规油气效益开发面临着技术、成本、管理及理念4个层面的挑战.针对上述挑战提出了六方面关键对策:(1)正确看待非常规资源;(2)推行"一全六化"工程管理理念与模式;(3)完善管理规则与考核办法;(4)充分利用大数据平台;(5)有效推进市场化运作与社会化支持;(6)制定非常规资源合理开发政策.通过采取以上措施,将有望破解中国石油非常规油气效益开发难题,为践行"能源的饭碗必须端在自己手里"贡献非常规力量.