Improve power quality of coal mine power network based on gray system theory

Unified Power Quality Controller（UPQC） was proposed to comprehensively improve power quality of coal mine power network and its basic structure and operation principle was introduced. In order to overcome time lag of Active Power Filter（APF） in compensating harmonic and reactive current, a novel method based on gray system theory was proposed to predict harmonic current and other distortion component. The mathematical model of component to be compensated was constructed by data sequence of distortion component, which could exactly forecast compensation signal of next period. The optimal control strategy was selected according to the principle of output signal approaching component to be compensated as near as possible. Before predicating each time the oldest data was eliminated while the latest data was added to data sequence. Then new predication model was established once again. The results show that the method can always construct mathematical model with variation of system parameters, reflect the latest state of system and not increase calculation quantity. The feasible and effective control strategy can improve power quality of coal mine power network.

Chatter free sliding mode control of a chaotic coal mine power grid with small energy inputs

An augmented proportional-integral sliding surface was designed for a sliding mode controller. A chatter free sliding mode control strategy for a chaotic coal mine power grid was developed. The stability of the control strategy was proven by Lyapunov stability theorem. The proposed sliding mode control strategy eliminated the chattering phenomenon by replacing the sign function with a saturation function, and by replacing the constant coefficients in the reaching law with adaptive ones. An immune genetic algorithm was used to optimize the parameters in the improved reaching law. The cut-in time of the controllers was optimized to reduce the peak energy of their output. Simulations showed that the proposed sliding mode controller has good, chatter flee performance.

3Dmine在南非某金矿资源量估算中的应用

以南非某金矿①号主矿体为例,本文介绍了3Dmine软件在资源量估算中的全过程应用。该过程包括原始数据的整理,统计分析样品,建立主矿体和构造模型,建立矿块模型并进行赋值,进行矿体资源量估值等步骤。本文侧重利用距离幂次反比法对建立的矿块模型进行品位估值,生成金品位分布模型,并完成估值参数合理性验证。这些步骤提供了科学依据,为下一步地质勘探工作和数字化矿山建设提供了支持。

基于PDMiner大数据挖掘平台的电力系统安全评估及故障诊断系统

电力系统中的数据复杂多样,电力大数据的挖掘处理是电力公司面临的难题之一。阐述了电力大数据发展现状,将电力云概念引入到电力系统大数据分析之中,提出了基于云计算理论的大数据挖掘平台PDMiner,介绍了其整体架构和原理,针对电力大数据的平台架构和关键技术,开发了一套基于PDMiner平台的电力系统安全评估与故障诊断系统,该系统配置在SCADA/EMS的数据管理子系统上,提高了数据处理的效率,并且能准确提取到故障类型、风险区域等数据背后的准确信息。

Influence of canopy ratio of powered roof support on longwall working stability——A case study

The case study describes longwall coal seam A in a hard coal mine,where longwall coal face stability loss and periodic roof fall occurrences had been registered.The authors have attempted to explain the situation based on in-situ measurements and observations of the longwall working as well as numerical simulation.The calculations included several parameters,such as powered roof support geometry in the form of the canopy ratio,which is a factor that influences load distribution along the canopy.Numerical simulations were realized based on a rock mass model representing realistic mining and geological conditions at a depth of 600 m below surface for coal seam A.Numerical model assumptions are described,while the obtained results were compared with the in-situ measurements.The conclusions drawn from this work can complement engineering knowledge utilized at the stage of powered roof support construction and selection in order to improve both personnel safety and longwall working stability,and to achieve better extraction.

Long-term economic sensitivity analysis of light duty underground mining vehicles by power source

LHD's are expensive vehicles; therefore, it is important to accurately define the financial consequences associated with the investment of purchasing the mining equipment. This study concentrates on longterm incremental and sensitivity analysis to determine whether it is feasible to incorporate current battery technology into these machines. When revenue was taken into account, decreasing the amount of haulage in battery operated equipment by 5% or 200 kg per h amounts to a $4.0 × 10~4 loss of profit per year. On average it was found that using battery operated equipment generated $9.5 × 10~4 more in income annually, reducing the payback period from seven to two years to pay back the additional $1.0 × 10~5 investment of buying battery powered equipment over cheaper diesel equipment. Due to the estimated 5% increase in capital, it was observed that electric vehicles must possess a lifetime that is a minimum of one year longer than that of diesel equipment.

Security Risk Assessment of Cyber Physical Power System Based on Rough Set and Gene Expression Programming

Risk assessment is essential for the safe and reliable operation of cyber physical power system. Traditional security risk assessment methods do not take integration of cyber system and physical system of power grid into account. In order to solve this problem, security risk assessment algorithm of cyber physical power system based on rough set and gene expression programming is proposed. Firstly, fast attribution reduction based on binary search algorithm is presented. Secondly, security risk assessment function for cyber physical power system is mined based on gene expression programming. Lastly, security risk levels of cyber physical power system are predicted and analyzed by the above function model. Experimental results show that security risk assessment function model based on the proposed algorithm has high efficiency of function mining, accuracy of security risk level prediction and strong practicality. © 2014 Chinese Association of Automation.

Sustainable Development around Small Scale Mining Areas by the Development of Micro Hydro Power: Application Cases in Cameroon

Of all the precious metals buried in the Cameroonian subsoil, gold is certainly the longest exploited. It has longtime been the subject of artisanal exploitation. In 2014, the monthly national production was estimated at around 170 kg. In these mining areas, people still live in a screaming precariousness of which one of the main causes is often the lack of electricity, because of the distance of these localities to the national electricity network. Cameroon has a great hydroelectric potential, but the access rate to electricity is still very low in isolate or rural areas of this country. The objective of this work is to show that it is possible to efficiently exploit gold in isolated areas and contribute to the sustainable development of these localities through the development of micro hydro power (MHP). The mining community of Tikondi in the East Region of Cameroon is the practical case study for an illustration. The results of this study show that the development of the MHP project can be developed with installed power of 87 kW, where the Banki-Michell turbine is recommended according to the Sulzer-Escher Wyss diagram. The investment cost evaluated at 79,832,775 FCFA (1 Euro = 656 FCFA). It is a profitable project with a maximum payback period of 8 years. This project can be easily funded by gold mining activity. That Tikondi’s MHP can make this village becoming attractive for others activities, improving the quality of education of children (there is not any school and lots of them do not go to school), the building of health centers and the quality of life in that locality and therefore contribute to their sustainable development too.

煤流-潮流协同的矿山供电系统低碳优化运行

双碳目标的提出对我国矿山绿色高效开采提出了更高的需求。为此,该文提出煤流-潮流协同的矿山供电系统优化调度方法。首先,基于煤流在采煤工作面、带式运输机、储煤筒仓等环节的连续性特征,抽象出运输煤流和节点功率耦合的运输设备模型;其次,整合煤流运输安全约束与配网潮流约束,建立煤流-潮流协同的运行优化模型;最后,以矿山用能的经济性和碳减排为目标,考虑主网实时碳计量水平,调节采煤时间、煤流速度、运输流量与设备用能,生成煤流运输和矿山电网低碳调度的优化方案。以山西某矿山供电系统为实例,验证所提模型与方法的有效性。仿真结果表明,所提模型与方法能够有效降低矿山生产的吨煤电耗、用能成本及碳排放量,实现了煤流-潮流协同的矿山低碳化经济运行。

基于模型迁移和SVM的煤矿电网单相接地电容电流预测方法

针对智慧化矿山背景下煤矿电网单相接地电容电流预测精度低和智能预测实现困难的问题,提出了一种单相接地电容电流智能预测方法。采用模型迁移思想扩充矿用橡套软电缆的电容电流样本数据,以解决智能预测中电容电流数据不完备的问题;基于Sobol’敏感性方法分析了影响单相接地电容电流的关键因素及其各因素的交互关系,确定智能预测模型输入特征量;在此基础上,通过基于稀疏技术的支持向量机建立煤矿电网单相接地电容电流智能预测模型,并引入鲸鱼算法优化预测模型超参数,克服了电容电流数据样本容量小的不足。采用厂家测试数据及多家煤矿电网现场实测数据进行试验,结果表明:电缆绝缘层外径和绝缘层内径是影响单相接地电容电流的关键因素;所提方法预测煤矿电网单相接地电容电流的平均误差为2.26%,相较于现有预测方法,误差分别下降了34.19%,24.91%和7.40%。该方法实现了煤矿电网单相接地电容电流的准确预测,并为其智能化预测提供了新思路。

Operating Analysis and Data Mining System for Power Grid Dispatching

The dispatching center of power-grid companies is also the data center of the power grid where gathers great amount of operating information. The valuable information contained in these data means a lot for power grid operating management, but at present there is no special method for the management of operating data resource. This paper introduces the operating analysis and data mining system for power grid dispatching. The technique of data warehousing online analytical processing has been used to manage and analysis the great capacity of data. This analysis system is based on the real-time data of the power grid to dig out the potential rule of the power grid operating. This system also provides a research platform for the dispatchers, help to improve the JIT (Just in Time) management of power system.

反转旋耕刀作业功耗仿真分析及试验验证

针对油莎豆收获过程中功率消耗过高的问题,设计了一种反转旋耕挖掘装置,确定了主要工作部件旋耕刀的结构参数,并明确了旋耕装置的作业功率消耗主要组成。建立沙壤土土壤颗粒模型和油莎豆植株颗粒模型,最终建立土壤-植株-旋耕刀相互作用离散元仿真模型,并进行反转旋耕刀功耗仿真试验。采用正交试验设计,以刀辊转速、前进速度、作业深度为试验因素,以功率消耗为试验指标,通过Design-Expert 10.0.1进行数据分析,得出旋耕刀最佳工作参数,确定最优作业参数为刀轴转速233r/min、前进速度0.65m/s、工作深度138mm,此时功率消耗为30.49kW。经田间试验验证,理论值与试验值相对误差平均值为4.22%,表明功率消耗数学模型具有较高的适用性。研究中旋耕刀功率消耗仿真分析结果和最优作业参数可为旋耕挖掘、减阻降耗提供参考。

基于碳捕集-电转气的矿区综合能源系统协同优化调度

“双碳”战略目标下,为促进风光消纳与能源电力低碳转型、提高矿区能源利用率,提出一种含伴生能源和碳捕集与电转气耦合的矿区综合能源系统低碳经济调度模型。首先,综合考虑瓦斯、乏风、涌水等矿区伴生能源利用,建立矿区综合能源系统基本模型,并以碳捕集和电转气设备为耦合单元,促进节能减排与可再生能源消纳。然后,引入奖惩阶梯式碳交易机制,以矿区综合能源系统运行成本最小为目标,建立矿区综合能源系统协同优化调度模型。最后,以中国云南某大型煤矿为例,通过设置不同场景进行仿真分析。结果表明,所提模型能够促进矿区综合能源系统低碳经济运行,提高风光消纳率。

A practical approach to improve alarm system performance: Application to power plant

Process safety in chemical industries is considered to be one of the important goals towards sustainable development. This is due to the fact that, major accidents still occur and continue to exert significant reputational and financial impacts on process industries. Alarm systems constitute an indispensable component of automation as they draw the attention of process operators to any abnormal conditi on in the plant. Therefore, if deployed properly, alarm systems can play a critical role in helping plant operators ensure process safety and profitability. How-ever, in practice, many process plants suffer from poor alarm system configuration which leads to nuisance alarms and alarm floods that compromise safety. A vast amount of research has primarily focused on developing sophisticated alarm management algorithms to address specific issues. In this article, we provide a simple, practical, systematic approach that can be applied by plant engineers (i.e., non-experts) to improve industrial alarm system performance. The proposed approach is demonstrated using an industrial power plant case study.

矿井无线电波防爆安全发射功率研究

5G,5.5G,WiFi6,WiFi7,UWB,ZigBee等矿井移动通信系统及人员和车辆定位系统等发射的大功率无线电波有点燃瓦斯和煤尘的风险。因此,需要合理设置防爆无线电设备发射的无线电波防爆安全功率阈值,限制防爆无线电设备发射的无线电波功率。欧洲标准CLC/TR 50427:2004《Assessment of inadvertent ignition of flammable atmospheres by radio-frequency radiation-Guide》规定了爆炸性气体环境中无线电波防爆安全接收点火功率阈值,但缺少无线电波防爆安全发射功率阈值的内容。国家标准GB/T 3836.1—2021《爆炸性环境第1部分:设备通用要求》和国际标准IEC 60079-0:2017《Explosive atmospheres-Part 0:Equipment-General requirements》虽然有无线电波防爆安全发射功率阈值的相关规定,但错误地将欧洲标准CLC/TR 50427:2004中的无线电波防爆安全接收点火功率阈值修改为无线电波防爆安全发射功率阈值,大大降低了爆炸性环境中无线电设备所能允许的最大发射功率。由于煤矿井下没有能作为接收天线的起重机这类细长结构物体,且现有矿井无线通信及定位系统工作频率均远大于30 MHz,所以,无线电波防爆安全接收点火功率阈值应为8 W,而不是国家标准GB/T 3836.1—2021和国际标准IEC 60079-0:2017规定的无线电波防爆安全发射功率阈值6 W。在发射天线发射的无线电波能量全部被等效天线吸收的最不利于无线电防爆的传输和耦合情况下,无线电设备工作频率为等效天线谐振频率时,接收点火功率达到最大,为等效天线接收的总功率的一半,即发射功率的一半。在实际工程中,无线传输效率和耦合效率均不会为1,因此,无线电波防爆安全发射功率阈值应是无线电波防爆安全接收点火功率阈值2倍以上。煤矿井下无线电波防爆安全接收点火功率阈值为8 W,因此,煤矿井下无线电波防爆安全发射功率阈值应大于16 W。

含废旧矿井抽蓄电站的源-荷-储协同控制调频研究

针对新能源在电网中渗透率不断提高导致系统调频容量和频率响应能力不足的问题,提出一种含废旧矿井抽蓄电站的源-荷-储协同控制调频方法。首先,建立了电解铝工业负荷、废旧矿井抽蓄电站和超级电容频率响应模型。然后,基于模型预测控制理论,以系统状态量和控制量的加权函数最小为目标,设计区域信息互动的分布式模型预测控制器,并提出含废旧矿井抽蓄电站的源-荷-储协同控制调频方法。最后,将分布式模型预测控制器应用在所提源-荷-储协同控制方法中,并在改进的IEEE标准两区域LFC模型中进行仿真。结果表明所提方法可以缩短频率恢复时间,减小最大频差值,改善系统调频动态性能。

超大采高综采工作面支护技术及装备研究现状

超大采高一次采全厚开采具有开采效率高、资源回收率高等特点。为探求超大采高综采技术进一步突破,分析其工作面围岩稳定性控制可行性,在调研超大采高综采发展历程的基础上,总结了超大采高综采工作面围矿压显现及煤壁片帮规律,分析了现有超大采高液压支架整体技术特征及其适用性能,并介绍了10 m超大采高工作面液压支架基本情况。通过分析发现:工作面矿压显现强度与采高基本呈现正相关关系,采高越大,工作面支护阻力越大,且煤壁片帮是困扰超大采高开采高效推进的主要因素之一,通过提高工作面液压支架的初撑能力能有效减小煤壁应力;液压支架随工作面采高增加,选型工作阻力增大,支架中心距加宽,大梯度过渡方式在提供可靠支护的同时,能有效提升端头区资源回收率;为适应大体量开采装备运输,超大采高工作面煤巷断面增加,超前支架工作阻力增大;工作面配套液压支架通过设计手段、整体结构、制造工艺等方面优化升级以提升可靠性及适应性;相对较低采高工作面支护,超大采高开采更注重支护过程中的安全技术需求,需要完善架前煤矸防护、架间防尘降尘、安全的后期维检等安全措施;工作面围岩稳定性控制及其配套装备是超大采高综采技术发展及推广的重点,从支护参数选择、支护结构设计到液压支架制造、后期维检的超大采高液压支架全寿命开发是支撑超大采高开采高效推进的基础。

Research and Application of Distributed Data Mining Method for Improving Rural Power Grid Enterprises in Production and Operation Status Evaluation

With the reform of rural network enterprise system,the speed of transfer property rights in rural power enterprises is accelerated.The evaluation of the operation and development status of rural power enterprises is directly related to the future development and investment direction of rural power enterprises.At present,the evaluation of the production and operation of rural network enterprises and the development status of power network only relies on the experience of the evaluation personnel,sets the reference index,and forms the evaluation results through artificial scoring.Due to the strong subjective consciousness of the evaluation results,the practical guiding significance is weak.Therefore,distributed data mining method in rural power enterprises status evaluation was proposed which had been applied in many fields,such as food science,economy or chemical industry.The distributed mathematical model was established by using principal component analysis(PCA)and regression analysis.By screening various technical indicators and determining their relevance,the reference value of evaluation results was improved.Combined with statistical program for social sciences(SPSS)data analysis software,the operation status of rural network enterprises was evaluated,and the rationality,effectiveness and economy of the evaluation was verified through comparison with current evaluation results and calculation examples of actual grid operation data.

工矿机车牵引双供电系统及其下垂控制策略

为了应对工矿机车距离和载重日益增长的发展趋势,同时满足工矿机车牵引对突变负荷的运行稳定性提升的要求,提出一种双供电系统及其下垂控制方法的工矿机车牵引供电方案。针对工矿牵引具有负荷突变、往返载荷差异大等工矿行业的特殊性,对比分析了站间精确均流和非精确均流策略对工矿机车牵引的适用性,根据分析结果提出了工矿机车双供电系统方式及其站间协同下垂控制策略,在此基础上引入电流前馈控制策略。搭建了仿真模型和包含牵引变电站的工矿机车低压试验牵引物理动模平台,试验结果表明所该策略在负荷突变工况下的机车电压稳定性显著优于与常规下垂控制方法。该研究为工矿机车牵引向大容量、远距离、高可靠性未来发展提供了有力的技术支撑。

煤矿供电系统防越级跳闸技术及其应用

随着煤矿生产过程中的电力需求不断增长,煤矿供电系统的安全运行成为了研究重点。首先,论述了防越级跳闸技术在煤矿供电系统中的重要性。然后,对防越级跳闸技术的实现方法进行了详细分析。接着,提出了一种基于智能电网技术的防越级跳闸方案,并通过实际煤矿供电系统的仿真实验验证了其有效性。