基于ERP全口径设备管理在资产全寿命周期中的应用

电力企业的设备管理具有规模庞大、种类繁杂、分布地域广、技术含量高等鲜明特征,同时资产全寿命周期中设备管理要求提高设备的可用率和运行效率,减少检修费用投入,因此设备管理一直是电力企业所面临的难题.通过对ERP系统以及专业设备管理系统特点的分析,提出基于ERP系统实现全口径设备管理,能够对资产全寿命周期过程以有力的支撑,达...     

基于电力资产全寿命周期的标签画像技术研究

利用大数据分析挖掘技术,以“标签”形式,构建多层次、多视角、立体化的资产全寿命周期画像,实现对电力资产特征的全面刻画,准确把握设备运行状态,实现资产全寿命周期的精细化、差异化管理。成果可对电网规划设计、设备运行、设备检修及退役工作给出有效的指导和建议,提升采购设备在全寿命周期中的质量以及电网的可靠性和安全性。     

断路器全寿命周期成本模型及其应用研究

在对断路器进行经济评估时,往往比较关注购置成本而忽略了其他阶段所发生的成本,容易造成资金得不到充分利用。根据全寿命周期理论,建立了考虑资金时间价值的断路器全寿命周期成本(life cycle cost,LCC)模型,该模型能够对断路器全寿命周期成本进行计算和分析,为断路器进行经济评估提供决策。通过实例验证了该模型的有效性,并且提出在LCC的计算过程中必须全面计及各阶段成本和合理评估断路器的使用寿命。全寿命周期理论为断路器的经济评估提供了方法,同时也为其他电力设备的经济评估提供了指导。     

计及可靠性的配电网全寿命周期成本模型及应用

随着现代经济的高速发展,对电力系统的设备可靠性要求更高,科学高效地管理是亟待解决的关键问题,全寿命周期成本管理(LCC)将是优化电网的重要手段。计及配电网设备运行寿命、设备可靠性性能和电网可靠性的影响,以成本效益分析原理为基础,提出了配电网设备级和系统级LCC计算模型,分析了贴现率、投资费用、单位停电损失费等参数对LCC值的影响。算例分析表明,该模型实用、正确,对降低工程综合成本、提高设备的整体效益和优选配电网规划方案具有重要意义。     

基于全寿命周期成本(LCC)理念的绝缘子选型

对500kV线路绝缘子选型采用LCC理念进行经济成本分析,结合各种绝缘子型式在以往500kV线路的工程实践情况,最终得出本工程各种污秽区采用悬垂、耐张绝缘子最适用的型式。     

全寿命设备管理的回归分析及应用

全寿命周期成本(LCC)电力设备管理中的运行和故障费用十分重要,但是设备的运行故障费用的模型却很难得到,同时全寿命的可靠性研究也需要设备故障模型的支持。在上海电网采购管理系统(PMS)的设备运行数据的基础上,对设备故障与设备成本、设备维修情况、设备使用年限等进行统计。通过选取设备管理的模型和回归分析方法,得到反映设备故障及其关键影响因素之间关系的数学模型,找到故障模型与关键因素之间的定量关系。在该数学模型的基础上,进行设备故障预测、全寿命评估和可靠性分析,使得上海电网目前已有的设备数据,采用回归分析在工程上更为实用。     

基于全寿命周期成本的配电网合环运行经济性评估方法

系统研究了基于全寿命周期成本的配电网合环运行经济性评估方法,并分析在南沙配电网中的应用。首先,从配电网合环运行的基本特点出发,系统建立配电网合环运行全寿命周期经济性评估框架;其次,提出一种配电网可用度的简化计算模型,以获得复杂配电网合环运行情况下的全寿命周期停电成本;再次,综合考虑配电网合环运行的资产投资成本、运维检修成本、停电成本、报废成本等,形成一套完整的全寿命周期经济性评估方法;最后,将所提方法应用于南沙配电网,结果表明了所提方法的有效性。     

考虑风险度量与成本最优的电网资产全寿命周期管理问题

针对电力企业资产管理问题,通过电网资产的风险度量评价方法,分析了电力企业对于投资各项电网资产的最优资金配置比例。建立了最小化风险最大化收益的双目标优化模型,利用电网资产的预算曲线和LCCt成本曲线,将电网资产的整个寿命周期划分为投资规划期、运行期和处置期,并分析了LCCt成本在不同寿命周期的变化情况,而LCCt成本曲线的最小值对应的年限即为该资产的最佳使用寿命。数值算例阐明了投资决策和资产管理的实际应用,并验证了模型的有效性。     

基于全寿命周期的变压器资产原值建模分析

从设备寿命周期费用的角度即以经济效益为中心来管理变压器。变压器寿命周期成本包含建设成本、运行成本、维修成本及废弃成本。使用计量经济学软件SPSS通过线性回归和关系式拟合估算的方法,并通过具体的算例得到了影响变压器资产原值的一般模型,以便更精确地对设备和系统进行评估,把寿命周期成本降到最低。     

基于全寿命周期成本管理的变电站配电装置比选研究

全寿命周期管理(LCC)设计要求按照统筹协调安全、效能和周期成本三者的关系,通过对设计方案进行比选,降低全寿命周期成本。介绍了全寿命周期成本的方法和计算模型,结合工程实际情况,基于全寿命周期成本设计,以资产全寿命周期成本作为重要经济性评价标准,对城市变电站中220kV配电装置按全户内气体绝缘组合电器设备(GIS)和户外混合气体绝缘组合电器设备(HGIS)进行方案比选,着重分析了220kV配电装置的LCC构成,给出配电装置选择的依据,并提出建议。     

A novel photovoltaic maximum power point tracking technique based on grasshopper optimized fuzzy logic approach

The maximum power point tracking (MPPT) in the PV system has become complex due to the stochastic nature of the load, intermittency in solar irradiance and ambient temperature. To address this problem, a novel Grasshopper optimized fuzzy logic control (FLC) approach based MPPT technique is proposed in this paper. In this proposed MPPT, grasshopper optimization is used to tune the membership functions (MFs) of FLC to handle all uncertainties caused by variable irradiances and temperatures. The performance of the proposed grasshopper optimized FLC based MPPT is studied under rapidly changing irradiance and temperature. The proposed MPPT overcomes the limitations such as slow convergence speed, steady-state oscillations, lower tracking efficiency as encountered in conventional methods viz. perturb & observed (P&O) and FLC techniques. The feasibility of the proposed MPPT is validated through experimentation. The effectiveness of the proposed scheme is compared with P&O and also with FLC MPPT.     

Frequency control in micro-grid power system combined with electrolyzer system and fuzzy PI controller

The widespread use of various kinds of distributed power sources would impact the quality of the power supply within a micro-grid power system, causing many control problems. This paper focuses on the stability of micro-grid operation and discusses the control techniques of combining a micro-turbine with the fuel cell and electrolyzer hybrid system to expand the micro-grid system's ability to solve power quality issues resulting from frequency fluctuations. The paper examines the feasibility of fuel cell and electrolyzer hybrid system control, especially dynamic control of an electrolyzer system, to secure a real power balance and enhance the operational capability of load frequency control. The proposed control and monitoring system can be considered to be a means of power quality control, both to improve the frequency fluctuations caused by random power fluctuations on the generation and load sides and to relax tie-line power flow fluctuations caused by frequency fluctuations in the interconnected micro-grid power system.     

A novel maximum power point tracking technique based on fuzzy logic for photovoltaic systems

Maximum power point tracking (MPPT) techniques are considered a crucial part in photovoltaic system design to maximise the output power of a photovoltaic array. Whilst several techniques have been designed, Perturb and Observe (P&O) is widely used for MPPT due to its low cost and simple implementation. Fuzzy logic (FL) is another common technique that achieves vastly improved performance for MPPT technique in terms of response speed and low fluctuation about the maximum power point. However, major issues of the conventional FL-MPPT are a drift problem associated with changing irradiance and complex implementation when compared with the P&O-MPPT. In this paper, a novel MPPT technique based on FL control and P&O algorithm is presented. The proposed method incorporates the advantages of the P&O-MPPT to account for slow and fast changes in solar irradiance and the reduced processing time for the FL-MPPT to address complex engineering problems when the membership functions are few. To evaluate the performance, the P&O-MPPT, FL-MPPT and the proposed method are simulated by a MATLAB-SIMULINK model for a grid-connected PV system. The EN 50530 standard test is used to calculate the efficiency of the proposed method under varying weather conditions. The simulation results demonstrate that the proposed technique accurately tracks the maximum power point and avoids the drift problem, whilst achieving efficiencies of greater than 99.6%.     

A fuzzy logic based supervisory controller for an FC/UC hybrid vehicular power system

Depending on growing concerns on energy crises and environmental issues, fuel cell (FC) powered electrical vehicles are favored for possible substitute to conventional internal combustion engine (ICE) based vehicular systems. However, the typical power profile of an automobile motor consisting of transients is not suitable for the use of a sole FC system for vehicle propulsion. This shortcoming could be partly overcome by hybridization. Two potential benefits of combining an FC system with an energy storage unit, ultra-capacitor (UC) has been presented in this study. Firstly, the durability of the FC system could be improved because the additional energy source can fulfill the transient power demand fluctuations. Secondly, the ability of the energy storage source to recover braking energy enhances the fuel economy greatly. An important aspect in designing a hybrid power structure is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. An integrated procedure for mathematical modeling and power control strategy design for an FC/UC hybrid vehicle is presented in this paper. A fuzzy logic supervisory controller based power management strategy that secures the power balance in hybrid structure, enhances the FC performance and minimizes the power losses is proposed. The main contribution of this paper apart from the previous studies of the authors is the modeling of the complete FC power system with air supply compressor and the integration of the control of the FC system internal dynamics (especially the oxygen excess ratio) into the overall supervisory control structure to maximize the efficiency and durability. To demonstrate the effectiveness of the proposed power management scheme, simulation studies were performed using MATLAB^®, Simulink^® and SimPowerSystems^® environments by integrating the detailed mathematical and electrical models of the hybrid vehicular system.     

基于聚类数据包络分析模型的可再生能源发电项目综合评判决策

在深入调研的基础上,针对可再生能源发电项目规划环节面临的开发排序问题及运行后的效率综合评估问题,建立了聚类分析和数据包络分析相结合的CA/DEA两阶段评价模型。基于文中所设计的综合评价指标体系,引入了模糊层次分析法对于环境协调度等定性指标进行了综合分析,并运用基于聚类分析的主导因素挖掘方法从众多指标中选出最具影响力的因素指标;采用非参数DEA最优化模型对发电项目综合效率进行评估,较好地解决了生产函数难以确定的问题。通过CA/DEA模型所确定的综合投入产出效率,实现了对发电项目优秀度的有效评价。最后通过实例分析,验证了该评估方法的有效性及实用性。     

THD reduction with reactive power compensation for fuzzy logic DVR based solar PV grid connected system

Dynamic voltage restorer (DVR) is used to protect sensitive loads from voltage disturbances of the distribution generation (DG) system. In this paper, a new control approach for the 200 kW solar photovoltaic grid connected system with perturb and observe maximum power point tracking (MPPT) technique is implemented. Power quality improvement with comparison is conducted during fault with proportional integral (PI) and artificial intelligence-based fuzzy logic controlled DVR. MPPT tracks the actual variable DC link voltage while deriving the maximum power from a photovoltaic array and maintains DC link voltage constant by changing modulation index of the converter. Simulation results during fault show that the fuzzy logic based DVR scheme demonstrates simultaneous exchange of active and reactive power with less total harmonic distortion (THD) present in voltage source converter (VSC) current and grid current with fast tracking of optimum operating point at unity power factor. Standards (IEEE-519/1547), stipulates that the current with THD greater than 5% cannot be injected into the grid by any distributed generation source. Simulation results and validations of MPPT technique and operation of fuzzy logic controlled DVR demonstrate the effectiveness of the proposed control schemes.     

Electricity tariffs based on long-run marginal costs for central grid system of Oman

The electricity tariffs in Oman are subsidized and are based on a cost accounting approach and do not reflect the true cost incurred in generating, transmitting and distributing a kilowatt-hour of electricity at the consumer end. This paper presents the electricity tariff based on the estimation of long-run marginal cost at generation, 33 kV, and 415 voltage level for Ministry of Housing, Electricity & Water (MHEW) interconnected power system of Oman. The result shows that at the generation level a marginal kW costs US$ 75 per year and a marginal kWh costs 2.07 ¢/kWh. These costs increase as we move downstream from generation to consumer end. The average cost of electricity at the consumer end connected at 415 V is 6.52 ¢/kWh or 25.17 Bz/kWh.     

基于加权模糊TOPSIS和灰色关联度的风电场选址研究

针对风电场选址标准要求的复杂性和不确定性,综合考虑地理因素、经济因素等对风电场选址决策的影响,构建了风电场选址的模糊评价体系。采用加权模糊TOPSIS与灰色关联分析法相结合的方法进行模糊多目标决策。为了避免确定权重过程中的主观性带来的影响,利用聚类方法确定专家权重,并用排列熵确定评价指标权重。在衡量贴近度方面,使用了欧氏距离和灰色关联度两项指标来衡量,以克服欧式距离在小样本情况下的不足。对大连某风电场选址案例的研究证明了该方案的有效性。     

Intelligent photovoltaic farms for robust frequency stabilization in multi-area interconnected power system based on PSO-based optimal Sugeno fuzzy logic control

Currently, the grid-connected large PV farms are extensively installed in power systems. Nevertheless, in addition to the load change, the intermittent power output of PV farms may lead to the serious problem of the system frequency fluctuation. To handle this problem, this paper proposes a new design of Sugeno fuzzy logic controller based on particle swarm optimization (PSO-SFLC) of intelligent PV farms for the frequency stabilization in a multi-area interconnected power system. To handle various scenarios, the frequency deviations and solar insolations are used as input signals of the PSO-SFLC. The output signal of the PSO-SFLC is a command signal for adjusting PV output power. The output power of PV is controlled by the PSO-SFLC to meet the load demand so that the system frequency fluctuation can be suppressed. Without the difficulty of trial and error, the optimal input and output membership functions, and control rules of PSO-SFLC are automatically achieved by PSO. Simulation study in a three-area loop interconnected power system with large PV farms elucidates that the frequency stabilizing performance and robustness of the PV equipped with the PSO-SFLC is much superior to that of the PV with the SFLC and the PV with the maximum power point tracking control in scenarios with various solar insolations and loading conditions.     

Optimal energy management system for stand-alone wind turbine/photovoltaic/hydrogen/battery hybrid system with supervisory control based on fuzzy logic

This paper presents a novel hourly energy management system (EMS) for a stand-alone hybrid renewable energy system (HRES). The HRES is composed of a wind turbine (WT) and photovoltaic (PV) solar panels as primary energy sources, and two energy storage systems (ESS), which are a hydrogen subsystem and a battery. The WT and PV panels are made to work at maximum power point, whereas the battery and the hydrogen subsystem, which is composed of fuel cell (FC), electrolyzer and hydrogen storage tank, act as support and storage system. The EMS uses a fuzzy logic control to satisfy the energy demanded by the load and maintain the state-of-charge (SOC) of the battery and the hydrogen tank level between certain target margins, while trying to optimize the utilization cost and lifetime of the ESS. Commercial available components and an expected life of the HRES of 25 years were considered in this study. Simulation results show that the proposed control meets the objectives established for the EMS of the HRES, and achieves a total cost saving of 13% over other simpler EMS based on control states presented in this paper.