A large number of distributed photovoltaics are linked to the distribution network, which may cause serious power quality problems. Based on edge computing, this article put forward a strategy that aggregates multiple distributed resources, such as distributed photovoltaics, energy storage, and controllable load to solve this problem, emphasizing the coordination and optimization between distributed resources. Firstly, an edge computing architecture that can be fully applicable to the coordination of source-storage-loads is constructed. Based on this architecture, the distributed photovoltaic, energy storage and interruptible loads are optimized with the minimum operating cost of edge computation nodes as the objective function. Combined with the operation requirements of the distribution system, lessen the system network loss and make sure the stable and safe operation of the net; Finally, the model is changed with a second-order cone model and verified in an improved IEEE 33 node example. The results show that this method can effectively reduce the loss cost of the system, and can effectively solve the problem of system voltage exceeding the limit, reduce the voltage fluctuation, and maintain the safe and stable operation of the system. (c) 2023 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

随着构建新型电力系统目标的提出和能源互联网的建设和发展,亟须针对虚拟电厂的海量分布式资源聚合调控,建立灵活、安全、高效的互动机制.基于多种通信技术的虚拟电厂异构通信网络架构是保障电网安全运行的基础.首先,从虚拟电厂的基本概念和元素构成出发,对虚拟电厂采用的通信技术和通信需求进行分析.其次,提出虚拟电厂基于云边端协同的两级通信网络架构.最后,对支撑虚拟电厂资源灵活互动的通信技术进行探讨和展望,旨在提供虚拟电厂多时间尺度、跨区域聚合调控的信息通信基础支撑,为虚拟电厂通信网络的建设提供解决方案.

能源互联网的发展推动了分布式资源配置规模与利用效率的逐步提高，规模化灵活资源虚拟电厂的构建将成为新型电力系统灵活性提升的关键研究领域。文中聚焦于规模化灵活资源可信聚合以及灵活资源辅助电力系统所需的信息-能量-价值耦合互动机理问题，提出了规模化灵活资源虚拟电厂的科学问题、技术路线与理论框架。在此基础上，分别从动态聚合、安全通信、协同调控、可信交易等4个领域，论述了具体的核心关键技术及其关联支撑关系。最后，围绕规模化灵活资源虚拟电厂的技术挑战与创新应用进行了总结和展望。

综合能源系统（integrated energy system, IES）具有灵活调度和多能互济的特点,针对当前综合能源系统供能可靠性研究尚不充分的问题,提出一种考虑最优负荷削减与热负荷惯性的综合能源系统可靠性评估方法。首先,建立了综合能源系统总停供损失期望指标,充分体现了综合能源系统停供能造成的经济损失;其次,考虑能源品位、负荷重要度、热负荷惯性,建立了故障场景下综合考虑运行成本最小与加权停供负荷量最小为目标的综合能源系统最优负荷削减模型,采用CPLEX软件求解获得电热负荷削减功率和元件设备出力;然后,基于序贯蒙特卡洛模拟原理,设计了综合能源系统可靠性评估方法和流程;最后,通过算例仿真进行验证。算例分析表明,采用最优负荷削减策略和考虑热负荷惯性能够有效提升综合能源系统的可靠性水平。

This paper studies the reliability evaluation technology of regional energy Internet and represents a reliability evaluation method considering the optimal load reduction strategy. The application scenario of regional Energy Internet with power system as the core is built. The specific form is that multiple Integrated Energy systems are connected to the superior distribution network through the tie line. The reliability evaluation index system of power system and regional energy Internet is introduced. Based on the modelling of components in the regional energy Internet application scenario in this paper, the operation model and two-state Markov model are mainly established for the renewable energy power generation devices, energy coupling devices and energy storage devices in IES. The optimal load reduction models based on load classification are established for the faults of distribution network lines and the faults of IES internal components connected to the distribution network in regional energy Internet respectively. Through the construction of different application scenarios, the load reduction situation under different faults and different component parameters is analysed, and the corresponding reliability index calculation and result analysis are carried out.

In this paper, an integrated energy system (IES) reliability assessment method based on sequential Monte Carlo simulation and fault recovery optimization is proposed considering the flexibility of dispatch and the complementary of multi-energy in IES. The reliability evaluation indices of IES are established considering the energy supply and thermal load delay characteristics. An IES failure recovery optimization model is established in which the shutdown loss and the minimum operating cost under the failure scenario are considered comprehensively. CPLEX software is applied to solve the proposed problem in order to obtain the electric and thermal load reduction power and component equipment output. Based on the principle of sequential Monte Carlo simulation, an IES reliability assessment method and process are designed. The analysis of calculation examples shows that the use of failure recovery optimization strategies and consideration of thermal load delay characteristics can effectively improve the reliability of IES.

为了在规划中充分考虑交直流混合配电网的功率控制能力,文章考虑电压源换流器(Voltage Source Converter,VSC)与分布式电源(Distributed Generation,DG)之间的影响特性,以全社会综合效益最优为目标,建立交直流混合配电网VSC与DG三层协调规划模型:上层模型以直流改造和接入建设成本最小为目标进行VSC的选址定容;中层以DG规划成本最小为目标进行DG选址定容;下层以规划阶段整体综合运行成本最小为目标优化系统的运行状态.采用精英保留遗传算法以及二阶锥规划算法进行求解.算例结果验证了所提方法的有效性.

The insulation paper loss of life (LOL) of a distribution transformer (DT) is largely determined by its winding hot-spot temperature. It is mainly estimated via the transformer load, ambient temperature, and related physical parameters. Fortunately, advanced metering infrastructure (AMI) can provide load profiles of DTs, allowing a cost-effective LOL estimation solution. However, the AMI dataset contains measurement errors that significantly reduce LOL estimation accuracy. A forecasting method is needed to recover the erroneous AMI data. This is a challenging problem, as the load profiles of DTs are nonstationary and volatile. We propose an ensemble of stacked long short-term memory (ES-LSTM) networks to simultaneously capture load consumption patterns of DTs and their correlations. The ES-LSTM consists of two independent LSTM networks and a feed-forward neural network (FFNN) stacked on top of them. A two-stage training procedure is applied. In the first stage, two LSTM networks are trained to capture the daily or weekly load patterns. In the second stage, the FFNN is trained to optimally combine the last hidden outputs of the two LSTM networks. Field verification is conducted using real AMI data obtained from an urban distribution utility in China. The test results confirmed the superiority of the proposed method.

针对多能互补的直流微电网光储系统中的光伏电池的随机性、不确定性问题,通过无源控制(Passivity Based Control,PBC)方法与滑模控制(Sliding Mode Control,SMC)结合构成PBC-SMC控制的复合控制器,在此基础上设计储能变换器,提出电流内环采用PBC控制方案使得系统满足能量耗散定律自动收敛,为补偿电流精度电压外环采用SMC控制的双闭环控制方案.通过光照突变、负载突变以及二者同时突变的情况下仿真对比了PBC控制器和PBC-SMC控制器的性能,验证PBC-SMC复合控制的有效性,确保光伏—储能直流微电网系统具有优良的稳态性能和动态性能,提升了微网持续供电能力.

针对孤岛微网不对称故障对逆变器的负面影响,以两级式光伏并网逆变器为研究对象,基于传统双二阶广义积分器锁相环(DSOGI-PLL),以提高锁相精度为目的 ,采用谐波消除模块(HCM)与改进锁频环(SOGI-FLL)融合技术,提出一种DSOGI-PLL优化设计方法.在此基础上,构建一种改进两级式光伏低压穿越(LVRT)优化控制方法.从稳定并网逆变器直流电压和平抑输出功率波动两方面入手,进一步提升微网故障发生时逆变器的故障穿越能力.最后,利用RT-LAB实时仿真平台,构建含光伏并网的孤岛微网模型,通过模拟微网线路不对称故障,验证了所提光伏逆变器改进锁相环以及LVRT优化控制方法的有效性.

在微网中,虚拟同步发电机(VSG)技术通过模拟同步发电机的运行机理,实现分布式电源的友好接入并提高电力系统稳定性.然而,VSG逆变器在由离网切换至并网运行模式的瞬间存在较大的冲击电流.为此,提出一种预同步控制策略来解决这个问题.首先介绍VSG控制策略的原理,分析其离网向并网切换时产生冲击电流的原因,在此基础上对基于PLL技术的VSG逆变器预同步并网控制策略进行设计,包括频率补偿和幅值补偿两部分,以实现单台VSG逆变器离并网的无缝切换.在此基础上实现了多台不同容量VSG逆变器的功率分配及预同步策略,并考虑了在电网出现负载不对称故障下的控制策略.最后通过MATLAB/Simulink进行仿真验证.

首先介绍了2019 CIGRE成都国际研讨会概况;然后报道了配电网规划和运行,分布式灵活性资源,微电网、光伏和电池储能,直流配电,综合能源系统规划和运行等技术领域或专题的新进展;最后,对主动配电系统规划与运行、交直流混合配电,以及综合能源系统等技术的发展趋势和相关前沿问题进行了展望.

由于含有多种具有互补特性的分布式电源,多能互补微电网在能源综合利用、供电可靠性和运行经济性方面具有明显的优势.然而与传统配电网相比,各类分布式电源的并入导致微电网拓扑结构和运行方式变得更为复杂,并网和离网运行对应的故障特性存在差异,使得传统继电保护方案难以满足此类微电网保护的要求.针对这一问题,首先围绕传统继电保方案的不足展开讨论,分析微电网网内故障特点,继而提出一种适用于微电网的改进故障辨识算法,以实现对网内故障的快速准确辨识.综合考虑多能互补微网继电保护的需求,结合改进故障辨识算法,将改进电流差动保护与广域自适应电流速断保护相结合,提出一种适用于微电网分布式电源上下游线路的综合继电保护算法,在缩小故障影响范围的基础上,提高保护响应速度并降低保护拒动的概率.最后,利用RT-LAB实时仿真系统构建含风、光、储、微型燃气轮机等分布式电源在内的多能互补微网模型,通过网内模拟不同类型故障,验证了所提故障辨识和继电保算法的有效性.

The energy use optimization can effectively improve the comprehensive operational benefit of the distribution court. Nowadays, the energy use optimization in distribution court is facing serious challenges under the background of large scale DG coupling. The global optimization of the energy use in distribution network with multiple distribution courts is more difficult. In order to solve this problem, a comprehensive solution is proposed in this paper. The goals for energy use optimization in the distribution court are firstly discussed. The virtual power plant technology, microgrid technology and demand response technology are introduced and compared. By combining and applying the three key supporting technologies, an idea is proposed for the energy use optimization in the multi-court distribution network. The structural composition, functional framework and optimal control of the multi-court distribution network for the idea implementation are illustrated. Finally, a conclusion and an outlook is given.

In order to control air pollution and protect environment, winter clean heating is being vigorously promoted in Northern China. In recent years, the integration of electric heating facilities has a great impact on power supply capability, for which traditional distribution network optimization methods need to be improved. This paper firstly presents multiple typical scenarios of distribution network with electric heating loads, then an evaluation method of power supply capability based on attribute theory is proposed. Lastly, considering seasonal fluctuation of electric heating load, a robust optimization model based on scenario analysis is established, which takes power losses, voltage quality and load balance as multi-objectives to optimize on-off of the switches. Ant colony algorithm based on the Pareto optimal is adopted to solve the model. Taking IEEE 33 nodes distribution system as example, the effectiveness of the proposed method is verified, which shows that the economy and power supply capability are balanced with ensuring the node voltage safety.

Through realizing the mutual supply of power, gas, heating, cooling and other energy systems, regional integrated micro-energy system (RIMS) could make full use of the absorption capacity of renewable energy, and improve the comprehensive utilization rate of energy. The capacity allocation of components is the key content of RIMS design. This paper establishes an optimization model with the objective of minimizing the cost of unit productivity and constraints of energy balance, equipment outputs and charging & discharging power of energy storage devices. A case of RIMS was studied to verify the model. Simulation results show that the proposed capacity allocation optimization model could effectively reduce the cost of unit productivity, reduce peak-valley difference of various types of loads and improve utilization efficiency of clean energy.

Hybrid AC/DC distribution networks will play an important role in the future, in which the influences of existing AC distribution network need to be considered during planning. Thus, the reliability evaluation of hybrid AC/DC distribution network is essential, because the influences of AC/DC conversions are not considered in traditional methods. Therefore, this paper firstly introduces the basic structure of the existing AC/DC hybrid distribution network. And then, the reliability evaluation method is proposed and the failure mode consequence analysis table is established according to the protection strategy. Finally, a reliability index for AC/DC hybrid distribution network is proposed and tested based on a modified RBTS system.

介绍了2018年国际大电网委员会(international council on large electric systems,CIGRE)配电系统和分布式发电技术专委会(SC6)关于主动配电系统和分布式能源技术的工作进展、主要专题和重要技术.根据会议录用论文归纳出3个优先专题,在专题内对该领域的研究现状与研究重点进行剖析.结合相关论文对研究思路进行分享,并且探讨了主动配电系统与分布式能源技术的未来发展趋势以及下一步研究计划等问题.

介绍了2018年国际大电网委员会(international council onlargeelectricsystems,CIGRE)配电系统和分布式发电技术专委会(SC6)关于主动配电系统和分布式能源技术的工作进展、主要专题和重要技术。根据会议录用论文归纳出3个优先专题,在专题内对该领域的研究现状与研究重点进行剖析。结合相关论文对研究思路进行分享,并且探讨了主动配电系统与分布式能源技术的未来发展趋势以及下一步研究计划等问题。

AC-DC hybrid distribution network refers to the distribution network with AC-DC conversion power electronic devices such as converters and inverters. Compared with the traditional AC distribution network, AC-DC hybrid distribution network is more suitable to connect high penetration DGs and DC loads. This paper summarized the advantages and typical structures of medium voltage AC-DC hybrid distribution network along with their characteristics, then the application scenarios of medium voltage AC-DC distribution network are categorized and their suitable structures are analyzed.