Coordinated Planning Transmission Tasks in Heterogeneous Space Networks:A Semi-Distributed Approach

This paper studies the coordinated planning of transmission tasks in the heterogeneous space networks to enable efficient sharing of ground stations cross satellite systems.Specifically,we first formulate the coordinated planning problem into a mixed integer liner programming(MILP)problem based on time expanded graph.Then,the problem is transferred and reformulated into a consensus optimization framework which can be solved by satellite systems parallelly.With alternating direction method of multipliers(ADMM),a semi-distributed coordinated transmission task planning algorithm is proposed,in which each satellite system plans its own tasks based on local information and limited communication with the coordination center.Simulation results demonstrate that compared with the centralized and fully-distributed methods,the proposed semi-distributed coordinated method can strike a better balance among task complete rate,complexity,and the amount of information required to be exchanged.

Multi-beam cooperative frequency reuse for coordinated multi-point transmission

Coordinated multi-point （CoMP） joint transmission is considered in the 3rd generation partnership project （3GPP） long term evolution （LTE）-advanced as a key technique to mitigate inter-cell interference and improve the cell-edge performance. To effectively apply CoMP joint transmission,efficient frequency reuse schemes need to be designed to support resource management cooperation among coordinated cells. However,most of the existing frequency reuse schemes are not suitable for CoMP systems due to not considering multi-point joint transmission scenarios in their frequency reuse rules. In addition,the restrictions of frequency resources in those schemes result in a high blocking probability. To solve the above two problems,a multi-beam cooperative frequency reuse （MBCFR） scheme is proposed in this paper,which reuses all the available frequency resources in each sector and supports multi-beam joint transmission for cell-edge users. Besides,the blocking probability is proved to be efficiently reduced. Moreover,a frequency-segment-sequence based MBCFR scheme is introduced to further reduce the inter-cell interference. System level simulations demonstrate that the proposed scheme results in higher cell-edge average throughput and cell-average throughput with lower blocking probability.

Hybrid coordinated strategy of downlink coordinated multi-point transmission

Coordinated multi-point （CoMP） transmission is put forward in the long term evolution-advanced （LTE-A） system to improve both average and cell-edge throughput. CoMP-joint pro- cessing （JP） scheme can get a larger cell-edge throughput and a lower bit error rate （BER） than the CoMP-coordinated beamform- ing （CB） scheme, but it also has higher complexity due to data sharing. A hybrid coordinated strategy with parameter c~, which indicates the proportion of users employing the CoMP-JP scheme, is proposed to apply the CoMP-JP scheme to improve the poorer communication quality of cell edge and employ the CoMP-CB scheme for other users to enhance average throughput and spec- tral efficiency. This paradigm selects users defined by the certain threshold of signal to interference plus noise power ratio （SINR） corresponding to the parameter a to the CoMP-JP scheme. This paper compares the BER performance between the block diag- onalization （BD） based precoding and the linear precoders by maximizing signal to leakage and noise ratio （SLNR）, and also in- dicates that the SLNR based precoding algorithm gets lower BER than the BD based precoding algorithm with certain signal-to-noise ratios （SNRs）. Finally, this paper discusses that the system perfor- mance is partially affected by the percentage of CoMP-JP users and concludes that 50% of users sorted to communicate under the CoMP-JP scheme will reach the best system performance.

Optimized transmission coordination mechanisms for opportunistic routing

The successful rate of transmission coordination of opportunistic routing （OK） is analyzea systematically, and then two efficient transmission coordination mechanisms （TCMs） are proposed for OR： a batch sliding window-based TCM and a bit map-based TCM, to reduce the total number of packet transmissions and improve end-to-end throughput for OR. The batch sliding window-based TCM avoids the oscillation of the successful rate of transmission coordination by transmitting packets in continuous batch mode so as to improve the average successful rate of transmission coordination efficiently, while the bit map-based TCM improves end-to-end throughput of OR by reducing the overhead of transmission coordination. Exhaustive simulations show that the average end-to-end throughput gains of the two proposed TCMs are 15.4% and 6.4% over the batch map-based TCM, respectively.

A Storage and Transmission Joint Planning Method for Centralized Wind Power Transmission

Centralized delivery has become the main operation mode under the scaled development of wind power.Transmission channels are usually the guarantee of out-delivered wind power for large-scale wind base.The configuration of transmission capacity,which has the features of low utilization and poor economy,is hardly matching correctly due to the volatility and low energy density of wind.The usage of energy storage can mitigate wind power fluctuations and reduce the requirement of out-delivery transmission capacity,but facing the issue of energy storage cost recovery.Therefore,it is necessary to optimize the allocation of energy storage while considering the problem of wind power transmission.This paper studies the joint optimization of large-scale wind power transmission capacity and energy storage,reveals the mechanism of energy storage in order to reduce the power fluctuation of wind power base and slow down the demand of transmission.Then,analyze the multi-functional cost-sharing mode of energy storage,improve the efficiency of energy storage cost recovery.Constructs the coordination optimization configuration model to deal with the problem of large-scale wind power transmission capacity and energy storage,and realizes the transmission capacity optimization coordination and optimization with energy storage.The proposed method is verified by a wind base located in Northeast China.

Basic Concept and Theoretical Study of Condition-based Maintenance for Power Transmission System

状态检修背景下,为解决电网运行整体与输变电设备个体之间的矛盾和冲突,在已有研究成果基础上,提出电网状态检修的概念,在输变电设备状态检修决策过程中,给出电网故障风险和电网检修风险的定义以及相应的量化表达式。依据设备状态预测,以电网故障风险和电网检修风险的和最小为目标,将设备检修、运行以及电网整体性能在概率引导下相互牵制,形成电网状态检修的数学模型,并给出相应的解决方法。最后,为验证该理论研究的可行性,分别以可靠性测试系统RBTS-BUS6和IEEE-RTS79系统为例,对各种情况进行分析,体现了预期的效果,并期望为电网检修与运行协调决策理论的深入研究提供必要的理论基础。

Distributed Robust Energy and Reserve Dispatch for Coordinated Transmission and Active Distribution Systems

The increasing penetration of renewable energy sources introduces higher requirements for the operation flexibility of transmission system(TS) and connected active distribution systems(DSs). This paper presents an efficient distributed framework for the TS and DSs to work cooperatively yet independently. In addition to conventional power interaction, upward and downward reserve capacities are exchanged to form the feasible access regions at the boundaries that apply to different system operation situations. A distributed robust energy and reserve dispatch approach is proposed under this framework. The approach utilizes the supply-and demand-side resources in different systems to handle various uncertainties and improve overall efficiency and reliability. In particular, integrated as aggregated virtual energy storage(AVES) devices, air-conditioning loads are incorporated into the optimal dispatch. In addition, a reserve model with charging/discharging-state elasticity is developed for AVESs to enhance system flexibility and provide additional reserve support. Different cases are compared to verify the effectiveness and superiority of the proposed approach.

Three-dimensional Model Analysis of Electric Field Excited by Multi-circuit Intersecting Overhead Transmission Lines

This work is carried out to predict the special distribution of electric field induced by multi-circuit intersecting overhead high-voltage (HV) transmission lines (TLs) within a large range without any expensive and time-consuming computation. The two main parts of the presented methodology are 1) setting up a three-dimensional (3D) model to calculate the electric field based on combining ca- tenary equations with charge simulation method and 2) calculating the hybrid electric field excited by multi-circuit intersecting TLs using coordinate transformation and superposition technique. Examples of different TLs configurations, including a 220 kV single-circuit hori- zontally configured TLs, a 500 kV single-circuit triangularly configured TLs and a combination of the 220 kV TLs and the 550 kV TLs, are illustrated to verify the validity of this methodology. A more complicatal configurations, including a 500 kV double-circuit TLs and two 220 kV single-circuit horizontally configured TLs, are also calculated. Conclusions were drawn from the simulation: 1) The presented 3D model outperforms 2D models in describing the electric field distribution generated by practical HV TLs with sag and span. 2) Coordinate trans- formation and superposition technique considerably simplify the electric field computation for multi-circuit TLs configurations, which makes it possible to deal with complex engineering problems. 3) The electric field in the area covered by multiple intersecting overhead TLs is distorted and the hybrid electric field strength in some partial region increases so sharply that it might exceed the admissible value. 4) The configuration parameters of the TLs and the spatial configuration of multi-circuit TLs, for instance, the height of TLs, the length of span and the intersection angle of multiple circuits, influence the strength and the distribution of hybrid electric field. The influence regularities sum- marized in this paper can be referred by future TL designs to meet the electromagnetic environmental protection regulations.

Peregrine Soliton and Akhmediev Breathers in a Chameleon Electrical Transmission Line

We analyze the particular behavior exhibited by a chaotic waves field containing Peregrine soliton and Akhmediev breathers. This behavior can be assimilated to a tree with “roots of propagation” which propagate randomly. Besides, this strange phenomenon can be called “tree structures”. So, we present the collapse of dark and bright solitons in order to build up the above mentioned chaotic waves field. The investigation is done in a particular nonlinear transmission line called chameleon nonlinear transmission line. Thus, we show that this line acts as a bandpass filter at low frequencies and the impact of distance, frequency and dimensionless capacitor are also presented. In addition, the chameleon’s behavior is due to the fact that without modifying the appearance structure, it can present alternatively purely right- or left-handed transmission line. This line is different to the composite one.

考虑电动汽车充放电的输配协同能量-灵活性市场出清机制

为应对输电网对灵活性资源的迫切需求,挖掘配电网分布式资源的灵活性支撑潜力,首先,构建市场环境下电动汽车的车-网互动响应模型,分析不同充放电方式下电动汽车的需求响应能力,为电动汽车参与市场环境下电网调度控制提供模型基础;然后,计及配电网运营商对需求侧灵活性资源的聚合作用,以购买电力和灵活性资源总成本最低为目标,构建考虑电动汽车充放电方式的输配协同能量-灵活性市场出清模型,通过协调控制输配电网中各类灵活性资源来满足输电网的灵活性需求;最后,通过修改的IEEE 33节点输电网与2个IEEE 33节点配电网耦合的测试系统对所提输配协同能量-灵活性市场出清方法的有效性进行分析与验证。结果表明,所提方法可提升电力系统的运行经济性和灵活性。

基于凸包算法的极端运行方式提取方法

在电力系统规划与运行的安全稳定计算中,一般选择对安全稳定最不利的运行方式进行校验,但随着新能源渗透率的增加,电网越发复杂多变,人工选择场景主观性较强,针对此问题,提出了一种基于快速凸包算法的极端运行方式提取,从而满足场景选取进行安全校核需求。从电源规划、发输电协调规划两个角度,考虑发电充裕性、火电爬坡需求、网络传输安全3个方面,分析影响规划的极端运行方式;基于凸包算法分别从上述3个方面构建坐标系进行极端运行方式提取;采用中国西北地区电网为算例进行极端运行方式提取,并与基于K-means算法的极端场景提取做对比,结果表明:所提方法能为场景选取提供有效数据支撑,满足电网规划要求。

区域新能源并网暂态功角稳定分析与紧急控制策略优化

随着新型电力系统发展和新能源机组不断投产,南方区域将形成多区域新能源与邻近常规电源联合集中接入系统的场景。新能源集中接入常与常规电源共用输电通道,将影响区域系统暂态稳定特性及输送通道的传输能力,使南方区域系统的安全稳定运行和风险防控面临了前所未有的挑战。为深入研究区域新能源送出的稳定特性建立了区域新能源交流集中送出的等值系统模型,分析了新能源并入对区域系统对暂态稳定特性影响的主要机理。基于等面积法则对区域送出系统暂态过程的加、减速面积进行了定量分析,提出了紧急控制切机策略的协调优化方法,实现区域送出传统机组与新能源机组紧急控制切机量及控制代价的最小化的切机策略配置。最终,基于广东区域海风火电打捆送出系统为例,对分析结果的正确性进行了验证。

动能侵彻弹装药起爆可靠性试验及敏感因素分析

为研究弹体结构设计对弹体装药起爆可靠性的影响,设计了一种低成本、便捷式引战静态匹配试验装置,开展了不同条件下引信与装药的传爆裕度试验。基于移动最小二乘法,构建了可表征起爆可靠性的多变量响应函数,定量分析了各敏感因素及其耦合作用对起爆可靠性的影响规律。结果表明:传爆间隙和缓冲层厚度对弹体装药起爆影响较大,而隔板厚度在预设3~5 mm范围内的影响较小;为保证动能侵彻弹在使用环境温度范围内可靠作用,引信相对偏离位置、隔板厚度、传爆间隙以及缓冲层厚度分别不应超过25、3.5、25以及22 mm。该试验装置、分析方法及研究成果可为动能侵彻弹结构设计及可靠性验证提供借鉴和指导。

稳健驾驭:巨型工程的国家治理逻辑及其实现--以“西气东输”项目为例

巨型工程因其超大规模引发复杂性治理难题,需要国家的全面介入与稳健驾驭。西气东输工程的案例研究显示,超大的工程规模会导致决策的信息缺失与方案模糊问题,以及工程建设中的项目集成交互和多主体协同困境等治理难题。为解决这些难题,国家通过战略框定与工程目标建构,以国家意志塑造巨型工程战略纵深与社会合法性;通过方案最优化决策与群体智慧支持,以集体理性弥合理想最优方案与群体决策结果的差距;以领导小组统筹部署、高层权威推动和政治性协调,整合碎片化治理权威,形成有效的府际治理合力;通过国家主导的组织结构网络,国家权力深刻嵌入工程建设场域,以国家能力的积极运作实现管理协同。巨型工程的国家治理逻辑可概括为全面介入、战略统筹、稳健驾驭和有效治理,其研究有助于拓展巨型工程治理的国家理论,加深对中国巨型工程治理和决策过程的理解。

考虑输配协同的电网并行恢复分区及机组启动次序统一优化决策方法

在电网恢复初期,黑启动资源紧缺,恢复所需时间长。随着配电网接入多种类型的资源,利用含源配电网自下而上支撑输电网恢复、加速黑启动进程逐步具备可行性。该文首先提出输配协同恢复理念,分析向上支撑输电网恢复的配电网需具备的条件,进而明确输配协同恢复方式;然后,结合输电网机组启动过程的功率需求和配电网发电资源特征,定义配电网向上送电外特性,并提出配电网向上支撑外特性建模方法;进一步,以机组启动总耗时最小为目标,构建考虑输配协同的电网并行恢复分区及机组启动次序统一优化决策的混合整数线性规划模型;最后,基于国内实际输配电网算例,验证该文所提方法的有效性。

计及交直流谐波传递的MMC-BTB系统阻抗特性分析及环流配合策略

基于模块化多电平换流器的背靠背系统(back-to-back system based on modular multilevel converter,MMC-BTB)中换流器间控制交互密切,导致振荡事故频发。现有研究中忽略谐波传递的单端模型无法准确刻画MMC-BTB阻抗特性,也较少从振荡抑制层面考虑两换流器间的协同配合。为此,该文考虑MMC-BTB中换流器间谐波传递与衰减机理,依据多种环流控制方式的阻抗等价性提出一种基于环流协调控制的振荡抑制策略。首先,基于等效电路定性分析谐波的流通路径,并定量推导MMC-BTB的双端模型;然后,沿谐波路径对两侧环流控制的交互机理开展分析,证明其对改善MMC-BTB阻抗特性的关键作用,并提出环流控制的协调配合与参数优化策略;最终,通过Matlab/Simulink仿真验证理论分析与所提策略的正确性。

应对高阶不确定性的输配电协同优化调度

为应对风力发电与负荷侧的不确定性,提高电力系统对可再生能源的消纳能力,实现输电网和配电网间的优化调度,该文提出应对高阶不确定性的输配电协同优化调度模型.该文模型考虑风力发电及负荷侧的不确定性,在输配电互联的基础上引入电气热综合能源系统.研究结果表明:该文模型能提高系统的风电并网能力,增强系统适应电负荷波动的性能,降低系统的碳排放,提升系统的经济性.该文研究结果可为电力系统应对高阶不确定性制定输配电调度策略时,提供依据和支撑.

分布式优化在互联电网中的应用分析及展望

在新能源随机性与波动性的影响下,互联电网能量与灵活性的跨区域互济重要性凸显,有效的分布式优化算法是不可或缺的技术支撑。为了在互联电网不同运行层级的重要场景中选择适宜的算法,文中归纳了分布式优化建模和求解的一般原理,并提出将现有分布式算法分为原始可行方向、对偶可行方向、原对偶、切平面、列生成和多参数法6类。针对互联电网的多区域输电网协同调度、输配协同优化调度以及配电网分布式资源协同调度不同运行层级这3个重要场景,阐明了采用分布式优化的必要性,总结了统一的变量/约束耦合问题的典型建模及变换关系,并分析了6类算法在各场景的实施情况和应用优缺点。从物理场景、数学模型以及算法整体角度分析分布式优化在互联电网3个重要场景应用存在的问题,并给出了不同场景的算法选取建议。结合配电网运行新场景、数学建模新问题、算法设计新技术,展望了未来互联电网应用分布式优化的方向。

基于双向安德森加速分解协调算法的输配协同无功优化

新型电力系统中新能源渗透率不断增加,输电网和配电网协同运行环境复杂多变,对输配协同优化算法的收敛性提出了更高的挑战。鉴于此,应用广义主从分裂法将输配协同无功优化问题分解为输电网和多个配电网的并行优化问题;为改善广义主从分裂法的计算效率,提出了基于功率、电压等多元信息交互及历史信息修正的双向安德森加速策略;在此基础上,提出了融合原对偶内点法、启发式算法和辅助函数的输配协同无功优化方法,实现了输电网和配电网多种类灵活性资源的协调配合和优化控制。算例仿真结果表明,所提方法能有效改善主从分裂法边界的收敛性能,在大规模分布式能源接入的输配协同无功优化场景中具有更好的应用价值。

面向缪子透射成像的BCD-NES算法

针对大规模缪子透射成像场景,提出一种基于块坐标下降(BCD)的缪子透射成像模型.设计具有抗噪能力的牛顿误差累积(NES)算法对该模型进行求解,构建一种面向缪子透射成像的BCDNES算法.该算法在求解缪子透射成像问题时能够避免对大规模优化问题的直接求解,显著降低计算复杂度和内存资源占用.仿真与实验结果表明,在有噪声和无噪声情形下,该算法均能有效实现对待测物体成像,还能避免实际应用中的异常体变形问题,弥补传统成像方法的不足.