能源互联网多能分布式优化研究挑战与展望

3 研究展望

能源互联网的多能分布式优化问题涉及领域十分广泛,需要多智能体、信息物理融合、智能能源管理等理论的应用和信息通信、电力电子、新型储能、能源转换等先进技术的支撑。在能源互联网的研究热潮中,新的理念与思路不断涌现,如何选取合适的运行控制体系和机制,如何实现多能流分布式优化调控,如何设计适应能源互联网的商业运营模式,成为未来的主要研究方向。

1)分布式运行控制体系。

目前在电力系统中广泛应用的先分层后分区的运行控制体系从电能传输与利用的角度将整个电网主要分为输电和配电2层。但由于在能源互联网中间歇性分布式可再生能源的渗透率大幅提升,呈现出源-网-荷-储深度融合的特点,同时不同能源的耦合互补也使得多能源系统具有调度灵活性、多样性,导致能源传输环节的控制作用被大大削弱。因此,有必要将上文所述的分层分布式控制架构结合智能电网Web  of  Cell(WoC)体系“弱中心化”的思想[56]构建能源互联网运行与控制新体系,将能源互联网分成若干个结构较为简单的能源自治区域(Cell),区内集中自治,区间分散协调,从而实现全局的优化运行。每个能源子网并不是单一的供能侧或用能侧,而是可以包含能源生产、传输、分配、使用等各个环节,结合开放系统互连模型(open  system interconnection/ reference  model,OSI/RM)按功能划分不同的层次结构[57],如图5所示。该体系可以在不改变现有能源系统网架结构和地理边界的情况下实现能源互联网的群体智能化,具有良好的发展前景,是下一步研究需要关注的重点。

图5 基于WoC体系的功能分层结构

2)多能流分布式优化调控。

目前,分布式优化调控研究多集中于主动配电网层面或互联微电网系统,对于包含多能量枢纽的多能源系统涉及较少,尤其是考虑到能源互联网多能流耦合、多时空尺度、多智能体控制的运行方式,需要对现有的分布式优化策略进行改进和创新[58]。首先,由于不同能源系统的量测精度差异,需要研究稀疏通信网络下的分布式状态估计算法,满足各能流耦合环节信息交互的快速性与可靠性要求。在此基础上,针对不同能流系统响应时间的差异以及动态过程的相互影响,需要提出多优化周期的分布式多能流调控模型,研究多重优化模型下不同分布式优化算法的适用性问题,并考虑针对可再生能源出力等不确定性的模型预测控制[59]。此外,在人工智能兴起的大背景下,未来能源互联网应是能源调控方式与人类行为紧密耦合的信息-物理-社会融合系统,如何利用调度机器人群体的平行机器学习[60]实现多能源系统的分布调控将是具有前瞻性和开创性的研究课题。

3)能源市场去中心化交易模式。

在能源互联网分布式运行体系下,电网调度中心的主导地位将逐渐弱化,需要对供能、用能、储能及中间商等交易实体采用基于分散化决策和帕累托最优的微平衡交易模式[61]。但由于目前还未建立起协同多能源系统的跨平台商业模式和激励相容机制,如何利用区块链技术协同自治、去中心化、合约执行自动化及可追溯性的特点构建高效透明、广泛参与和全面信任的金融交易体系,形成面向分布式交易主体的可交易能源系统是实现能源互联网信息-物理-社会系统与金融体系之间立体化融合的关键[62-65]。然而我国区块链技术在能源互联网中的发展还处于理想化的场景分析阶段,面临计算能力不足、网络信息安全保障不充分、智能合约责任主体不明确等技术瓶颈,同时缺乏相应的政策约束与监管体系,需要结合能源互联网基础设施建设与改造进程探索分阶段的能源市场化发展策略,丰富去中心化交易模式的理论基础与工程实证。

4 结语

针对能源互联网开放互联、以用户为中心、共享对等的特点,相关协调运行与控制问题成为限制其规模与融合深度的瓶颈之一,需要分布式优化策略与调控技术的支撑。本文基于能源互联网“横向多能互补,纵向源-网-荷-储一体化协调”的互联模式,从能量枢纽建模、多能流网络建模与优化运行策略3个方面对多能协调运行优化基本方法和研究现状做了简要介绍与评述。随后,在分层分布式控制架构的基础上分析了适用于分布式设备广泛接入、即插即用的分布式优化算法与控制策略,并进一步介绍了多智能体系统的应用现状。最后展望了能源互联网在运行控制体系、多能流优化调控以及能源市场交易模式等方面的发展前景,对于日后能源互联网的应用与实践具有一定的指导意义和参考价值。

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