Electrochemical energy storage systems have the advantages of fast power response, intensive energy storage, flexible and convenient deployment, but the output characteristics of the battery system directly affect the service effect of the energy storage power plant. Therefore, it is quite necessary to analyze the reliability of battery energy storage and scientifically assess the system’s performance. This paper considers the aging state of the battery storage system as well as sudden failures and establishes a comprehensive reliability assessment method for battery energy storage systems that take into account the battery health index and the impact of thermal runaway failures, which makes up for the shortcomings of existing reliability assessment methods.

为研究储能站在多站融合中的多功能优化配置方法,首先探讨用储能站替代传统柴油发电机和不间断电源(uninterruptible power supply, UPS)的可能性,通过可靠度计算对传统模式及储能站模式进行对比,结果表明用储能站替代的可靠度更高。进而对储能站的经济性进行分析,建立储能寿命模型并进行成本分析,通过对比储能站的投资成本、运行维护成本以及度电成本确定储能类型。最后综合考虑多站融合中储能站的可靠性以及经济性,以储能站的可靠性最佳和年净收益值最大为目标函数配置储能容量,采用粒子群优化(particle swarm optimization PSO)算法得到储能的最佳配置容量为可用容量3 500 kWh,备用容量150 kWh,所提出的两阶段优化方法使得多站融合中储能的配置容量更加精确并且贴合实际。

To study a multifunction optimization configuration method for energy storage stations in multi-station integration, the possibility of replacing the traditional diesel generator and UPS with energy storage is discussed. The traditional and energy storage modes were compared using reliability calculations, and the results showed that the reliability of energy storage was higher. Then, the economy of energy storage was analyzed, a life model of energy storage was established, the cost was analyzed, and the type of energy storage was determined by comparing the investment, operation and maintenance, and kilowatt-hour costs of energy storage. Finally, considering the reliability and economy of the storage station in multi-station integration, we configured the energy storage with optimal reliability of the storage station and maximum annual net return value as the objective function. The particle swarm optimization algorithm was used to obtain an optimal allocation of energy storage capacity, with 3 500 and 150 kWh of usable and standby capacity, respectively. The example results show that the two-stage optimization method proposed in this study makes the allocation capacity of energy storage in multi-station fusion more accurate and realistic.

Lithium-ion batteries (LIBs) are widely used in electric vehicles (EVs) and energy storage systems (ESSs) because of their high energy density, low self-discharge rate, good cycling performance, and environmental friendliness. Nevertheless, with the extensive utilization of LIBs, incidents of fires and explosions resulting from thermal runaway (TR) have become increasingly prevalent. The resolution of safety concerns associated with LIBs and the reduction in operational risks have become pivotal to the operation and control of ESSs. This paper proposes a model for the TR process of LIBs. By simplifying the modeling of TR reactions, it is possible to calculate the starting temperature of the battery self-heating reaction. Subsequently, this paper puts forth an operational reliability evaluation algorithm for a reconfigurable battery energy storage system (BESS). Finally, this paper develops a control algorithm for reliability improvement, with the objective of ensuring safe and stable control of the ESS.

随着大规模新能源的逐步接入，混合直流输电系统（hybrid multiple sending terminals HVDC， H-MSTDC）逐步由单送端结构发展为多送端多受端结构，多个换流站的运行方式及送端换流站之间容量分配增加了可靠性评估的复杂度。考虑多个送端和受端换流站之间的容量分配系数，分析了混合多送端直流输电系统的典型接线和运行方式，构建了混合多送端直流输电系统各受端及系统综合可靠性指标体系，基于子系统划分和均匀设计法提出了H-MSTDC可靠性评估模型。最后，基于我国藏东南工程某二送二受备选接线结构，计及容量分配系数，进行直流输电系统可靠性评估，并分析了极端地理环境影响下系统可靠性的变化趋势，为实际工程提供参考。

With the gradual integration of large-scale new energy, hybrid multiple sending terminals HVDC (H-MSTDC) system gradually develops from single terminal structure to multiple sending and receiving terminals. The operation mode of multiple converter stations and capacity allocation among converter stations increase the complexity of reliability evaluation. The typical connection structure and operation mode of H-MSTDC system are analyzed by considering the capacity distribution coefficient among converter stations in multiple sending terminals and receiving terminals, and the comprehensive reliability index of each receiver and system of H-MSTDC system is constructed. The reliability evaluation model is proposed based on subsystem division and uniform design method. Finally, based on the alternative connection structure of a two-sending and two-receiving project in southeast Tibet and considering the capacity allocation coefficient, the reliability evaluation of H-MSTDC system is carried out, and the variation trend of system reliability under the influence of extreme geographical environment is analyzed, which can provide reference for practical projects.

随着我国能源战略的实施和坚强智能电网的建设,混合多端特高压直流输电技术迅速发展,未来将成为我国电网的重要组成部分,准确量化评估混合多端特高压直流输电系统的可靠性对我国电网未来的安全可靠运行具有重要意义。基于此,本文梳理了常规高压直流系统与柔性直流系统的典型接线结构与运行方式,进一步研究了二者组成的混合多端特高压直流输电系统的主要接线方案。针对每一种接线方案,根据主要元件故障后果及其在一次接线中的位置,将直流输电系统划分为:交流滤波器子系统、换流变压器子系统等多个子系统,然后对子系统分别建模。最后,基于状态枚举法组合各子系统可靠性评估模型,建立了整个混合多端特高压直流输电系统可靠性评估模型。以乌东德电站送电广东广西特高压混合三端直流输电工程为例进行算例分析,对工程可能的7种接线方案分别进行了可靠性评估和对比分析,并对直流输电线路的故障率进行了可靠性灵敏度分析。

With the implementation of energy strategy and the construction of a strong smart grid in our country, hybrid multi-terminal UHVDC transmission technology is rapidly developing and will be an important part of the China power grid in the future. Therefore, the accurate and quantitative evaluation of reliability of the hybrid multi-terminal UHVDC transmission system is of great significance to the safety and reliability of power grid. Based on this, the typical structure and operation modes of conventional HVDC systems and flexible HVDC systems are combed, and main wiring diagrams of hybrid multi-terminal UHVDC transmission system composed of aforementioned two systems are further studied. For each wiring diagram, according to the effect of main component failure and its position in primary connection, the HVDC system is divided into several subsystems such as AC filter subsystem and converter transformer subsystem, and then subsystems are modeled respectively. Finally, based on the state enumeration method, evaluation reliability model of hybrid multi-terminal UHVDC transmission system combined by the subsystem reliability evaluation models is established. Take Wudongde hybrid three-terminal HVDC transmission project as an example, the reliabilities under seven possible wiring diagrams in the project are evaluated and compared, the reliability sensitivity analysis of the failure rate of HVDC transmission line is also carried out.

Common cause failure (CCF) is concealed and harmful. With the increase in the number of redundant systems in aircraft, quantifying the impact of CCF is crucial for accurately calculating system failure probabilities. However, the diverse and complex redundancy configurations prevalent in modern aircraft systems often limit the applicability and analytical efficiency of existing CCF quantification methods. To address these challenges, the applicability of three CCF modeling approaches, namely the β-factor model, the α-factor model, and the square root model is analyzed. Furthermore, a failure probability correction model is constructed to quantify CCF impacts across systems with varying redundancy levels and configurations. The effectiveness and versatility are then validated on three typical aircraft system failure cases. Further, a software for correcting the failure probability of complex systems considering CCF is developed, which is highly applicable and efficient in calculation. This study not only enriches the methodologies for system safety analysis but also significantly enhances the efficiency and accuracy of CCF quantification in aerospace engineering.