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 eff...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.展开更多
The bane of achieving a scalable distributed file sharing system is the centralized data system and single server oriented file [sharing] system. In this paper, the solution to the problems in a distributed environmen...The bane of achieving a scalable distributed file sharing system is the centralized data system and single server oriented file [sharing] system. In this paper, the solution to the problems in a distributed environment is presented. Thus, inability to upload sizeable files, slow transportation of files, weak security and lack of fault tolerance are the major problems in the existing system. Hence, the utmost need is to build a client-server network that runs on two or more server systems in order to implement scalability, such that when one server is down, the other(s) would still hold up the activities within the network. And to achieve this reliable network environment, LINUX network operating system is recommended among others as a preferred platform for the synchronization of the server systems, such that every user activity like sending of internal memos/mails, publication of academic articles, is replicated;thereby, achieving the proposed result. Hence, Scalable Distributed File Sharing System provides the robustness required to having a reliable intranet.展开更多
Quorum system is a preferable model to construct distributed access control architecture, but not all quorum system can satisfy the requirements of distributed access control architecture. Aiming at the dependable pro...Quorum system is a preferable model to construct distributed access control architecture, but not all quorum system can satisfy the requirements of distributed access control architecture. Aiming at the dependable problem of authorization server in distributed system and combining the requirements of access control, a set of criterions to select and evaluate quorum system is presented. The scheme and algorithm of constructing an authorization server system based on Paths quorum system are designed, and the integrated sys- tem performance under some servers attacked is fully analyzed. Role-based access control on the Web implemented by this scheme is introduced. Analysis shows that with certain node failure probability, the scheme not only has high dependability but also can satisfy the special requirements of distributed access control such as real-time, parallelism, and consistency of security policy.展开更多
基于某规划直流工程,分析了基于电网换相换流器(line commutated converter,LCC)和模块化多电平换流器(modular multileve converter,MMC)的混合级联型输电系统受端接线和控制方式。具体考虑因素包括接入受端交流系统的形式(集中接入或...基于某规划直流工程,分析了基于电网换相换流器(line commutated converter,LCC)和模块化多电平换流器(modular multileve converter,MMC)的混合级联型输电系统受端接线和控制方式。具体考虑因素包括接入受端交流系统的形式(集中接入或分散接入),逆变侧并联MMC的控制方式(定直流电压或定有功功率),以及多端接入条件下LCC和M M C换流站建设形式(合站建设或分站建设)。结果显示:分散接入有助于减小逆变侧交流故障下LCC和M M C在直流侧的交互影响;并联M M C均采用定直流电压控制有助于M M C交流侧故障后系统快速恢复稳定,且利用电流均衡控制策略能够消除潜在器件参数偏差导致的电流分配不对称现象;合站建设有助于减小直流故障风险,提高系统可靠性并降低投资成本。展开更多
基金supported by the Scientific Research Startup Foundation of Recruiting Talents of Nanjing Institute of Technology (No. YKJ202225)。
文摘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.
文摘The bane of achieving a scalable distributed file sharing system is the centralized data system and single server oriented file [sharing] system. In this paper, the solution to the problems in a distributed environment is presented. Thus, inability to upload sizeable files, slow transportation of files, weak security and lack of fault tolerance are the major problems in the existing system. Hence, the utmost need is to build a client-server network that runs on two or more server systems in order to implement scalability, such that when one server is down, the other(s) would still hold up the activities within the network. And to achieve this reliable network environment, LINUX network operating system is recommended among others as a preferred platform for the synchronization of the server systems, such that every user activity like sending of internal memos/mails, publication of academic articles, is replicated;thereby, achieving the proposed result. Hence, Scalable Distributed File Sharing System provides the robustness required to having a reliable intranet.
基金Supported by the National Natural Science Foundation of China (70771043, 60873225, 60773191)
文摘Quorum system is a preferable model to construct distributed access control architecture, but not all quorum system can satisfy the requirements of distributed access control architecture. Aiming at the dependable problem of authorization server in distributed system and combining the requirements of access control, a set of criterions to select and evaluate quorum system is presented. The scheme and algorithm of constructing an authorization server system based on Paths quorum system are designed, and the integrated sys- tem performance under some servers attacked is fully analyzed. Role-based access control on the Web implemented by this scheme is introduced. Analysis shows that with certain node failure probability, the scheme not only has high dependability but also can satisfy the special requirements of distributed access control such as real-time, parallelism, and consistency of security policy.
文摘基于某规划直流工程,分析了基于电网换相换流器(line commutated converter,LCC)和模块化多电平换流器(modular multileve converter,MMC)的混合级联型输电系统受端接线和控制方式。具体考虑因素包括接入受端交流系统的形式(集中接入或分散接入),逆变侧并联MMC的控制方式(定直流电压或定有功功率),以及多端接入条件下LCC和M M C换流站建设形式(合站建设或分站建设)。结果显示:分散接入有助于减小逆变侧交流故障下LCC和M M C在直流侧的交互影响;并联M M C均采用定直流电压控制有助于M M C交流侧故障后系统快速恢复稳定,且利用电流均衡控制策略能够消除潜在器件参数偏差导致的电流分配不对称现象;合站建设有助于减小直流故障风险,提高系统可靠性并降低投资成本。
