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并网分散电源的解列与孤岛运行 总被引:5,自引:0,他引:5
根据有功功率平衡原则、分散电源的产权关系和电气分布,提出了一种配电网分层孤岛运行的概念,可充分利用分散电源的供电能力,提高供电可靠性。接入多个分散电源的配电网络可划分为电厂级孤岛和变电站级孤岛,故障后的网络根据负荷匹配情况分层逐级解列。孤岛形成过程中,通过监测联络线的稳态功率变化计算孤岛内的功率不平衡,充分考虑孤岛的调节能力实现实时减载。最后,介绍了一种实现分层孤岛运行的分层分布式控制系统,借助高速通信网络,完成分层解列、实时减载、再同步与重合闸等功能。 相似文献
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分布式电源的接入给配电网的运行方式带来了较大影响,同时也使配电网对故障恢复方案提出了更高的要求。通过对配电网重合闸和分布式电源处电压变化的分析,考虑重合闸对DG低电压穿越的影响,提出了一种重合闸与低电压穿越相配合的有源配电网的故障恢复方案。该方案预先对分布式电源划分计划孤岛区域,并根据故障位置、孤岛区域以及分布式电源处电压变化等不同故障情况对有源配电网实施不同的供电恢复方法。最后通过PSCAD模型仿真验证了所提方案的可行性和有效性。 相似文献
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检母线无压重合闸方式在小电源并网通道上的应用 总被引:3,自引:0,他引:3
检母线无压重合闸方式应用在小电源并网通道的某些线路上,既可以避免小机组与系统发生非同期并列,又可以有效地提高对用电负荷的供电可靠性。 相似文献
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以某一次山区电网故障为例说明了小电源侧重合闸投检母线无压重合闸方式存在的缺点,即该重合闸需要较长等待时间,并且以解列该地区所有小电源为代价,恢复正常电网运行方式需要很长时间.对此,在研究自动捕捉准同期以及低周减载相结合的相关原理基础上,提出了一种适用于小电源地区联络线的自适应重合闸方案,即在丰水期的重合闸模式自动选择为捕捉准同期合闸模式;在枯水期则自动选择为检母线无压重合闸模式,同时结合低周减载控制措施,以达到快速恢复地区供电的目的.目前,该方案已在重合闸装置中实现,并利用近几年的故障录波数据以及电网运行参数对保护装置进行了模拟实验.实验证明,该自适应重合闸的使用能有效提高电网安全稳定运行和供电可靠性. 相似文献
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并网型微网凭借独立组网、高度自治的特点,可有效保证内部重要负荷的短期持续供电。首先,分析了微网中光伏电源和风电机组的输出随机特性,针对并网型微网两种运行方式,提出并网运行时微网和外网输出协调工作策略,并建立了孤岛运行时全时序可靠性模型;其次,基于孤岛运行特征和负荷切除原则,提出新的评估微网持续供电能力的可靠性指标;最后,对传统时序蒙特卡罗法进行改进,提出基于微网随机、时序等运行特性的可靠性评估方法,并以RBTS BUS6改进系统为例进行了仿真计算,验证所提方法的可行性。在此基础上,通过改变微网内电源的位置和储能容量大小,分析了电源位置和储能容量对配电系统和微网可靠性的影响。 相似文献
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配电网低压反孤岛装置设计原理及参数计算 总被引:2,自引:0,他引:2
针对分布式光伏发电接入配电网发生孤岛效应对电力检修人员现场安全作业的影响,设计了一种应用于220 V/380 V配电网中的低压反孤岛装置。装置基于光伏发电的孤岛运行机理和防孤岛保护策略,通过破坏分布式光伏发电孤岛运行的条件,实现反孤岛功能。提出了3种类型(阻性、感性、容性)低压反孤岛装置的设计原理,结合工程实际,计算了系列化低压反孤岛装置设计参数。通过试验对设计原理进行了验证和分析,通过比较不同类型低压反孤岛装置的试验结果和负载特性,建议低压反孤岛装置优先选用电阻型扰动负载。 相似文献
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One of the problems encountered when connecting distributed generators to a distribution system is the possibility of islanded operation. Traditionally this has been prevented through the application of passive under/over voltage and frequency relays which are triggered if the island contains mismatched amounts of active and/or reactive power, respectively. Various active techniques which reduce the power mismatch required for operation of the passive relays have been developed. These active techniques may fail to detect islanding in multiple generator islands if all the generators do not have identical active anti-islanding strategies. An islanding detection technique based on the correlation between disturbances in system voltage and a pseudo-random sequence used to perturb the generator’s output was developed for use in islands where generators may have different anti-islanding strategies. Previous investigations have always used pseudo-random sequences from the maximal length family of sequences. It is demonstrated in this paper that using either a Gold or Kasami sequence instead of a maximal length sequence can improve the performance of the correlation technique. 相似文献
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Vieira J.C.M. Freitas W. Wilsun Xu Morelato A. 《Power Delivery, IEEE Transactions on》2008,23(2):593-600
Anti-islanding protection is an important technical requirement when interconnecting distributed generators. Unfortunately, most anti-islanding protection schemes cannot detect islanding situations under certain system operating conditions - there are nondetection zones within which anti-islanding protection schemes are ineffective. This paper investigates these nondetection zones associated with the common anti-islanding protection schemes of synchronous distributed generators: frequency and voltage-based relays. Moreover, the characteristics of the nondetection zones and the key factors that influence them are analyzed. The results are useful for utility companies and distributed generators owners to design and to evaluate the effectiveness of anti-islanding protection schemes proposed for various distributed generation interconnection projects. 相似文献
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Pradit Fuangfoo Wei-Jen Lee Ming-Tse Kuo 《Industry Applications, IEEE Transactions on》2007,43(6):1491-1498
Traditional interconnection standards avoid the islanding operation of distributed generators (DGs) because of concerns of equipment failure and safety. However, in some cases, allowing the islanding operation of DGs in a radial subtransmission system could improve system reliability and decrease outage cost during power outages or a scheduled maintenance. This paper presents an impact study on a DG connected to a radial subtransmission system. The dynamic study is conducted to show how to manage DGs and electric power systems for the proper intentional islanding in specific cases. 相似文献
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目前孤岛检测和防孤岛策略主要是基于并网分布式电源的特性而设计,而鲜有以孤岛发生时公用电网的电气特性为核心的继电保护防孤岛策略的研究。为了找到一种利用公用电网继电保护防孤岛的新方法,结合苏州电网,通过对孤岛形成机理的分析,找出了孤岛发生前后零序电压的变化规律。进而基于零序电压的变化规律设计了公用电网防孤岛的继电保护控制策略。数值仿真及苏州电网的防孤岛实例验证了该并网分布式电源防孤岛的继电保护控制策略的有效性。结果表明,该控制策略具有较高可靠性和实用前景。 相似文献
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一种低畸变的主动移频式孤岛检测算法 总被引:6,自引:0,他引:6
孤岛检测是光伏系统并网必备的功能,要求既能快速检测出孤岛状态,同时又尽量减少对电网的不良影响.该文对主动移频式孤岛检测方法进行研究,分析了并网逆变器的输出电流总畸变率与孤岛检测算法间的关系,针对现有算法畸变率略高的情况提出了一种改进方案,新方案实现简单,能有效降低主动式孤岛检测对电能质量的不良影响,同时达到孤岛检测标准的要求.仿真和实验验证了该方案的有效性. 相似文献
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Intentional islanding is a feasible solution to improve the reliability of the smart distribution system with distributed generations (DGs) when the electrical connections between the smart distribution system and upstream network are lost. In this paper, a heuristic method is proposed for the intentional islanding of microgrids. In this method, some practical and important factors such as reduction of problem solution space; load controllability; load priority; bus voltage; line capacity constraints; and the ability to construct larger islands by the combination of islands are taken into account. The proposed method is a two-stage method. In the first stage, the intentional islanding problem is relaxed and in the second stage, the feasibility of the solution is verified. In the first stage, the intentional islanding problem is assumed as a series of tree knapsack problems (TKPs) and solved by the modified shuffled frog leap algorithm (SFLA). In the second stage, the power flow calculation is carried out to check the feasibility of the islands and essential modifications are provided. The proposed method is applied to IEEE 69-bus test system with 6 DGs. The results are compared with other methods and the effects of different methods on the system reliability indices are discussed. These comparisons indicate that the proposed method is feasible and valid. 相似文献
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主动移频式孤岛检测方法的参数优化 总被引:8,自引:1,他引:7
孤岛检测是光伏系统并网必备的功能,要求既能快速检测出孤岛状态,同时又尽量减少对电网的不良影响。孤岛检测性能的好坏不仅取决于所采用的孤岛检测策略,也取决于检测策略中参数的设置是否合理,但目前的研究在参数优化的理论指导方面严重不足。该文通过对主动移频式孤岛检测方法的检测盲区进行分析,推导了带线性正反馈主动移频式(active frequency drift with positive feedback, AFDPF)孤岛检测方法的盲区大小与反馈增益间的关系,并得出特定负载下孤岛检测无盲区AFDPF反馈增益的取值范围,从而为AFDPF孤岛检测方法的参数优化提供了理论指导。 相似文献
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孤岛检测是光伏系统并网必备的功能,要求既能快速地检出孤岛状态,同时又尽量减少对电网的不良影响。孤岛检测性能的好坏不仅取决于所采用的孤岛检测策略,也取决于检测策略中参数的设置是否合理,遗憾的是目前在参数优化的理论指导方面严重不足。该文通过对主动移频式孤岛检测方法的检测盲区进行分析,推导了带线性正反馈主动移频式(AFDPF)孤岛检测方法的盲区大小与反馈增益间的关系,并得出特定负载下孤岛检测无盲区AFDPF反馈增益的取值范围,从而为AFDPF孤岛检测方法的参数优化提供了理论指导。 相似文献
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