共查询到20条相似文献,搜索用时 46 毫秒
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为了提高过流速断保护在 CT 饱和时的可靠性,避免保护拒动,提出了一种保护测量值随短路电流的变化趋势的分析方法。通过分析电流互感器( CT )过饱和时的传变特性和输出波形特征,以及继电保护装置的测量性能,说明当故障电流达到数倍于 CT 准确限值电流(即 CT 处于过饱和状态)时, CT 二次电流的特征量随故障电流的增加呈现缓慢单调上升趋势,但保护装置的电流测量值却可能呈现下降趋势,从而引起过流速断保护拒动。分析表明,该分析方法可根据回路参数估算测量值随短路电流的变化趋势,以校验过流速断保护整定值的可靠性,以便采取适当措施避免保护拒动,在工程应用中具有很好的经济效益。 相似文献
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Pan Y. Steurer M. Baldwin T.L. McLaren P.G. 《Power Delivery, IEEE Transactions on》2008,23(3):1310-1318
This paper investigates in detail the impacts of distorted current waveforms, produced by certain types of fault current limiters on time-overcurrent protection relays. A thyristor-based solid-state fault current limiter is chosen as representative of such a device for a case study which investigates its effects on two coordinated protection relays. A detailed software model of the current limiter has been developed and implemented on the real-time digital simulator platform, modeling a typical distribution system. Relay models are used to obtain initial results, which are later validated by an actual protective relay connected in a hardware-in-the-loop simulation setup. The results illustrate the increase of relay tripping times due to severe current limitation caused by the fixed firing angle control of the current limiter. It is revealed that different current measurement principles employed by the relays, such as fundamental, peak, or true rms, can lead to miscoordination due to the distorted fault current waveform. It is demonstrated that these undesirable effects can be mitigated by employing appropriate control strategies for the firing angle in the current limiter. 相似文献
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一种继电保护应用软件仿真验证系统的设计 总被引:1,自引:0,他引:1
针对电力系统暂态故障时间短导致使用仿真器调试不便的缺陷,运用MATLAB与C混合编程方式,在PC平台上实现了对继电保护装置保护应用程序的仿真验证。采用MEX函数接口实现读取故障波形和MATLAB仿真波形,并将数据转化为电流、电压通道的数据流,实现对继电保护故障的模拟。该系统可直接移植DSP程序代码,保证了保护应用代码与仿真验证代码的一致性,提供了脱离继电保护装置的试验验证环境,能使用各种录波波形验证保护程序逻辑。在设备运行过程中,针对现场故障,可采用该系统进行单步跟踪调试,准确判断装置保护程序逻辑正确性。实际运行表明,本系统不依赖于保护装置硬件,缩短了新型继电保护装置的研发流程,提高了研发效率。 相似文献
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为提高智能变电站继电保护测试效率,解决数字式继电保护试验装置无法对整个测试过程中出现的故障自动进行诊断的问题,提出基于长短期记忆(Long Short-Term Memory,LSTM)网络的继电保护测试故障诊断方法.梳理了故障断面特征信息和故障类别,建立了多故障诊断模型,构建了故障诊断流程.以典型220 kV继电保护... 相似文献
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新型微机电抗器保护的研制与开发 总被引:5,自引:2,他引:5
分析了目前超高压并联电抗器保护所存在的一些问题,包括电抗器匝间短路保护灵敏度与可靠性、电流互感器暂态特性不一致对差动保护的影响等。介绍了新一代数字式电抗器成套保护装置的总体设计思想(双主双后配置)、新型高灵敏度高安全可靠的匝间短路保护原理以及考虑电流互感器暂态特性不一致的差动保护原理。新型电抗器匝间短路保护由自适应补偿的零序功率方向元件、零序阻抗元件、故障开放元件、谐波闭锁元件以及具有工频变化量浮动门槛的匝间短路保护启动元件共同构成。给出了这些保护原理的数字仿真、动模试验及现场运行结果。 相似文献
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In conventional transmission line protection, a distance relay is used to provide the primary as well as remote backup protection. The voltage and current phasors measurement needed by the distance relay for determining the impedance may be affected by the power disturbances such as power swing. Consequently, this power swing may cause mal-operation of Zone three distance relays which in turn may affect on the reliability of the whole protective scheme. To mitigate these effects and hence improve the relay reliability, this work proposes a new real-time power swing detector using phasor measurement units for blinding the distance relay only during this transient disturbance. However, this developed detector will not block relay when the power swing accompanied with faults. To validate the present work, the performance of developed enhanced distance relay is tested by signals generated by Simulink/MATLAB simulator under different conditions. The test results show that this proposed scheme provides good discrimination between the transient currents and the fault current which in turn it may contribute in enhancing the reliability of Distance relay. 相似文献
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基于注入变频信号法的经消弧线圈接地系统控制与保护新方法 总被引:88,自引:8,他引:88
提出基于注入信号法的控制与保护新方法采用注入零序恒流信号,测量系统谐振频率,计算电容电流,进行消弧线圈自动调谐;采用测量零序信号电压,计算接地电阻,进行高阻接地故障辨识;采用测量各出线零序信号功角,计算线路阻尼率,进行故障选线。该方法不受系统运行的影响,易实现就地保护控制,精度高、抗干扰能力强。样机已通过动模实验,其中消弧线圈自动调整系统已形成产品,在现场运行多年,效果良好。 相似文献
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研究了电流互感器二次侧发生短路故障,尤其是相间短路时,保护装置测量电流的变化情况。通过公式推导和向量分析,简要分析了其对某些保护功能尤其是距离保护和差动保护的影响,并提出了电流互感器二次侧短路的判据对策。 相似文献
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从同杆并架并架双回线跨线故障和单回线故障的不同电气特征出发,分析了现有的主要选相元件在同杆并架线路发生跨线故障时所存在的问题,提出了基于跨线故障识别的同杆并架双回线故障选相的新方案。系统发生故障后,保护首先根据故障后的零序电流和零序电压,正负序电流之间的关系等特征判别故障性质(跨线或者单线故障),单回线故障和跨线故障采用不同的选相方案。可以有效地解决发生跨线故障时突变量选相元件和稳态选相元件存在的误动或者拒动的问题。 相似文献
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1.IntroductionBecauseofitsgoodselectivity,highsensitivityandrapidaction,thedifferentialprotectionisusedwidelyasmain-protectionforelectricequipment.BecauseverylargeunbalancedcurrentmaytakeplaceduringexternaIfaultcausingmistrippingbytraditionalbusdifferentialreIay.Andduringinternalfault,ifthereisout-flowingcurrent,thesensitivityofthetraditionalrelaywillbemuchreduced.Althoughthehighimpedancebusdifferentialrelaycanensureitsselectivityduringexternalfault,highvoItagewillbeinducedinCT'ssecondarycir… 相似文献
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分布式发电接入中低压配电网使传统配网成为有源配网,对继电保护提出了新的挑战。本文围绕有源配网继电保护问题展开研究,分析了有源配电网故障电流的特征以及DG接入对传统保护和安全自动装置运行的影响,并结合国内外主要的标准和技术规程,综述了当前主要的解决方案。最后以典型的辐射状配电网为算例,利用ETAP软件建立仿真模型,研究双馈风机接入配电网后潮流和短路电流的变化以及反时限保护的动作情况。结果表明,高渗透DG接入后,潮流双向流动,短路电流变化复杂,反时限保护较难满足要求,有必要利用微网技术,构建更为完善和智能的有源配网保护体系。 相似文献
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小波变换在微机母线保护中的应用研究 总被引:1,自引:0,他引:1
提出了一种利用小波变换原理精确地检测故障发生和差流出现的时刻,根据同步测量法的基本原理判断差流的出现是否是由于电流互感器馆和造成的,有效地防止了区外短路故障时,因此流互感器饱和造成的母线保护误动;并利用小波变换分析电流互感器饱和前后的暂态特性,准确地检测出故障电流进入饱和与退出饱和的时刻,有效地防止了故障由区外转入区内时,造成的母线保护拒动现象。仿真结果验证了上述算法的有效性。 相似文献
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Agent-based self-healing protection system 总被引:1,自引:0,他引:1
Su Sheng Li K.K. Chan W.L. Zeng Xiangjun Duan Xianzhong 《Power Delivery, IEEE Transactions on》2006,21(2):610-618
This paper proposes an agent-based paradigm for self-healing protection systems. Numerical relays implemented with intelligent electronic devices are designed as a relay agent to perform a protective relaying function in cooperation with other relay agents. A graph-theory-based expert system, which can be integrated with supervisory control and a data acquisition system, has been developed to divide the power grid into primary and backup protection zones online and all relay agents are assigned to specific zones according to system topological configuration. In order to facilitate a more robust, less vulnerable protection system, predictive and corrective self-healing strategies are implemented as guideline regulations of the relay agent, and the relay agents within the same protection zone communicate and cooperate to detect, locate, and trip fault precisely with primary and backup protection. Performance of the proposed protection system has been simulated with cascading fault, failures in communication and protection units, and compared with a coordinated directional overcurrent protection system. 相似文献
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500kV六氟化硫(SF6)电流互感器内部故障时其端部高压外壳通过绝缘支撑件或均压电容屏或支撑玻璃钢筒对地放电,而其二次电流随着电流互感器一次接线方式的不同而不同,从而影响到保护的动作。为此,探讨了母线侧开关单元电流互感器故障时,一次侧在并联接线方式和串联接线方式下线路保护和母线保护的动作情况及需要注意的问题。即当电流互感器发生外壳接地故障时,若为并联接线方式,则线路保护可靠动作,母线保护可靠不动作;若为串联接线方式时,则线路保护和母线保护都有可能不动作。 相似文献