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多机组大型核电厂通常采用发电机-变压器组单元接线,厂内设置高压配电装置,有多回输电线路与电力系统相连,备用电源一般从外部独立可靠电源引接。电厂外线输电线路发生断相故障(不接地)后故障现象不明显,现有的保护不一定能够检测到,厂用电系统可能继续带故障运行,长期持续运行会对厂用电系统造成不良影响甚至使系统丧失功能,核电厂则可能因核安全相关系统不可用而导致重大后果。基于PSCAD/EMTDC软件对此类故障进行仿真分析,给出厂内电气系统在此类故障下的现象和参数,为厂内运行人员判别故障或新增针对此故障的保护提供依据。 相似文献
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厂用电快切原理认为切换前工作电源电压与备用电源电压同相位,然而此种假设仅出现在电气系统无故障时,实际上电厂运行工况较为复杂。论证了电气系统故障对快切方式的影响,首先用对称分量法对厂内高压电气系统发生两相接地短路的情况进行故障分析,认为当厂用电系统发生故障并切换电源时,工作电源电压与备用电源电压相位并不相同,进而估算电气系统故障时母线残压特性的实际曲线,说明残压实际曲线与理论曲线的差别,并分析母线残压特性的变化对各种快切方式的影响,指出快切不成功的可能性及其原因,提出快切装置定值整定时应考虑电气系统故障情况的建议。 相似文献
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介绍九江电厂三期2×350MW机组厂用电系统结线方式和特点,以及DCS对电气系统控制的要求及遵循的基本原则;结合实际逻辑阐述DCS系统在厂用电系统中的运用;针对该系统运行中出现的问题进行了归类和分析。 相似文献
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依托三门核电1号机组,应用ETAP实时数字仿真系统,对该厂厂用电系统进行建模.利用仿真模型,对厂用电系统的不同快速切换工况进行仿真.仿真波形能直观反映快切时厂用电母线的动态响应,从而使得电厂不再需要进行实际的试验来获得数据. 相似文献
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数学模型是电厂仿真的基础。该文将电厂电气系统中的每一设备或元件作为一模块并编写相应的算法存入算法库,通过图形建模方法对其进行组态,实现了对电厂电气系统的仿真。目前,该算法已应用于上海石化热电总厂的仿真系统中,仿真结果表明,该算法速度快且不存在收敛问题,仿真精度能够满足现场要求。 相似文献
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数学模型是电厂仿真的基础.该文将电厂电气系统中的每一设备或元件作为一模块并编写相应的算法存入算法库,通过图形建模方法对其进行组态,实现了对电厂电气系统的仿真.目前,该算法已应用于上海石化热电总厂的仿真系统中,仿真结果表明,该算法速度快且不存在收敛问题,仿真精度能够满足现场要求. 相似文献
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发电厂发电机或一次系统出现异常运行时,如果处理不正确,会诱发运行事故。出现异常运行时,应采取以下处理措施:根据表计、信号指示及保护动作情况正确判断故障性质;如果对人身和设备安全有严重威胁,应立即消除威胁;迅速切除故障点;确保厂用电源正常工作,如果因为故障造成厂用电源失压,应优先恢复厂用电源。在事故处理过程中,首先应保证人员安全,其次是保证事故不扩大,再次则是尽快恢复正常设备运行,优先恢复厂用电源。以上处理措施可为电厂运行人员提供参考。 相似文献
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现代大容量火力发电厂要求其生产过程自动化和采用计算机控制 ,为了实现这一要求 ,需要有众多厂用机械设备和自动化监控设备作为电厂主要设备和辅助设备服务。因此 ,厂用电系统是否合理 ,能否安全、可靠地运行 ,对发电厂至关重要。图 1 30 0 MW机组厂用电系统1 厂用电系统接线原则(1 )必须保证对厂用负荷可靠连续供电。在任何运行方式下 ,一台机组故障停运或其辅机的电气故障不应影响另一台机组的运行。(2 )厂用电系统接线方式灵活方便 ,在系统故障或设备检修时 ,能灵活简便地进行倒换方式 ,尽快获得机组启动电源 ,使影响范围最小、停电… 相似文献
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Proper application of grounding systems, signal isolation, electrical safety, and power quality are key to the successful installation and operation of any electrical and data system, whether in a building or a plant. This paper necessitates an effective data quality and grounding design that considers the neutral, power grounding, bonding, shielding, and transient protection. With consistent design, installation, and maintenance of the grounding system, noise disturbances can be controlled. 相似文献
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《Industry Applications, IEEE Transactions on》1974,(5):581-600
Actual ground faults were applied to a high-resistance grounded 13.8-kV electrical distribution system supplying power to a large chemical plant. These tests show that such a system will restrict overvoltage transients and reduce damage to equipment under ground fault conditions. Such a system is inherently safer and more reliable than an ungrounded system and offers some operating features not possible with a low-resistance grounded system. The maximum overvoltage transient recorded during many ground faults, involving several different ground conditions imposed on the system during six hours of testing, was about 2000 V. The effect of these ground faults on the 13.8-kV electrical distribution system supplying an operating plant was negligible. In fact, the operating personnel, anticipating the worst, were not aware that the tests had been performed. 相似文献
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Abstract—In this article, a controller based on a multi-variable sliding mode is provided for pumped storage with four goals. (1) Full-state variables of the plant, generator, and hydro turbine are developed to improve transient responses under fault conditions by compensating the fast electrical dynamics. (2) The sliding-mode controller is designed for robustness against uncertainty in both the power system parameters and its topology. (3) Two surfaces (power angle and output voltage) are proposed to coordinate both the turbine and excitation inputs of the generator in transient conditions. (4) The decentralized method is used to decrease the complexity of the controller equations and cost of implementation. To show the effectiveness of the proposed controller, two other controllers—full-state variables feedback linearization and a generic power system stabilizer—are simulated by MATLAB/Simpower (The MathWorks, Natick, Massachusetts, USA). The simulation results show full-state variables feedback linearization cannot be robust against model uncertainty; it is also shown that the power plant with linear controller has unpleasant transient responses in both fault conditions and low-frequency oscillations. In contrast, the proposed method plays an effective role in solving the mentioned problems and limits the stator current magnitude and terminal voltage post-fault. 相似文献
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This paper presents the simulation and transient analysis of conventional and advanced aircraft electric power systems with harmonics mitigation. Complete modeling of aircraft electric power systems is proposed. The conventional aircraft electrical power system is analyzed considering equivalent passive AC and DC loads under transient and steady-state operating conditions. The electric power source is simulated to ensure constant frequency and voltage which meet the aircraft electrical standards for all loading cases. To mitigate the harmonics generated by the converters, passive input filters are designed to keep THD values within the standard limits. Furthermore, the advanced aircraft electrical system is simulated and analyzed under the same electric power source and loads. The results are compared to those of the conventional aircraft electric power system. 相似文献
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保证火电厂DCS电源系统可靠性浅析 总被引:2,自引:0,他引:2
韩银玲 《可编程控制器与工厂自动化(PLC FA)》2006,(7):51-52
随着计算机技术的飞速发展,网络结构日益复杂,微机化、计算机控制系统在生产中广泛应用,作为系统的源动力(心脏)电源系统的安全可靠日益体现出来。近几年来,电源系统中广泛应用UPS电源,保安电源合理分配,电源系统的可靠性大大提高。但是目前使用情况有些不尽人意,下面就电厂DCS系统电源系统的安全浅谈一下个人的认识。 相似文献
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针对不同电气输入特征与电力系统暂态稳定关联程度不同以及当输入特征受到干扰时评估准确率明显下降的问题,提出一种基于Fisher Score特征选择的电力系统暂态稳定评估方法。设计一种面向电力系统暂态稳定评估二分类问题的样本特征Fisher Score值计算方案;通过Fisher Score值排序有效区分重要特征与冗余特征、噪声特征与非噪声特征;将选择的电气特征输入不同机器学习模型中进行训练和评估。新英格兰39节点系统和IEEE 145节点系统的仿真结果表明,所提特征选择方案能有效筛选电力系统暂态稳定评估中重要度高的特征,提升了评估模型的预测性能。 相似文献
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基于我国现行的安全稳定导则,发电厂送出线路的重合闸时间可能直接影响电厂的送出能力。为保证电厂送出能力不因重合闸时间整定不合理而降低,建立了考虑重合闸时间对系统暂态稳定性影响的数学模型。应用EEAC(Extended Equl-Area Criterion)暂态稳定量化分析方法研究了考虑重合闸时间的电厂送出系统暂态稳定特性,提出了一种计及暂态稳定约束的电厂送出系统重合闸时间整定方法。实际系统仿真表明,利用该方法能快速确定重合闸时间整定的合理区间,保证重合闸时间整定值满足系统暂态稳定要求。 相似文献
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介绍了制约我国火电厂电气监控系统由DCS实现的原因,提出在火电厂由DCS代替传统的电气监控系统是现代火电厂的必然发展方向,以及由DCS实现电气控制的功能要求。 相似文献