1) negative sequence current
负序电流
1.
Design and application of generator negative sequence current monitoring instrument;
发电机负序电流监测仪的设计与实现
2.
Much more attention is paid to the analysis of the method how to define the characteristic curves of phase sensitive symmetrical short circuit protection, the design of negative sequence current filter and the definition of the mathematical model of overload.
重点介绍了对称短路相敏保护特性曲线的确定方法 ,设计了负序电流滤波器 ,建立了过负荷保护的数学模型 。
3.
Aiming to characteristic of 3-phase to 2-phase power supply based on balance transformer, a new current balance compensation method utilizing inverter is proposed, which is mainly used to compensate negative sequence current.
从而使平衡变压器两相侧的输出电流对称,消除平衡变压器三相侧产生负序电流的条件,达到三相电流对称的目的。
2) negative-sequence current
负序电流
1.
Electric railways have witnessed great development in Chinese railway system;however,the serious negative-sequence current,harmonics,reactive power and load fluctuation during the running process influence the electric power quality.
电气化铁道在全国铁道系统中都有了很大的发展,然而运行中易产生严重的负序电流、谐波、无功及负荷波动,对电能质量有一定程度的影响。
2.
The running state of three-phase asynchronous motor is monitored by negative-sequence current method and zero-sequence current method.
利用负序电流法和零序电流法监测三相异步电动机的运行状态,并设计电动机保护电路和PLC的控制梯形图,用FX系列PLC进行故障类型判别和报警处理,设计方案原理简单、工作可靠。
3.
The harm of negative-sequence current produced by electric train is analyzed.
介绍了沪杭电气化铁道工程的简况以及电气化列车运行时输出的负序电流的危害。
3) negative current
负序电流
1.
Analysis of negative current in switching tests for load tap on-load tap-changers of transformers;
变压器有载分接开关切换试验中负序电流分析
2.
Analysis of the operation of the generator negative current protection impacted on by the electric railway loading
电气化铁路负序电流对发电机负序过流保护的影响
3.
According to the frequency excursion in power systems, this paper proposes a detecting method of harmonic negative current instructions.
针对电网出现的频率偏差 ,提出一种谐波负序电流指令的检测方法。
4) negative phase sequence current
负序电流
1.
The unbalanced degrees of current in primary winding under different load conditions are discussed,which are based on the general expressions of negative phase sequence current.
结合负序电流的通用表达式,讨论了在不同负荷条件下的原边电流不平衡度。
2.
Discussions are carried out on the widely used power supply systems in international electrified railways ,which featureload un-equilibrium , and the conventional limitation to decrease the negative phase sequence current by increase the short circuit capacityof incoming system of railway substations.
针对目前国际上电气化铁道主要采用的供电方式,相应的负荷不平衡的特点,以及传统的通过提高电气化铁道变电所接入系统的短路容量来减小负序电流等做法的局限性进行了讨论。
5) Negative phase-sequence current
负序电流
1.
The general expressions of negative phase-sequence current in the traction transformer with arbitrary connection are presented.
三相电压到二相电压间的对称变换可有效减弱负序对电力系统的影响,为此,给出了适用于任意接线牵引变压器的通用负序电流表达式,分析了阻抗匹配平衡变压器的负序特性,讨论了其不同负荷条件下一次侧电流不平衡度,并结合某牵引变电所的一组实测数据将其与YN d11接线牵引变压器进行分析比较,结果表明,阻抗匹配平衡变压器能有效减弱负序电流。
6) negative sequence electric current
负序电流
1.
Fully considering the hot accumulation and the negative sequence electric current, using the combined heat balance differential equation methods.
在充分考虑热积累和负序电流效应的前提条件下,通过求解热平衡微分方程的方法,研究了电动机运行过程中的任意时刻的温度变化情况,模拟出电动机的温度实际变化过程,为过载保护提供了依据。
2.
This paper introduces the impac of the negative sequence electric current on the power system whichcaused by traction load, and the way to reduce it, explains the impairment of the unbalanced harmonic on the power systemin the views of project and economy, and puts forward a series of measures for preventing the impairment.
本文介绍牵引负荷在电力系统中引起的负序电流对电力系统的影响及降低和限制负序电流的措施;从工程和经济两个角度说明了不平衡谐波对电力系统的危害,并提出了一些应对措施;针对电铁负荷功率因数较低的现象,分析了无功补偿的必要性以及目前存在的问题和解决措施。
3.
This paper introduces the impact of the negative sequence electric current on the power system which caused by traction load,and the way to reduce it.
文章介绍了牵引负荷在电力系统中引起的负序电流对电力系统的影响及降低和限制负序电流的措施;针对电气化铁路负荷功率因数较低的现象,分析了无功补偿的必要性以及目前存在的问题和解决措施。
补充资料：负序电流承载能力
负序电流承载能力
negative phase sequence current carrying capability
fuxu dlonl一u ehengzo一nengl-负序电流承载能j7(negative phase一sequenceeurrent carrying eapability)同步发电机能承受三相不平衡负载的负序电流标么值和时间的限额。同步发电机在故障状态下短时承受不平衡负载的能力以负序电流标么值12的平方和时间t(s)的乘积12’t表示。这是不考虑发电机转子向外散热而定的。此值也可作为整定发电机负序过电流保护的参考。连续负序电流承载能力以负序电流相当于额定定子电流IN的百分数表示，此时发电机任一相最大定子电流不能超过额定值。同步发电机在三相不平衡负载下运行时，转子表面将由定子负序电流感应出两倍工频的涡流(见旋转磁动势)，该电流通过没有电气绝缘的转子槽楔、齿部、阻尼绕组和护环构成的环路而引起局部过热;在匝数较多的励磁绕组两端也会出现两倍工频的高达20一3。倍额定励磁电压的过电压，因此负序电流应有一个限额.对同步发电机的负序电流承载能力各国的标准有不同的规定，一般的取值范围见表。同步发电机负序电流承峨能力┌──────┬─────────┬────────┐│发电机型式 │连续运行负序电流 │故障短时负序电流││ │承载能力几/I、(%) │承载能力I22t(s) │├──────┼─────────┼────────┤│凸极发电机 │12 │40 │├──────┼─────────┼────────┤│隐极发电机 │ │ │├──────┼─────────┼────────┤│转子间接冷却│10 │15~30’ │├──────┼─────────┼────────┤│转子直接冷却│5~8’. │5~10“. │└──────┴─────────┴────────┘ 中国国家标准规定:空气冷却为305，氮气冷却为155。 中国国家标准规定:300 MW及以下为8%和8s，600 MW为7%和75。几份的限额可以通过理论分析或作发电机暂态负序渔升试验求得。对直接内冷的大型发电机，为了提高负序电流承载能力，在转子端部装设阻尼环和在转子的箱楔下设t全转子长的阻尼条。除此之外，阻尼绕组还对抑制发电机的振荡和避免在系统发生次同步谐振时的负阻尼现象起有利作用。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条