适用于柔性直流互联交流系统的无电压方向元件判据

发布时间：2019-04-01 14:23

【摘要】：背靠背柔性环网控制装置的应用使配电网由单端电源供电的辐射状网络变为多端电源供电网络,三段式电流保护无法判断故障方向。为了既保证配电网保护动作可靠性又保留三段式电流保护,需要为保护安装方向元件。文中通过研究背靠背柔性环网控制装置接入的交流配电网发生不同位置相间故障时序电流间的相位规律,提出了基于流过保护的负序电流和同一母线上无源支路正序电流间相位关系的故障方向判别元件,并给出了正反方向故障时方向元件的动作区间。该方向元件适用于由传统电源、采用负序电流抑制的柔性环网控制装置或分布式电源构成的且母线含无源支路的多端供电网络。该元件受过渡电阻影响小,无需安装电压互感器,在三相对称故障时仍可保证保护的正确动作,不存在传统功率方向元件出口三相故障时的死区问题。经PSCAD仿真验证了该方向元件在系统不同位置发生各种相间故障时的正确性和有效性。
[Abstract]:The application of the back-to-back flexible loop network control device makes the distribution network change from a radial network supplied by a single-ended power supply to a multi-terminal power supply network, and the fault direction cannot be judged by three-stage current protection. In order to ensure the reliability of the distribution network protection and retain the three-segment current protection, it is necessary to install the directional elements for the protection. In this paper, the phase law of phase-to-phase faults occurred in AC distribution network connected to the back-to-back flexible loop network control device is studied in this paper. A fault direction discriminator based on the phase relationship between the negative sequence current and the positive sequence current of the passive branch on the same bus is proposed, and the action interval of the direction element in the positive and negative direction fault is given. The directional element is suitable for the multi-terminal power supply network composed of traditional power supply, flexible loop network control device with negative sequence current suppression or distributed power supply, and the bus contains passive branch. The element is less affected by the transition resistance and does not need to install a voltage transformer. It can still guarantee the correct action of the protection in the case of three-phase symmetrical fault, and there is no dead-time problem in the three-phase fault of the outlet of the traditional power direction element. The PSCAD simulation verifies the correctness and effectiveness of the directional element when various interphase faults occur in different positions of the system.
【作者单位】：智能电网教育部重点实验室(天津大学);国网北京市电力公司;
【基金】：国家高技术研究发展计划(863计划)资助项目(2015AA050102) 国家自然科学基金资助项目(51577129) 天津市自然科学基金资助项目(14JCYBJC21000)~~
【分类号】：TM77;TM721.3

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