微电网新型保护控制方案与实现技术

发布时间：2018-04-30 02:26

本文选题：微电网 + 逆变型电源　；参考：《山东大学》2017年硕士论文

【摘要】：一种由分布式电源、储能装置、智能化用户与可控负荷、监控和保护装置构成的新型供电系统,即"微电网",成为了解决配电网分布式电源高度渗透的重要途径。然而,微电网运行方式灵活多变,且内部分布式电源以逆变型电源为主,给传统配电网保护原理带来了严峻的考验。微电网拓扑结构复杂多样,上级电网馈线保护、并网点保护、微电网内部元件保护间的合理配合也成为了微电网保护研究的难点之一。对此,本文以微电网并网点保护与微电网馈线保护为对象开展研究,论文的主要工作与取得的成果如下所述。(1)在逆变型分布式电源故障特征的研究基础上,分别分析了传统保护原理中功率方向元件与正序故障分量方向元件在含逆变型电源配电网中的适用性,为微电网并网点保护及内部馈线保护原理的研究提供理论基础。(2)根据故障隔离策略对并网点开关动作行为的要求,利用不同故障情形下的延时环节实现并网点保护与上级电网馈线保护、微电网内部馈线保护、并网运行规范要求间的逻辑配合。利用并网点故障前后正序功率方向与正序电流幅值变化,提出了一种并网点处新型故障方向判别方法,并设计了过电流保护、低电压保护作为辅助判据,解决了三相金属性短路故障时的方向判别死区问题。(3)借鉴电流差动保护原理思想,基于微电网馈线区内外故障时正序差动阻抗的幅值差异,提出了一种适用于微电网馈线故障特征的正序阻抗差动保护原理。为进一步改善保护性能,有效应对分支负荷的影响,构造了带制动特性的动作判据。针对区内三相金属性短路故障时保护存在的死区问题,利用故障时正序阻抗与正序电流幅值特征构造了辅助判据。与传统电流差动保护相比,所提方法无需两端数据同步采样,对通信要求较低。以智能测控终端为平台,设计了保护软件流程,开发了面向工程实际的正序阻抗差动保护装置。软件仿真与装置测试结果均验证了保护原理的有效性。(4)基于不同故障类型下微电网馈线保护安装处各故障相能量函数的特征分析,提出了一种基于故障超前相的能量方向纵联保护方法。构造了幅值辅助判据以克服区内分支负荷投切的影响,研究了正序分量控制的逆变型分布式电源接入情形下保护原理的适应性。仿真结果表明,保护原理能够正确识别故障方向,并能躲过负荷投切的影响,且具有一定的抗过渡电阻的能力。
[Abstract]:A new type of power supply system, which is composed of distributed power supply, energy storage device, intelligent user and controllable load, monitoring and protection device, has become an important way to solve the problem of high penetration of distributed power supply in distribution network. However, the operation mode of microgrid is flexible and changeable, and the internal distributed power supply is mainly inverter, which brings a severe test to the traditional distribution network protection principle. The topology of microgrid is complex and diverse, the feeder protection of higher power network, and the protection of dot point, and the reasonable cooperation between the protection elements of microgrid has become one of the difficulties in the research of microgrid protection. In this paper, the microgrid parallel network protection and microgrid feeder protection are studied. The main work and achievements are as follows: 1) on the basis of the research on the fault characteristics of inverter distributed generation, The applicability of the power directional element and the positive sequence fault component directional element in the traditional protection principle in the distribution network with inverter power supply is analyzed respectively. To provide a theoretical basis for the study of the principle of parallel network protection and internal feeder protection in microgrid. (2) according to the requirements of fault isolation strategy, the operation behavior of parallel node switch is required. The logic cooperation between parallel dot protection and feeder protection of higher power network, internal feeder protection of microgrid, and operation specification of grid connection is realized by using delay link in different fault cases. Based on the change of the positive sequence power direction and the positive sequence current amplitude before and after the fault, a new fault direction discrimination method is proposed, and the overcurrent protection is designed, and the low voltage protection is used as the auxiliary criterion. The problem of direction-discriminating dead zone in three-phase gold attribute short-circuit fault is solved. The principle of current differential protection is used for reference. Based on the amplitude difference of positive sequence differential impedance when the fault inside and outside the feeder area of microgrid is used as reference, A positive sequence impedance differential protection principle is proposed for microgrid feeder fault characteristics. In order to further improve the protection performance and effectively deal with the influence of branch load, an action criterion with braking characteristics is constructed. In view of the dead zone problem in the fault of three-phase gold attribute short-circuit fault, an auxiliary criterion is constructed by using the characteristics of the positive sequence impedance and the amplitude of positive sequence current. Compared with the traditional current differential protection, the proposed method does not require simultaneous data sampling at both ends, and requires less communication. On the platform of intelligent measurement and control terminal, the protection software flow is designed, and a positive sequence impedance differential protection device is developed for engineering practice. Software simulation and device test results both verify the validity of the protection principle. Based on the characteristic analysis of each fault phase energy function of the microgrid feeder protection installation under different fault types, the software simulation and the device test results verify the effectiveness of the protection principle. An energy directional longitudinal protection method based on fault leading phase is proposed. The amplitude auxiliary criterion is constructed to overcome the influence of branch load switching in the region, and the adaptability of the protection principle in the case of inverse distributed power supply with positive sequence component control is studied. The simulation results show that the protection principle can correctly identify the fault direction, avoid the influence of load switching, and has the ability to resist the transition resistance.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM77

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