The typical secondary circuit of three-phase inconsistent protection for a circuit breaker is described along with its influence on the safe operation of the power grid.Also, the action reliability of the protection circuit is analyzed.Based on the performance test results of the time relay for the three-phase inconsistent protection, the action time and the action voltage are thoroughly investigated.Then an improved secondary circuit of three-phase inconsistent protection is proposed to solve the incorrect operation problems of relay protection, which are caused by the relay failure, contactor failure, or action time migration of the time relay.Finally, several measures have also been proposed to enhance the maintenance of three-phase inconsistent protection.

为全面了解冀北电网220 kV及以上电压等级交流系统继电保护设备配置及运行情况,利用部署在调控运行管理系统(Operation Management System,OMS)的继电保护统计分析及运行管理高级应用获取相关数据信息.基于基础数据对2015年冀北电网220 kV及以上电压等级交流系统继电保护及安全自动装置设备情况、继电保护及安全自动装置缺陷情况、一次设备故障及装置动作情况进行统计分析和信息挖掘.在此基础上,针对继电保护及安全自动装置的运行维护和专业管理等工作提出建议.

冀北电网继电保护定值在线校核及预警系统以智能电网调度控制系统技术支持平台为基础,为电网继电保护、系统运行、调度计划等专业人员分析处理电网检修方式和故障情况提供实时和便捷的技术手段.文章首先提出了该系统的系统功能和总体结构,对该系统逻辑架构、软件功能、硬件配置等内容进行了论述,然后说明了接口设计、短路电流计算方法、通用模型等关键技术,最后对冀北电网系统建设情况及运行效果进行了介绍.

智能变电站以网络通信方式替代大量的二次回路电缆,常规变电站的二次硬回路转变为智能变电站的二次虚回路,配置保存于SCD文件内。由于缺乏可视化工具而导致SCD文件中虚回路"看不见,摸不到"。提出了一种可视化方案,能够快速解析SCD文件,自动输出单装置虚端子图、装置虚回路图、装置逻辑链路图、网络结构图等图纸,从而方便智能变电站的运行维护人员调试查看。

智能变电站配置文件作为全站电子化图纸,其管控水平关系到电网的安全生产及稳定运行.文章系统性地提出了智能站配置文件管控策略,建立了SCD离线管控与在线管控协同运转的设计架构,并利用配置文件比对、配置文件在线校核、在线状态监测、比对方案创建等具体技术方案进行支撑,最后以刘其营站为例,对智能变电站配置文件管控策略在冀北电网的试点情况进行实例分析,验证该策略的有效性和合理性.

Dynamic short-circuit current computing method（DSCCCM） is obtained based on transient simulation.The advantages of DSCCCM are pointed out by comparing the difference on grid model processing between static impedance equivalent method and DSCCCM.The on-line verification system of relay protection settings is built based on the design of DSCCCM.The true current operation state of the power grid is gained from energy management system.The short-circuit currents throughout the system are automatically calculated with the transient simulation calculation of different fault situations,achieving on-line relay setting real-time verification calculation.By comparing with the current relay settings,the security risks are pre-warned.The implementation plan and specific functions of on-line verification system of relay settings are elaborated.The application of the proposed system in North China Power Grid is introduced.

The constant failure rate plays a fundamental role in reliability analysis for the protection devices.The paper focuses on the computation approaches for the constant failure rate with the field data.It first lists the evaluation methods,which are the maximum likelihood estimation（MLE） and least square estimation with linear fitting（LSF）,for the constant failure rate according to the natural of the field data.In detail,the MLE（point estimation and interval estimation） with the censored data and incomplete data is deduced.Finally,the estimation of the constant failure rate for the protection equipment of a power system with the field data is carried out,and the difference of the estimation approaches are compared.Results indicate that it is important to take data censor problem into consideration when calculating constant failure rate with field data.Furthermore,the adaptability for different methods with different data types is also analyzed.

To be adaptable to smart dispatch, overall renovation of existing protective relaying fault information system of North China power grid is performed. The renovation scheme is analyzed in detail in system structure, communication protocol, information format and fault diagnosis. Firstly, according to the differences between newly built substations and renovated substations several typical system structures are conceived and proposed, and the necessity of independent networking for protection devices and fault recorders is analyzed. Then adopting proven technique and combining with related international standards such as IEC 61850 and so on, the speed and quality of information uploading are improved; based on the standard of extensible markup language （XML） the content of fault report and the format of HDR are standardized with detail to perfect device information and fault character information, thus in master station system the convenience in information filtering is swinging implemented. Finally, several different fault diagnosis methods are explored to improve overall operation level of this system. Actual operational experiences of several months show that the proposed renovation scheme for existing protective relaying fault information system is reasonable and effective.

调度自动化系统失效是美加大停电的重要原因.故障信息系统,独立于调度自动化系统,可作为调度人员掌握现场第一手资料的另一途径,但不能作为调度自动化的替代品.分析了建设故障信息系统的必要性.

电网继电保护及故障信息系统网络组网在国内是新兴的课题,可以为调度部门准确、及时地掌握电网故障情况和断电保护动作情况,提供翔实的信息支持.为贯彻<国家电网公司电网二次系统"十五"规划>,以及在"创国际一流电网调度机构"考核项目中达到95%的普及率,组建信息系统网络是继电保护专业人员今后一段时间面临的一项重大工作.根据华北电网的实践,本文探讨了信息系统组网中的问题,指出了可行性的组网方案.