A new wide area damping controller design method considering signal transmission delay to damp interarea oscillations in power system

Wide area damping controller(WADC) is usually utilized to damp interarea low frequency oscillation in power system. However, conventional WADC design method neglects the influence of signal transmission delay and damping performance of WADC designed by the conventional method may deteriorate or even has no effect when signal transmission delay is beyond delay margin, an index that denotes delay endurance degree of power system. Therefore, a new design method for WADC under the condition of expected damping factor and required signal transmission delay is presented in this work. An improved delay margin with less conservatism is derived by adopting a new Lyapunov-Krasovskii function and more compact bounding technique on the derivative of Lyapunov-Krasovskii functional. The improved delay margin, which constructs the correlation of damping factor and signal transmission delay, can be used to design WADC. WADC designed by the proposed method can ensure that power system satisfies expected damping factor when WADC input signal is delayed within delay margin. Satisfactory test results demonstrate the effectiveness of the proposed method.

Architecture Design for Integrated Wide Area Protection and Control Systems

This paper firstly reviews the recent development in power system protection and control, with special attention paid to the wide-area and integrated protection, in order to look into future development of integration of protection and control for smart grids. This paper mainly reports on the development of integrated wide area protection and control for power systems. The concept of integrated wide area protection and control is introduced, in which a hierarchical protection and control system provides the protection and control of wide area or regional power substations/ plants and their associated power network. The system is mainly divided into three levels, the local, the substation/plant and the wide area/regional protection and control. The integrated functions at each level are described in details with an aim to develop an optimal coordination mechanism between the levels. One of the core elements in the system is the synchronised wide area communication network between the substations and the protection and control system, in which latest communication technology is employed. Another important player in the system is the wide area synchronized protection and control information platform, which not only enables the fusion three line of defence for power system protection and control, but also provides a perfect tool for the application of cloud computing to substations and power networks.

Advancement in Wide Area Monitoring Protection and Control Using PMU’s Model in MATLAB/SIMULINK

A big step forward to improve power system monitoring and performance, continued load growth without a corresponding increase in transmission resources has resulted in reduced operational margins for many power systems worldwide and has led to operation of power systems closer to their stability limits and to power exchange in new patterns. These issues, as well as the on-going worldwide trend towards deregulation of the entire industry on the one hand and the increased need for accurate and better network monitoring on the other hand, force power utilities exposed to this pressure to demand new solutions for wide area monitoring, protection and control. Wide-area monitoring, protection, and control require communicating the specific-node information to a remote station but all information should be time synchronized so that to neutralize the time difference between information. It gives a complete simultaneous snap shot of the power system. The conventional system is not able to satisfy the time-synchronized requirement of power system. Phasor Measurement Unit (PMU) is enabler of time-synchronized measurement, it communicate the synchronized local information to remote station.

Integrated Wide Area Protection and Control for Power Grid Security

The traditional“three defense lines”for power systems are based on local information and static protection&control strategy,which are not suitable to modern large-scale power systems.In order to improve the security of UHV hybrid power grids,the Integrated Wide Area Protection&Control(IWAPC)is proposed in this paper by applying the new technologies of synchronized high-speed communication,which integrates“three defense lines”and promotes existing wide area protection only for security control.The IWAPC is the hierarchical protection and control system which provides the protection and control for wide area power networks to improve their reliability and security.It is divided into three levels,the local bay level,the substation integrated protection level and the wide area protection level.The wide area real-time protection and control information platform is the most important part of the IWAPC,which is based on a synchronized wide area communication network.The key technologies and new development trends include network topology analysis,wide area backup protection,wide area intelligent reclosing,wide area load shedding,wide area auto-switching,overload cutoff and transfer,transmission section protection,intelligent system splitting and dynamic stability control.It cannot only integrate three lines of defense for power system protection and control,but also improve security of the power grid.

Technology and engineering application of cross area HVDC interconnection system high-precision simulation modeling based on ADPSS

In recent years, a large number of high voltage direct current(HVDC) transmission projects have been connected to AC systems. This has started to have an impact on AC/DC hybrid power grids, particularly receiving terminal power grids. An HVDC system is a large-scale power electronic integrated nonlinear system, and it includes a primary system and a control and protection system. Hence, the precision and degree of detail of HVDC systems directly affect the actual effect of simulation. In recent years, in the case of the normal operation and failure of AC power grids, the abnormal fluctuation and even locking of HVDC systems caused by the inappropriate strategies of the control and protection system component have strongly affected power grids. This has significantly affected the safety and stability of receiving power grids and normal operation. In this study, the actual engineering HVDC control logic provided by a manufacturer is analyzed and simulated based on the user defined component library of the ADPSS electromagnetic transient calculation program, and an HVDC control model based on an actual system is established. The accuracy of the DC control custom model based on ADPSS is verified through the simulation of an actual power grid.

基于广域信息分析的智能配电网故障自愈技术研究

针对传统电网接地故障检测和自愈方法存在识别速度慢且精确度较低的问题,文中结合信号广域信息提出了一种配电网故障自愈方法。该方法构建了单相接地故障模型,并将零序电流作为分析的对象。将零序电流信号分解为时域、频域以及小波域分量来作为广域特征向量,并采用随机森林算法对其权重进行分类,利用LightGBM算法对分类后的广域特征向量加以训练,进而得到故障预测结果。在仿真测试中,所提算法能够抵抗过渡电阻与初始相位角变化对预测结果的影响,且其故障分析准确率的平均值为98.9%,在对比算法中为最优,表明该算法可为配电网故障自愈提供有效的技术支撑。

Comparison and Performance Analysis of FACTs Controller in System Stability

In large inter connected power systems, inter-area oscillations are turned to be a severe problem. Hence inter-area oscillations cause severe problems like damage to generators, reduce the power transfer capability of transmission lines, increase wear and tear on network components, increase line losses etc. This paper is to maintain the stability of system by damping inter-area oscillations. Implementation of new equipment consists of high power electronics based technologies such as FACTs and proper controller design has become an essential to provide better damping performance than Power System Stabilizer (PSS). With development of Wide Area Measurement System (WAMS), remote signals have become as feedback signals to design Wide Area Damping Controller (WADC) for FACTs devices. In this work, POD is applied to both SVC and SSSC. Simulation studies are carried out in Power System Analysis Toolbox (PSAT) environment to evaluate the effectiveness of the FACTs controller in a large area power system. Results show that extensive analysis of FACTs controller for improving stability of system.

构网逆变电源故障穿越控制策略及其对保护影响的研究综述

构网(grid-forming,GFM)逆变电源(inverter-based resources,IBRs)可模拟传统同步电机行为,自主提供电压以及惯量支撑,是实现高比例新能源接入电网的必然途径。继电保护是保障电力系统安全稳定运行的第一道防线,其动作性能取决于对系统故障特征的辨识能力,而构网逆变电源主导下电力系统的故障特征则与逆变电源的物理极限和控制策略高度相关。该文首先梳理了典型构网逆变电源在正常及故障穿越时的控制策略及特点;进而归纳了电源的简化等值模型及故障特性分析研究成果;最后,总结了构网型逆变电源并网系统相关的保护技术研究现状,初步评述了构网逆变电源对当前保护技术的影响以及该领域未来所面临的问题。

Improving the performance of power system protection using wide area monitoring systems

Wide area monitoring(WAM) offers many opportunities to improve the performance of power system protection. This paper presents some of these opportunities and the motivation for their development. This methods include monitoring the suitability of relay characteristics,supervisory control of backup protection, more adaptive and intelligent system protection and the creation of novel system integrity protection scheme. The speed of response required for primary protection means that the role WAM in enhancing protection is limited to backup and system protection. The opportunities offered by WAM for enhancing protection are attractive because of the emerging challenges faced by the modern power system protection. The increasingly variable operating conditions of power systems are making it ever more difficult to select relay characteristics that will be a suitable compromise for all loading conditions and contingencies. The maloperation of relays has contributed to the inception and evolution of 70 % of blackouts,thus the supervision of the backup protection may prove a valuable tool for preventing or limiting the scale of blackouts. The increasing interconnection and complexity of modern power systems has made them more vulnerable to wide area disturbances and this has contributed to several recent blackouts. The proper management of these wide area disturbances is beyond the scope of most of the existing protection and new, adaptive system integrity protection schemes are needed to protect power system security.

Guest editorial: special issue on wide area monitoring, protection and control in smart grid

Complexity of modern electrical power systems is steadily increasing.This is inspiring researchers and developers to propose new solutions capable to address a number of challenges,particularly those related to power system operation.A massive penetration of asynchronously connected renewable energy generation,the generation connected over inverters,is significantly changing the dynamics of modern power systems.From one hand,the power system response time is becoming shorter and at the same time the fault level is becoming smaller.This is significantly affecting requirements of control loops,as well as power system protection.

高速铁路牵引变电所智能化建设方案研究

智能牵引变电所是智能牵引供电系统的核心,由智能化一次系统、广域保护测控系统和智能辅助系统构成。为提高目前在建高铁牵引供电系统智能化水平,探讨并提出了针对其牵引变电所的智能化改造方案。

计及新型柔性限流器的直流系统故障暂态特性分析研究

为解决传统柔性限流装置在直流电网中存在经济性、实用性不足的问题,提出一种新型直流柔性限流装置,采用模块化限流电感结构,并提出模块化限流电感投入方案,基于该结构提出与其相适应的控制设计方案。该结构提升柔性限流装置的经济性,增强限流装置的容错率,并快速、有效抑制故障电流,实现直流线路永久性故障快速隔离,瞬时性故障无断路器动作行为的自行恢复。为进一步验证所提新型柔性限流装置的有效性,在软件平台搭建多端柔性直流仿真系统,并进行直流线路永久性与瞬时性故障仿真分析。

考虑并网变流器调节能力的广域阻尼控制策略研究

针对含并网变流器电力系统,提出了一种利用并网变流器来提升系统小干扰功角稳定的广域阻尼控制策略及其设计方案。基于含并网变流器电力系统的小干扰稳定模型,该方案以模态线性二次型调节器为依据设计了状态反馈控制策略,可以实现不同功角振荡模式的解耦控制。考虑到不同并网变流器具有不同的调节能力,进一步构建了以模态线性二次型调节器权重矩阵为待优化变量,以关键振荡模式的阻尼比和并网变流器调节能力作为约束的阻尼控制分配模型,并利用遗传算法进行求解。在PSAT中搭建IEEE 68节点系统模型,对所提控制方案进行验证,结果表明该控制方案能够有效利用各个并网变流器向系统提供足够的阻尼支持。

智能电网中的继电保护技术分析

阐述智能电网环境下继电保护的特点,探讨继电保护技术的应用,包括信息技术、广域保护技术、区块链技术的应用,从而做出实时、高效的识别,有效控制相关继电保护装置拒动、误动状况。

大电网广域安全稳定控制系统远传测试技术研究

为应对电力系统数字化、复杂化导致的安全稳定控制系统可靠性降低的问题,研究了一种大电网广域安全稳定控制系统远传测试技术,通过对关键技术的研究应用,构建大电网广域安控系统远传测试系统,实现对安控系统的系统级功能逻辑及动作可靠性检测。最后基于该技术搭建测试系统并进行验证,结果表明:该测试系统能够方便快捷地实现异地安控系统联合测试,具有较高的应用价值。

基于混合馈入型自适应补偿的电网谐波功率放大器超宽频控制

基于电力电子变换器的功率放大器因其灵活易控成为电网电压模拟的理想物理接口之一。针对现有功率放大器控制方法会放大频率偏差、使滤波电路参数漂移以及难以模拟高频谐波的弊病,首先,提出一种混合馈入型自适应补偿的谐波功率放大器超宽频控制策略,以高精度复现宽频电压信号并兼顾动态与稳态性能;然后,设计多变量混合馈入型环路以补偿系统暂态特性;在时域下利用Lyapunov函数推导计及参数漂移的自适应方法以补偿滤波参数不确定性;深入分析并克服混合自适应补偿的数字实现局限性;讨论所提方法作为重复内嵌控制的性能提升;最后,制作样机,进行所提策略动态性能与稳态精度的仿真及实验验证。结果表明:所提方法相较于既有控制具备更快的动态响应、更高的稳态精度以及更宽的跟踪谐波频率范围,可以实现对超宽频参考电压的快速无差跟踪。

一种自动监测站多功能电源模块的方案研究

针对水利自动监测站设备的电源供电问题,提出了一种基于Mini-PCIe模块的多功能电源模块方案。该方案通过集成电源转换和控制等功能,实现结构简单、体积小、移植方便、运维便捷的效果。同时,采用各类瞬态抑制稳压管配合光电隔离芯片实现防雷击与浪涌,保证AC采样通道的安全。该方案具有较高的电源转换效率、丰富的功能和良好的安全性能,可广泛应用于各类场景。

广域分布式光伏接入电网极限承载力估计模型

为避免电力网络运行过程中电信号过量负荷行为的出现,设计广域分布式光伏接入电网极限承载力估计模型。在分布式光伏回路中,根据熔断电流求解结果,统计电量潮流水平,完成广域分布式光伏接入电网的潮流量计算。根据计算结果,获取动态配电参数,依据该参数的取值结果,确定电信号参量的极值负荷区间,联合极限绕组负荷条件,推导预估表达式,实现广域分布式光伏接入电网极限承载力估计模型的设计。实验结果表明,在电信号输出功率不超过额定数值水平的情况下,上述模型对于电网极限承载能力的预估准确率达到了100%,可以有效避免电信号过量负荷行为的出现,符合实际应用需求。

面向电网安全的零信任动态访问控制

随着信息通信技术在电力信息系统中的不断发展和应用,电网的防护边界逐渐模糊,外部攻击和内部威胁日益严重,急需对电力系统信息资源的访问进行有效控制,确保数据安全。本文在电网二次系统安全防护总体框架的基础上,结合零信任安全机制,提出面向电网信息安全的零信任动态访问控制模型。该模型通过分析电网系统的访问主体属性与行为信息的特点,综合考虑威胁行为、滑动窗口、惩罚机制等因素对访问控制的影响,实现对访问主体信任值的持续评估和动态控制。仿真实验结果表明,增加推荐信任能合理兼顾主观和客观2种信任评价,使电网访问主体的信任值评估更准确。此外,针对外部威胁行为,信任评估引擎会迅速更新访问者的综合信任值,使非法主体无法获得系统的访问权限,具有更好的控制细粒度。

智能电网中的继电保护技术应用

阐述智能电网继电保护技术的应用,包括智能传感技术、广域保护技术、网络通信技术、数字化技术、自身重构技术的应用。分析可再生能源的并网技术和智能电网继电保护技术的优化措施。