Design of a Proportional-Integral-Derivative Controller for an Automatic Generation Control of Multi-area Power Thermal Systems Using Firefly Algorithm

Essentially, it is significant to supply the consumer with reliable and sufficient power. Since, power quality is measured by the consistency in frequency and power flow between control areas. Thus, in a power system operation and control,automatic generation control(AGC) plays a crucial role. In this paper, multi-area(Five areas: area 1, area 2, area 3, area 4 and area 5) reheat thermal power systems are considered with proportional-integral-derivative(PID) controller as a supplementary controller. Each area in the investigated power system is equipped with appropriate governor unit, turbine with reheater unit, generator and speed regulator unit. The PID controller parameters are optimized by considering nature bio-inspired firefly algorithm(FFA). The experimental results demonstrated the comparison of the proposed system performance(FFA-PID)with optimized PID controller based genetic algorithm(GAPID) and particle swarm optimization(PSO) technique(PSOPID) for the same investigated power system. The results proved the efficiency of employing the integral time absolute error(ITAE) cost function with one percent step load perturbation(1 % SLP) in area 1. The proposed system based FFA achieved the least settling time compared to using the GA or the PSO algorithms, while, it attained good results with respect to the peak overshoot/undershoot. In addition, the FFA performance is improved with the increased number of iterations which outperformed the other optimization algorithms based controller.

A Novel Cascaded PID Controller for Automatic Generation Control Analysis With Renewable Sources

Present day power scenarios demand a high quality uninterrupted power supply and needs environmental issues to be addressed. Both concerns can be dealt with by the introduction of the renewable sources to the existing power system. Thus, automatic generation control(AGC) with diverse renewable sources and a modified-cascaded controller are presented in the paper.Also, a new hybrid scheme of the improved teaching learning based optimization-differential evolution(hITLBO-DE) algorithm is applied for providing optimization of controller parameters. A study of the system with a technique such as TLBO applied to a proportional integral derivative(PID), integral double derivative(IDD) and PIDD is compared to hITLBO-DE tuned cascaded controller with dynamic load change.The suggested methodology has been extensively applied to a 2-area system with a diverse source power system with various operation time non-linearities such as dead-band of, generation rate constraint and reheat thermal units. The multi-area system with reheat thermal plants, hydel plants and a unit of a wind-diesel combination is tested with the cascaded controller scheme with a different controller setting for each area. The variation of the load is taken within 1% to 5% of the connected load and robustness analysis is shown by modifying essential factors simultaneously by± 30%. Finally, the proposed scheme of controller and optimization technique is also tested with a 5-equal area thermal system with non-linearities. The simulation results demonstrate the superiority of the proposed controller and algorithm under a dynamically changing load.

MAS Based Distributed Automatic Generation Control for Cyber-Physical Microgrid System

The microgrid is a typical cyber-physical microgrid system(CPMS). The physical unconventional distributed generators(DGs) are intermittent and inverter-interfaced which makes them very different to control. The cyber components,such as the embedded computer and communication network,are equipped with DGs, to process and transmit the necessary information for the controllers. In order to ensure system-wide observability, controllability and stabilization for the microgrid,the cyber and physical component need to be integrated. For the physical component of CPMS, the droop-control method is popular as it can be applied in both modes of operation to improve the grid transient performance. Traditional droop control methods have the drawback of the inherent trade-off between power sharing and voltage and frequency regulation. In this paper, the global information(such as the average voltage and the output active power of the microgrid and so on) are acquired distributedly based on multi-agent system(MAS). Based on the global information from cyber components of CPMS, automatic generation control(AGC) and automatic voltage control(AVC)are proposed to deal with the drawback of traditional droop control. Simulation studies in PSCAD demonstrate the effectiveness of the proposed control methods.

Automatic Generation Control with Virtual Synchronous Renewables

As synchronous generators(SGs)are gradually displaced by renewable energy sources(RESs),the frequency stability of power systems deteriorates because RESs,represented by utility-scale solar and wind power sources,do not provide the inertial response,primary frequency response,secondary frequency response,and tertiary frequency regulation.As a result,the remaining SGs may not be sufficient to maintain the power balance and frequency stability.The concept and control strategies of virtual synchronous generators(VSGs)enable the inverter-based wind and solar power sources to emulate the outer characteristics of traditional SGs and participate in the active power and frequency control of power systems.This paper focuses on the automatic generation control(AGC)with virtual synchronous renewables(VSRs).First,the VSR strategy that enables the RESs to participate in AGC is introduced.Second,based on the interval representation of uncertainty,the output of RES is transformed into two portions,i.e.,the dispatchable portion and the stochastic portion.In the dispatchable portion,the RESs can participate in AGC jointly with SGs.Accordingly,a security-constrained economic dispatch(SCED)model is built considering the RESs operating in VSR mode.Third,the solution strategy that employs the slack variables to acquire deterministic constraints is introduced.Finally,the proposed SCED model is solved based on the 6-bus and 39-bus systems.The results show that,compared with the maximum power point tracking(MPPT)mode,VSRs can participate in the active power and frequency control jointly with SGs,increase the maximum penetration level of RESs,and decrease the operating cost.

大动态范围AGC电路在接收机中的应用

自动增益控制电路(AGC)是接收机的重要控制电路之一。具体分析了自动增益控制电路的工作原理以及AGC的分类方式。利用可变增益放大器AD8367和其他模拟电路以及外部检波方式,设计了思维简洁、电路控制速度快的峰值型AGC电路。详细解释了芯片版图、增益控制与电压关系以及基于AD8367的闭环AGC电路系统。实验结果表明,基于AD8367的两级AGC控制电路频率达到70 MHz,动态范围80 dB等预期指标,可以方便地调整所需要的输出电平值,确保接收机正常工作。

大动态范围抗干扰导航接收机AGC电路性能分析与优化设计

导航接收机的特点是信号比较微弱,通常淹没于噪声以下,其入口电平的波动几乎都由干扰引起。针对这一特点,存在干扰情况下,要求接收机的噪声系数不能显著恶化。射频通道的噪声系数是制约接收机噪声系数的因素之一,本文在给定射频通道噪声系数恶化容限的条件下,以射频通道能实现最大动态范围为优化目标,分析了动态范围及各级电路增益的求解方法;进一步,针对特殊的纯电阻网络AGC电路,得到了更为简洁的求解方法;最后,本文给出了该类AGC电路动态范围的设计实例并进行了测试,设计预期与测试结果得到较好的吻合。本文虽然针对导航接收机设计,但可推广应用于指导各类接收机的设计。

基于AD8367的大动态范围AGC系统设计

介绍AD8367的特点及工作原理,在此基础上讨论通过两级AD8367串连构造具有70dB动态范围的70MHz中频大动态自动增益控制AGC的方法,并给出AGC检波特性曲线。

一种用于振动数据采集的AGC设计

针对随机采集场合中事前难以确定幅值的大小,无法设置最合适的增益的问题,提出了利用卡尔曼滤波实现自动增益控制功能的设计方案。详述了设计方案的硬件原理、实现算法,并进行了实验验证。结果表明,这种设计不仅能实现振动数据采集中的自动增益控制功能,而且不需预设增益初值的情况下可获得宽广的增益幅度动态范围,对高动态范围的数据采集具有重要的实际应用价值。

数字中频接收机中数字AGC的设计与实现

基于软件无线电思想,提出了一种应用于数字中频接收机(DIFR)的数字自动增益控制(AGC)系统的设计实现方案,通过外部AGC与内部AGC改善整个链路的动态性能。分别介绍了外部数控AGC和三种数字AGC的增益迭代原理,并进行了仿真分析,给出了基于FPGA的数控AGC和指数型数字AGC的低复杂度实现方法 。

大动态范围AGC系统的构建与仿真

针对科研实践中需要采集大动态范围模拟信号的问题,构建基于可变增益放大器8369的数字AGC系统。采用基于双斜率滤波技术的设计,给出AGC控制算法的实现流程,利用Matlab仿真引入算例证明算法的可行性,并讨论算法中关键参数取值对控制精度的影响。实际系统达到50dB动态范围的设计目标。

A Two-stage Kalman Filter for Cyber-attack Detection in Automatic Generation Control System

Communication plays a vital role in incorporating smartness into the interconnected power system.However,historical records prove that the data transfer has always been vulnerable to cyber-attacks.Unless these cyber-attacks are identified and cordoned off,they may lead to black-out and result in national security issues.This paper proposes an optimal two-stage Kalman filter(OTS-KF)for simultaneous state and cyber-attack estimation in automatic generation control(AGC)system.Biases/cyber-attacks are modeled as unknown inputs in the AGC dynamics.Five types of cyber-attacks,i.e.,false data injection(FDI),data replay attack,denial of service(DoS),scaling,and ramp attacks,are injected into the measurements and estimated using OTS-KF.As the load variations of each area are seldom available,OTS-KF is reformulated to estimate the states and outliers along with the load variations of the system.The proposed technique is validated on the benchmark two-area,three-area,and five-area power system models.The simulation results under various test conditions demonstrate the efficacy of the proposed filter.

A novel statistically tracked particle swarm optimization method for automatic generation control

Particle swarm optimization(PSO)is one of the popular stochastic optimization based on swarm intelligence algorithm.This simple and promising algorithm has applications in many research fields.In PSO,each particle can adjust its‘flying’according to its own flying experience and its companions’flying experience.This paper proposes a new PSO variant,called the statistically tracked PSO,which uses group statistical characteristics to update the velocity of the particle after certain iterations,thus avoiding localminima and helping particles to explore global optimum with an improved convergence.The performance of the proposed algorithm is tested on a deregulated automatic generation control problem in power systems and encouraging results are obtained.

1100MW超超临界机组AGC功能优化及试验

超临界机组具有热惯性大、迟滞性强、参数耦合关系强的特性,同时,单机负荷大的机组相对蓄热能力小,导致机组自动发电控制功能投入存在较大困难。通过对国内首台单机容量1 100 MW机组协调控制系统的优化,在重新设定机组滑压曲线基础上,对煤水比、负荷变化等环节进行调整优化,克服热惯性对AGC造成的影响。在AGC模式下以15 MW/min的变负荷速率进行了100 MW的负荷变动试验,能够保证主蒸汽温度变动范围小于10℃;主蒸汽压力变动范围小于1 MPa;同时其它主要参数的变化在控制范围之内。作为单机容量最大的机组,其AGC功能的投入对同类型机组的调试及运行有着重要的借鉴意义。

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.

基于风场AGC调度控制的三区域控制法

针对电网调度中心对风场的自动功率调度目标要求,在分析MW级双馈变桨风机机组运行特性的基础上,采用传统的PID控制为基础、结合控制保护区域检测单元、机组控制输出保护单元组合的三区域控制系统建立的风场有功控制单元,针对莱州风电场进行AGC控制测试,证明三区域控制系统具有良好的系统控制性能。

具有可调增益前移的自适应预估控制及其在电厂DCS中的应用

在分析模型参考自适应预估控制系统 (MRAPC)的基础上 ,提出了一种改进算法 ,通过将自适应结构中可调增益前移的办法克服原算法在自适应过程中存在滞后的问题。同时还给出了该改进算法的全局收敛性分析结果。这一算法已在大坝电厂 30 0MW机组的主汽温、再热汽温、燃烧及协调等主要控制系统中得到成功应用 ,取得了良好的控制效果。

干涉型光纤传感器相位生成载波技术研究与改进

对干涉型光纤传感器的相位生成载波解调技术进行了研究.对PGC算法进行了数学推导和仿真计算,对数字低通滤波器进行了详细分析,给出了其影响PGC解调性能的原因及数字滤波器的设计方法.讨论了传感器干涉光强对PGC算法输出结果的影响,提出了改进的PGC算法,该算法可以有效的实现自动增益控制,消除干涉光强漂移对解调的影响,并大大减小由干涉光强引入的系统噪音;还可以在有限阶数低通滤波器的情况下,极大的增加系统可解调的大信号幅度,提高系统动态范围12dB以上.

多时间尺度协调的区域控制偏差超前控制方法

根据机组响应控制指令时间长短不同,提出一种多时间尺度协调的区域控制偏差(area control error,ACE)超前控制方法。首先分析了现有ACE超前控制方法的不足,给出目标时刻控制区理想总发电的预测模型;然后分析了计划机组计划与执行的关系,提出计划机组出力偏差的预估方法;进而综合考虑总发电、计划机组发电和自动发电控制(auto generation control,AGC)机组的希望运行点,计算出目标时刻协调AGC机组的希望总出力;最后,通过一个优化模型把协调AGC机组的希望总出力分配到各协调AGC机组上。文章所提方法已在四川电网投入现场试运行,结果证明了该方法的可行性。

CCD相机实时自动调光系统

为了实时调整高帧频CCD相机,获得高质量图像,提出了一种基于分档电子快门控制和增益控制相结合的复合控制方法,实现了快速、高精度调光。其算法主要由三部分构成:二次均值灰度权值的累加,基于分段二次函数的自动快门控制和基于数据分析的自动增益控制。采用共享的乒乓缓存策略来保证算法在自行设计的硬件平台得到有效验证并连续显示。实验结果表明,该算法具有良好的图像质量,捕获的视频图像在各种条件下,均具有快速的收敛性和适应性。