Energy storage for black start services:A review

With the increasing deployment of renewable energy-based power generation plants,the power system is becoming increasingly vulnerable due to the intermittent nature of renewable energy,and a blackout can be the worst scenario.The current auxiliary generators must be upgraded to energy sources with substantially high power and storage capacity,a short response time,good profitability,and minimal environmental concern.Difficulties in the power restoration of renewable energy generators should also be addressed.The different energy storage methods can store and release electrical/thermal/mechanical energy and provide flexibility and stability to the power system.Herein,a review of the use of energy storage methods for black start services is provided,for which little has been discussed in the literature.First,the challenges that impede a stable,environmentally friendly,and cost-effective energy storage-based black start are identified.The energy storagebased black start service may lack supply resilience.Second,the typical energy storage-based black start service,including explanations on its steps and configurations,is introduced.Black start services with different energy storage technologies,including electrochemical,thermal,and electromechanical resources,are compared.Results suggest that hybridization of energy storage technologies should be developed,which mitigates the disadvantages of individual energy storage methods,considering the deployment of energy storage-based black start services.

Review of Black Start on New Power System Based on Energy Storage Technology

With the continuous development of new energy generation technology and the increasingly complex power grid environment,the traditional black start scheme cannot meet the requirements of today’s power grid in order to ensure the stable operation of the power system can be restored quickly in the face of large power outages,so a more complete black start scheme needs to be developed to cope with the new power system.With the development of energy storage technology,the limitations of the traditional black-start scheme can be solved by new energy farms with energy storage configuration.Therefore,this paper investigates the problems faced by black-start,the key technologies of energy storage assisted new energy black-start,and introduces the research related to new energy black-start technology to provide reference for future research and application of new energy black-start.

Investigation and Mitigation of Transformer Inrush Current during Black Start of an Independent Power Producer Plant

The energizing of large power transformers has long been considered a critical event in the operation of an electric power system. When a transformer is energized by the utility, a typical inrush current could be as high as ten times its rated current. This could cause many problems from mechanical stress on transformer windings to harmonics injection, and system protection malfunction. There have been numerous researches focusing on calculation and mitigation of the transformer inrush current. With the development of smart grid, distributed generation from independent power producers (IPPs) is growing rapidly. This paper investigates the inrush current due to black start of an IPP system with several parallel transformers, through a simulation model in DIgSILENT Power Factory software. The study demonstrates that a single genset is capable of energizing a group of transformers since the overall inrush current is slightly above the inrush of the transformer directly connected to the generator. In addition, a simple method is proposed to mitigate the inrush current of the transformers using an auxiliary transformer.

Regional Power System Black Start with Run-of-river Hydropower Plant and Battery Energy Storage

Battery energy storage systems(BESSs)are a kind of important asset for power systems with high integration levels of renewable energy,and they can be controlled to provide various critical services to the power grid.This paper presents the real-world experience of using a megawatt-scale BESS with grid-following(GFL)and grid-forming(GFM)controls and a run-of-river(ROR)hydropower plant to restore a regional power system.To demonstrate this,we carry out power-hardwarein-the-loop experiments integrating an actual GFL-or GFM-controlled BESS and a load bank.Both the simulation and experimental results presented in this paper show the different roles of GFL-or GFM-controlled BESS in power system black starts.The results provide further insight for system operators on how GFL-or GFM-controlled BESS can enhance grid stability and how an ROR hydropower plant can be converted into a black-start-capable unit with the support of a small-capacity BESS.The results show that an ROR hydropower plant combined with a BESS has the potential of becoming one of enabling elements to perform bottom-up black-start schemes as opposed to conventional bottom-down method,thus enhancing the system resiliency and robustness.

Clustering Analysis of Black-start Decision-making with a Large Group of Decision-makers

The optimization of black-start decision-making plays an important role in the rapid restoration of a power system after a major failure/outage.With the introduction of the concept of smart grids and the development of real-time communication networks,the black-start decision-makers are no longer limited to only one or a few power system experts such as dispatchers,but rather a large group of professional people in practice.The overall behaviors of a large decision-making group of decision-makers/experts are more complicated and unpredictable.However,the existing methods for black-start decision-making cannot handle the situations with a large group of decision-makers.Given this background,a clustering algorithm is presented to optimize the black-start decision-making problem with a large group of decision-makers.Group decision-making preferences are obtained by clustering analysis,and the final black-start decision-making results are achieved by combining the weights of black-start indexes and the preferences of the decision-making group.The effectiveness of the proposed method is validated by a practical case.This work extends the black-start decision-making problem to situations with a large group of decision-makers.

A New Algorithm for Black-start Zone Partitioning Based on Fuzzy Clustering Analysis

On the process of power system black start after an accident, it can help to optimize the resources allocation and accelerate the recovery process that decomposing the power system into several independent partitions for parallel recovery. On the basis of adequate consideration of fuzziness of black-start zone partitioning, a new algorithm based on fuzzy clustering analysis is presented. Characteristic indexes are extracted fully and accurately. The raw data matrix is made up of the electrical distance between every nodes and blackstart resources. Closure transfer method is utilized to get the dynamic clustering. The availability and feasibility of the proposed algorithm are verified on the New-England 39 bus system at last.

基于虚拟同步发电机的构网型光储变流器控制策略研究

为了抑制光伏发电的随机性和波动性的影响,提高微电网的供电可靠性,对离网工况下的微电网黑启动方案进行分析,并将其与虚拟同步发电机(Virtual Synchronous Generator,VSG)控制策略一起应用于储能变流器中,建立了储能变流器的VSG数学模型,推导了小信号模型表达式,通过在光储微电网系统引入惯性和阻尼,提高了系统电压和频率的稳定性。最后,在Matlab/Simulink仿真平台上搭建模型,验证了零起升压策略的有效性,确保了黑启动过程中线路电压的稳定;并在并网工况下分析了光储微电网系统各个微源之间的协调控制,验证了构网型光储变流器控制策略的有效性。

具备黑启动和构网能力的远海风电经DRU-MMC送出方案

由于具有成本低、体积重量小和可靠性高等特点,送端采用二极管整流器(DRU)、受端采用模块化多电平换流器(MMC)的送出方案在远海风电送出领域备受关注。鉴于DRU不能构建交流电网且无法倒送有功功率,文中提出一种具备黑启动和构网能力的远海风电经DRU-MMC送出方案。所提方案在DRU-MMC送出技术的基础上增加了常规小容量电压源型辅助换流器、耗能单元和必要的快速开关,通过直流海缆复用和快速开关倒闸重构拓扑,分别构建黑启动电源低压回路和风电传输高压回路,实现黑启动和功率传输2种工况在线切换;提出辅助换流器在不同运行阶段的构网控制策略,解决海上交流电网构建、DRU无功补偿和谐波抑制等问题,消除DRU-MMC送出方案对风电场类型的限制。最后,通过经济性分析和算例仿真,验证了所提方案的优越性和有效性。

基于多储能动态调控的光储黑启动控制策略

首先,建立多储能光伏联合系统,根据储能实时状态将储能系统进行分级,设计3种不同优先等级的储能分别承担不同任务;然后,将不同优先等级的储能设定相应的控制方案,提出基于多储能动态调控的光储黑启动控制策略,实时监控储能的运行状态,以防止多储能系统因越限等原因造成黑启动任务失败;最后,通过Matlab对3种不同工况进行仿真模拟,验证多储能动态调控的黑启动控制策略的有效性。

基于光储联合系统的电网分段恢复策略

当前新能源大量引入至电力系统,为了使其代替传统的水电、燃气机组作为黑启动电源,文中研究了基于光储联合系统的电网分段恢复策略。首先,根据光储系统的结构和控制方式,提出由储能系统建立稳定的并网母线线电压,光伏系统分步并网的启动方式;其次,为了增强光伏发电系统的惯性阻尼支撑,提出在光伏系统逆变器侧加入虚拟同步控制;最后,在待启动机组和系统负荷并网过程中,利用储能系统配置附加阻尼控制器抑制电网黑启动产生的次同步振荡,保证电网稳定恢复。在PSCAD/EMTDC中搭建光储联合系统黑启动的电磁暂态仿真模型并进行分析,结果表明系统恢复过程中母线线电压偏差不超过0.65%、系统频率偏差不超过1%,满足黑启动要求,验证了文中所提启动策略的可行性。

基于基频调制电流源换流器的海上风电送出系统的启动控制策略

基频调制电流源换流器(FFM-CSC)可以显著提高海上风电送出系统的功率密度和经济性,现有黑启动方法需要在交流侧投切黑启动电阻,但该方式会增大海上平台的建设成本。为此,提出一种利用FFM-CSC交流侧LC滤波器的启动方法,可以提高系统黑启动方案的经济性。分析了海上风电送出系统的结构和稳态控制策略。为了分析黑启动原理,建立了送端CSC交流侧空载时的数学模型,并提出了其交流侧等效的基波和谐波通路。在此基础上,提出了海上风电送出系统的黑启动控制策略。在PSCAD/EMTDC进行仿真验证,结果表明:所提黑启动策略可以在交流侧空载时建立起风电场电网电压,平稳完成海上风电场黑启动。

Two-stage power system restoration model

In response to the need for robust black-start strategies in modern smart grids during blackouts,this paper proposes a two-stage black-start model that integrates wind turbines(WT),photovoltaic generators(PV),and energy storage systems(ESS).The system restoration path model in the first stage utilizes the Dijkstra algorithm to create a skeleton network and formulate a post-outage generator start-up plan.The second stage involved a load pick-up model,structured as a mixed-integer linear programming problem,aimed at restoring the load with the assistance of the ESS.This stage was designed for computational efficiency,allowing solutions to be obtained using standard commercial solvers.The performance and efficacy of the proposed model were demonstrated through its application to modified IEEE 39/118-bus transmission systems,with the results affirming its high efficiency and effectiveness in power system restoration scenarios.

考虑输配协同的电网并行恢复分区及机组启动次序统一优化决策方法

在电网恢复初期,黑启动资源紧缺,恢复所需时间长。随着配电网接入多种类型的资源,利用含源配电网自下而上支撑输电网恢复、加速黑启动进程逐步具备可行性。该文首先提出输配协同恢复理念,分析向上支撑输电网恢复的配电网需具备的条件,进而明确输配协同恢复方式;然后,结合输电网机组启动过程的功率需求和配电网发电资源特征,定义配电网向上送电外特性,并提出配电网向上支撑外特性建模方法;进一步,以机组启动总耗时最小为目标,构建考虑输配协同的电网并行恢复分区及机组启动次序统一优化决策的混合整数线性规划模型;最后,基于国内实际输配电网算例,验证该文所提方法的有效性。

考虑储能电站恢复能力的风储联合黑启动协调控制策略

储能电站与风电场联合参与系统黑启动,可减少负荷停电时间和加速系统恢复。文章针对大型风储联合发电系统,提出了考虑储能电站恢复能力的黑启动协调控制策略。风电场采用最大功率跟踪控制方式,储能电站采用恒频恒压控制方式,二者联合构成黑启动电源;储能电站采用软启动技术自启动,先恢复部分重要负荷,再启动风电机组,提高了风电并网的稳定性。提出了考虑储能电站恢复能力的负荷恢复量估算方法,基于被启动火电厂辅机负荷需求和风功率预测,对黑启动过程中储能电站的荷电状态进行预估,进而考虑储能电站的功率和荷电状态约束,确定重要负荷的恢复量,从而在确保启动火电机组的前提下,尽可能恢复重要负荷。基于PSCAD/EMTDC的暂态仿真结果验证了所提策略的有效性。

全功率直驱风机电网友好型控制策略

基于构网型控制的电网友好型风电机组具有黑启动、电网支撑和弱电网运行等优势,近年来逐渐被广泛研究。为探究不同电网友好型控制在不同场景下的运行性能,以全功率直驱风机为研究对象,总结归纳了4种典型的电网友好型风电机组控制策略。基于不同控制策略的架构和特点,在PSCAD/EMTDC仿真平台上搭建了相应电网友好型风电机组模型。分别在黑启动、风速变化、功率减载、频率支撑、电压支撑、故障恢复以及故障限流7种工况下探究不同控制策略的运行性能。最后,综合不同工况下的仿真结果,得到了总体性能最优的控制策略。

黑启动中考虑新能源不确定性的移动-固定式混合储能优化配置方法

近年来极端天气频发,电力系统的弹性水平亟须有效提升。针对黑启动中电网的储能配置展开研究,提出了一种考虑新能源不确定性的移动式储能与固定式储能的混合配置方案,以增强电网黑启动的灵活性与可靠性。首先,考虑移动式储能在电网中的行驶状态、行驶时间等动态运行过程,建立了移动式储能的时空交互模型和运行调度模型;其次,对电力系统中各黑启动电源进行分析与建模,应用场景法考虑新能源出力的不确定性,并对火电机组在恢复过程中的爬坡率和有功功率变化进行分析;然后,结合固定式储能的运行模型,以移动式储能和固定式储能的投资成本和运维成本最小化为目标函数,建立了面向电力系统黑启动的混合储能优化配置模型。该模型考虑了黑启动中系统对负荷的恢复要求,并从负荷稳定角度应对系统的不安全扰动,构建了黑启动中各机组、节点和线路的恢复模型。最后,以改进的IEEE30节点算例验证了混合配置移动式储能和固定式储能对提升极端事件中电力系统恢复能力的有效性,为实际工程提供参考价值。

考虑抑制励磁涌流的风储一体化系统黑启动技术研究

风储一体化系统即配备储能的风力发电,具有黑启动能力,对其加以控制可将该系统作为黑启动电源。基于此,在单台风机的基础上,制定了风储一体化系统的黑启动方案。首先,通过构网型控制的储能装置进行启动,为避免变压器投入过程中的励磁涌流或谐振产生的自励磁,在原有的电压环控制基础上,加入了惯性环节来实现软启动策略;然后,储能系统建立交流频率和电压后,实现风电机组及负荷的恢复;在风储一体化系统稳定启动后,经过主变压器和输电线路将电能输送到35 kV母线,完成黑启动过程。最后,在PSCAD/EMTDC软件平台建立风储一体化仿真模型,验证了采用软启动策略的黑启动方案,验证过程电压保持稳定,功率平衡,系统完成启动,同时有效地抑制了励磁涌流。

兼容跟网和构网远海风场送出的送端DRU+MMC混合换流器控制策略

为兼容当下跟网型和未来构网型远海风场的送出需求,提出一种送端采用由二极管整流器(diode rectifier unit,DRU)和小容量电压源型辅助换流器交流侧单端并联组成混合换流器的低成本直流送出方案。新方案利用常规小容量电压源换流器结合耗能单元和若干快速开关,通过直流海缆复用和快速开关倒闸拓扑重构,在不影响风能向外传输的基础上实现了海上风场黑启动。针对跟网型风场的运行要求,提出一种由辅助换流器同时控制其交流侧和直流侧电压的构网策略,解决了海上交流电网构建、调控和无功平衡等问题;为适应未来构网型风场,提出一种辅助换流器构网-跟网控制模式切换策略,无需进行方案拓扑改造。最后,通过算例仿真,验证了所提方案和控制策略的有效性。

超级电容储能辅助燃气轮机黑启动系统调频技术应用研究

针对燃气轮机机组黑启动项目中频率波动大的案例,结合燃气机组黑启动系统及静止变频器(SFC)启动时波形图,对故障现象进行详细描述及具体故障原因分析。在考虑柴油发电机组响应速度较为缓慢的特性基础上,提出了一种超容辅助黑启动调频策略,将SFC功率分为基础功率与频率波动功率,基础功率由柴油发电机组承担,以保证系统的稳定运行;频率波动功率则由超级电容快速响应,以有效抑制频率波动。通过某4F燃气轮机机组的黑启动实验验证,该策略不仅有效降低了黑启动过程中频率的波动且避免了升速变负荷阶段的过电流故障,从而提高了燃气机组黑启动的可靠性和安全性。

基于动态孤岛的主动配电网多阶段故障恢复策略

极端天气频发对配电网的弹性提出了更高要求,传统配电网故障恢复策略无法完全发挥主动配电网的潜能。为此,提出一种基于动态孤岛的主动配电网多阶段故障恢复策略。首先,分析了基于动态孤岛的配电网重构可行域,并考虑非黑启动机组(non-black start units,NBSU)等分布式电源的时序特征,从而建立上层负荷恢复模型,确定了多阶段的网络拓扑计划;其次,建立下层发电规划模型,给出相应的发电规划,在孤岛潮流层面对上层负荷恢复方案的可行性进行检验;然后,利用改进离散粒子群算法结合CPLEX求解器对所建立模型进行求解;最后,以改进43节点城市配电网为例,验证所提方法在弹性提升方面的有效性和优越性。