Service-oriented architectural model for generating system adequacy evaluation

A service-oriented architectural (SOA) model is proposed for power system reliability analysis especially for generating capacity adequacy evaluation. Generating system adequacy evaluation is performed to evaluate the ability of the system generating capacity to meet the total system demand. The proposed SOA model is composed of generation system reliability (GSR) service provider, power system service registry and service requester. The data pertaining to power system reliability analysis are represented in extensible markup language (XML) for exchanging the reliability data among the users and service providers. The GSR service provider describes the reliability evaluation services and publishes them to the power system service registry. The calling sequences of reliability evaluation services along with required data are configured as SOAP (Simple Object Access Protocol) messages and the proposed SOA model communicates between the service provider and the service requester with formally defined messages. The proposed model for generating system reliability analysis is highly distributed and has inherent features such as scalability and flexibility and provides a loosely coupled environment for power system reliability analysis.     

风/柴/储能系统发电容量充裕度评估

提出一种用于含风能和能量储存设备的小型孤立电力系统(SIPS)发电容量充裕度评估仿真方法。该仿真方法根据每小时计算的随机事件模拟发电系统的运行历史记录,考虑现场风资源的时序性、系统中发电机组的故障和修复特性。使用几个样例系统说明了该方法的应用,该系统的充裕度取决于许多因素,它们是能量储存容量、系统负荷需求、风能注入水平、发电机组强迫停运率(FOR)和其地理位置。能量储存设备对该系统可靠性能有积极的影响;SIPS随着系统负荷的增加,充裕度减少;风力发电机组FOR的变化对系统充裕度的影响不大;增加风能注入水平可以改善可靠性;位于高平均风速处的系统明显比低平均风速处的系统可靠性高。     

多馈入直流输电系统充裕度评估的模型和方法

建立了多馈入直流系统充裕度评估的容量模型,该模型将直流系统分为阀组、极、双极3个子系统,通过串联和并联的形式将这3个子系统组合成整个直流系统,将合成的直流系统与发电系统串联形成单馈入直流系统,将各单馈入直流系统并联组成多馈入直流系统.文中提出了子系统串联和并联连接时容量模型的等效方法,并基于多馈入直流系统的容量模型计算了充裕度指标,算例分析结果表明文中提出的模型和方法是合理的,对多馈入直流系统的充裕度评估有一定的指导意义.     

Reliability/cost evaluation of a wind power delivery system

When the geographical locations with good wind resources are not close to the main load centers, it becomes extremely important to assess adequate transmission facility to deliver wind power to the power grid. A probabilistic method is presented to evaluate the contribution of a wind power delivery system to the overall system reliability. The basic model incorporates transmission line connecting a remotely located large wind farm to a conventional grid system. The classical generation system adequacy evaluation model is extended to incorporate limited transmission system. The mean Capacity Outage Probability Table (mean-COPT) concept is used to increase the computational efficiency as it allows determination of EUE (expected unserved energy) and LOLE (loss of load expectation) simultaneously in calculation of reliability indices of the generating system. The wind farm generation model is obtained by superimposing simulated wind speed, obtained from developed ARMA time series model, on power curve of WTG. An apportioning method has been used to reduce the number of states in the resulting model, obtaining an equivalent reduced 5-state model. Applying transmission line constraints result in wind generation model ranging from 2- to 5-state models. The study recognizes benefits from fuel offset by wind power, reliability worth and environmental improvement and determines appropriate transmission line capacity based on its contribution to the overall system risk and associated transmission system cost. The paper illustrates results using a real wind farm. The presented methods and discussions should be useful to power system planners and policy makers.     

Effects of Wind Power on Bulk System Adequacy Evaluation Using the Well-Being Analysis Framework

The well-being analysis framework provides a bridge between the deterministic and probabilistic approaches to bulk power system adequacy and security assessment using the operating states designated as healthy, marginal and at risk. This paper illustrates the effects on the probability, frequency and average duration of the three operating states of adding wind power to a system or replacing some existing conventional generating capacity by wind power. The described studies incorporate the effects of load forecast uncertainty on the operating state reliability indices and are conducted using sequential Monte Carlo simulation.      

基于发电容量充裕度估计的发电公司检修策略

电力市场环境下,发电公司在制定下一年度的发电机组检修计划时,首先需要预测未来1年各交易时段的电价,并尽可能将检修安排在电价较低的时期内进行,以减少收益损失。针对装机容量不太充裕的电力现货市场中电价波动大、难以直接准确预测的问题,提出了首先基于历史数据模拟市场电价与发电容量充裕度之间的函数关系,然后根据负荷预测结果和对其他发电公司检修起始时间的概率估计求取系统发电容量充裕度,进而预测现货市场电价的新方法。在此基础上构造了基于机会约束规划的发电公司最优检修策略模型,给出了求解方法,并用算例进行了说明。     

基于互转换Ornstein-Uhlenbeck过程的风速仿真模型及应用

准确的风速仿真是研究含风能发电系统的重要且基础步骤.为此,提出基于互转换Ornstein-Uhlenbeck过程的风速仿真模型,该模型可产生任意时间步长的仿真风速样本,将其与时序Monte Carlo模拟法结合,提出仿真时间步长可变的含风能发电系统充裕度评估方法.然后,采用某观测站的实测风速样本验证所提模型,结果表明,...     

Capacity reserve assessment using system well-being analysis

Deterministic methods are widely used in operating reserve assessment and in small isolated power system capacity planning. These approaches do not normally include any explicit recognition of system risk and do not provide comparable risks for systems of different size or composition. Many large power systems, therefore, use probabilistic methods for generation adequacy evaluation. The reluctance to utilize the existing probabilistic techniques in both large and small systems dictates a need to create a bridge between the two different approaches. This paper presents a new probabilistic method designated as `system well-being analysis', which incorporates the accepted deterministic criteria in the definition of `healthy' and `marginal' power system states. This paper illustrates methodologies to evaluate the system well-being indices of practical systems and describes how they can be used in the assessment of power system capacity reserves     

基于网损灵敏度二阶指标的电压稳定概率评估

大多数电力系统电压稳定评估主要采用的是确定性的分析方法。简要介绍了概率的分析方法在进行电力系统电压稳定分析中的应用,提出了一种以蒙特卡罗法和网损灵敏度二阶指标确定电压稳定负荷裕度相结合的方法,同时引入两个概率指标———电压崩溃概率指标和电压崩溃点负荷水平期望值。采用该方法对重载下的AEP30节点系统进行了电压崩溃的概率评估,并侧重于分析负荷的随机特性对负荷水平(电压崩溃点)的影响,以及输电线断线的概率评估和相应减小电压崩溃概率的措施比较。     

Criteria used by Canadian utilities in the planning and operationof generating capacity

The author reviews the reliability criteria used by Canadian utilities in regard to planning and operating generating capacity. These results have been obtained from surveys conducted by the Power System Reliability Subsection of the Canadian Electrical Association. These surveys cover both operating and planning generating capacity criteria. In the case of adequacy assessment, a comparison of the different utility criteria is presented using the IEEE Reliability Test System. It is concluded that virtually all Canadian utilities now use probabilistic techniques in planning future-generating-capacity requirements     

Impacts of COVID-19 on Kuwait’s electric power grid

In response to a request from Kuwait’s Ministry of Electricity and Water, a resource adequacy model was developed to assess Kuwait’s ability to supply sufficient energy to meet the load demand during the COVID-19 pandemic. Power system operators and utilities use this type of model to ascertain their ability to meet demand, most notably peak demand. The model includes active power loss as well as the loss of resource capacity under medium and large contingencies. As resource adequacy models do not take into account security constraints such as transmission limits and voltage, they cannot be used for operations. However, due to their simplicity, they are appropriate for studying a wide range of scenarios for formulating policy decisions. Resource adequacy analysis can provide valuable insights into the performance of a system under urgent conditions such as the one posed by COVID-19 and similar unforeseen disruptions. This model utilizes an analysis of historical load data to forecast the 2020 peak load and develop a number of scenarios to test the capacity margin of Kuwait’s power system. The scenarios vary based upon load growth (2–25 %) and whether there is an outage or unavailable generation (no outage, 720 MW outage, 1440 MW, and 2400 MW outage).     

基于蒙特卡罗算法的发输电系统充裕性模型及评估方法研究

发电容量充裕性评估可为电力系统的规划及运行提供决策依据,通过对发电容量充裕性的相关指标和蒙特卡罗仿真算法研究,建立了考虑电网主要随机因素的发输电系统充裕度概率评估模型,设计了基于蒙特卡罗法的可靠性仿真流程,并用该方法评估了基于现有系统备用配置情况的南方电网发电容量充裕性,验证了该方案和模型的正确性及可行性,结合仿真结果推荐了南方电网备用确定原则,为电网的规划设计及其安全运行提供了有价值的参考依据。     

充裕度计算在电网规划中应用的探讨

充裕度是保障电力系统安全稳定运行、衡量电力系统可靠性的一个重要指标。介绍了评价电力系统充裕度的原则、应用现状及存在的问题。论述了定量衡量系统充裕度在电网规划中的意义。参照IEEE可靠性计算测试系统中的概率数据,建立了用蒙特卡罗算法计算IEEE-30节点可靠性的概率模型。探讨了充裕度概率计算的特点及概率指标在规划中的应用。运用充裕度计算对量化电网建设投资、提高电力系统的可靠性进行了一些尝试,提出了改进的方向。     

Evaluating resource adequacy impacts on energy market prices across wind and solar penetration levels

This study evaluates market impacts of excess capacity across various wind and solar system penetrations. First, different fleet compositions are simulated in a production cost model to yield price outputs. Price statistics reveal a strong relationship between scarcity price events, resource adequacy, and the mean and standard deviation of prices. Next, a method is presented for adjusting resource adequacy to a chosen level, which links a capacity expansion model with a probabilistic resource adequacy model.     

基于博弈论的发电公司检修决策

电力市场环境下,发电公司在制定机组检修计划时,必须考虑竞争对手检修策略的影响,以追求收益损失最小化。根据预测电价和系统发电容量充裕度,构造了发电公司机组检修非合作博弈模型。当系统允许检修容量不太充裕时,考虑了可中断负荷的合理利用。局中人的策略包括检修起始时间和检修报价策略,收益函数由检修损失和风险损失构成。博弈过程考虑了多均衡点的协调,并采用随机求解方法。仿真算例说明了该方法的合理性和有效性。     

Comparison of Capacity Credit Calculation Methods for Conventional Power Plants and Wind Power

Several methods for computing capacity credit values of power plants have been presented over the years. This paper uses an empirical approach to investigate and compare different properties of four typical capacity credit definitions. It is shown that the choice of definition indeed can have a significant impact on the results. Concerning three of the analyzed methods, it is found that important factors that influence the capacity credit are the overall generation adequacy and the penetration factor of the power plant; this means that the same generating unit will generally have a higher capacity credit if added to a system with high loss of load probability, and the unit will have a higher capacity credit if its installed capacity is small compared to the total installed capacity of the system. The results of the fourth method only depend on the size and availability of the generating units.     

基于时序和随机风速模型的含风电场发电系统充裕性评估

建立基于蒙特卡洛模拟(MCS)的含风电场发电系统可靠性评估模型,包含时序和随机风速模型的建立及序贯和非序贯蒙特卡洛模型的建立,并把该模型应用到RBTS测试系统中。由不同风速模型和不同MCS方法构成4种组合可靠性评估模型,本文分析4种组合模型的系统缺电概率LOLP、缺供电时间期望LOLE、期望缺供电量EENS、可靠性指标,并确定时序和随机风速模型及序贯和非序贯MCS方法对系统充裕性的影响,同时分析了风电场装机容量、系统峰值负荷等因素对系统充裕性指标的影响。     

Dynamic optimizations of Monte Carlo simulation to assess locational capacity, transmission, and market parameters

Risk indices of loss-of-load expectation and loss-of-energy expectation were traditionally used to determine generation adequacy. However, because responsibility of generation installation and transmission upgrades rests with different entities, both generation and transmission need to be examined to evaluate the resource adequacy of today's deregulated power systems. Further, it is important to delineate the contribution to curtailments arising from insufficient installed capacity and bottlenecks in transmission system. Hence, risk-based planning and market decision-makings have to address both generation and transmission jointly. This paper presents a procedure to combine dynamic optimization and Monte Carlo simulation to generate a vector space of solution, from which optimal solutions for different objectives can then be easily obtained. Determining locational capacity and transmission requirements serves the example of such an application. This paper closes with a discussion on some possible changes to risk criteria.     

采用通用生成函数法的自治微网旋转备用充裕性评估

自治微网中可再生能源的随机波动特性对旋转备用容量的运行规划提出了新的要求。基于通用生成函数法(UGF),结合马尔可夫技术建立了自治微网内各元件的多状态概率预测模型,提出了自治微网旋转备用概率预测充裕性评估方法与流程。模型综合考虑了风速、光照强度的预测不确定性,以及风机、光伏系统的随机故障特性和拓扑结构。针对UGF处理多状态会产生组合爆炸问题,采用合并同类项、均摊法以及改进K-means聚类进行状态削减,以减小计算负担、提高计算速度。通过MATLAB编程对自治微网算例系统进行仿真分析,结果表明增大传统机组爬坡速率、合理设置光风容量以及初始储能状态有助于提升旋转备用裕度程度。