考虑源荷协调的风电并网系统旋转备用容量优化

风电的接入给电力系统带来更大不确定性,要求电网公司购买更多的旋转备用以维持电力系统的功率平衡和稳定,兼顾系统运行可靠性与经济性的旋转备用优化配置具有重要意义。考虑风电、需求侧互动资源,提出一种基于多场景的概率性旋转备用优化方法。该方法综合考虑风电预测误差、负荷波动及发电机非计划停运不确定性因素对旋转备用的需求,将弃风、可中断负荷分别作为部分负、正旋转备用融入发电日前调度计划,以购电总费用最低为目标函数建立日前机组组合优化模型,获得各时段旋转备用优化配置量。通过对IEEE 30节点、IEEE 118节点系统进行算例分析,验证了所提方法的正确性和有效性。     

A Framework to Implement Supply and Demand Side Contingency Management in Reliability Assessment of Restructured Power Systems

This paper presents a framework to implement supply and demand side contingency management in the reliability assessment of hybrid power markets. A model for the independent system operator (ISO) to coordinate reserve and load curtailment bids for contingency states is introduced to balance reliability worth and reliability cost. The load curtailments and generation re-dispatch for a contingency state are determined based on minimizing the market interruption cost using an optimization technique. A nonsequential Monte Carlo simulation technique based on this framework has been proposed to evaluate the customer reliability of restructured power systems with the hybrid market model. The modified IEEE Reliability Test System (RTS) is used to illustrate the proposed technique     

计及源-荷多灵活备用资源的随机优化调度

大规模新能源并网给电力系统的调度运行带来了新的挑战。为缓解系统的备用压力,提出一种计及源-荷多灵活备用资源的随机优化调度方法。首先,基于场景生成方法建立可变场景模型,考虑了风电并网容量和光伏并网面积对新能源出力不确定性的影响。其次,建立电力系统中多种灵活资源的备用模型:在源侧,分别建立常规机组和风电/光伏的备用模型,并考虑了风电/光伏备用的不确定性;在负荷侧,引入激励型需求响应,对需求侧备用进行建模。然后,基于两阶段随机优化方法建立备用调度模型。该模型考虑了日前的运行和备用决策以及日内不确定场景下的弃风、弃光以及切负荷风险。最后,基于改进的IEEE RTS-24测试系统验证了所提模型的有效性。     

考虑备用共享的区域电力现货市场出清模型

在推进我国新一轮电力体制改革和建设全国统一电力市场的背景下,为了打破省间壁垒,缓解现行区域电力市场部分省份因备用容量不足和源荷逆向分布而存在的电力紧缺或“三弃”问题,引入备用共享机制和联络线协调优化的运行方式,构建了包括安全约束机组组合模型和安全约束经济调度模型在内的区域电力现货市场电能与备用联合出清模型。通过考虑备用共享的区域电力现货市场电能与备用联合出清,实现了电力资源在更大范围的优化配置,有效提高了系统运行的经济性和可靠性。以两个互联的IEEE 30节点系统模拟区域内两省间电力市场交易,验证了所提模型的正确性和有效性。     

Load levelling by control of air conditioner operation

The recent drastic increase in the number of air conditioners has caused sharp and narrow peaks in summer seasons due to the inherent temperature-sensitive characteristics. The authors propose a method to reduce the peak power demand by controlling air conditioner operations, and verify its effectiveness on clipping peak demand. However, former study has shortcomings in that no qualitative treatment of room temperature or comfort was attempted, and it did not provide a way of assessing peak demand clipping in a power system as a whole. In this paper, the authors propose a new control method that can deal with the maintaining of comfort and the reduction in power demand. Although air conditioners are used for “comfort,” this contradicts the reduction of power consumption and furthermore the concept of “comfort” is very vague. Hence, Weber-Fechner's law is utilized to quantify the pleasant feeling which is treated as a fuzzy quantity. A fuzzy coordination method is used to resolve this difference between power demand curtailment and comfort. The second part of this paper prepares an approach for assessing the amount of peak load clipping when the newly proposed control strategy is adopted in a real-size power system. A decrease in the required generation capacity is estimated provided that the loss of load probability (LOLP) is maintained at the same level before and after the application of the new control strategy. The reduction can be regarded as a dividend of load management.     

Effects of Load Forecast Uncertainty on Bulk Electric System Reliability Evaluation

Load forecast uncertainty is an important factor in long-range system planning and has been shown to have a significant impact on the calculated reliability indices in generating capacity studies. In general, a higher capacity reserve is required to satisfy a future uncertainty load than to serve a known load, at a specified level of reliability. Load forecast considerations are also important in composite generation and transmission system reliability studies, and their associated probability distributions. This paper examines the effects of load forecast uncertainty in bulk system reliability assessment incorporating changes in system composition, topology, load curtailment policies and bus load correlation levels.     

考虑多负荷聚集商参与的系统日前-日内分层优化调度策略

需求响应（demand response,DR）技术是系统削峰填谷,提高运行经济性和风电消纳的重要手段。针对风电和需求侧资源的时间特性,考虑到电网调度层和负荷聚集商（load aggregator,LA)之间主从博弈的关系,建立了多负荷聚集商参与的日前-日内分层优化调度模型。针对日前风电和价格型需求响应(price-based demand response, PDR)资源的不确定性,采用基于场景和模糊机会约束相结合的方法建立日前调度模型;针对日内多聚集商参与系统运行,采用目标级联分析(analytical target cascading,ATC)法对日内模型解耦,实现了各部分的并行求解。文章算例中通过对PDR和负荷聚集商的调度分别使系统综合运行成本降低了4.5%和6%,且各负荷聚集商收益均高于最低收益率8%,说明所提出的分层优化调度策略能在减小系统综合经济成本的同时保证各负荷聚集商的收益,且在一定程度上增强了系统的调峰能力。     

A procedure for evaluating interrupted energy assessment rates inan overall electric power system

The authors present a method for evaluating an interrupted energy assessment rate (IEAR) at each system customer load point considering the influence of outages in all parts of the electric power system. The developed IEAR can be used with the available adequacy indices in order to assess the severity associated with unsupplied energy due to supply interruptions. The IEAR can be used as a customer related index in making decisions regarding load curtailment philosophies and reliability related rate setting. The concept of utilizing a customer damage function in association with customer reliability indices is presented and illustrated using a reliability test system     

计及输电线路约束的华东电网备用容量可靠性评估

电力系统必须具有一定的备用容量来满足非计划的负荷需求,由于输电线路的约束、备用容量的数量及分布是否合理,关系到系统运行的安全性和经济性。通过建立计及输电线路约束的电力系统备用容量模型,采用蒙特卡罗重要抽样法对系统备用容量进行短期可靠性评估,给出相应的可靠性概率指标,并针对华东电网的实际运行数据进行分析,为华东电网备用容量管理办法的制定提供参考和依据。     

Reliability analysis of electric utility SCADA systems

Electric utility SCADA systems must be highly reliable given the potential for the SCADA system to directly contribute to load curtailment. This paper presents an analysis of SCADA system reliability in terms of its expected, aggregate contribution to load curtailment on the power system. Expressing this aggregate in system minutes and applying an appropriate damage cost function then provides an annual cost measure of SCADA system reliability worth. A composite generation and transmission system reliability evaluation technique is used to perform the numerical analysis of the joint SCADA and power system model. This performs a Monte Carlo simulation and includes an optimal power flow for enumerating grid load curtailment states and analysis of SCADA system component connectivity to determine availability of SCADA control. The application of this analysis is illustrated in a comparison of two alternative SCADA architectures. Trans Power (New Zealand) has adopted a subtransmission SCADA architecture which utilises terminals operating off its national SCADA system. These terminals have replaced separate systems located in each area. The objective of the evaluation being to quantify the increased exposure to financial losses due to joint load curtailment     

一种考虑电压稳定的评估发输电组合系统可靠性的新方法

考虑电压稳定的因素,基于蒙特卡罗模拟法对发输电组合系统可靠性中的充裕度进行评估。对利用静态等值法进行电压稳定计算和基于热稳定计算得到的各输电线路传输功率的极限值进行比较,可以得到每条线路的传输功率的极限值,再对系统进行切负荷计算,最后进行系统的充裕度评估。采用本文的算法对RTS-24系统进行仿真,并与前人计算的结果相比较,结果表明这种方法提高了计算结果的精度。     

Identifying the optimum wind capacity for a power system with interconnection lines

This paper presents a general framework for identifying the optimum wind capacity to be integrated in a power system with interconnection lines. Wind generation is treated as negative demand, together with the load demand, which must be covered by the conventional power generation and the energy interchange with neighboring systems. Under the presumption that the time-varying wind and load together with the trading price with neighboring systems could be statistically modeled by specified probability distributions, a chance constrained programming (CCP) model is formulated to address the wind capacity planning problem. The objective is to maximize the yearly net profit of the entire power system subject to the operational constraints and the reliability requirement. Wind power curtailment and load shedding are allowed to improve the system flexibility but incur penalty costs. The optimization problem is solved using a hybrid intelligence algorithm incorporating Monte Carlo simulations, a neural network and a genetic algorithm. The feasibility of the proposed approach is verified by a case study on a given power system.     

含风电和储能的电力系统安全约束机组组合问题研究

针对含风电的电力系统安全约束机组组合问题,利用储能的快速双向调节能力改善风电出力的波动性和不确定性,提高系统运行的经济性。机组组合模型中考虑风电、负荷预测误差对机组组合的影响,并引入基于可信理论的旋转备用机会约束条件,可避免造成备用的过度配置。另外,通过考虑合理弃风提高消纳风电能力和降低系统运行成本,分析了储能参数以及接入系统方式对机组组合模型中系统运行成本和风电弃风量的影响。最后,采用新英格兰10机系统验证了所提模型的有效性。     

计及含氢储能与电价型需求响应的能量枢纽日前经济调度

为了解耦冷热电联供(combined cool,heat and power system,CCHP)机组“以热定电”的运行约束,提高风电消纳能力,降低社会碳排放,提出了计及含氢储能与电价型需求响应的能量枢纽日前经济调度模型。源侧利用冷、热、电、氢4种储能装置,打破CCHP机组热电耦合约束;荷侧引入电价型需求响应改变用户用电行为,通过优化各机组出力与电负荷曲线,增加风机出力。该模型以系统日运行成本最低为目标,引入弃风惩罚成本增加风电消纳,综合功率平衡等约束,调用Gurobi求解器进行优化求解。对不同场景下能量枢纽的优化结果进行分析,并计算燃油汽车的碳排放量以量化氢燃料电池汽车节约的社会碳排放。结果表明:在电价型需求响应策略下,考虑CCHP与含氢储能的能量枢纽系统在增加风电消纳能力的同时降低了系统的日运行总成本,减少了社会碳排放。     

COMPOSITE RELIABILITY EVALUATION OF INTERCONNECTED POWER SYSTEMS

ABSTRACT

A power network can be divided into several subsystems such as generation, transmission and distribution subsystems. The most popular approaches for reliability evaluation, namely contingency enumeration and Monte-Carlo simulations, have been combined in this paper to form a hybrid algorithm for reliability assessment of composite generation and transmission subsystems. The main objective of this hybrid approach is to enumerate transmission outages and then sample generation states, conditioned to each enumerated transmission state, to evaluate the annualized reliability indices of the entire system and different load centers

Within the proposed hybrid algorithm for generation rescheduling, correction of voltage levels or alleviating of component overloading in order to minimize the amount of load curtailment, a linear programming model is implemented. This algorithm has been utilized for assessing the reliability of the Unified Egyptian Power System. Moreover a weak point analysis is carried out to define the different measures to improve the system reliability. These measures include generation capacity addition, increasing transmission capacity or regional interconnection with other utilities.     

考虑微网市场交易影响的配电网可靠性分析

微网内分布式资源分属于不同主体,市场主体的趋利性市场行为影响微网的源荷功率特性,进而影响电力设备和配电网的可靠性。文中提出了一种考虑微网日前市场交易影响的配电网可靠性分析模型。首先,构建各类市场参与者的日前市场投标策略和市场出清模型。其次,考虑不同时段源荷水平对可靠性的影响,提出载荷相关的元件老化失效模型,并针对源、荷、投标及外部电网电价的随机性及时序性,生成“源-荷-市”联合时序场景。最后,在改进的RBTS BUS 6算例系统上进行仿真分析。结果表明,需求侧分布式资源参与市场能降低峰值时段的元件失效概率且增加系统容量备用,起到一定的削峰填谷作用,根据不同电源的出力水平合理地配置备用容量能有效提高供电可靠性。     

考虑储能备用的电动汽车负荷连续追踪弃风曲线优化模型

在大力推动高比例可再生能源并网的背景下,风电的强随机波动特征导致的大量弃风问题给电力系统的经济可靠运行带来了挑战,而电动汽车、储能等作为需求侧的灵活性资源参与曲线追踪交易为弃风问题带来了解决方案。首先,分析了电动汽车消纳风电的可行性;然后,对电动汽车聚合负荷消纳风电的交易模式进行了梳理,聚焦连续曲线追踪交易,在充分考虑电动汽车聚合的物理经济约束下建立了混合整数线性规划模型以求解聚合调用方案。由于电动汽车的移动储能能力与追踪效果有限,引入储能系统进行联合优化,采用逐步搜索法在降低聚合成本的同时,得到储能的最优容量与功率配置以及同时优化物理弃风电量与经济成本的聚合方案。算例分析结果表明：考虑储能备用的聚合方法能够提高风电曲线的追踪精度,减小聚合成本,验证了所建模型在连续曲线追踪中的可行性与适用性,可为曲线追踪交易市场的完善与新型电力系统的建设提供借鉴。     

A Monte Carlo method for multi-area generation system reliabilityassessment

The authors present a method for multiarea generation system reliability assessment. It is based on direct sampling of generating unit states, the clustering technique, and the correlative normal distribution sampling technique of the load states. A linear programming model was used to minimize the total load curtailment. Area load uncertainty, correlation between area loads, and generating unit derated state were considered. Incorporation of these factors does not create a significant increase in computing time. Sensitivity indices of both system and each area to area generation and tie line capacities can be calculated. These indices provide information regarding which tie line or which area generating capacity should be reinforced from the overall system and each area point of view. Calculation results of a four-area system are given to demonstrate the effectiveness of the method     

基于需求响应调度容量上报策略博弈的电网多代理系统调度模式

负荷能够作为系统备用资源,通过需求响应平衡间歇性能源带来的系统功率波动。但是,由于调度工作量巨大,电网难以直接调度庞大且分散的负荷资源。因而提出基于多代理系统的负荷调度策略,建立了计及负荷违约的代理需求响应可调度容量上报博弈模型,同时构建了基于信任度的电网调度容量和调度量分配模型。代理根据自身负荷特点,向电网上报可调度容量,电网公司根据代理上报容量和信任度进行调度容量分配,并在实时调度时分配调度量,实现各个代理调度容量以及调度量的合理分配和电网调度费用低、代理收益高的目标。结果表明,该模型能够在计及负荷违约的条件下有效实现负荷需求响应调度容量和调度量的合理分配。     

风电功率弃风数据特征识别方法研究

在风力发电过程中,由于负荷需求量的不同,存在对风力发电量的限制,弃风现象普遍存在。弃风数据的存在会对风电功率预测和风电场等值模型的建立产生较大影响,因此对弃风数据的剔除非常关键。对此,分析了正常运行数据的特征和弃风数据的特点,在风电机组的标准风速-功率传变特性（功率曲线）的基础上,依据正态分布的均值和标准差提出了粘滞区间的概念,并基于此建立了对弃风数据进行辨别与剔除的方法。以东北某风电场的实测数据为例,对含有弃风的数据进行剔除,验证了所提方法的有效性。