压水型核反应堆功率控制系统的优化设计

在分析了压水型反应堆功率控制系统的前提下，针对其特殊的控制要求，运用基于输出反馈的次最优控制的设计方法和Matlab中的NCD模块，最终实现了系统的优化设计，并对系统进行了某一功率水平下的仿真试验和其它工况下的鲁棒性试验．结果表明。改进后的系统性能有了较大改善。     

全复用多小区系统下行链路用户调度与功率分配

对全复用多小区系统下行链路用户调度与功率分配问题进行了研究,提出了一种半分布式的用户调度与功率分配方案.首先,各小区根据自身所辖用户的信道与干扰信息,采用最大信干噪比准则进行用户调度,然后各基站将所调度用户的信息上报给中央资源控制器,最后中央资源控制器基于最速下降法的思想,采用贪婪功率分配(GPA)算法为各用户分配相应的发射功率.所提方案利用小区之间的相互协作有效地弱化了小区间干扰,与现有方法相比获得了更好的吞吐量性能和更高的功率效率.     

Spinning reserve scheduling of power systems: An ant colony approach

Abstract

This paper presents an Ant Colony System (ACS) based optimization approach to solve the optimal spinning reserve problem for a power system. Unit commitment risk is used as an index to evaluate the level of spinning reserve. The outage cost and the fuel cost of thermal units were considered in the unit commitment program. The optimal spinning reserve and unit commitment risk were reached while the sum of fuel cost and outage cost was minimized.

A 52 units power system was used as a numerical example to test the new algorithm. The optimal spinning reserve and unit commitment risk could be reached in the testing while satisfying the requirement of the objective function.     

Experiments with hybrid Bernstein global optimization algorithm for the OPF problem in power systems

This article presents an algorithm based on the Bernstein form of polynomials for solving the optimal power flow (OPF) problem in electrical power networks. The proposed algorithm combines local and global optimization methods and is therefore referred to as a ‘hybrid’ Bernstein algorithm in the context of this work. The proposed algorithm is a branch-and-bound procedure wherein a local search method is used to obtain a good upper bound on the global minimum at each branching node. Subsequently, the Bernstein form of polynomials is used to obtain a lower bound on the global minimum. The performance of the proposed algorithm is compared with the previously reported Bernstein algorithm to demonstrate its efficacy in terms of the chosen performance metrics. Furthermore, the proposed algorithm is tested on the OPF problem for several benchmark IEEE power system examples and its performance is compared with generic global optimization solvers such as BARON and COUENNE. The test results demonstrate that the hybrid Bernstein global optimization algorithm delivers satisfactory performance in terms of solution optimality.     

多时滞无线通信网络的功率和速率最优跟踪

研究了无线通信网络的功率和速率控制这一热点问题。针对传统的无线通信网络模型并没有同时考虑状态时滞和输入时滞,已有的功率和速率控制算法也不能保证系统具有最优输出跟踪性能的情况,重新建立了无线通信网络的模型,在建模过程中考虑了多时滞,得到了含有不同的状态时滞和输入时滞的功率和速率控制系统模型,在此基础上,研究了一般形式的多时滞模型的时滞补偿算法,并将该算法应用在提出的多时滞模型中,给出了无线通信网络功率和速率的最优跟踪控制律。经过计算机仿真验证,提出的最优控制律具有良好的控制性能。     

Systemic risk: the dynamics of model banking systems

The recent banking crises have made it clear that increasingly complex strategies for managing risk in individual banks have not been matched by corresponding attention to overall systemic risks. We explore some simple mathematical caricatures for ‘banking ecosystems’, with emphasis on the interplay between the characteristics of individual banks (capital reserves in relation to total assets, etc.) and the overall dynamical behaviour of the system. The results are discussed in relation to potential regulations aimed at reducing systemic risk.     

Some features of the procedure for measuring electric power by automated measuring systems

The components of the error of electric-power loss are investigated. The results can provide a basis for a standard document regulating the procedure for measuring electric power using measuring systems. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 62–64, April, 2006.     

考虑运行风险的含储能综合能源系统优化调度

为解决综合能源系统（integrated energy system,IES）中供需双侧不确定因素对运行调度带来的风险问题,提出了一种考虑运行风险的含储能IES优化调度模型。在目标函数中,用设备调整费用、失负荷惩罚费用和弃风弃光惩罚费用来量化系统运行风险。在约束条件中,区分了电能和热能的时间尺度差异,并计及储能的时间耦合性,建立了储能多时段耦合约束。然后提出了一种基于Benders分解的算法进行求解。最后通过算例分析了置信水平、储能功率及容量对IES运行费用及运行风险的影响。     

Deterministic and stochastic approach for safety and reliability optimization of captive power plant maintenance scheduling using GA/SA-based hybrid techniques: A comparison of results

This paper presents a comparison of results for optimization of captive power plant maintenance scheduling using genetic algorithm (GA) as well as hybrid GA/simulated annealing (SA) techniques. As utilities catered by captive power plants are very sensitive to power failure, therefore both deterministic and stochastic reliability objective functions have been considered to incorporate statutory safety regulations for maintenance of boilers, turbines and generators. The significant contribution of this paper is to incorporate stochastic feature of generating units and that of load using levelized risk method. Another significant contribution of this paper is to evaluate confidence interval for loss of load probability (LOLP) because some variations from optimum schedule are anticipated while executing maintenance schedules due to different real-life unforeseen exigencies. Such exigencies are incorporated in terms of near-optimum schedules obtained from hybrid GA/SA technique during the final stages of convergence. Case studies corroborate that same optimum schedules are obtained using GA and hybrid GA/SA for respective deterministic and stochastic formulations. The comparison of results in terms of interval of confidence for LOLP indicates that levelized risk method adequately incorporates the stochastic nature of power system as compared with levelized reserve method. Also the interval of confidence for LOLP denotes the possible risk in a quantified manner and it is of immense use from perspective of captive power plants intended for quality power.     

Blends of carbon dioxide and HFCs as working fluids for the low-temperature circuit in cascade refrigerating systems

This paper describes an analysis on the performances of a cascade refrigeration cycle operated with blends of carbon dioxide (CO₂, or R744) and hydrofluorocarbons (HFC) as the low-temperature working fluid. The aim of this work was to study the possibility of using carbon dioxide mixtures in those applications where temperatures below CO₂ triple point (216.58 K) are needed. The analysis was carried out by developing a software based on the Carnahan–Starling–De Santis (CSD) equation of state (EoS) using binary interaction parameters derived from our experimental data. The properties of the investigated blends (R744/R125, R744/R41, R744/R32, R744/R23) were used to simulate the behavior of a cascade cycle using ammonia (R717) as the high-temperature-circuit working fluid and operating at evaporating temperatures down to −70 °C. The use of a suction–liquid heat exchanger on the low-temperature side of the circuit was also investigated. Results show that the R744 blends are an attractive option for the low-temperature circuit of cascade systems operating at temperatures approaching 200 K.