Overall Framework and Module of Distribution Network Coordinated Planning Considering Distributed Generation

Combining with the characteristics of China's energy and the strategy of sustainable development, analyzing the pros and cons which caused by the appearance of DG and their operation connecting to grid, this paper points out that the two sides can achieve win-win under a reasonable combination between DG and distribution system, so as to optimize the allocation of resources, improve the utilization ratio of resource, and obtain maximum social benefit, harmoniously promote the development of power industry, economy and environment. As a word, this paper puts forward a new model of distribution network planning including DG and brings in penalty factorto guide the investment and construction of DG. Last of all, this paper presents the adoption of the coordination development coefficients which is to evaluate the power planning.

Coordinated Planning Transmission Tasks in Heterogeneous Space Networks:A Semi-Distributed Approach

This paper studies the coordinated planning of transmission tasks in the heterogeneous space networks to enable efficient sharing of ground stations cross satellite systems.Specifically,we first formulate the coordinated planning problem into a mixed integer liner programming(MILP)problem based on time expanded graph.Then,the problem is transferred and reformulated into a consensus optimization framework which can be solved by satellite systems parallelly.With alternating direction method of multipliers(ADMM),a semi-distributed coordinated transmission task planning algorithm is proposed,in which each satellite system plans its own tasks based on local information and limited communication with the coordination center.Simulation results demonstrate that compared with the centralized and fully-distributed methods,the proposed semi-distributed coordinated method can strike a better balance among task complete rate,complexity,and the amount of information required to be exchanged.

Coordinated Planning of Large-Scale Wind Farm Integration System and Transmission Network

Large-scale centralized exploitation of intermittent wind energy resources has become popular in many countries.However,as a result of the frequent occurrence of largescale wind curtailment,expansion of corresponding transmission projects has fallen behind the speed at which installed wind capacity can be developed.In this paper,a coordinated planning approach for a large-scale wind farm integration system and its related regional transmission network is proposed.A bilevel programming model is formulated with the objective of minimizing cost.To reach the global optimum of the bi-level model,this work proposes that the upper-level wind farm integration system planning problem needs to be solved jointly with the lower-level regional transmission planning problem.The bi-level model is expressed in terms of a linearized mathematical problem with equilibrium constraints(MPEC)by Karush-KuhnTucker conditions.It is then solved using mixed integer linear programming solvers.Numerical simulations are conducted to show the validity of the proposed coordinated planning method.

A production-cost-simulation-based method for optimal planning of the grid interconnection between countries with rich hydro energy

Cross-border grid interconnection is a critical means to achieve wide-area share of hydro and other clean energy.Economic benefit assessment of cross-border grid interconnection projects should be carefully performed during early stage.In this paper,a method based on cost-benefit economic assessment for optimal planning of cross-border grid interconnection is proposed.An economic index for comprehensively assessing the cost of a transmission project and its resulting benefits of more usage of hydro energy is designed first.A chronological production cost simulation model considering hydro energy spillage due to transmission congestion and thermal operational limitation is then proposed to calculate the economic index.A case study is performed using the proposed method to determine the optimal capacity of a potential transmission link between Brazil and Argentina,which have rich and complementary hydro energy resources.

Peregrine Soliton and Akhmediev Breathers in a Chameleon Electrical Transmission Line

We analyze the particular behavior exhibited by a chaotic waves field containing Peregrine soliton and Akhmediev breathers. This behavior can be assimilated to a tree with “roots of propagation” which propagate randomly. Besides, this strange phenomenon can be called “tree structures”. So, we present the collapse of dark and bright solitons in order to build up the above mentioned chaotic waves field. The investigation is done in a particular nonlinear transmission line called chameleon nonlinear transmission line. Thus, we show that this line acts as a bandpass filter at low frequencies and the impact of distance, frequency and dimensionless capacitor are also presented. In addition, the chameleon’s behavior is due to the fact that without modifying the appearance structure, it can present alternatively purely right- or left-handed transmission line. This line is different to the composite one.

Integrated generation-transmission expansion planning for offshore oilfield power systems based on genetic Tabu hybrid algorithm

To address the planning issue of offshore oil-field power systems, an integrated generation-transmission expansion planning model is proposed. The outage cost is considered and the genetic Tabu hybrid algorithm(GTHA)is developed to find the optimal solution. With the proposed integrated model, the planning of generators and transmission lines can be worked out simultaneously,which outweighs the disadvantages of separate planning,for instance, unable to consider the influence of power grid during the planning of generation, or insufficient to plan the transmission system without enough information of generation. The integrated planning model takes into account both the outage cost and the shipping cost, which makes the model more practical for offshore oilfield power systems. The planning problem formulated based on the proposed model is a mixed integer nonlinear programming problem of very high computational complexity, which is difficult to solve by regular mathematical methods. A comprehensive optimization method based on GTHA is also developed to search the best solution efficiently.Finally, a case study on the planning of a 50-bus offshore oilfield power system is conducted, and the obtained results fully demonstrate the effectiveness of the presented model and method.

Distributionally Robust Co-optimization of Transmission Network Expansion Planning and Penetration Level of Renewable Generation

Transmission network expansion can significantly improve the penetration level of renewable generation.However,existing studies have not explicitly revealed and quantified the trade-off between the investment cost and penetration level of renewable generation.This paper proposes a distributionally robust optimization model to minimize the cost of transmission network expansion under uncertainty and maximize the penetration level of renewable generation.The proposed model includes distributionally robust joint chance constraints,which maximize the minimum expectation of the renewable utilization probability among a set of certain probability distributions within an ambiguity set.The proposed formulation yields a twostage robust optimization model with variable bounds of the uncertain sets,which is hard to solve.By applying the affine decision rule,second-order conic reformulation,and duality,we reformulate it into a single-stage standard robust optimization model and solve it efficiently via commercial solvers.Case studies are carried on the Garver 6-bus and IEEE 118-bus systems to illustrate the validity of the proposed method.

A Defense Planning Model for a Power System Against Coordinated Cyber-physical Attack

This paper proposes a tri-level defense planning model to defend a power system against a coor-dinated cyber-physical attack(CCPA).The defense plan considers not only the standalone physical attack or the cyber attack,but also coordinated attacks.The defense strategy adopts coordinated generation and transmission expansion planning to defend against the attacks.In the process of modeling,the upper-level plan represents the perspective of the planner,aiming to minimize the critical load shedding of the planning system after the attack.The load resources available to planners are extended to flex-ible loads and critical loads.The middle-level plan is from the viewpoint of the attacker,and aims at generating an optimal CCPA scheme in the light of the planning strategy determined by the upper-level plan to maximize the load shedding caused by the attack.The optimal operational behavior of the operator is described by the lower-level plan,which minimizes the load shedding by defending against the CCPA.The tri-level model is analyzed by the column and constraint generation algorithm,which decomposes the defense model into a master problem and subproblem.Case studies on a modified IEEE RTS-79 system are performed to demonstrate the economic effi-ciency of the proposed model.

基于凸包算法的极端运行方式提取方法

在电力系统规划与运行的安全稳定计算中,一般选择对安全稳定最不利的运行方式进行校验,但随着新能源渗透率的增加,电网越发复杂多变,人工选择场景主观性较强,针对此问题,提出了一种基于快速凸包算法的极端运行方式提取,从而满足场景选取进行安全校核需求。从电源规划、发输电协调规划两个角度,考虑发电充裕性、火电爬坡需求、网络传输安全3个方面,分析影响规划的极端运行方式;基于凸包算法分别从上述3个方面构建坐标系进行极端运行方式提取;采用中国西北地区电网为算例进行极端运行方式提取,并与基于K-means算法的极端场景提取做对比,结果表明:所提方法能为场景选取提供有效数据支撑,满足电网规划要求。

Transmission Network Expansion Planning Considering Uncertainties in Loads and Renewable Energy Resources

This paper proposes a novel method for transmission network expansion planning(TNEP)that take into account uncertainties in loads and renewable energy resources.The goal of TNEP is to minimize the expansion cost of candidate lines without any load curtailment.A robust linear optimization algorithm is adopted to minimize the load curtailment with uncertainties considered under feasible expansion costs.Hence,the optimal planning scheme obtained through an iterative process would be to serve loads and provide a sufficient margin for renewable energy integration.In this paper,two uncertainty budget parameters are introduced in the optimization process to limit the considered variation ranges for both the load and the renewable generation.Simulation results obtained from two test systems indicate that the uncertainty budget parameters used to describe uncertainties are essential to arrive at a compromise for the robustness and optimality,and hence,offer a range of preferences to power system planners and decision makers.

Security value based expansion planning of power system with integration of large-scale wind power

Concerning the integration of large-scale wind power,an integrated model of generation and transmission expansion planning is proposed based on the assessment of the value of steady state and dynamic security.In the assessment of security value,the unit commitment simulation based on the predicted hourly load and wind power output data in the planning horizon is used to evaluate the costs of preventive control,emergency control and social losses due to the uncertainty of load and wind power.The cost of preventive control consists of the fuel cost of power generation,the environmental cost and the load shedding cost.This not only provides a systematic method of security assessment of power system expansion planning schemes,but also broadens the perspective of power system planning from the technology and economic assessment to the measure of the whole social value.In the assessment process,the preventive control and emergency control of cascading failures are also presented,which provides a convincing tool for cascading failure analysis of planning schemes and makes the security assessment more comprehensive and reasonable.The proposed model and method have been demonstrated by the assessment of two power system planning schemes on the New England 10-genarator 39-bus System.The importance of considering the value of security and simulating hourly system operation for the planning horizon,in expansion planning of power system with integration of large-scale wind power,has been confirmed.

A Scenario-Based Robust Transmission Network Expansion Planning Method for Consideration of Wind Power Uncertainties

This paper uses a novel scenario generation method for tackling the uncertainties of wind power in the transmission network expansion planning(TNEP)problem.A heuristic moment matching(HMM)method is first applied to generate the typical scenarios for capturing the stochastic features of wind power,including expectation,standard deviation,skewness,kurtosis,and correlation of multiple wind farms.Then,based on the typical scenarios,a robust TNEP problem is presented and formulated.The solution of the problem is robust against all the scenarios that represent the stochastic features of wind power.Three test systems are used to verify the HMM method and is compared against Taguchi’s Orthogonal Array(OA)method.The simulation results show that the HMM method has better performance than the OA method in terms of the trade-off between robustness and economy.Additionally,the main factors influencing the planning scheme are studied,including the number of scenarios,wind farm capacity,and penalty factors,which provide a reference for system operators choosing parameters.

Expansion Planning for Renewable Integration in Power System of Regions with Very High Solar Irradiation

In this paper,we address the long-term generation and transmission expansion planning for power systems of regions with very high solar irradiation.We target the power systems that currently rely mainly on thermal generators and that aim to adopt high shares of renewable sources.We propose a stochastic programming model with expansion alternatives including transmission lines,solar power plants(photovoltaic and concentrated solar),wind farms,energy storage,and flexible combined cycle gas turbines.The model represents the longterm uncertainty to characterize the demand growth,and the short-term uncertainty to characterize daily solar,wind,and demand patterns.We use the Saudi Arabian power system to illustrate the functioning of the proposed model for several cases with different renewable integration targets.The results show that a strong dependence on solar power for high shares of renewable sources requires high generation capacity and storage to meet the night demand.

An approach for evaluating the impact of an intermittent renewable energy source on transmission expansion planning

We propose a new robust optimization approach to evaluate the impact of an intermittent renewable energy source on transmission expansion planning （TEP）. The objective function of TEP is composed of the investment cost of the transmission line and the operating cost of conventional generators. A method to select suitable scenarios representing the intermittent renewable energy generation and loads is proposed to obtain robust expansion planning for all possible scenarios. A meta-heuristic algorithm called adaptive tabu search （ATS） is employed in the proposed TEE ATS iterates between the main problem, which minimizes the investment and operating costs, and the subproblem, which minimizes the cost of power generation from conventional generators and curtailments of renewable energy generation and loads. The subproblem is solved by nonlinear programming （NLP） based on an interior point method. Moreover, the impact of an intermittent renewable energy source on TEP was evaluated by comparing expansion planning with and without consideration of a renewable energy source. The IEEE Reliability Test System 79 （RTS 79） was used for testing the proposed method and evaluating the impact of an intermittent renewable energy source on TEP. The results show that the proposed robust optimization approach provides a more robust solution than other methods and that the impact of an intermittent renewable energy source on TEP should bc considered.

面向高比例可再生能源的输电网规划方法研究进展与展望

为应对高比例可再生能源接入带来的消纳问题,提出了以多场景技术、鲁棒优化技术和协同规划技术为核心的输电网规划理论,涵盖不同适用条件或需求场景下的4种不同规划方法,即基于多场景的输电网随机规划方法、基于概率驱动的输电网鲁棒规划方法、考虑多源互补的网-源协同规划方法以及与配电网相协同的输电网规划方法,能够从输电网规划的角度在安全稳定前提下提高可再生能源消纳能力。在此基础上,对未来输电网规划方法进行了展望,提出了满足更高安全稳定需求、协同更广泛的源-网-荷-储柔性互动、推动大数据应用和挖掘电力市场机制激励空间的可能研究方向,并探讨了研究难点和解决方式。

考虑高比例可再生能源的交直流输电网规划挑战与展望

未来高比例可再生能源的时空分布特性将给电力系统规划带来前所未有的挑战,电力系统基本形态与运行特性将发生根本性变化。文中在调研国内外研究现状的基础上,阐述了高比例可再生能源并网的输电网规划面临的科学问题,分别从网源协同规划、输电网柔性规划、与配电网协同的输电网规划、输电规划方案综合评价与决策方法四个方面,提出了考虑高比例可再生能源并网的输电网规划的研究思路与框架。最后,对未来高比例可再生能源并网的输电网规划进行了展望与总结。

计及随机模糊双重不确定性的源网荷协同规划模型

为应对电源与电网规划建设脱节导致的"弃风"等问题,文中提出一种将电源电网协同规划的模型。同时,鉴于需求侧在电力供需平衡中的潜力,将电力需求侧的能效电厂也纳入电力规划统筹考虑,提出了源网荷协同规划的概念与模型。另外,针对风电等新能源发电给电力系统带来的不确定性,从随机性和模糊性两个角度予以分析和建模,并在源网荷协同规划模型中计及双重不确定性。最后,通过IEEE 30节点系统的算例应用,表明该模型能够有效协调电源与电网的规划建设方案以及能效电厂项目的开展,实现系统总成本最小化,并可合理确定风电机组建设规模,保障资源优化利用。

基于可靠性均衡优化的含风电电网协调规划

集群开发、远距离外送的规模化风电开发对电力系统规划提出了新的挑战,串序开展电源和电网规划往往将新能源接入的矛盾积压到电网规划阶段,使得电网规划方案难以求解甚至得不到合理方案。为此,从可靠性均衡的角度,提出一种利用虚拟机组进行源网协调规划的方法。该方法针对风电大规模接入后的电网规划,在规划电网的同时对电源规划方案进行反馈及微调,以经济性最优为目标,均衡优化源、网可靠性,确定电源及电网的可靠性优化值,从而得到与电源协调优化的电网规划方案。该方法可以有效减少电网建设投资及电力系统整体投资,并校验电源、电网规划中可靠性均衡的协调性。通过原型系统和测试系统的仿真及分析,验证了所提方法的有效性。

考虑需求方响应资源的智能输电网扩展规划

以智能工程理论和不确定理论机会测度为基础,扩充了智能工程优化理论,提出了智能工程优化协调算子、机会路径和αβ—机会解。将风电出力视为随机变量、将需求方响应资源视为模糊变量,对智能输电网规划问题进行智能工程混合模型建模,并采用分层协调机制求解,通过各参与方的交互协调得到满足各方目标的智能工程机会解。利用IEEE 30节点系统算例对所提方法进行验证,结果表明,分层协调求解算法可有效处理电网规划中面临的多重不确定性,考虑需求方响应资源的电网规划统筹考虑了各方利益,规划效果更优。

大规模风电接入下输电网扩展规划的启发式优化算法

提出了大规模风电接入下的输电网有功和无功扩展规划的解决方法。计及了风电与负荷的全年时序数据,并将网络设备投资的年值成本与方案在全年所有不满足安全约束场景下采取控制措施的成本之和最小作为规划目标。为了降低求解计算的复杂性,将原问题分解为网络设备投资决策与方案的控制措施成本评估2个子问题,二者借助原问题的规划目标进行总体协调。在此基础上,通过分析规划目标与问题本身的特性,设计了启发式的优化算法,明显地提高了计算速度。算例分析验证了所提方法的正确性和求解算法的有效性。