The maximum transportation power of large grid-connected renewable energy system is restricted by static voltage stability, and the multiple renewable energy stations short-circuit ratio (MRSCR) is the most important critical index for the indication of the static voltage stability. A quantitative evaluation method based on MRSCR for maximum transportation power of large grid-connected renewable energy system is proposed. Firstly, the whole bus of the power system is divided into renewable energy nodes and other nodes, and it forms the nodal admittance of the power system after the nominal value of transmission line and transformer parameters. The maximum transportation power satisfying the static voltage stability constraint is derived based on the nodal impedance matrix of the renewable energy nodes. Secondly, the renewable energy stations are grouped combined with other stability constraints, by which the generation limit is corrected until satisfying all the stability constraints. Finally, the maximum transportation power of renewable energy sending system is derived by the generation limit which belongs to the renewable energy sending system. The simulation results of 220kV renewable energy collection system and 500/1000 kV UHV renewable energy collection system verifies the accuracy and effectiveness of the proposed method.

Power market is booming in China right after the 9th order. Conventionally, transmission planning is performed mainly based on purpose of transmission security in a regulated environment. However, when power market takes place, economic planning of transmission system should be carefully designed and considered, since transmission infrastructure could heavily impact the efficiency of the power market, as well as the benefit of all kinds of market participants. Transmission economic planning had been developed in almost all mature power markets overseas. In the paper, such practices in several RTOs/ISOs in United States and TSOs in Europe are investigated. The implementation process, evaluate method and key economic benefit indices of transmission economic planning are summarized in the paper. In the end, based on the current transmission planning and the development of power market in China, the suggestions how transmission economic planning should be performed is given.

Coal-fired power has played an important role in the power systems, but its operational characteristics, especially the flexibility characteristics is modelled relatively simple in the current operation simulations. Given the background of a rapid development of renewable energy and a sustainable transformation of power systems in China, it is essential to build a refined model of coal-fired power units that can be incorporated into an operation simulation method. First, this study provides an analysis on the flexibility characteristics of coal-fired power units, including the minimum stable output, ramp limit and minimum up/down time. Subsequently, a multi-state probabilistic model of coal-fired power units is proposed. This study also constructs a sequential operation simulation method based on the universal generation function (UGF) method that incorporates multiple states of coal-fired power units. Finally, this study provides a development and transformation pathway for coal-fired power plants in the North Hebei (NH) region and suggestions for promoting a sustainable development of the power system based on the proposed method and multi-state model.

As the uncertainty of power system increases with each passing day, energy storage facilities become more and more significant and they are widely used to cope with uncertainties. However, the existing power system production simulation methods usually neglect the temporal characteristic of power system and thus difficult to consider the effect of energy storage. To address this limitation, this paper firstly analyzes the charging and discharging process and builds the multi-state model of energy storage. In combination of the energy storage model, the universal generating function based production simulation method is introduced and the production simulation considering energy storage is also put forward. Taking North Hebei Power Grid as an example, this paper finally analyzes the effect of different scales of energy storage on power system reliability and renewable energy curtailment, and thus proposes some development proposals for North Hebei.

As an important power generation mode of renewable energy, the distributed generation (DG) is increasingly integrated into distribution networks. Aiming at the uncertainties in investment structure and investment benefits of the regional distribution network with DG, an investment decision-making method is proposed for distribution network planning considering DG integration. Firstly, based on analysis of the DG impact on the distribution network, an association analytic method is given for investment benefits of the distribution network, and intermediate variables, such as distribution network renovation measures, affected operating parameters and investment benefit indicators, are introduced to associate the investment with benefits. Secondly, by taking the optimal comprehensive benefits as the objective, an investment decision-making method is proposed for distribution network planning, and the main processes and key steps are given. At last, the effectiveness of the proposed method is verified through case study of a power supply area in a northern China province.

Developing the digital economy and promoting the digital transformation of enterprises has been an important direction for the development of enterprises in various countries. This article systematically analyzes the information organization, communication network, digital platform, business application system, information security and information operation and maintenance status of the company in Jibei Electric Power Company. Based on the analysis of the development environment and advantages and disadvantages of digital transformation in Jibei Electric Power Company, the development strategy of establishing unified digital development committee, improving the digitalization ability of power transmission and distribution business, improving the digitalization capability of internal operation and building the toB terminal service platform of integrated energy services are put forward.

随着电网规模的不断扩大,短路电流计算耗时逐渐增加,并且对计算软件的要求也不断提高,为提高短路电流计算效率,研究了一种适用于地区短路电流计算的外网数据等值方法,首先对全网的节点导纳矩阵进行等值化简,形成边界区域的新增注入元素,然后构造出仅包含研究区域和边界区域的简化电网模型,用于研究区域内的短路电流计算,并从理论上分析了该等值方法的效果与优势。在IEEE 39节点系统上对所提方法进行了验证,证明了所提方法的正确性和有效性,最后以华北电网为实例进行了外网等值简化,形成某一地区的短路计算用电网数据,大大降低了电网规模,能有效提高该地区短路电流计算的效率。

在大型风电场经柔性直流输电系统并入交流电网的场合,传统的电网调频方法难以适用。提出一种频率控制策略,分别在逆变侧换流器、整流侧换流器和风电机组上设计响应频率变化的控制环节。所有控制环节均基于本地测量的信号,无需远距离通信。该方法可以使风电场参与交流系统调频,此外,当系统故障引起柔性直流送出容量受限时,该方法可以自动降低风电机组功率,防止直流侧过压保护动作。

2018年,国家及河北省出台了新的可再生能源政策,河北省可再生能源行业快速发展,装机规模持续扩大.可再生能源利用水平不断提升,弃风、弃光率实现“双降”.2019-2020年,风电、光伏发电无补贴平价上网项目建设将加快推进,竞争配置工作机制全面推行,预测未来两年河北省可再生能源发展将继续保持较快势头.面对新的发展形势,应推动网源协调发展,加快抽水蓄能电站等调峰电源建设、完善电力辅助服务市场机制、加快外送通道建设、多渠道拓展清洁能源的消纳能力、推动本省可再生能源高质量发展.

A power system risk assessment model considering the time-sequence characteristic of wind power ramp events is pro-posed in this paper. By sampling the possible shutdown time and operation state of conventional units, the effect of time-sequence relation between wind power ramp events and the outage of conventional units is considered. In the evaluation process, the correlation between time intervals is taken into account, and the operating risk of the system is assessed by with times of frequency off-limits and loss load expectation. This assessment result the impact of wind power ramp events on system operation risks and provides guidance for the dispatcher to take preventive and control measures, which has practical application and reference value.

为提高新能源高占比电网中的风电利用率,研究风氢耦合发电系统,建立考虑风电出力随机性的混合整数规划模型,并提出就地消纳风电的新模式。模型中以风氢耦合发电的系统收益最大化为目标,兼顾风电场与氢气储能系统联合出力的跟随特性。结合实际设计算例,利用风电场独立运行的对照仿真验证氢气储能系统的有效性,提升系统收益27%,并测试电解槽与燃料电池容量对系统的影响。

Double fed induction generator (DFIG) is the main type of wind power generation,thus the electromechanical transient simulation model of DFIG is the basis for studying the interaction between the scale wind power farm and power grid.We established an overall architecture of DFIG's electromechanical transient simulation model according to the DFIG's active and reactive power regulation control as well as different function partition in DFIG interfacing with the AC grid.Model structure and relationships of functions are analyzed in detail.The applicability and limitation of the model are specified.The disturbed power characteristics of wind farm accessing into the power grid are studied,and the influences of voltage feedback control,voltage fluctuation rate and amplitude on the power characteristic are also studied.In the accessing of scale wind power and photovoltaic (PV) power farm into the Qinghai-Haixi pwer grid,measures are proposed to reduce the tripping threat of PV power generation under low voltage by utilizing the reactive power features of wind power pooling bus.Simulation results verify the effectiveness of the measures.

To alleviate the computational complexity of power system reliability evaluation,the probabilistic model of external system static equivalence was proposed in this paper.With using the traditional static Ward technique,the equivalent parameters of extern system in the state of random failures of generator and transmission line in the extern system were calculated,and then the joint probability density distribution for equivalent injection powers and series branch impedances of the extern system was achieved by utilizing probability density estimation technique.As the randomness of extern system equivalent parameters are considered,the proposed model can improve both calculation accuracy and efficiency.The proposed model is verified through the RBTS and IEEE-RTS79 test system.

柔性直流输电技术是采用全控型电力电子器件以及电压源换流器的新型输电技术.本文分析了两电平、三电平以及模块化多电平三大类换流器拓扑结构的特点,从器件层面、换流器层面以及系统层面展开了柔性直流与传统直流技术的比较,展望了柔性直流技术的发展局限性以及应用场景.

Wind power ramp event can bring serious impact on active power balance of power system, which may cause system frequency differential out-of-limit or load lost. A reserve demand analysis and preventive control model to deal with wind power ramp event is proposed to solve the above problems. Firstly, the probability distributions of wind power ramp event predication information in time series is converted to the probability distributions in single time sections based on sequence operation theory, and the reserve demand to deal with ramp event is analyzed based on it. And then, a preventive control model is proposed, the dispatching schedule is adjusted according to the newest predication information with it, and the adjustments include the curtailed amount of wind power, the output power and reserve capacity of conventional generators. The simulation results with IEEE RTS 24 system show that the proposed model can assess the operation risk of power system accurately and the operation risk can be controlled within acceptable range.

高岭直流工程与冀北电网形成复杂的交直流混联系统,为准确分析该典型交直流系统的安全稳定运行问题,削弱传统BPA在直流模拟方面的不准确性给仿真结果带来的影响,引入PSCAD电磁暂态仿真作为交直流系统稳控分析的校验手段,经对实际系统的仿真对比发现,两种仿真软件在多种应用场合下存在差异.在大量仿真计算的基础上,总结出两种软件存在差异的具体应用场景,并分析了产生差异的原因.提供的基于BPA和PSCAD的稳控分析手段,以及两种仿真软件存在差异时的处理方法,可为其他交直流系统的稳控分析提供借鉴.

风力发电是洁净清洁的发电方式,大规模发展风电对转变传统发电模式具有积极作用.风电技术的优化和完善使得风电场的发电水平不断增加,为了迎合电力用户和电力调峰的基本需求,需要开展风电场AGC系统建设.文章对风电场AGC系统建设与协同控制展开了探讨,对AGC系统建设实践、协同控制的原理、结构设计和具体的控制过程等进行了阐述.

结合用电市场影响因素及原因分析路径,提出了一种基于加权贡献偏离度的异动分析方法,通过基础数据准备及预处理、异动点逐级界定、异动原因分析三个步骤对用电市场异动进行深入分析,最终确定异动的产生原因.利用某地区的实际异动数据分析证明了此方法的有效性.

随着柔性直流输电(voltage source converter based high voltage direct current,VSC-HVDC)直流电压等级提升和传输容量增大,其在大容量远距离资源优化配置中将发挥更加重要的作用.以往的研究中,大多利用电磁暂态仿真软件,针对虚拟构建的小电网,仿真分析VSC-HVDC的技术性能.针对实际交流电网的VSC-HVDC动态性能验证等研究,则少有报道.本文首先针对PSD-BPA中新近开发的对应实际电网换相换流器高压直流(line commutated converter based high voltage direct current,LCC-HVDC)工程的DA卡仿真模型以及VSC-HVDC仿真模型,分析两者的技术特点.在此基础上,面向西藏藏中弱交流受端电网,仿真对比2种直流供电方案下,受端电网大扰动冲击后的暂态恢复特性.仿真研究结果为应用VSC-HVDC改善弱受端电网受扰特性和提升电网稳定水平提供了技术支撑.

频率限制控制器(frequency limit controller,FLC)作为一种重要的直流有功功率调制手段,可提高交直流混联系统的频率稳定水平,但直流有功功率的调节会改变换流站无功功率水平,进而影响系统电压特性.针对楚穗特高压送端直流孤岛系统,分析了交流系统发生短路故障后,FLC调节有功功率对整流站电压恢复特性的影响机理.在此基础上,提出了基于无功功率变化率的FLC优化控制策略,来提高送端系统的电压稳定性.仿真结果表明,该策略在抑制频率波动的同时,可改善孤岛系统的电压恢复特性.