基于IPSO-SVC的含风电配电网稳压控制策略

当配电网含风电接入时,电能质量会受到较大的影响。为解决不同风速下风力机出力不同影响配电网电压稳定性的问题,利用静止无功补偿器提高含风电配电网电压稳定性。在考虑不同风速场景下,引入改进粒子群算法并以配电网系统有功损耗最小为目标函数,优化SVC控制参数,改善SVC对电压的控制性能。以含风电IEEE 33节点算例进行仿真计算,验证了该算法的正确性和可行性。

浅析民用飞机配电网中保护装置的选用

随着电子技术的迅猛发展,大量电子设备被运用于民用飞机中,飞机中的配电系统起到了越来越大的作用。文章主要介绍了正确选择配电网中保护装置的基本要求以及常用的电路保护装置熔断器和断路器的类型、工作原理及选用方法等内容。

智能化含风电配电网多目标协同调度模型

由于风电场的随机不可控变量较多,难以达到理想调度效果,提出了智能化含风电配电网多目标协同调度模型。将经济性指标和电压偏差作为目标函数,确定机组潮流、响应速度、传输线路、出力以及爬坡指标的约束条件;在考虑风电场波动情况的基础上,利用PLSPP算法预测风电场的负荷及出力值,修正误差,制定不同时段下的机组出力计划,结合MIPSO算法得到协调度最高值,实现智能化协同调度模型的构建。仿真测试结果表明,所构建模型风电场预测曲线的拟合程度为99.6%,其最低日均费用为3.914 8万元、日均电压偏差仅为23.514 7 pu,由此证明该模型可以在花费最低成本的前提下实现高效、精准的调度。

配电网中分布式风电可调鲁棒优化规划

随着分布式风力发电接入配电网的比例不断提高,考虑风电出力随机性的分布式风电规划成为了配电网规划中的重要研究内容。提出了一个计及风速不确定性的鲁棒优化规划方法,为了简化配电网中鲁棒优化的计算,首先对配电网的潮流计算进行了线性化处理,然后又利用线性优化强对偶理论将鲁棒优化模型转变成了一个混合整型线性规划(mixed integer linear program,MILP)问题。接着又引入了可调鲁棒优化规划模型,通过不确定度弥补鲁棒优化偏于保守的不足。最后通过商业软件CPLEX对上述问题进行求解计算,算例分析表明,使用所提的鲁棒优化模型可以快速有效的计算出规划结果,可调鲁棒优化模型可以提高系统的性能鲁棒性。

油田配电网防窃电及用电监察技术浅析

用电监察和防窃电工作一直是电力管理部门重要的日常工作,也直接关乎电力企业的经济效益和供电的可靠性。油田配电网因其用户的特殊性,除主要是油田企业外,还带有油田社区及外部市场,查处违章用电形式相对严峻。本文结合油田供电特点分析了电力部门在用电监察和防窃电技术的做法和措施。

电力现货市场环境下的增量配电网售电公司储能配置方法研究

我国电力现货市场建设步伐正不断加快,在这一背景下,投资储能成为增量配电网售电公司应对现货市场冲击批发与零售市场电价的重要手段。增量配电网售电公司的运营核心就是投资回报率,精准计算投资回报率是提高增量配电网售电公司储能配置效益和售电经济性的关键。在电力现货市场背景下,以投资回报率最大为目标,提出了一种考虑投资回报和可调资源的增量配电网售电公司储能配置方法。首先介绍了增量配电网售电公司的基本运营结构和储能配置原理,提出了投资回报率和可调资源调节潜力的计算方法;其次建立了考虑投资回报和可调资源的储能配置模型来实现储能的选址定容,给出储能的配置方案和运行模式;最后,算例结果表明所提方法在保证同等运营收益增量的情况下,提高了投资回报率,验证了所提方法的有效性。

贵港配电网综合防误操作系统技术设计与应用

贵港供电局下辖开闭所、户外环网柜、电缆分支箱、架空线路、柱上设备等所有操作的设备,由于这些设备的覆盖范围相当广,其操作环境极其复杂,容易发生误操作,目前设计一种可以防止误操作系统,避免误操作的事件发生。本设计主要介绍目前贵港配电网运行方式、接线方式、和一次设备的情况。并根据现有接线方式分析贵港配网操作中存在的风险。针对贵港供电局配电网网架特点、接线方式、运行方式、管理水平及电气操作习惯,建设满足贵港供电局配电网电气操作防误平台,为配电网的安全运行提供保证,同时提高配电网的管理水平。讲述贵港供电局配网防误系统建设的目标及成功应用解决的问题。

基于粒子群算法的含风电配电网无功优化研究

本文基于粒子群算法研究了含风电配电网的无功优化问题,介绍了含风电配电网的模型和约束条件,并提出了适合该问题的目标函数,通过实例验证了算法的有效性,对算法的参数设置、收敛性和稳定性等进行了分析。

高寒山区电网配电线路的特点及融冰装置分析

随着社会的发展,电网的覆盖面越来越大,其面临的运行环境也越来越复杂,尤其是高寒山区受到海拔因素的影响,温度较低,极易出现覆冰灾害,出现大规模停电现象。文章首先分析了高寒山区电网配电线路的特点,阐述了丽水配电网由于受到高寒山区的影响,在电压质量方面存在严重不足,并基于我国电网配电线路现有的融冰方法、装置的基础上,提出了一种基于无功流动的新型非失电配电网融冰方法,实践证明了此种融冰方法的有效性。

改进等效容量法在含风电配网线损计算中的应用

在研究等效容量法的基础上,结合含风电配网的特点,提出对于潮流多变的含风电的配电网,该方法存在一定的局限性。提出了结合风电出力的波动性,合理划分计算时段和灵活选择馈线首端的改进等效容量法,采用该方法计算含风电的配网线损,能够适应含风电的配电网潮流多变的特点,减少由于配电网首端功率流动方向变化频繁及首端功率流动较小时引起的线损计算误差。最后以某实际电网为算例,验证了利用改进等效容量法计算含风电配网线损的有效性和可行性。

New Principle for Grounding Fault Feeder Detection in MV Distributions with Neutral Ineffectively Earthed

A new principle for grounding fault feeder detection based on negative sequence current variation and energy dissipated in the fault point is presented. It has high precision in both isolated systems and resonance earthed systems, even in full compensated systems. And it can be installed at the local control unit of feeder in distribution automation systems, such as field terminal unit (FTU). This principle is verified by EMTP simulator and experimentation.

Analyses of Current Electricity Price and Its Changing Trend Forecast in the Coming Five Years

This paper analyzes the level, characteristics and existing problems of current electricityprice in China. Under the present circumstances the overall orientation of power price reform inthe 10th Five-year Plan period should satisfy the requirements of power industry restructuring.Therefore, it is necessary to set up an appropriate pricing mechanism and system including thelinks of sales price to network, transmission and distribution price (T&D price) and sales price.In the light of various factors influencing increase and decrease in price, a forecast of electricitytariff is given in the five years to come.[

Multi-objective planning model for simultaneous reconfiguration of power distribution network and allocation of renewable energy resources and capacitors with considering uncertainties

This research develops a comprehensive method to solve a combinatorial problem consisting of distribution system reconfiguration, capacitor allocation, and renewable energy resources sizing and siting simultaneously and to improve power system's accountability and system performance parameters. Due to finding solution which is closer to realistic characteristics, load forecasting, market price errors and the uncertainties related to the variable output power of wind based DG units are put in consideration. This work employs NSGA-II accompanied by the fuzzy set theory to solve the aforementioned multi-objective problem. The proposed scheme finally leads to a solution with a minimum voltage deviation, a maximum voltage stability, lower amount of pollutant and lower cost. The cost includes the installation costs of new equipment, reconfiguration costs, power loss cost, reliability cost, cost of energy purchased from power market, upgrade costs of lines and operation and maintenance costs of DGs. Therefore, the proposed methodology improves power quality, reliability and security in lower costs besides its preserve, with the operational indices of power distribution networks in acceptable level. To validate the proposed methodology's usefulness, it was applied on the IEEE 33-bus distribution system then the outcomes were compared with initial configuration.

New reclosing scheme of distribution system for utilization of BESS using wavelet transform

This paper proposed the reclosing method in distribution system with battery energy storage system(BESS)using wavelet transform(WT).The proposed method performs the WT of load current and then calculates the absolute value of slope of detail coefficient.The mother wavelet used is db4of level6.The fault clearing is detected using the rapid increase of this value.After the detection of fault clearing,the reclosing is performed.To verify the proposed method,various simulations according to the fault clearing times,fault resistances,and fault lengths are performed using EMTP.The simulation results show that fault clearing can be detected using proposed absolute value of slope of detail coefficient and hence the reclosing can be performed successfully.

Grey series time-delay predicting model in state estimation for power distribution networks

A new combined model is proposed to obtain predictive data value applied in state estimation for radial power distribution networks. The time delay part of the model is calculated by a recursive least squares algorithm of system identification, which can gradually forget past information. The grey series part of the model uses an equal dimension new information model (EDNIM) and it applies 3 points smoothing method to preprocess the original data and modify remnant difference by GM(1,1). Through the optimization of the coefficient of the model, we are able to minimize the error variance of predictive data. A case study shows that the proposed method achieved high calculation precision and speed and it can be used to obtain the predictive value in real time state estimation of power distribution networks.

Optimized PI controller for 7-level inverter to aid grid interactive RES controller

With the huge rise of energy demand,the power system in the current era is moving to a new standard with increased access to renewable energy sources(RESs)integrated with distribution generation(DG)network.The RESs necessitate interfaces for controlling the power generation.The multilevel inverter(MLI)can be exploited for RESs in two diverse modes,namely,the power generation mode(stand-alone mode),and compensator mode(statcom).Few works have been carried out in optimization of controller gains with the load variations of the single type such as reactive load variation in different cases.Nevertheless,this load type may be unbalanced hence,to overcome such issues.So,a sophisticated optimization algorithm is important.This paper aims to introduce a control design via an optimization assisted PI controller for a 7-level inverter.In the present technique,the gains of the PI controller are adjusted dynamically by the adopted hybrid scheme,grey optimizer with dragon levy update(GD-LU),based on the operating conditions of the system.Here,the gains are adjusted such that the error between the reference signal and fault signal should be minimal.Thus,better dynamic performance could be attained by the present optimized PI controller.The proposed algorithm is the combined version of grey wolf optimization(GWO)and dragonfly algorithm(DA).Finally,the performance of the proposed work is compared and validated over other state-of-the-art models concerning error measures.

One Step on the Smart Grid Path： Load and Generation Coordination in a Virtual Power System

Worldwide the introduction of dispersed generators （DG） in the distribution network is assuming a significant importance. There is an increasing relevance of the energy process efficiency improvement; as for electric power systems, the most interesting perspective concerns the capability of the system to increase the exploitation of the renewable resources. The integration of DGs in the electric distribution network requires a revision of this infrastructure, so far designed and developed assuming that power flows in one direction： from the high voltage transmission network to the medium voltage distribution, to reach final customers on the low voltage network. The attention to an efficient operation of distribution networks is increasing all over the world; this interest is becoming higher and higher also in Italy, where the high energy prices push in the direction of fostering efficiency as much as possible. This work describes a study developed in the AlpEnergy project framework： an International Cooperation Program aimed at introducing an efficient operational model for the distributed production and consumption. In particular it is proposed a new model for the integration and the management of the DG in the distribution network. The new model （defined VPS： Virtual Power System） is based on a communication channel between the active users （generators）, the loads and, eventually, the Distribution System Operators （DSOs）.

Combining Market-Based Control with Distribution Grid Constraints when Coordinating Electric Vehicle Charging

The charging of electric vehicles(EVs) impacts the distribution grid, and its cost depends on the price of electricity when charging. An aggregator that is responsible for a large fleet of EVs can use a market-based control algorithm to coordinate the charging of these vehicles, in order to minimize the costs. In such an optimization, the operational parameters of the distribution grid, to which the EVs are connected, are not considered. This can lead to violations of the technical constraints of the grid(e.g., undervoltage, phase unbalances); for example, because many vehicles start charging simultaneously when the price is low. An optimization that simultaneously takes the economic and technical aspects into account is complex, because it has to combine time-driven control at the market level with eventdriven control at the operational level. Diff erent case studies investigate under which circumstances the market-based control, which coordinates EV charging, conflicts with the operational constraints of the distribution grid. Especially in weak grids, phase unbalance and voltage issues arise with a high share of EVs. A low-level voltage droop controller at the charging point of the EV can be used to avoid many grid constraint violations, by reducing the charge power if the local voltage is too low. While this action implies a deviation from the cost-optimal operating point, it is shown that this has a very limited impact on the business case of an aggregator, and is able to comply with the technical distribution grid constraints, even in weak distribution grids with many EVs.

Improved Voltage Control Strategy for Photovoltaic Grid-Connected System Based on DoubleLayer Coordination Control

An improved automatic voltage coordination control strategy （AVCCS） based on ;automatic voltage control （AVC） and battery energy storage control （BESC） is proposed for photovoltaic grid-connected system （PVGS） to mitigate the voltage fluctuations caused by environmental disturbances. Only AVC is used when small environ- mental disturbances happen, while BESC is incorporated with AVC to restrain the voltage fluctuations when large disturbances happen. An adjustable parameter determining the allowed amplitudes of voltage fluctuations is introduced to realize the above switching process. A benchmark low voltage distribution system including ]？VGS is established by using the commercial software Dig SILENT. Simulation results show that the voltage under AVCCS satisfies the IEEE Standard 1547, and the installed battery capacity is also reduced. Meanwhile, the battery＇s service life is ex- tended by avoiding frequent charges/discharges in the control process.

A New Round of Reform in Electricity Pricing System in China

The State Council issued the Scheme for Reforming Electricity Pricing System m the second half of year 2003. It touches upon separating price of plant from that of network, sales price to network, transmission and distribution price, sales price and system principles in regard to electricity tariff mainly.