基于智能开关的配网电能质量监测及其分布式治理技术研究

以太阳能发电和风力发电为代表的新能源在解决能源短缺、环境污染和可持续发展等问题中扮演着重要的角色,新能源的应用和发展也越来越快,配电网中的新能源并网发电情况也越来越普遍,但分布式光伏和分布式风电的输出功率具有间歇性和不确定性,分布式电源并网发电会引起配电网电压偏差变化和电压波形畸变率变大等电能质量问题,而电能质量问题与人们的生活息息相关,人们对电能质量问题日益关注和重视。因此,为有效提高配电网的电能质量及运行的安全稳定性,并更好地发挥新能源并网发电的优势,需深入研究新能源并网发电对电能质量的影响规律。对分布式治理技术在配电网电能质量情况进行了仿真分析,但也未对配电网其余节点的电能质量进行相应的分析。研究了单个新能源并网后配电网各节点的电能质量情况。以上文献在分析新能源并网发电造成的电能质量的影响时,未对各节点的电能质量进行有效分析,也未对存在多个新能源并网时的电能质量做系统的深入研究。对新能源在不同并网位置、不同并网容量及多个新能源不同并网方式下的各节点电能质量进行了仿真计算,获得了新能源并网发电对配电网电能质量的影响规律。基于此,本篇文章对基于智能开关的配网电能质量监测及其分布式治理技术进行研究,以供参考。

配网电能质量的测试过程探究

配电网由于供电线路长,且供电网络中即存在三相生产用电,也有单相生活负载,导致供电的质量非常差,从而产生不利的后果。因此配网电能质量的测试就显得非常重要。笔者根据相关工作经验,主要探析配网电能质量的测试过程,供大家参考和借鉴。

Smart Grids with Intelligent Periphery:An Architecture for the Energy Internet

A future smart grid must fulfill the vision of the Energy Internet in which millions of people produce their own energy from renewables in their homes, offices, and factories and share it with each other. Electric vehicles and local energy storage will be widely deployed. Internet technology will be utilized to transform the power grid into an energysharing inter-grid. To prepare for the future, a smart grid with intelligent periphery, or smart GRIP, is proposed. The building blocks of GRIP architecture are called clusters and include an energy-management system （EMS）-controlled transmission grid in the core and distribution grids, micro-grids, and smart buildings and homes on the periphery; all of which are hierarchically structured. The layered architecture of GRIP allows a seamless transition from the present to the future and plug-and-play interoperability. The basic functions of a cluster consist of （1） dispatch, （2） smoothing, and （3） mitigation. A risk-limiting dispatch methodology is presented; a new device, called the electric spring, is developed for smoothing out fluctuations in periphery clusters; and means to mitigate failures are discussed.

Grid tie inverter energy stabilizing in smart distribution grid with energy storage

With the growing deployment of smart distribution grid,it has become urgent to investigate the smart distribution grid behavior during transient faults and improve the system stability.The feasibility of segmenting large power grids and multiple smart distribution grids interconnections using energy storage technology for improving the system dynamic stability was studied.The segmentation validity of the large power grids and smart distribution grid inverter output interconnections power system using energy storage technology was proved in terms of theoretical analysis.Then,the influences of the energy storage device location and capacity on the proposed method were discussed in detail.The conclusion is obtained that the ESD optimal locations are allocated at the tie line terminal buses in the interconnected grid,respectively.The effectiveness of the proposed method was verified by simulations in an actual power system.

Energy Efficient Power Allocation for Relay-Aided D2D Communications in 5G Networks

As one of the key technologies for the fifth generation(5G) wireless networks,device-to-device(D2D) communications allow user equipment(UE) in close proximity to communicate with each other directly.Forwarded by a relay,the relay-aided D2D(RA-D2D) communications can not only be applied to communications in much longer distance but also achieve a high quality of service(Qo S) .In this paper,we first propose a two-layer system model allowing RA-D2 D links to underlay traditional cellular uplinks.Then we maximize the energy efficiency of the RA-D2 D link while satisfying the minimum data-rate of the cellular link.The optimal transmit power at both D2 D transmitter and D2 D relay sides is obtained by transforming the nonlinear fractional programming into a nonlinear parameter programming.Simulation results show that our proposed power allocation method is more energy efficient than the existing works,and the proposed RA-D2 D scheme outperformed direct D2 D scheme when the distance between two D2 D users is longer.

A Parallel Approach for Real-Time Power Flow in Distribution Networks

The new reality of smart distribution systems with use of generation sources of small and medium sizes brings new challenges for the operation of these systems. The complexity and the large number of nodes requires use of methods which can reduce the processing time of algorithms such as power flow, allowing its use in real time. This paper presents a known methodology for calculating the power flow in three phases using backward/forward sweep method, and also considering other network elements such as voltage regulators, shunt capacitors and sources of dispersed generation of types PV （active power and voltage） and PQ （active and reactive power）. After that, new elements are introduced that allow the parallelization of this algorithm and an adequate distribution of work between the available processors. The algorithm was implemented using a multi-tiered architecture; the processing times were measured in many network configurations and compared with the same algorithm in the serial version.

Strategies Regarding Operating Voltage Levels in Distribution Networks

The power/energy losses reduction in distribution systems is an important issue during planning and operation, with important technical and economical implications. Thus, the energy losses minimization implies not only the technical improvement of the network, through its renewal with the introduction of the technological innovations in the equipment and circuit components as well as the optimal planning of the design and development of the network, but also requires the use of the methods and software tools to facilitate the operation process. The paper presents a strategy for power / energy saving which is replacement of the 6 kV voltage level with 20 kV voltage level. In this line, different urban distribution networks were analyzed using fuzzy techniques for load modeling.

Assessing Micro-generation＇s and Non-linear Loads＇ Impact in the Power Quality of Low Voltage Distribution Networks

Distribution networks face an increasing penetration of solar PV （photovoltaic） and small WTG （wind turbine generator） as well as other forms of micro-generation. To this scenario, one must add the dissemination of non-linear loads such as EV （electric vehicles）. There is something in common between those loads and sources： the extensive use of power electronic converters with commutated switches. These devices may be a source of medium-to-high frequency harmonic distortion and their impact on the local distribution grid must be carefully assessed in order to evaluate their negative impacts on the network, on the existing conventional loads and also on other active devices. In this paper, methodologies to characterize effects such as： harmonics, network unbalances, damaging power line resonance conditions, and over/under voltages are described and applied to a real local grid configuration.

An Approach for Cost-Efficient Grid Integration of Distributed Renewable Energy Sources

We describe a specific approach to capacity man a ge ment for distribution grids. Based on simulations, it has been found that by curtailing a maximum of 5% of the yearly energy production on a per-generator basis, distribution grid connection capacity can be doubled. We also present the setting and fi rst results of a fi eld test for validating the approach in a rural distribution grid in northern Germany.

Design and Realization of Distribution Network Intelligent Monitoring based on GSM Network

the power network fault detection system can only analyze all kinds of fault signal in stationary sequence： the internal grid and external disturbance presents degeneration, tiny, signal intensity changes randomly fluctuate, that will cause the system to detect the fault isolation ability of confusion and small fault signal is not strong; The article propose a method of power network fault detection for based on GSM, Through the underlying sensing equipment acquisition abnormal information of current, voltage power in the network and GSM networking scheme can filter the interference factors in extraction of fault information from and attribute value. The embedded gateway take STM32 chip as the core to monitoring data processing, to achieve a unified data management and user remote access, realizing method of system software are given, to construct the monitor management information platform. The actual test system show that, identification diagnosis ability of fault signal separation ability and small signal increases 17%, also meet the requirements.

Reliability-aware mapping and links voltage assignment for energy-efficient networks-on-chip

As feature sizes shrink,low energy consumption,high reliability and high performance become key objectives of network-on-chip(NoC) design.In this paper,an integrated approach is presented to map IP cores onto NoC architecture and assign voltage levels for each link,such that the communication energy is minimized under constraints of bandwidth and reliability.The design space is explored using tabu search.In order to select optimal voltage level for the links,an energy-efficiency driven heuristic algorithm is proposed to perform energy/reliability trade-off by exploiting communication slack.Experimental results show that the ordinary energy optimization techniques ignoring the influence of voltage on fault rates could lead to drastically decreased communication reliability of NoCs,and the proposed approach can produce reliable and energy-efficient implementations.

Geospatial Solutions in Practice for Smart Grids

Recently, smart grid solutions have started to extend the visibility of the electrical grid to the entire network; including high voltage transmission lines, medium voltage distribution networks, and the low voltage networks to households. The typical data monitored includes： voltage, current, phase, and power measurements, together with network events and alarms. This paper analyses the key challenges facing smart grid solutions in providing effective access to large volumes of sensory data that is distributed over a large geographic area. A case study is described that outlines how the use of geospatial technology together with Web 2.0 technologies may be applied to improve user access and control to this data. The results show that a geospatial solution provides an effective mechanism for visualizing telemetry data monitored within the smart grid.

Innovative Control Strategy for Islanded Small Hydro Power Plant

In many developing countries, there are regions where the electrical grid is weak or nonexistent. However, in these areas, large amounts of distributed energy sources, such as hydro, are often available and could be suitably exploited. To this aim, the low head hydro power plants can play a significant role. In fact, recent technological advances in mini-hydro turbines and decreasing costs of static electricity conversion devices enable to realize suitable power plants for an efficient and profitable exploitation of these sites. One of the major challenges is the integration of the above-mentioned power plants into autonomous electrical systems, islanded and/or disconnectable from the main distribution network. In this paper, an innovative control strategy for a low head hydro power plant supplying users in small clusters of villages is proposed.

Three Projects of Intelligent Distribution Automation System in East Asia

Intelligent distribution automation system （IDAS） was developed based on distribution automation system that was installed in all distribution offices of Korea. IDAS was designed the combined system with the function of supervisory control and data acquisition （SCADA） and distribution automation system （DAS） for network operation from substation to high voltage customer, and it has been installed in Vietnam, China and Indonesia. This paper explains the project scope, system configuration, and the function of each sy stem.

Additional Overloading Assessment for Future Low Voltage Networks Based on Smart Metering

The purpose of this article is to present an additional overloading assessment scheme to the current protection scheme, which can be applied in the low voltage distribution network to prevent overloading of network assets. As higher penetration of distributed generators is envisioned among distribution networks, the network operators will have an challenging task in the future to maintain the reliability and quality of supply. The distribution networks are going to be challenged simultaneously by increasing penetration of distributed generators and by increasing loading （inter alia heat pumps, air conditioners or electric vehicles）, which will change the operational perspective of the future distribution networks. Presented simulation results show that the increasing penetration of those appliances can jeopardize the functionality of current protection scheme in distribution networks. Therefore, an additional scheme for assessment of network overloading applicable at low voltage distribution networks is proposed and the application of this scheme, supported by smart metering infrastructure, is demonstrated in a case study. The proposed overloading assessment scheme should help the network operators to increase the flexibility of distribution networks, their hosting capacity, safety and reliability.

Economic Dispatch of Smart Distribution Networks for Electricity Cost Reduction

Consumers＇ electricity cost keeps increasing over the time in most countries across the world. The main reason is that importing electricity from generation plants far from a load center is relatively expensive, as costs are paid not only for generation but also for energy loss and network use. To this end, it is more economi- cal to use electricity generated by local distributed generations. In order to reduce customers＇ electricity cost, a new economic dispatch of smart distribution networks is proposed. Economic dispatch of smart distribution network is to meet load demand with the least consumers＇ electricity cost considering distributed generators, while recognizing all operational limits of generation and transmission facilities in a distribution network. Case study shows that consumers＇ electricity cost can be reduced by about 200/o through economic dispatch of distri- bution network. Further, generation cost and emission of distribution network are reduced as well.

A calculation method for a power user's CIC under specific conditions in smart distribution grid

This paper presents a practical method for calculating a power user’s customer interruption costs(CIC)under specific conditions.This novel method has been developed,based on the CIC results predicted by Lawrence Berkeley National Laboratory(LBNL),so that the key factors,such as customer type,customer size,interruption occurrence time and interruption duration can be considered.As compared to the LBNL method,the method proposed here is easy to understand and easy to execute with an acceptable error.It lays a solid foundation for further investigation of distributed generators and demand response in assessing reliability value of smart distribution grid(SDG).The effectiveness of the proposed method is confirmed through the assessment of RBTS-Bus2.