在现代电力系统中,配网低电压问题常由多种因素引起,包括不平衡负荷、过长的供电距离或设备老化等。这些问题不仅影响电能质量,而且会降低用户满意度和电网运行效率。而智能电表的广泛部署为实时监控和管理配网提供了新的可能。文章深...在现代电力系统中,配网低电压问题常由多种因素引起,包括不平衡负荷、过长的供电距离或设备老化等。这些问题不仅影响电能质量,而且会降低用户满意度和电网运行效率。而智能电表的广泛部署为实时监控和管理配网提供了新的可能。文章深入探讨基于智能电表高速电力线载波(High-speed Power Line Carrier,HPLC)模块96点数据的配网低电压治理方法,根据自动识别和分类低电压问题,开发数据驱动的电压调节策略,并结合预测模型和预防措施,提出一套综合治理方案。然后,通过系统测试,验证所提方法的有效性和实用性。展开更多
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）...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.展开更多
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 n...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.展开更多
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 as...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.展开更多
It is to be expected that the number of electric vehicles will be growing in the near future. This trend comes together with the development of smaller decentralized generation units, like PV （photo voltaic）. Togeth...It is to be expected that the number of electric vehicles will be growing in the near future. This trend comes together with the development of smaller decentralized generation units, like PV （photo voltaic）. Together with the change on demand side that comes with the global ＂electrification＂, this can lead to serious grid congestion in low voltage grids and massive grid investments in solving this congestion. Smart charging can partly solve this issue, but with using a connected EV （electric vehicle） as a small distribution unit, combined with bi-directional charging or V2G （vehicle-to-grid） technology, these investments can be reduced to a minimum. In Lombok, Utrecht, the Netherlands, an innovative pilot was initiated with smart solar charging stations, shared electric vehicles and AC （alternating current） V2G technology. This unique combination proves that EVs are an opportunity for the grid rather than a threat. A unique partnership with OEM Renault was established to develop an AC V2G vehicle product line and work on open standardized communication between the EV, the charging station and the grid.展开更多
Since the amount of decentralised power generation is increasing, it is important to develop an energy management system for low-voltage grids. This paper presents a method to operate such a management system. The sys...Since the amount of decentralised power generation is increasing, it is important to develop an energy management system for low-voltage grids. This paper presents a method to operate such a management system. The system is designed for managing a group of smart houses which can consume or supply electrical energy. The aims are to reduce the transmission losses and to stay within the permitted limits of both the voltage drop and the utilisation of lines and transformers. The reduction of the losses is implemented in the LOMA （loss-optimising-management-algorithm）. This algorithm tries to find the power flow situation where minimal losses occur. The results of LOMA, the current power situation （in the low- and medium-voltage system） and the maximum power situation （based on grid parameters） are summarised in an individual incentive signal for every smart home, The simulations show the feasibility of such an energy management and a significant loss reduction.展开更多
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 o...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.展开更多
The results of the implementation of an actual microgrid in the Netherlands are presented. This microgrid has photovoltaic panels as microsources, energy storage, and a flexible AC distribution interfacing system that...The results of the implementation of an actual microgrid in the Netherlands are presented. This microgrid has photovoltaic panels as microsources, energy storage, and a flexible AC distribution interfacing system that can operate connected to the public grid or autonomously where it regulates the site＇s voltage and frequency. In this paper, the potential of the microgrid in improving power quality issues of the site, specifically harmonic distortions, is demonstrated. Results show that flexible AC distribution interfacing system devices were able to compensate voltage harmonics when the microgrid was operating connected to the public grid and when operating autonomously. Other tests such as short-circuit, synchronization and blackstart were also conducted. The improvement in power quality and positive results of the other tests demonstrate that a self-supporting, reliable and efficient operation of the microgrid can be achieved.展开更多
Power-line networks are designed to deliver electricity. They reach most of the domiciles and other buildings nowadays, so most of the people have access to it. On the other hand the backbone for the communications ne...Power-line networks are designed to deliver electricity. They reach most of the domiciles and other buildings nowadays, so most of the people have access to it. On the other hand the backbone for the communications networks is not available in all countries especially the developing ones. A high cost and changing the design for the networks may be needed to construct this backbone. If data can be transmitted over the power-line networks, a recognized cost and time save can be achieved. In Egypt, the infrastructure is not always available for constructing a communications network backbone due to the already designed buildings before the need for these backbones. In this paper, we overcome this problem by designing a reliable Power-line Modem that operates safely on the low voltage grid. The modem is based on the Direct Sequence Spread Spectrum technique. It uses the mains zero crossing as an efficient way for the synchronization between the transmitter and the receiver. The Modem takes into account the problems of the Power-line including noise, attenuation and impedance dismatching.展开更多
There is a danger of power generation efficiency decreasing due to voltage increase when clustered residential PV systems are grid-interconnected to a single distribution line. As a countermeasure, installation of the...There is a danger of power generation efficiency decreasing due to voltage increase when clustered residential PV systems are grid-interconnected to a single distribution line. As a countermeasure, installation of the reactive power control of an inverter at each residence has been considered. However, there are not many types of inverters that can operate reactive power control because there are insufficient effects on a low voltage distribution line with low penetration PV with reactive power control. Therefore, it is necessary to consider how to increase generation efficiency with a lower number of inverters. In this paper, four Japanese standard distribution line structures, for example of a residential area on ＂C1＂, where 2,160 residential PV systems are grid-interconnected, are selected. The optimal setting of reactive power control at each residence is computed on the distribution lines with a greedy method.展开更多
This paper presents the basic principle of OFDM technology and some key technologies, and do the simulation of OFDM technology. Secondly, on the basis of the design of intelligent Home Furnishing system demand, this p...This paper presents the basic principle of OFDM technology and some key technologies, and do the simulation of OFDM technology. Secondly, on the basis of the design of intelligent Home Furnishing system demand, this paper research and design low voltage power line carrier communication based on Intelligent Home Furnishing system for. The circuit takes ARM Cortex-M3 based on the ARM kernel as the central controller, and realize remote monitoring and control of equipment through the transplantation of uC/OS-II system and the design of Web Serve program. Using OFDM power line carrier communication modes as networking mode of the intelligent Home Furnishing system. Finally, the paper realize the intelligent node and relevant software that constitute a complete system of intelligent Home Furnishing.展开更多
文摘在现代电力系统中,配网低电压问题常由多种因素引起,包括不平衡负荷、过长的供电距离或设备老化等。这些问题不仅影响电能质量,而且会降低用户满意度和电网运行效率。而智能电表的广泛部署为实时监控和管理配网提供了新的可能。文章深入探讨基于智能电表高速电力线载波(High-speed Power Line Carrier,HPLC)模块96点数据的配网低电压治理方法,根据自动识别和分类低电压问题,开发数据驱动的电压调节策略,并结合预测模型和预防措施,提出一套综合治理方案。然后,通过系统测试,验证所提方法的有效性和实用性。
基金Supported by National Basic Research Program of China ("973" Program,No. 2009CB219701 and No. 2010CB234608)Tianjin Municipal Science and Technology Development Program (No. 09JCZDJC25000)Specialized Research Fund for Doctor Discipline of Ministry of Education of China (No. 20090032110064)
文摘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.
文摘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.
文摘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.
文摘It is to be expected that the number of electric vehicles will be growing in the near future. This trend comes together with the development of smaller decentralized generation units, like PV （photo voltaic）. Together with the change on demand side that comes with the global ＂electrification＂, this can lead to serious grid congestion in low voltage grids and massive grid investments in solving this congestion. Smart charging can partly solve this issue, but with using a connected EV （electric vehicle） as a small distribution unit, combined with bi-directional charging or V2G （vehicle-to-grid） technology, these investments can be reduced to a minimum. In Lombok, Utrecht, the Netherlands, an innovative pilot was initiated with smart solar charging stations, shared electric vehicles and AC （alternating current） V2G technology. This unique combination proves that EVs are an opportunity for the grid rather than a threat. A unique partnership with OEM Renault was established to develop an AC V2G vehicle product line and work on open standardized communication between the EV, the charging station and the grid.
文摘Since the amount of decentralised power generation is increasing, it is important to develop an energy management system for low-voltage grids. This paper presents a method to operate such a management system. The system is designed for managing a group of smart houses which can consume or supply electrical energy. The aims are to reduce the transmission losses and to stay within the permitted limits of both the voltage drop and the utilisation of lines and transformers. The reduction of the losses is implemented in the LOMA （loss-optimising-management-algorithm）. This algorithm tries to find the power flow situation where minimal losses occur. The results of LOMA, the current power situation （in the low- and medium-voltage system） and the maximum power situation （based on grid parameters） are summarised in an individual incentive signal for every smart home, The simulations show the feasibility of such an energy management and a significant loss reduction.
文摘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.
文摘The results of the implementation of an actual microgrid in the Netherlands are presented. This microgrid has photovoltaic panels as microsources, energy storage, and a flexible AC distribution interfacing system that can operate connected to the public grid or autonomously where it regulates the site＇s voltage and frequency. In this paper, the potential of the microgrid in improving power quality issues of the site, specifically harmonic distortions, is demonstrated. Results show that flexible AC distribution interfacing system devices were able to compensate voltage harmonics when the microgrid was operating connected to the public grid and when operating autonomously. Other tests such as short-circuit, synchronization and blackstart were also conducted. The improvement in power quality and positive results of the other tests demonstrate that a self-supporting, reliable and efficient operation of the microgrid can be achieved.
文摘Power-line networks are designed to deliver electricity. They reach most of the domiciles and other buildings nowadays, so most of the people have access to it. On the other hand the backbone for the communications networks is not available in all countries especially the developing ones. A high cost and changing the design for the networks may be needed to construct this backbone. If data can be transmitted over the power-line networks, a recognized cost and time save can be achieved. In Egypt, the infrastructure is not always available for constructing a communications network backbone due to the already designed buildings before the need for these backbones. In this paper, we overcome this problem by designing a reliable Power-line Modem that operates safely on the low voltage grid. The modem is based on the Direct Sequence Spread Spectrum technique. It uses the mains zero crossing as an efficient way for the synchronization between the transmitter and the receiver. The Modem takes into account the problems of the Power-line including noise, attenuation and impedance dismatching.
文摘There is a danger of power generation efficiency decreasing due to voltage increase when clustered residential PV systems are grid-interconnected to a single distribution line. As a countermeasure, installation of the reactive power control of an inverter at each residence has been considered. However, there are not many types of inverters that can operate reactive power control because there are insufficient effects on a low voltage distribution line with low penetration PV with reactive power control. Therefore, it is necessary to consider how to increase generation efficiency with a lower number of inverters. In this paper, four Japanese standard distribution line structures, for example of a residential area on ＂C1＂, where 2,160 residential PV systems are grid-interconnected, are selected. The optimal setting of reactive power control at each residence is computed on the distribution lines with a greedy method.
文摘This paper presents the basic principle of OFDM technology and some key technologies, and do the simulation of OFDM technology. Secondly, on the basis of the design of intelligent Home Furnishing system demand, this paper research and design low voltage power line carrier communication based on Intelligent Home Furnishing system for. The circuit takes ARM Cortex-M3 based on the ARM kernel as the central controller, and realize remote monitoring and control of equipment through the transplantation of uC/OS-II system and the design of Web Serve program. Using OFDM power line carrier communication modes as networking mode of the intelligent Home Furnishing system. Finally, the paper realize the intelligent node and relevant software that constitute a complete system of intelligent Home Furnishing.
