The aim of this paper is to present the concept of a simple and cheap upgrade for electric water boilers, allowing them to provide power quality services to the distribution grid. The upgrade requires only minimum add...The aim of this paper is to present the concept of a simple and cheap upgrade for electric water boilers, allowing them to provide power quality services to the distribution grid. The upgrade requires only minimum additional hardware and it is easily installable. “Smart Boilers”, as the upgraded boilers are named, perform precise active and reactive power control, but most significantly mitigate line current harmonics. Αctive and reactive power control is implemented by appropriate regulation of the modulation sinewave amplitude and phase, respectively. This type of control is easily customizable in order to accommodate a variety of power quality targets, depending on the required level of services and available grid monitoring equipment. The method used for line current harmonic compensation is based on the injection of mirror harmonics created at the modulation stage of the converter. It is indifferent of harmonic source: it is equally successful at mitigating harmonics caused by the power electronic converter of the Smart Boiler, other sources of current harmonics or loads. The achieved grid services are clearly beyond the “on/off” operation of electric boilers, currently implemented by Demand Side Management (DSM) in order to shift load away from peak hours. It has been demonstrated through simulations, that Smart Boilers can assist voltage regulation at terminal buses, compensate reactive power and suppress harmonic currents at lines.展开更多
This paper focuses on the wind energy conversion system (WECS) with the three main electrical aspects: 1) wind turbine generators (WTGs), 2) power electronics converters (PECs) and 3) grid-connection issues. The curre...This paper focuses on the wind energy conversion system (WECS) with the three main electrical aspects: 1) wind turbine generators (WTGs), 2) power electronics converters (PECs) and 3) grid-connection issues. The current state of wind turbine generators are discussed and compared in some criteria along with the trends in the current WECS market, which are ‘Variable Speed’, ‘Multi-MW’ and ‘Offshore’. In addition, the other crucial component in the WECS, PECs will be discussed with its topologies available in the current WECS market along with their modulation strategies. Moreover, three main issues of the WECS associating with the grid-connection, fault-ride through (FRT) capability, harmonics/interharmonics emission and flicker, which are the power quality issues, will be discussed due to the increasing responsibility of WECS as utility power station. Some key findings from the review such as the attractiveness of BDFRG are presented in the conclusion of this paper.展开更多
文摘The aim of this paper is to present the concept of a simple and cheap upgrade for electric water boilers, allowing them to provide power quality services to the distribution grid. The upgrade requires only minimum additional hardware and it is easily installable. “Smart Boilers”, as the upgraded boilers are named, perform precise active and reactive power control, but most significantly mitigate line current harmonics. Αctive and reactive power control is implemented by appropriate regulation of the modulation sinewave amplitude and phase, respectively. This type of control is easily customizable in order to accommodate a variety of power quality targets, depending on the required level of services and available grid monitoring equipment. The method used for line current harmonic compensation is based on the injection of mirror harmonics created at the modulation stage of the converter. It is indifferent of harmonic source: it is equally successful at mitigating harmonics caused by the power electronic converter of the Smart Boiler, other sources of current harmonics or loads. The achieved grid services are clearly beyond the “on/off” operation of electric boilers, currently implemented by Demand Side Management (DSM) in order to shift load away from peak hours. It has been demonstrated through simulations, that Smart Boilers can assist voltage regulation at terminal buses, compensate reactive power and suppress harmonic currents at lines.
文摘This paper focuses on the wind energy conversion system (WECS) with the three main electrical aspects: 1) wind turbine generators (WTGs), 2) power electronics converters (PECs) and 3) grid-connection issues. The current state of wind turbine generators are discussed and compared in some criteria along with the trends in the current WECS market, which are ‘Variable Speed’, ‘Multi-MW’ and ‘Offshore’. In addition, the other crucial component in the WECS, PECs will be discussed with its topologies available in the current WECS market along with their modulation strategies. Moreover, three main issues of the WECS associating with the grid-connection, fault-ride through (FRT) capability, harmonics/interharmonics emission and flicker, which are the power quality issues, will be discussed due to the increasing responsibility of WECS as utility power station. Some key findings from the review such as the attractiveness of BDFRG are presented in the conclusion of this paper.
