The cumulative installed capacity of wind power worldwide has grown rapidly in recent years. Fixed reactive powercontrol is adopted by wind turbines (WTs) to receive cycle instruction of wind farm (WF) automatic volt...
ISBN:
(数字)9781839531248
ISBN:
(纸本)9781839531255
The cumulative installed capacity of wind power worldwide has grown rapidly in recent years. Fixed reactive powercontrol is adopted by wind turbines (WTs) to receive cycle instruction of wind farm (WF) automatic voltage controlsystem (AVCS). It does not have active voltage regulation (AVR) capability, which reduces the reliability of powersystem operation. Firstly, two ways of WTs AVR which QV droop control and Vac control mode are introduced in this paper. On the basis, the problems of reactive power circulation and control points inconsistency during multi-WTs voltage regulation are discussed. The problems are solved by coordination of WTs of WF AVR strategy. WF voltage transient support capability is promoted by the strategy. Effectiveness is verified by simulation case of the proposed method.
Nowadays, the network mode of the most energy recovery power battery testing instruments adopts AC-microgrid, which has the drawbacks of low energy recovery efficiency, complicated power circuit topology, cumbersome o...
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Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The he...
Polyethylene (PE) is a major kind of internal insulating material. With great progresses of space charge measurement technologies in the last three decades, lots of researches are focused on space charge in PE. The heat pressing and annealing condition of polyethylene affect its morphology obviously. During the heat pressing, the surface of PE forms different surface topographies because of different substrate materials. Surface topography has great relation to the epitaxial crystallization layer and influences the space charge characteristic of PE dramatically. This paper studied the formation process of different surface topographies and their micrographic characters in low density polyethylene (LDPE). pulsed electro-acoustic (PEA) method was used to measure the space charge distribution of samples with different surface topographies and morphologies in LDPE. The effect of surface topography and morphology to space charge packet were studied. The surface topography has great influence on space charge packet polarity and morphology has influence on both movement speed rate and polarity of space charge packet.
In this paper, the characteristics of electrical tree ageing in silicone rubber (SIR) under AC voltage were studied. The electrical tree initiation rate is 20% after the application of 6 kV AC voltage for 1000 hours. ...
In this paper, the characteristics of electrical tree ageing in silicone rubber (SIR) under AC voltage were studied. The electrical tree initiation rate is 20% after the application of 6 kV AC voltage for 1000 hours. Samples are separated into three kinds according to processes of electrical tree formation: virgin samples without voltage application, non-treed samples without electrical tree formation after 1000 hours and treed samples with electrical tree formation after 1000 hours. Certain physicochemical diagnostic tests were carried out to understand the degradation of material, ascribed to long-time voltage application, using differential scanning calorimetry (DSC) and thermogravimetric-differential thermal analysis (TG-DTA). Physicochemical analyses, especially the DSC results, show that no additional phases are formed in the processes of electrical tree ageing in SIR. Reduction of the melting point and crystallinity of SIR is observed in the sequence of virgin samples, non-treed samples and treed samples. The activation energy values were calculated from the TG-DTA data. Compared to virgin samples, obvious reduction of activation energy value is observed in non-treed samples. Degradation in SIR has already occurred before electrical tree formation and charge injection and extraction by high field electrode under AC voltage is regarded as the reason.
As a new type of mechanical energy storage, compressed air energy storage (CAES) has attracted wide attention in recent years. This paper studies the optimal sizing problem of CAES in power distribution network (PDN)....
As a new type of mechanical energy storage, compressed air energy storage (CAES) has attracted wide attention in recent years. This paper studies the optimal sizing problem of CAES in power distribution network (PDN). CAES plays a role in shaving the peak and filling the valley at demand side and thus reduces the operation cost of PDN to purchase electricity from the main grid. A multi-parametric linear programming (MP-LP) model is formulated where the power and energy capacities of CAES are regarded as parameters; the parameterized optimal value function (OVF) provides a graphical tool to describe the impact on operation cost of CAES configuration, which helps determine the planning strategy in a visual manner. The visualized results reveal not only the optimal solution, but also some useful information, like the sensitivity of operation cost to parameters. Case studies conducted on the IEEE 33-bus distribution system verifies the effectiveness of the proposed method.
With the construction of Global Energy Internet, Intelligent distribution network has more and more characteristics of multi scene, multi service and changeable measurement and control objects. In order to realize dat...
With the construction of Global Energy Internet, Intelligent distribution network has more and more characteristics of multi scene, multi service and changeable measurement and control objects. In order to realize data collection and information exchange among the intelligent terminal and energy, power grid, load, energy storage and other control resources in distribution network, we should research an architecture which can adapt to various data sources Based on dynamic self describing protocol.
Introduce the IoT platform technology based on SDN (Software Defined Network), cloud-based, flexible management and configuration of smart terminals, and support access to millions of terminal devices and smart operat...
Introduce the IoT platform technology based on SDN (Software Defined Network), cloud-based, flexible management and configuration of smart terminals, and support access to millions of terminal devices and smart operation and maintenance management. The traditional monitoring system is integrated with the Internet of Things platform, and on the basis of realizing the general SCADA system monitoring function, through the side-cloud collab.ration, the lean management of the distribution station area is realized.
Advanced adiabatic compressed air energy storage (AA-CAES) could play an important role in power distribution system for mitigating the intermittency of distributed renewable generations and reducing the peak-valley d...
Advanced adiabatic compressed air energy storage (AA-CAES) could play an important role in power distribution system for mitigating the intermittency of distributed renewable generations and reducing the peak-valley difference of load demand, which requires to operate AA-CAES under off-design conditions. A powersystem dispatch oriented AA-CAES model was proposed based on the technically thermodynamic performance curves of compressor and expansion calibrated from experiments, highlighting the impact of AA-CAES part-lard features on charging/discharging efficiency and capacity. The proposed model is integrated with economic dispatch problem of power distribution systems, giving rise to a nonlinear program due to the state-dependent charging and discharging performances. The dispatch model is further linearized via piecewise linear approximation and special-ordered set of type 2, and its equivalent mixed integer linear formulation is presented. A modified IEEE 33-bus system is adopted to verify the effectiveness of proposed model for renewables accommodation.
With the development of science and technology, the hardware and software design of transformer intelligent measurement and control terminal is very important. Based on the hardware and software appization of internet...
With the development of science and technology, the hardware and software design of transformer intelligent measurement and control terminal is very important. Based on the hardware and software appization of internet of things, the design scheme of hardware and software structure is given. Supported by high-performance operating system, the terminal device can be upgraded flexibly through APP application software. The intelligent terminal pair can realize full data collection, full control and full fusion, and real-time exchange of key operation data with the power distribution master station. The intelligent terminal can support 5G communication and realize full compatibility of communication conditions downward.
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