The Experts below are selected from a list of 11208 Experts worldwide ranked by ideXlab platform
U Borup - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the voltage support strategies for the low voltage grid connected pv generators
Energy Conversion Congress and Exposition, 2010Co-Authors: Erhan Demirok, Dezso Sera, Remus Teodorescu, Pedro Rodriguez, U BorupAbstract:Admissible range of grid voltage is one of the strictest constraints for the penetration of distributed photovoltaic (PV) generators especially connection to low voltage (LV) public networks. Voltage limits are usually fulfilled either by network reinforcements or limiting of power injections from PVs. In order to increase PV penetration level further, new voltage support control functions for individual inverters are required. This paper investigates distributed reactive power regulation and active power Curtailment strategies regarding the development of PV connection capacity by evaluation of reactive power efforts and requirement of minimum active power Curtailment. Furthermore, a small scale experimental setup is built to reflect real grid interaction in the laboratory by achieving critical types of grid (weak and sufficiently stiff).
Paul Denholm - One of the best experts on this subject based on the ideXlab platform.
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timescales of energy storage needed for reducing renewable energy Curtailment
Renewable Energy, 2019Co-Authors: Paul Denholm, Trieu MaiAbstract:Abstract Integrating large amounts of variable generation (VG) resources such as wind and solar into a region's power grid without causing significant VG Curtailment will likely require increased system flexibility via changing grid operation and deploying enabling technologies such as energy storage. This article analyzes the storage duration required to reduce VG Curtailment under high-VG scenarios. The three analysis scenarios assume VG provides 55% of the electricity demand in the largely isolated Electricity Reliability Council of Texas grid system in 2050, with three different proportions of wind and solar generation. Across the three scenarios, 11%–16% of VG energy is curtailed without storage due to system-generation constraints. When 8.5 GW of storage capacity with 4 h of duration are added, Curtailment is reduced to 8%–10% of VG. Additional storage duration further reduces Curtailment, but with rapidly diminishing returns. At least half the potential avoided-Curtailment benefits are realized with 8 h of storage, and the first 4 h provide the largest benefit. At VG penetrations up to 55%, there appears to be little incremental benefit in deploying very-long-duration or seasonal storage.
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grid flexibility and storage required to achieve very high penetration of variable renewable electricity
Energy Policy, 2011Co-Authors: Paul Denholm, Mauree HandAbstract:We examine the changes to the electric power system required to incorporate high penetration of variable wind and solar electricity generation in a transmission constrained grid. Simulations were performed in the Texas, US (ERCOT) grid where different mixes of wind, solar photovoltaic and concentrating solar power meet up to 80% of the electric demand. The primary constraints on incorporation of these sources at large scale are the limited time coincidence of the resource with normal electricity demand, combined with the limited flexibility of thermal generators to reduce output. An additional constraint in the ERCOT system is the current inability to exchange power with neighboring grids. By themselves, these constraints would result in unusable renewable generation and increased costs. But a highly flexible system - with must-run baseload generators virtually eliminated - allows for penetrations of up to about 50% variable generation with Curtailment rates of less than 10%. For penetration levels up to 80% of the system's electricity demand, keeping Curtailments to less than 10% requires a combination of load shifting and storage equal to about one day of average demand.
Peter Palensky - One of the best experts on this subject based on the ideXlab platform.
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quantification and mitigation of unfairness in active power Curtailment of rooftop photovoltaic systems using sensitivity based coordinated control
Energies, 2016Co-Authors: Aadil Latif, Wolfgang Gawlik, Peter PalenskyAbstract:With increasing photovoltaic (PV) penetration in low voltage networks (LVNs), voltage regulation is a challenge. Active power Curtailment (APC) is one possible solution for mitigating over voltages resulting from active power injection in LVNs. There is an inherent unfairness in the APC scheme. When generation is high and consumption is low, the voltages at the end of the feeder tend to be the highest. This results in high Curtailment of active power output of the inverters located at the end of the feeder and low or even no Curtailment for the inverts located closer to the transformer. A secondary voltage controller has been implemented to mitigate this unfairness in APC based voltage support schemes. The focus of this work is to quantify this unfairness and develop methods that enable residential PV owners serviced by the same feeder to participate equally in voltage regulation in the LVN.
Haitao Liu - One of the best experts on this subject based on the ideXlab platform.
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dynamic reactive power optimal allocation to decrease wind power Curtailment in a large scale wind power integration area
Iet Renewable Power Generation, 2017Co-Authors: Tao Niu, Qinglai Guo, Hongyang Jin, Hongbin Sun, Boming Zhang, Haitao LiuAbstract:Autonomous voltage security regions (AVSRs) have been proposed to prevent cascading trip faults in wind farms. However, due to insufficient dynamic reactive power (DRP) support and unreasonable DRP allocation in large-scale, centralised wind power integration areas, especially for high wind power penetrations, AVSRs may be too small to guarantee secure wind farm operation, resulting in large amounts of wind power Curtailment. DRP allocation is crucial for wind farms to accommodate more wind power and decrease Curtailment. Therefore, a DRP allocation scheme based on the AVSR to accommodate more wind power is proposed in this work. An improved AVSR considering wind power Curtailment is first derived; the function between the AVSR, DRP reserves and Curtailment is then obtained, and an optimal DRP allocation scheme using Benders decomposition is finally proposed. Good performance is observed when tested on a real large-scale wind power base in Northern China.
Yuguang Niu - One of the best experts on this subject based on the ideXlab platform.
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solar energy Curtailment in china status quo reasons and solutions
Renewable & Sustainable Energy Reviews, 2018Co-Authors: Ningning Tang, Yuning Zhang, Yuguang NiuAbstract:Abstract Recently, parts of the solar energy (especially photovoltaic power station) could not be connected to power system, leading to a serious solar energy Curtailment problem. Generally speaking, in 2017, 91.4% of the rejected solar energy occurs in the northwestern China with the total electricity reaching 6670 GW h. Because China is of a large amount of the installed solar capacity, the existing large-scale solar energy Curtailment problem have greatly affected the development of the solar power industry (e.g. the investors' profits) and the long-term development of the China's clean energy policy. In this review, based on the statistical data released by the authorities, the current status of the solar energy Curtailment are reviewed with a detailed analysis of the reasons from the aspects of power generation and electric grid. This review focuses on the cases of the two typical provinces (Gansu province and Xinjiang Uygur Autonomous Region) with large-scale solar energy Curtailment together with related analysis. Several practical solutions are also proposed to further relieve the problem in the near future. Detailed comparisons between different schemes are also given in order to help policy makers in China and also other countries for the further development of the solar power generation.
