China's power system is currently undergoing a transformation and upgrade towards new power system that prioritizes renewable energy sources. Strengthening reactive power and voltage control is crucial to ensure t...
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ISBN:
(纸本)9798350373486;9798350373479
China's power system is currently undergoing a transformation and upgrade towards new power system that prioritizes renewable energy sources. Strengthening reactive power and voltage control is crucial to ensure the safe and economical operation of this system. In this paper, we propose a siting and sizing method of shunt reactive power compensation that considers dynamic reactive power optimization strategy, aiming to minimize power transmission loss in each time period from an economic perspective. The dynamic reactive power optimization problem is characterized by its large-scale, multi-period, and strong coupling nature, which makes it a mixed-integer nonlinear programming problem. The main challenges with solving this problem lie in handling the highly nonlinear AC power flow equation constraints and the constraints associated with switching operation times of discrete reactive power compensation devices. To address these challenges, we propose a siting and sizing method of shunt reactive power compensation that considers operational optimization. The AC power flow equation constraints are handled using second-ordercone relaxation, while the switching operation times constraints are equivalently transformed into a linear inequality constraint set. This approach reduces computational complexity while ensuring sufficient accuracy to meet practical engineering needs. The proposed method's effectiveness and economic viability are validated through case studies conducted on the IEEE 30-bus system.
With the explosive growth of smart devices and mobile data traffic, limited fronthaul capacity has become a notable bottleneck of green communication access networks, such as cloud radio access networks(C-RANs). In th...
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ISBN:
(纸本)9781509013289
With the explosive growth of smart devices and mobile data traffic, limited fronthaul capacity has become a notable bottleneck of green communication access networks, such as cloud radio access networks(C-RANs). In this paper, we proposed a joint user association and downlink beamforming scheme for green C-RANs to minimize the network power consumption with the limited fronthaul links. We first formulate the design problem as a mixedinteger nonlinear programming (MINLP), and then transformed the MINLP problem into a mixedintegersecond-ordercone program (MI-SOCP) which is a convex program when the integer variables are fixed. By relaxing the integer variables to continuous ones, an inflation algorithm, which can be finished within polynomial time, was proposed to solve the problem. The simulation results are presented to validate the effectiveness of our proposed algorithm compared with the the scheme adopted by LTE-A.
Reliability improvement is a fundamental aspect of modern power distribution systems and smart grids. The optimal distribution network reconfiguration (DNR) has been proven an effective and economic way to improve sys...
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ISBN:
(纸本)9781728129563
Reliability improvement is a fundamental aspect of modern power distribution systems and smart grids. The optimal distribution network reconfiguration (DNR) has been proven an effective and economic way to improve system's reliability. This paper overcomes the nonlinearity of the DNR problem constraints and thus presents a convex model for optimal DNR with the objective of 1) reliability indices improvement, and 2) power loss minimization. The proposed second-orderconeprogramming based method is tested on a 69-bus distribution system examining different scenarios for the weighting coefficients of the objective function's terms. The obtained results demonstrate the effectiveness and usefulness of the proposed optimization model.
With the extensive access of distributed energy resources (DER) and the development of load control technology, the distribution network is gradually becoming more and more initiative, and the economy of power grid ca...
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ISBN:
(纸本)9781538685495
With the extensive access of distributed energy resources (DER) and the development of load control technology, the distribution network is gradually becoming more and more initiative, and the economy of power grid can be effectively improved through reasonable scheduling. For this purpose, a two-stage stochastic optimization approach for distribution network with load control is established. The scenario analysis is used to characterize the uncertainty of DER. The first stage of optimization generates a day-ahead power purchase curve and load adjustment curves and calculates the corresponding costs;In the second stage, the mathematic expectation of the difference between the actual purchased electricity in each scenario and the day-ahead purchased electricity is calculated to obtain the reserve costs. The mathematical nature of the model is a large-scale nonlinear mixedintegerprogramming problem, which is difficult to solve. By using the second-ordercone (SOC) relaxation technique, the above model can be transformed into a mixed integer second-order cone programming (MISOCP) form, which can be solved effectively. Finally, the simulation analysis of the custom IEEE 14-bus system is carried out to verify the effectiveness of the proposed model.
Energy storage system (ESS) has been advocated as one of the key elements for the future energy system by the fast power regulation and energy transfer capabilities. In particular, for distribution networks with high ...
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Energy storage system (ESS) has been advocated as one of the key elements for the future energy system by the fast power regulation and energy transfer capabilities. In particular, for distribution networks with high penetration of renewables, ESS plays an important role in bridging the gap between the supply and demand, maximizing the benefits of renewables and providing various types of ancillary services to cope the intermittences and fluctuations, consequently improving the resilience, reliability and flexibility. To solve the voltage fluctuations caused by the high permeability of renewables in distribution networks, an optimal capacity allocation strategy of ESS is proposed in this paper. Taking the life cycle cost, arbitrage income and the benefit of reducing network losses into consideration, a bilevel optimization model of ESS capacity allocation is established, the coordination between active/reactive power of associate power conversion system is considered, and the large scale nonlinear programming problem is solved using genetic algorithm, simulated annealing and mixed integer second-order cone programming method. The feasibility and effectiveness of the proposed algorithm have been verified.
With the explosive growth of smart devices and mobile data traffic, limited fronthaul capacity has become a notable bottleneck of green communication access networks, such as cloud radio access networks (C-RANs). In t...
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ISBN:
(纸本)9781509013296
With the explosive growth of smart devices and mobile data traffic, limited fronthaul capacity has become a notable bottleneck of green communication access networks, such as cloud radio access networks (C-RANs). In this paper, we proposed a joint user association and downlink beamforming scheme for green C-RANs to minimize the network power consumption with the limited fronthaul links. We first formulate the design problem as a mixedinteger nonlinear programming (MINLP), and then transformed the MINLP problem into a mixedintegersecond-ordercone program (MI-SOCP) which is a convex program when the integer variables are fixed. By relaxing the integer variables to continuous ones, an inflation algorithm, which can be finished within polynomial time, was proposed to solve the problem. The simulation results are presented to validate the effectiveness of our proposed algorithm compared with the scheme adopted by LTE-A.
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