The urban power grid(UPG)combines transmission and distribution networks.Past studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with s...The urban power grid(UPG)combines transmission and distribution networks.Past studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with safety margins and load balancing.This situation is expected to worsen with the proliferation of renewable energy and electric vehicles.In this paper,a two-layer congestion mitigation framework is proposed,one which considers the congestion of the UPG with flexible topologies.In the upper-layer,the particle swarm optimization algorithm is employed to optimize the power supply distribution(PSD)of substation transformers.This is known as the upper-layer PSD.The lower-layer model recalculates the new PSD,known as the lower-layer PSD,based on the topology candidates.A candidate topology is at an optimum when the Euclidean distance mismatch between the upper-and lower-layer PSDs is the smallest.This optimum topology is tested by standard power flow to ascertain its feasibility.The optimum transitioning sequence between the initial and optimum topologies is also determined by the two-layer framework to minimize voltage deviation and line overloading of the UPG considering dynamic thermal rating.The proposed framework is tested on a 56-node test system.Results show that the proposed framework can significantly reduce congestion,maintain safety margins,and determine the optimum transitioning sequence.展开更多
In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented...In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.展开更多
首先详述了基于不同控制策略(电压同相位补偿UPQC-P以及最小输出视在功率UPQC-VA下,统一电能质量控制器UPQC(unified power quality conditioner)的输出视在功率及其容量设计;然后提出一种新型UPQC设计方法和相应的控制算法以优化UPQC...首先详述了基于不同控制策略(电压同相位补偿UPQC-P以及最小输出视在功率UPQC-VA下,统一电能质量控制器UPQC(unified power quality conditioner)的输出视在功率及其容量设计;然后提出一种新型UPQC设计方法和相应的控制算法以优化UPQC设计容量,提高UPQC容量利用率;最后,详述了该算法原理,通过基于所提算法以及UPQC-P、UPQC-VA算法的UPQC容量设计、UPQC利用率大小的对比分析,有效证明了该控制算法的优越性。展开更多
This paper introduces how Longyuan Power Group Company successfully carried out foreign debt financing for Jiangsu's power projects through its overseas financing window-Xiongya (Virgin) Co. Ltd. The entire proces...This paper introduces how Longyuan Power Group Company successfully carried out foreign debt financing for Jiangsu's power projects through its overseas financing window-Xiongya (Virgin) Co. Ltd. The entire process of raising funds is revealed with regard to employment of foreign debt financing, selection of funded projects, preparation of project and financing documents, credit rating, roadshow, line of credit, and financing experiences.展开更多
Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions a...Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.展开更多
基金supported by the Universiti Sains Malaysia,Research University Team(RUTeam)Grant Scheme(No.1001/PELECT/8580011).
文摘The urban power grid(UPG)combines transmission and distribution networks.Past studies on UPG congestion mitigation have primarily focused on relieving local congestion while ignoring large-scale energy transfer with safety margins and load balancing.This situation is expected to worsen with the proliferation of renewable energy and electric vehicles.In this paper,a two-layer congestion mitigation framework is proposed,one which considers the congestion of the UPG with flexible topologies.In the upper-layer,the particle swarm optimization algorithm is employed to optimize the power supply distribution(PSD)of substation transformers.This is known as the upper-layer PSD.The lower-layer model recalculates the new PSD,known as the lower-layer PSD,based on the topology candidates.A candidate topology is at an optimum when the Euclidean distance mismatch between the upper-and lower-layer PSDs is the smallest.This optimum topology is tested by standard power flow to ascertain its feasibility.The optimum transitioning sequence between the initial and optimum topologies is also determined by the two-layer framework to minimize voltage deviation and line overloading of the UPG considering dynamic thermal rating.The proposed framework is tested on a 56-node test system.Results show that the proposed framework can significantly reduce congestion,maintain safety margins,and determine the optimum transitioning sequence.
文摘In order to improve the Power Quality(PQ)of traction power supply system and reduce the power rating and operation cost of compensator,a Static VAR Compensator(SVC)integrated Railway Power Conditioner(RPC)is presented in this paper.RPC is a widely used device in the AC electrified railway systems to enhance the PQ indices of the main network.The next generation of this equipment is Active Power Quality Compensator(APQC).The major concern of these compensators is their high kVA rating.In this paper,a hybrid technique is proposed to solve aforementioned problems.A combination of SVC as an auxiliary device is employed together with the main compensators,i.e.,RPC and APQC that leads on to the reduction of power rating of the main compensators.The use of proposed scheme will cause to reduce significantly the initial investment cost of compensation system.The main compensators are only utilized to balance active powers of two adjacent feeder sections and suppress harmonic currents.The SVCs are used to compensate reactive power and suppress the third and fifth harmonic currents.In this paper firstly,the PQ compensation procedure in AC electrified railway is analyzed step by step.Then,the control strategies for SVC and the main compensators are presented.Finally,a simulation is fulfilled using Matlab/Simulink software to verify the effectiveness and validity of the proposed scheme and compensation strategy and also demonstrate that this technique could compensate all PQ problems.
文摘首先详述了基于不同控制策略(电压同相位补偿UPQC-P以及最小输出视在功率UPQC-VA下,统一电能质量控制器UPQC(unified power quality conditioner)的输出视在功率及其容量设计;然后提出一种新型UPQC设计方法和相应的控制算法以优化UPQC设计容量,提高UPQC容量利用率;最后,详述了该算法原理,通过基于所提算法以及UPQC-P、UPQC-VA算法的UPQC容量设计、UPQC利用率大小的对比分析,有效证明了该控制算法的优越性。
文摘This paper introduces how Longyuan Power Group Company successfully carried out foreign debt financing for Jiangsu's power projects through its overseas financing window-Xiongya (Virgin) Co. Ltd. The entire process of raising funds is revealed with regard to employment of foreign debt financing, selection of funded projects, preparation of project and financing documents, credit rating, roadshow, line of credit, and financing experiences.
文摘Analyzing the effects of heat rejection from condensers of split-type air-conditioning units at lower-floors of MLABs （multi-level apartment buildings）, using field measurements to monitor environmental conditions and condenser operation, revealed increases in the inlet air temperature at the condensers at the upper floors, which in turn increased the power and energy requirements for these units and decreased their cooling capacities. Results indicated that a decrease of up to 16,000 tons in cooling capacity and an increase of up to 67.2 MW in the national peak load demand might be reached for a 4 ℃ temperature differential for Kuwait conditions. It is recommended that the condensers be placed in the wind pathway to minimize the impact of heat rejection and stack effect and to optimize the operation of split-type air-conditioning units, and that other factors regarding installation setup and location are investigated.
