Reliability Evaluation of a Distribution System with wind Turbine Generators Based on the Switch-section Partitioning Method

Wu, Hongbin,Guo, Jinjin,Ding, Ming The Korean Institute of Electrical Engineers 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

Considering the randomness and uncertainty of wind power, a reliability model of WTGs is established based on the combination of the Weibull distribution and the Markov chain. To analyze the failure mode quickly, we use the switch-section partitioning method. After defining the first-level load zone node, we can obtain the supply power sets of the first-level load zone nodes with each WTG. Based on the supply sets, we propose the dynamic division strategy of island operation. By adopting the fault analysis method with the attributes defined in the switch-section, we evaluate the reliability of the distribution network with WTGs using a sequential Monte Carlo simulation method. Finally, using the IEEE RBTS Bus6 test system, we demonstrate the efficacy of the proposed model and method by comparing different schemes to access the WTGs.

Reliability Evaluation of a Distribution System with wind Turbine Generators Based on the Switch-section Partitioning Method

Hongbin Wu,Jinjin Guo,Ming Ding 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

Considering the randomness and uncertainty of wind power, a reliability model of WTGs is established based on the combination of the Weibull distribution and the Markov chain. To analyze the failure mode quickly, we use the switch-section partitioning method. After defining the first-level load zone node, we can obtain the supply power sets of the first-level load zone nodes with each WTG. Based on the supply sets, we propose the dynamic division strategy of island operation. By adopting the fault analysis method with the attributes defined in the switch-section, we evaluate the reliability of the distribution network with WTGs using a sequential Monte Carlo simulation method. Finally, using the IEEE RBTS Bus6 test system, we demonstrate the efficacy of the proposed model and method by comparing different schemes to access the WTGs.

Optimal Configuration of Flexible Interconnection Devices for Transferring Photovoltaic Power in Active Distribution Network

Wu Hongbin,He Ye,Lin Xueshan,Bi Rui,Hua Yuting,Sun Ming,Xu Bin 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.2

With the increasing penetration of distributed photovoltaic in distribution network, it is more difficult to control active distribution network (ADN). A flexible interconnection device (FID) can realize regional interconnection of the ADN through transferring power. However, the influence of installation position and number of FIDs on the ADN varies, it is necessary to analyze its operational planning model. In this study, first, a photovoltaic power and load forecasting model is established, followed by reduction of the typical scenarios. Second, the ADN operational planning model is established according to the line load balance index to analyze the coordination and determine the power transfer value of the FID in different installation positions and numbers for the ADN. Third, the net income index of the distribution network in the entire life cycle is established to analyze the economy of the ADN and determine the optimal FID installation location and quantity. Finally, numerous simulations and comparisons are carried out on the actual example system, and the results show that the FID can effectively transfer the active power, strengthen the ADN power supply level, and solve the problem of power supply imbalance caused by distributed photovoltaic access.

A New Algorithm to Reduce the Mal-Operation of DOCR in Bi-directional Power Distribution Systems

Hongbin Wu,Jinjin Guo,Ming Ding 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.3

Considering the randomness and uncertainty of wind power, a reliability model of WTGs is established based on the combination of the Weibull distribution and the Markov chain. To analyze the failure mode quickly, we use the switch-section partitioning method. After defining the first-level load zone node, we can obtain the supply power sets of the first-level load zone nodes with each WTG. Based on the supply sets, we propose the dynamic division strategy of island operation. By adopting the fault analysis method with the attributes defined in the switch-section, we evaluate the reliability of the distribution network with WTGs using a sequential Monte Carlo simulation method. Finally, using the IEEE RBTS Bus6 test system, we demonstrate th

Optimal Control Of Two-Hop Routing In Dtns With Time-Varying Selfish Behavior

( Yahui Wu ),( Su Deng ),( Hongbin Huang ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.9

The transmission opportunities between nodes in Delay Tolerant Network (DTNs) are uncertain, and routing algorithms in DTNs often need nodes serving as relays for others to carry and forward messages. Due to selfishness, nodes may ask the source to pay a certain reward, and the reward may be varying with time. Moreover, the reward that the source obtains from the destination may also be varying with time. For example, the sooner the destination gets the message, the more rewards the source may obtain. The goal of this paper is to explore efficient ways for the source to maximize its total reward in such complex applications when it uses the probabilistic two-hop routing policy. We first propose a theoretical framework, which can be used to evaluate the total reward that the source can obtain. Then based on the model, we prove that the optimal forwarding policy confirms to the threshold form by the Pontryagin`s Maximum Principle. Simulations based on both synthetic and real motion traces show the accuracy of our theoretical framework. Furthermore, we demonstrate that the performance of the optimal forwarding policy with threshold form is better through extensive numerical results, which conforms to the result obtained by the Maximum Principle.

Energy-efficient Joint Control of Epidemic Routing in Delay Tolerant Networks

( Yahui Wu ),( Su Deng ),( Hongbin Huang ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.2

Due to the uncertain of connections in Delay Tolerant Networks (DTNs), most routing algorithms in DTNs need nodes to forward the message to others based on the opportunistic contact. The contact is related with the beaconing rate. In particular, nodes have more chances to encounter with each other with bigger beaconing rate, but more energy will be used. On the other hand, if the nodes forward the message to every node all the time, the efficiency of the routing algorithm is better, but it needs more energy, too. This paper tries to exploit the optimal beaconing rate and forwarding rate when the total energy is constraint. First, a theoretical framework is proposed, which can be used to evaluate the performance with different forwarding rate and beaconing rate. Then, this paper formulates a joint optimization problem based on the framework. Through Pontryagin`s Maximal Principle, this paper obtains the optimal policy and proves that both the optimal forwarding and beaconing rates conform to threshold form. Simulation results show the accuracy of the theoretical framework. Extensive numerical results show that the optimal policy obtained in this paper is the best.

Dynamic Equivalent Modeling of Motors Based on Improved Hierarchical Clustering Algorithm

Xueshan Lin,Hongbin Wu,Bin Ye,Bin Xu,Weiqing Tao 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3

As the most important part of the power system load, the dynamic characteristics of motors are very important for power system simulation. The calculation is very large if all motors are modeled respectively. In order to reduce the amount of calculations, a dynamic equivalent modeling method of motors based on the improved hierarchical clustering algorithm is proposed in this paper. The two state parameters, the load rate and the product of inertia time constant and rotor resistance, are taken as clustering indexes. The improved hierarchical clustering algorithm is used to cluster dynamically the motors. And with the pseudo t 2 statistics, it can obtain the best clustering results. Then it establishes the dynamic multi-machine equivalent model after each motor group equivalent. With the example system, the simulation results show that the proposed dynamic equivalent method can keep the dynamic characteristics of models and improve the equivalent accuracy.

Finite Element Analysis of the Axial Mechanical Properties of Piezoelectric Actuator with Tubular Interdigitated Electrodes

Liu Yonggang,Wu Zhou,Wang Hongbin,Zhang Ting 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.77 No.10

We theoretically investigate a new type of piezoelectric actuator with tubular interdigitated electrodes. A partial model is adopted due to the axial symmetry of the actuator, which is divided into non-overlapping opposing electrode pairs on the center plane of the branch electrode. We present a finite element model of actuator and analyze its static-dynamic properties by using the commercially available finite element software ABAQUS. The length-to-diameter ratio of the tubular actuator can be as larger as necessary, so we are more concerned with the axial mechanical properties of the actuator. Thus we studied the influence of the electrode's shape and structure size on the clamping stress and free strain of the partial models. We also analyzed an ordinary piezoelectric model of the same size. We demonstrated that the partial model displayed significantly improved axial performance over the ordinary one. The axial stress of the partial model can reach 2.75 times that of the ordinary one, and the axial free strain can reach 1.55 times that of the ordinary one. According to the results of the static analysis, appropriate electrodes and structural parameters were selected to establish a tubular actuator model, with which modal and harmonic response analysis were performed. A modal analysis was used to obtain the frequencies and the shapes of the axial vibration. Each pair of electrodes is shunted to a sinusoidal varying voltage. Using the results of the harmonic response analysis, we obtained the actuator's axial resonance curve.

Performance analysis of information propagation in DTN-like scale-free mobile social network

( Zhifei Wang ),( Su Deng ),( Hongbin Huang ),( Yahui Wu ) 한국인터넷정보학회 2014 KSII Transactions on Internet and Information Syst Vol.8 No.11

Mobile social network can be seen as a specific application of the DTN (Delay Tolerant Network), in which the information propagation can be impacted by many social behaviors of the nodes. For a specific node, its social behaviors are various. For example, the node may not be interested in the information before receiving it and may also discard the information after getting it. On the other hand, people are more willing to forward the message to his friends. These interactive behaviors between nodes can be seen as social behaviors. It is easy to see that the impact of the social behaviors is related to the social ties, which can be manifested by the structure of the social network. State of the art works often simply assumes that the social networks can be divided into some communities. At present, some works find that the structure of some social networks is scale-free. To overcome this problem, this paper proposes a theoretical model to evaluate the impact of above social behaviors in the DTN-like scale-free network. Simulation shows the accuracy of the model. Numerical results show that both social behaviors and scale-free character have significant impact on information propagation. Moreover, the impact of social behaviors is related to the scale-free character of the networks.

Analysis of Emergency Demand Response Levels of Central Air-Conditioning

Xianjun Qi,Zongshuo Ji,Hongbin Wu,Jingjing Zhang,Hejun Yang 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.6

Central air-conditioning (CAC) is a fl exible load which can be dispatched during an emergency demand response (EDR) program. However, consumers’ trade-off between thermal comfort levels (TCLs) and profi ts will aff ect the potential of CAC. Therefore, this paper proposes a method to evaluate CAC’S response levels. An EDR optimization model simulating consumers’ trade-off between TCLs and profi ts is established and it is solved by a particle swarm optimization (PSO) algorithm. Then the defi nition of EDR levels is presented to quantitatively analyze the capability of CAC providing the EDR. Furthermore, uncertainty of EDR levels caused by stochastic initial indoor temperature is analyzed through a Monte Carlo (MC) simulation. A case study shows the rationality of the presented method, and the eff ects of weight coeffi cients, compensation prices and penalty prices on EDR levels are also analyzed.