Abstract In order to solve the problem of voltage sags in low-voltage power grid, the control strategy and application of Unified Power Quality Controller (UPQC) are given. Based on the main circuit of UPQC, the method of Second-Order Generalized Integral (SOGI) is used to detect the voltage drop quickly and accurately, and the direct control method is used to compensate the voltage drop. The method is simulated by PSCAD/EMTDC, and the theoretical results are verified. TMS320F28335 controller is used to realize the algorithm, and a physical platform is built. The test waveform verifies the feasibility of the method.

The power wireless private network is a wireless broadband access system that is deeply customized for the development of smart grid terminal communication access, and is integrated with the power dedicated 230 MHz spectrum to meet the wide coverage, large capacity, strong real-time performance, high security, flexibility and easy-to-expand of the power intelligent terminal, and provide integrated wireless communication private network solutions for various services such as distribution automation, electrical information collection, and precise load control. This paper proposes a data collection node planning algorithm in wireless power private network, which can realize the data measurement of large-scale intelligent power terminals at a small cost. Simulation results show the reliability of our algorithm.

Soft Frequency Reuse (SFR) can coordinate the inter-cell interference (ICI) by control the carriers and transmitting power. It will be used in the 5G. With the energy consumption increasing in the wireless network, the energy efficiency is an important index to evaluate the network performance in 5G. In this paper, we investigates the global energy efficiency optimization problem in SFR-based cellular networks. We formulate the global energy efficiency optimization as a fractional program model. It is very hard to solve directly the optimization model. To find the optimal solution of this model, we utilize the Lagrange function and KKT condition to attain the optimal transmitting power allocations. Then, we utilize the simulated annealing method to find the transmitting power allocations and sub-channel assignments. Finally, we make a numerical simulation to validate the algorithm proposed. The simulation results show that our algorithm proposed is feasible.

Network traffic embodies network behaviors and users' activity patterns, which holds many inherent features and dynamic properties. Feature extraction for network traffic in the network plays an significantly important role in time-frequency synchronization applications. How to accurately extract the hidden properties and features of network traffic has an important impact on network activities, such as network failure positioning, anomaly detection, and performance analysis. To this end, this paper propose a new feature extraction method to characterize network traffic. Firstly, the time-frequency analysis theory is used to transform network traffic in time-frequency synchronization applications to the time-frequency domain. Then the cluster analysis theory is used to dig and extract network traffic feature components. And the k-means analysis method is exploited to refine the hidden features of network traffic in the time domain. Finally, to validate our feature analysis method, we conduct an anomaly detection test. Simulation results show that our approach is promising.

When the PD occurs, the charge moves rapidly, producing high-frequency currents while also radiating electromagnetic waves. While the switchgear is a metal closed structure, but also make a partial discharge signal to produce multiple reflections. Usually there is a gap in the surface of the switchgear, electromagnetic waves can leak through the gap to continue in the air and switch cabinet surface propagation. TEV detection is based on this principle. However, when there is interference outside, the interference of electromagnetic waves can also be coupled to the switchgear surface, affecting the partial discharge pulse of the correct assessment. Based on this, the project uses the finite element method to study the propagation characteristics of the electromagnetic wave on the surface and the gap of the switchgear, and provides theoretical guidance for the research on the anti-jamming measures of the partial discharge detection of the switchgear.

With the rapid development of Internet, the network traffic explosively grows with the emergence of new network business. The existing electric power communication networks still have the traditional architecture that is the closed system highly integrated with devices and software, which cannot satisfy the development requirements of smart grids. In this paper, we combine the electric power communication networks with Software Defined Network (SDN) that includes the NOX controller in the control plane, switches in the data forwarding plane, and the OpenFlow protocol supporting the communication between controller and switches. Especially for the scenario of the network expansion, the NOX controller dynamically configures end-to-end paths, and we then demonstrate the feasibility of our design by checking the flow tables in switches. Additionally, the CPU utilization of the NOX controller and end-to-end delay are both analyzed in our experimental platform.

This paper mainly introduced a congestion management based on Open-flow to solve the problem in the traditional routing strategies. When the congestion happens, the routers cannot fully use the resource of the whole network to reroute the link in congestion in traditional routing strategies. Due to this reason, traditional strategies cannot solve the congestion problem effectively. In network working under open-flow, the controller of whole network is in charge of the routing management about the whole network resources and can use them to effectively solve the problems. This management takes the advantage of Open-flow that can monitor and control the whole network data strings and topology map, and solve the congestion problem more proficiency than other algorithm. In this way, it can solve the congestion problem. What's more, the service qualities will be maintained, and the throughput of network and resources utilization will be improved at the same time.