The paper presents the modeling and simulation of the power flow control strategy of a single-phase AC-DC Hybrid Micro-Grid (HMG). The proposed system topology for HMG contains two AC and DC zones delimitated by a bidirectional interlinking converter (BIC) in a full bridge IGBT structure which is a regular H-Bridge inverter/rectifier. The switching pattern of BIC is provided from two power control loops and one voltage loop (Vdc) based on the DQ transformation theory. This control strategy allows, in a controlled matter, the transfer of both active and reactive power between the HMG and the public AC Grid. Moreover, this is performed in both directions by working with the bidirectional converter in rectifying or inverting modes. The simulation model is implemented and tested using Matlab-Simulink.

Power factor compensation for a single-phase AC-DC Hybrid Micro-Grid

In order to realize network topology visualization and fast network fault location for smart substations,based on topology identifying methods for conventional switch networks,a dynamical topology identification approach is proposed for smart substation networks using media access control(MAC)address matching.In order to realize dynamical topology identification for smart substation networks including switches and intelligent electronic devices(IEDs),the approach matches information from MAC access tables,captured network packets,and substation configuration files.In addition,a Linux-based software tool is developed and applied in a simulation system to validate the proposed approach.

Dynamical Topology Identification of Smart Substation Network Equipment Based on MAC Address Matching

Although there is no specific communication media in the international standard IEC 61850 for the communication networks and systems in substations,in view of the current researches and practices,Ethernet,in which TCP/IP protocol is widely used in low layer communication protocol,has become the mainstream network to implement IEC 61850. However,TCP/IP protocol does not provide any security capabilities. This paper researches the IEC 62351: Power systems management and associated information exchange-Data and communications security,PartⅢ-Communication network and system security including TCP/IP protocols to solve this problem. The final security solutions to protect the profile including TCP/IP and communications security are embedding Kerberos protocol in TLS handshake protocol and SSL/TLS based VPN tunneling technology.

The Security Solutions for TCP/IP Communication Network of Smart Substation

Intelligent substation has the characteristics of information networking and digital transmission. The coupling degree between secondary equipment is increasing, which makes it more and more difficult to judge the functional effectiveness of substation operation control. This paper proposed on-line diagnosis method based on equipment function correlation, established a secondary system function correlation library including actual physical ports, and used DTW method to quickly match the actual function information with the standard information in the function correlation library on line, thus completing the operation control obstacle location of the secondary system of the intelligent substation. Aiming at the fiber link failure, combining with the physical port mapping relation, the fault optical port is further located. At the same time, this paper established an optical power prediction model, which can realize the early warning of optical link communication status before the occurrence of link failure and give the function affected by the link. Finally, the feasibility of this method is verified in the commissioning of a 220kV intelligent substation.

Method for Peration Control Obstacle location and Fault Prediction of Substation Based on Information Driven

This paper presents a feasibility study of exploiting the symmetry of some parameters for series arc fault detection in electrical circuits. The considered parameters are defined in the time domain and they are based on the current signal derivative and the evaluation of cross-correlation between subsequent observation windows. The analysis is carried out for AC systems, starting from an experimental characterization, which has been carried out in accordance with the Standard UL 1699 requirements for "unwanted tripping tests" and "operation inhibition tests" of arc fault circuit interrupters (AFCIs). The results obtained in different load conditions show that the proposed parameters can be useful for detecting the arc faults presence, with the advantage of low computational costs. 

Time domain symmetry parameters analysis for series arc fault detection

The occurrence of electric arcs poses a huge threat to personal and equipment safety. As one of the effective ways to actively protect personnel and equipment away from serious arcing incidents, the signature recognition based arcing identification method has drawn much attention. However, since the strong nonlinear dynamics of the arcs, merely based on a specific time-domain or frequency-domain feature to develop the identification criteria may not be applicable in practice. To overcome the limitations, this article proposes a novel arc fault identification approach, which evaluated both the transient and steady dynamic states of arcing faults by time-frequency analysis. The complete ensemble empirical mode decomposition with adaptive noise, incorporated with Hilbert transform, has been designed to realize the rapid and reliable signatures extraction from arc fault profiles. Moreover, for dimension reduction purposes, correlation coefficient and partial least square regression based time-series dominant features selection method was developed. For ensuring the accuracy and robustness of the identification algorithm, a multiscenario based long short-term memory was also proposed. With the series of actual arc fault cases under different configurations, the effectiveness of the proposed method has.

Novel Approach for Arc Fault Identification With Transient and Steady State Based Time-Frequency Analysis

Information communication system is one of the keys to the implementation of a smart substation, therefore monitoring of optical power for the secondary equipment network is helpful to improve the security and stability of communication in substation. Based on a study of the existing monitoring methods of optical fiber communication in smart substation, a monitoring system of optical power is proposed by analyzing the historical data and historical trend. Some key parts such as the framework for the monitoring system of optical power, template library of component, historical database and the analysis of historical trend are implemented. In this monitoring system, prediction of changes in optical power based on historical trend is designed and analyzed. Finally, the feasibility of the monitoring method of optical power in fiber communication for secondary equipment and using it as a prejudgment to retrieve abnormal communication state are verified by a practical example.

Monitoring of optical power in fiber communication for secondary equipment in smart substation

Feed forward decoupling control under Rotating coordinate can suppress the static error of single-phase PWM rectifier's current. But due to the variation inductance in the actual situation, the performance of control will be poor. The feedforward decoupling control method without inductance value is adopted in this paper to solve the problem that the inductance value is not accurate. Simulink simulation results show that the control method can be completed when the L value is not accurate.

A control strategy of single phase voltage source PWM rectifier under rotating coordinate

This paper starts with an introduction of the defects of safety measures taken by traditional detection. Then, a scheme in which safety measures for detection can be automatically formed, is proposed. In the new scheme, the safety measures are graphically demonstrated, so that the maintenance crews can learn the measures easily. The paper presents the principles of detection safety measures, making of detection template library, and the logic of automatically forming detection safety measures. It is expected to provide ideologies and references for making detection safety measures for new generation smart substation.

Design of detection supporting system for smart substation maintenance crew

Accurate and reliable arcing fault identification in distribution systems ensures the safety of personnel and equipment during operations and maintenance works. However, the different configurations of circuit components, under various operating scenes, may distort the fault dynamics inconsistently and continuously impact to the representation form of the faults’ signature characteristics, which poses substantial challenges to arc fault identification. This paper proposed various operating scenes adapted robust arc identification approach, incorporating the Hilbert Transform (HT) based nonlinear circuit impedance representation and chaotic characteristic analysis of fault circuit. With establish the equivalent variable coefficient differential equation based impedance model of arc faults, the mechanism of how circuit parameters impact the representation of arc fault dynamic has been revealed. Then, to decouple the correlation between arc fault features and circuits parameters, meanwhile obtaining the signature feature set, HT based modulus of voltage and current dynamic phasor ratio (MVCR) has been calculated, which directly represents the fault dynamic in time/frequency domain. Meanwhile, to enhance the robustness of feature selection, chaotic features of fault signals have been studied and extracted in phase space. In addition, LSTM based classification algorithm has been designed for arc fault identification with the distinction of time-series features. With the series of actual arc fault cases under different configurations, the effectiveness and robustness of the proposed method have been thoroughly validated.

Jie Ren

Papers

Novel Approach for Arc Fault Identification With Transient and Steady State Based Time-Frequency Analysis

Monitoring of optical power in fiber communication for secondary equipment in smart substation

A control strategy of single phase voltage source PWM rectifier under rotating coordinate

Design of detection supporting system for smart substation maintenance crew

Chaotic Characteristic Analysis based Robust Identification Approach for Arcing Faults with Considering Various Operating Scenes