Shaanxi Electrical Power Research Institute

Xian, China

Shaanxi Electrical Power Research Institute

Xian, China

Time filter

Source Type

Liu J.,Shaanxi Electrical Power Research Institute | Zhao S.,Shaanxi Electrical Power Research Institute | Zhang X.,Shaanxi Electrical Power Research Institute
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2012

The development of distribution automation (DA) in China is summarized including the information integration by the IEC 61968 based enterprise service bus (ESB); the well-developed and robust fault location, isolation and restoration program; wide application of the advanced communication technologies, such as Ethernet passive optical network (EPON), general packet radio service(GPRS), WiMax, etc; super-capacitor based back-up supplies for terminal units. The progress in the test of the distribution automation system (DAS) is described, which can evaluate the fault location, isolation and restoration property of a DAS by simulation of various fault scenarios. Three suggestions are given, namely, coordination between relay protection and DA, improvement of the capacity of distribution grids by DAS, and enhancement of the ability to handle the emergency situations by DAS. © 2012 State Grid Electric Power Research Institute Press.


Liu J.,Shaanxi Electrical Power Research Institute | Lin T.,State Grid Corporation of China | Tong X.,Xi'an University of Technology | Li L.,State Grid Corporation of China | Zhang Z.,Shaanxi Electrical Power Research Institute
Dianwang Jishu/Power System Technology | Year: 2013

To address the challenge due to connecting distributed photovoltaic (PV) generation to distribution network, based on the circuit topology of grid-connecting inverter of PV generation and its control strategy the simulation analysis on variation of output current characteristics of grid-connecting inverter under three-phase short-circuit fault and interphase short-circuit fault occurred in distribution network as well as that under different output of distributed PV generation are performed; meanwhile, the simulation analysis on variation of output current characteristics of grid-connecting inverter under open-circuit of insulated gate bipolar transistor (IGBT) device of the inverter and single-phase disconnection fault occurred in AC side are carried out. All simulation results show that whether three-phase fault or interphase fault occurs in distribution network, the short-circuit current output by grid-connecting inverter does not exceed 1.5 times of its rated current, and the approaches to cope with fault occurred in the inverter itself are put forward.


Wei H.,Xi'an University of Technology | Wei H.,Shaanxi Electrical Power Research Institute | Liu J.,Xi'an University of Technology | Liu J.,Shaanxi Electrical Power Research Institute | Yang B.,University of Sheffield
Applied Energy | Year: 2014

There is a competitive relationship between Domestic Solar Water Heater (DSWH) and Building Integrated Photovoltaic (BIPV) system in terms of roof area owned by households. Hence the implementations of solar Virtual Power Plant (VPP) in urban China should be carefully assessed from cost-benefit aspects, considering the existence of widely used DSWH systems. This study comprehensively collected the information related to the cost and benefit of DSWH and BIPV systems from literatures and conducted surveys on available roof area of households in Xi'an city with 96 samples. Then 25year lifetime cost-benefit analyses were performed to demonstrate the comparison between the two solar utilization systems with different roof area. The results indicated that only when the available roof area is more than 6m2, BIPV system can utilize more solar energy than DSWH could. One typical set of DSWH requiring 3-4m2 roof area is the optimal setting, and 84% urban China households are capable to install it. BIPV system has an equivalent cost-benefit performance only if the system cost is as low as RMB 0.6/kWh, and with the presence of RMB 1.00/kWh incentive feed-in tariff. If the system cost of BIPV is RMB 0.9/kWh, available roof area of 14m2 is required but only 18% households can afford it. These results are expected to raise a potential decision making issue between DSWH and BIPV, and provide basis of guideline for implementation of projects of both systems in urban area, particularly in China. © 2014 Elsevier Ltd.


Liu J.,Shaanxi Electrical Power Research Institute | Si Y.,Xi'an University of Technology
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011

To help better evaluate the safety and utilization of distribution networks, a linear programming-based approach to obtaining the maximum utilization ratio of distribution systems with arbitrary topologies and capacities is put forward. A series of safety indices considering load variation are proposed, including the real-time utilization ratio, real-time shortage ratio, averaged utilization ratio, averaged shortage ratio, N-1 criterion meeting to duration ratio, N-1 criterion meeting, N-1 criterion meeting risk, and regulating ratio of N-1 criterion meeting critical load. The steps of evaluation are suggested. Several examples are given to illustrate typical applications of the approaches proposed showing that it is feasible and can provide more information to planning, operation and engineering of distribution systems. It is also shown that the indices of utilization and extent for meeting N-1 criterion can be improved by optimizing the allocation of the sectionalizing switches on the feeders. © 2011 State Grid Electric Power Research Institute Press.


Ma L.,Xi'an University of Science and Technology | Zhou Q.,Shaanxi Electrical Power Research Institute
Proceedings - 2016 IEEE International Symposium on Computer, Consumer and Control, IS3C 2016 | Year: 2016

Voltage sag has become one of the most power quality problems of customer complaints. This paper researches on how to use fault current limiter (FCL) to relieve the voltage sag of sensitive load node. Assuming that three phase short circuit fault occur on every bus in power grid respectively, the voltage sag matrix is determined, buses in vulnerability area of sensitive load node are found. Sensitive load node as the center, the branches of power grid are searched outward and stratified. The relevance between branch and buses in the vulnerability area determine FCL installation branch. The dichotomy is used to calculate the reactance value of FCL. The IEEE-30 nodes system is taken as an example, the correctness and applicability of the method are verified. The method can provide the FCL installation scheme to relieve the voltage sag of sensitive load node. © 2016 IEEE.


Shao W.,Polytechnic University of Mozambique | Qiao N.,Polytechnic University of Mozambique | Wang J.,Shaanxi Electrical Power Research Institute
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

The inrush current is the main factor that leads to misoperation for transformer differential current protection. This paper proposes a novel algorithm based on waveform cross correlation principle for distinguishing between magnetizing inrush current and internal fault currents. Either in the case of no-load switching or internal faults, a short sampling data-window is used to produce a normal sine wave as reference, and then calculate the normalized cross-correlation coefficient between the practical sampled waveform and the reference. In the condition of internal faults, the normalized cross-correlation coefficient is close to 1.But in the situation of inrush current, it is deviated from 1 and waves notably. Therefore, the calculated normalized cross-correlation coefficient is used to detect internal faults and inrush current. PACAD simulation results indicate that the proposed algorithm can identify inrush current and internal faults correctly and quickly, and it is helpful to supply theoretical basis for improving the performance of differential protection and optimizing protection scheme in transformers. © 2015, Power System Protection and Control Press. All right reserved.


Wang J.,Xi'an University of Science and Technology | Feng L.,Xi'an University of Science and Technology | Feng Y.,Xi'an University of Science and Technology | Yan A.,Shaanxi Electrical Power Research Institute | Ma X.,Northwestern University
Polymer - Plastics Technology and Engineering | Year: 2012

Five kinds of organic rectorite (OREC)-reinforced Epoxy Resin (EP) composites (OREC/EP) were prepared by using different ORECs as modifiers. The curing process of EP, the functional groups of OREC and its interlayer distance (d-spacing) are demonstrated by Fourier Transform Infrared Radiation (FTIR) and XRD (X-Ray Diffraction). The morphologies of OREC/EP composites and the dispersion of OREC in the cured EP matrix were investigated using XRD and scanning electron microscopy (SEM). The mechanical properties, thermal deformed temperature (HDT), hot-wet resistance, alkali resistance and water adsorption of the resulting OREC/EP composites were evaluated. It is found that the addition of OREC can improve the comprehensive properties of EP. The maximum mechanical properties of OREC/EP can be obtained by OREC3/EMI-2, 4/E-51 due to the high stiffness and uniform dispersion of OREC in matrixes. The most desirable properties of OREC/EP composites were obtained with impact strength of 9.5 kJ/m2, bent strength of 86 KPa and HDT of 182°C, all of which is improved by 8.0%, 8.9% and 28.2% than those of pure EP, respectively. © 2012 Copyright Taylor and Francis Group, LLC.


Liu J.,Shaanxi Electrical Power Research Institute | Huang W.,Xi'an University of Science and Technology
Dianwang Jishu/Power System Technology | Year: 2015

To offer reasonable foundation for the planning of grid-connection of distributed photovoltaic (PV) generations, the mathematical models for voltage deviation and voltage fluctuation caused by various distributions of loads and PV generations are established. Taking the maximum upper deviation of voltage and the maximum voltage fluctuation caused by distributed PV generations and the maximum lower voltage deviation caused by the load only when the PV generation does not exist as constraints, the capacity range of allowed grid-connected distributed PV generations, by which the demand on voltage quality can be met under six distribution conditions of load and distributed PV generations along the feeder, is derived. Taking typical parameters of urban distribution network and those of rural distribution network for example, the proposed method is analyzed and illustrated, results of the analysis show that the proposed method is feasible, and using the proposed method the allowed grid-connected capacity range of distributed PV generations can be determined. ©, 2015, Power System Technology Press. All right reserved.


Liu J.,Shaanxi Electrical Power Research Institute | Zhang X.,Shaanxi Electrical Power Research Institute | Tong X.,Xi'an University of Technology | Zhang Z.,Shaanxi Electrical Power Research Institute | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

In order to solve the problem of fault location for distribution systems with distributed generation (DG), the fault current behavior of various DGs and the short-circuit current of the distribution systems with DGs are analyzed. The feasibility of the traditional fault location approach based on the information of overcurrent for distribution systems with DGs is investigated. An improved fault location process is proposed for overhead line based feeders, in which the reclosing procedure and the escape of DGs in case of fault situation are coordinated. Conclusions are drawn on DG connected to the bus and DG connected to the feeders based on cables with an appropriate limit to the total capacity, the fault can be identified with the traditional overcurrent based criteria. As for the case of DG connected to the overhead line based feeder of a rather long distance, it is necessary to utilize the improved fault location process proposed. © State Grid Electric Power Research Institute Press.


Liu J.,Shaanxi Electrical Power Research Institute | Cheng H.,Xi'an University of Science and Technology | Zhang Z.,Shaanxi Electrical Power Research Institute
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2013

To help with the planning and design of distribution automation systems (DASs), the best amount of terminal units (TUs) mounted in a DAS is analyzed from the perspective of benefit/cost ratio first. From the perspective of reliability, the amount of various kinds of TUs in different situations is studied, that is only TUs with tele-control function, only TUs without tele-control function, a hybrid of TUs with tele-control function and TUs without tele-control function. Some circuit breakers with current protection mounted on some branches are investigated at length. The following conclusions are drawn that only one TU for each feeder is the best choice from the viewpoint of benefit/cost ratio, and that the demanded amount of various kinds of TUs depends on the reliability performance desired, the time of isolating the fault section by manual operation, the time of reparation, and the frequency of failure per-year. A DAS planning example with 220 feeders is given to illustrate the proposed methodology. © 2013 State Grid Electric Power Research Institute Press.

Loading Shaanxi Electrical Power Research Institute collaborators
Loading Shaanxi Electrical Power Research Institute collaborators