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Zhang J.,Hangzhou Dianzi University | Zhang J.,Zhejiang Creaway Automation Engineering Co. | Chen H.,Hangzhou Dianzi University | Zhou M.,Hangzhou Electric Power | And 3 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

A novel substation-centralized uniformly-distributed distribution network one-line diagram is put forward to overcome many shortcomings of regular distribution network diagrams in situation awareness visualization. An improved F&R force-direction algorithm is developed to automatically generate such a diagram, which introduces traction force to shorten the long lines, the pull force to avoid the load being too close to the nearby lines, and the pull force to avoid the closeness between the nearby feeders and the section lines. Based on a qualitative analysis of situation visualization performance of the geographical connection diagram and uniformly-distributed connection diagram, an evaluation method for performance of situation awareness is put forward and the numerical calculation has been applied for those base diagram schemes, the numerical results showing that the situation visualization performance based on the uniformly-distributed connection diagram is evidently much better than what is based on the geographical connection diagram. © 2014 State Grid Electric Power Research Institute Press Source


Zhang J.,Hangzhou Dianzi University | Zhang J.,Zhejiang Creaway Automation Engineering Co. | Zhang Q.,Shandong University of Technology | Wang N.,Hangzhou Dianzi University | And 2 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011

For the grid-connected photovoltaic (PV) power plant and other alternative energy power plants, the electricity must be produced totally from the designated primary energy form due to its special high tariff priority. Such plants must be monitored by the existing energy data acquisition and supervisory system of grid company regardless of capacity or voltage level. Since complicated power, energy exchanges and complicated settlement relationship may exist between the grid-connected PV power plant and power grid, apart from the general requirements for monitoring power, energy exchange, and power quality, a special task is to monitor the PV generation characteristics and possible maximum power generated from PV power plants to prevent the energy measurement errors and inappropriate power generation. A comprehensive, accurate, economic and practical power generation model is necessary. A PV battery theoretic model with the steady parameters provided by the general component supplier is selected. Then, a plant level power generation model is built based on the topology of the main equipment elements. Finally, the identification method of calibrated parameters based on the historical data is also provided. The model has been verified by a real operated PV power plant, and a satisfactory performance is demonstrated. © 2011 State Grid Electric Power Research Institute Press. Source


Li Y.-C.,Zhejiang Creaway Automation Engineering Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010

In order to avoid the zero-sequence current, a new method based on Zigzag transformer and active power filter is introduced in this paper. Zigzag transformer can decrease the tolerated voltage of the active power filter while the active power filter is used to increase the equivalent zero-sequence impedance of distribution transformer. This method can effectively improve the performance and at the same time reduce the capacity and cost of Zigzag transformer. This method shows high performance-price ratio and bright market prospects. The simulation and experimental results proved that it is a feasible method to deal with the zero-sequence current problem. Source


Zhang J.,Hangzhou Dianzi University | Zhang J.,Zhejiang Creaway Automation Engineering Co. | Chen H.,Hangzhou Dianzi University | Chen J.,Hangzhou Electric Power | And 3 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2014

A conceptual model for smart grid situation management is provided together with the object model of situation awareness visualization as well as the core algorithm. The core of situation visualization is the situation diagram modeling. A situation diagram constitution model is put forward, and a real time situation diagram generation scheme and a condition trigger storage scheme for historic diagrams have been designed. The stored historic diagrams with time stamp can be assembled for historic situation play back of historic situation explaining and reasoning. A graph generation scheme for future situation prediction is also presented from which future situation visualization is accessible. The judgment criterion for situation diagram is also discussed and it is observed that the base graph selection will have a serious impact on the performance of situation induction as well as situation perception. The engineering application theory and method under discussion have been applied in the electric power distribution network situation awareness visualization. ©2014 State Grid Electric Power Research Institute Press. Source


Zhang J.,Hangzhou Dianzi University | Zhang J.,Zhejiang Creaway Automation Engineering Co. | Jiang S.,Zhejiang Creaway Automation Engineering Co. | Jin N.,Shaoxing Electrical Power Bureau | And 3 more authors.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2010

Electric energy remote terminal unit (ERTU), an important plant-level device for periodic data acquisition of substation, is obviously a part of digital substation system. However, as the basis of digital substation, IEC 61850 has not covered all measurement of quantities of substation electric energy. Therefore, based on IEC 61850 standard extend principle, a new common data class (CDC) FEE, a series new data object (DO), and a new logic node (LN) MEEE, are introduced to build a complete ERTU object model and its instance. Such extension meets the principle according to corresponding articles in IEC 61850. In accordance with the practical application demand and analysis of digital energy meter as well as ERTU, a complete data service scheme using URCB controlled report and LOG mechanism based on a series DATA-SET definition, is designed for periodic data communication between energy meters, ERTU, master station. A novel ERTU based on above modeling was developed and implemented in a 110 kV substation in Zhejiang Province. © 2010 State Grid Electric Power Research Institute Press. Source

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