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Cai F.,Quanzhou Normal University | Yu H.,Guangdong Power Grid Co.
Journal of High Speed Networks | Year: 2016

Index data distribution is an important approach that provides parallelism and can improve the usability of a distributed parallel database. B+ tree is a storage structure, which perfectly fits for distributed and parallel indexing, and the distributed B+ tree is adopted to index the massive and rapidly increasing data available in a distributed network. This paper proposes an index data distribution strategy using distributed parallel B+ tree in a distributed network environment. In our proposal, the basic data distribution strategy can improve the efficiency of a query by utilizing a data fragment method based on the scope of value, and the replica distribution can be adjusted dynamically, according to the number of system access. The performance evaluation and experiment results show that this index data distribution strategy can improve the query's efficiency and load balance. © 2016 - IOS Press and the authors. All rights reserved.

Liu J.,Guangdong Power Grid Co. | Zhang W.,Guangdong Power Grid Co. | Zhou R.,Guangdong Power Grid Co. | Zhong J.,University of Hong Kong
IEEE Power and Energy Society General Meeting | Year: 2012

Distributed generations and renewable energy generations have been widely installed in the distribution systems all over the world. The intermittence of distributed renewable energy generations and their special characteristics have various impacts on power system operation and dispatch. In this paper, the impacts of distributed generations on dispatch modes of power systems are discussed based on the Guangdong power grid in China. We introduce the situations of Guangdong power system, and its installation of distributed generations. The impacts of various distributed renewable energy generations on the system dispatch from the system operator's view point have been discussed. Based on the Guangdong existing generation resources and potential distributed generation grid integration, we provide suggestions to smooth the future integration of large amount of distributed renewable energy generations. © 2012 IEEE.

Liang G.,Guangdong Power Grid Co. | Duan X.,Guangdong Power Grid Co. | Gao X.,Guangdong Power Grid Co.
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2011

The basic structure and networking schemes of digital substation are introduced, and some networking schemes are proposed for the process level of digital substation based on the message transmission tests. As star structure is superior over bus and ring structures in operational maintenance, transmission time and so on, dual-star structure is proposed for process level networking. The transmission of sampling value message and protection trip message is tested under different conditions of switch data flow. Results show that large flow will cause sampling value change and GOOSE transmission delay. Three net-working schemes are proposed for process level: the sampling data transmission network adopts IEC60044-8 or IEC61850-9-1 via point-to-point fiber, separated from the GOOSE network; the sampling data transmission network adopts IEC61850-9-2 via 100 M Ethernet, separated from the GOOSE network; one network for both sampling data and GOOSE transmission. The scheme is selected according to the structure, scale and importance of substation and the applied network devices.

Zhang Y.,South China University of Technology | Zhang H.,South China University of Technology | Tang J.,Guangdong Power Grid Company
Dianwang Jishu/Power System Technology | Year: 2013

It is difficult for existing automatic voltage control (AVC) strategy to ensure fully utilization of votlage/var regulation devices in 220 kV substation to meet both demands of votlage/var control from upper- and lower-level power networks, especially under light load flow operation mode the mismatching of votlage/var control between provinical and district power networks happens. Based on administration authority of provinical and district power networks, the objective of votlage/var and AVC strategy, the mechanism of mismatching of AVC-based voltage and reactive power control occurred in 220 kV substation is analyzed, and an anti-mismatching strategy that can implement coordinated control of votlage/var between provincial and district power networks is proposed. Through the characteristics of voltage and reactive power reflected by equivalent assessment model, it is revealed that the boundary voltage is the key to solve the mismatching, and the boundary voltages reflecting the voltage control states of upper- and lower-level power networks are added into local votlage correction strategy of AVC to compose a three-dimensional anti-mismatch criterion, thus under routine operation mode the votlage/var regulation devices in 220 kV substation can preferentially help the lower-level power network to carry out district voltage control and under the light load flow mode the votlage/var regulation devices in 220 kV substation can preferentially help the upper-level power network to execute anti-mismatch strategy for regional votlage/var control. Simulation results of actual case show that the proposed anti-mismatch strategy is effective.

Chen J.,Guangdong Power Grid Co.
Gaoya Dianqi/High Voltage Apparatus | Year: 2016

Bird damage has become one of the most important factors endangering the safe operation of transmission lines, which degree of harm is second only to lighting and external forces, while streamer flashover is the most typical type, ranking the first of all bird damage. The paper presents a preventive measure against streamer flashover by wrapping insulation sheath to wire. Tests results show that the potential of equalizing ring decreases after wrapping insulation sheath, which effectively avoid the occurrence of discharge between streamer channel and equalizing ring, as a result, scope of risk area decreases. Besides, the paper also establishes three-dimensional simulation model, calculating the effect of insulation sheath on composite insulator under different value of dielectric constant, thickness of insulation sheath and length of fittings. Results show that wrapping insulation sheath decreases the potential of equalizing ring and decrease the possibility of streamer flashover, besides, the electric field distribution along the surface of the composite insulator is improved, enabling its safe operation. © 2016, Xi'an High Voltage Apparatus Research Institute Co., Ltd. All right reserved.

Liang G.,Guangdong Power Grid Co.
Dianli Xitong Zidonghua/Automation of Electric Power Systems | Year: 2011

Usually, electromagnetic transformer is still in use during the digital substation construction. The electromagnetic transformer accessing solution during digital substations modernization is introduced. The causes of errors generation are analyzed when the electronic and electromagnetic transformers simultaneously access for bus differential protection. Through the delaying parameter setting of sampling data, the method to eliminate errors is put forward. Data synchronization between two kinds of transformer is discussed. Based on the adjustment of receiving and sending sequential control logic, the problem of synchronized transmission for the merging unit sampling data is solved. A solution for the practical case of Sanxiang digital substation modernization is proposed. © 2011 State Grid Electric Power Research Institute Press.

Li S.-Y.,Guangdong Power Grid Co.
Gaoya Dianqi/High Voltage Apparatus | Year: 2010

Using the 200 kV high-voltage DC generator and RCD type resistive current measuring instrument, through carrying out DC leakage testing, on-line detecting full current and resistive current on MOA, the most effective method, which can find out arrestor damp, has been obtained. The method is MOA DC leakage testing in blackout. Moreover, the charged detecting MOA full current and resistive current only be effectively in a single arrester, for 2 assembled arrester above 220 kV is invalid.

Zhong B.,Guangdong Power Grid Co.
World Information on Earthquake Engineering | Year: 2015

The tall frame-shear wall structure in highly seismic region introduced isolation technology, the aim is to reduce earthquake load to the greatest extent, increase the range of Elastic deformation in the structure, make the the design target in the anti-seismic period easier to realize and ensure. The tall frame-shear isolation system in isolation system simplified analysis model, studying the effect of Isolation bearing thickness changed to earthquake response frame-shear isolation system, doing structural dynamic time analysis under highly seismic fortification intensity earthquake. The calculation results show that increasing the thickness of isolation bearing can reduce earthquake load of frame-shear isolation system to some extent. Under fortification intensity earthquake, in 8 degrees, frame-shear isolation system which the upper structure natural vibration period is 1-2s can completely meet the requirements of the current specification displacement limit, in 8.5 degrees, frame-shear isolation system which the upper structure natural vibration period is 1~1.4s can meet the requirements of the current specification displacement limit, while in 9 degrees, it generally can not meet the design requirements. ©, 2015, Science and Technology Periodical Press. All right reserved.

Zhang X.,South China University of Technology | Yu T.,South China University of Technology | Tang J.,Guangdong Power Grid Company
Diangong Jishu Xuebao/Transactions of China Electrotechnical Society | Year: 2016

Although automatic generation control under CPS standard can be addressed by classic reinforcement learning Q(λ) algorithm, such problems as slow convergence and small optimal searching space still exist from the view point of multi-agent equilibrium solution. Therefore, this paper proposes correlated-equilibrium-Q(λ) (CEQ(λ)) learning. According to the response time delay of thermal plants, AGC adjustment units are first divided into different kinds of unit, such as coal, gas, hydro and so on. Then dynamic allocation orders of generators are analyzed by CEQ(λ) learning based multi-agent control framework. Simulation tests of two-area load frequency control model and China South Power Grid demonstrate that the CEQ(λ)-learning algorithm is more suitable for CPS instruction dynamic optimal allocation in stochastic and complex interconnection network, and it can enhance the robustness and adaptability of power systems in CPS assessment. © 2016, The editorial office of Transaction of China Electrotechnical Society. All right reserved.

Pan B.,Guangdong Power Grid Company | Zhang Y.,South China University of Technology | Huang H.,Guangdong Power Grid Company
Dianwang Jishu/Power System Technology | Year: 2012

To evaluate the power system risk due to ice disaster, the impacts of ice disaster, design parameters and emergency management of power grid on the risk are researched, and five key factors such as probability distribution of annual extremum of ice-thickness, extreme value of a certain ice disaster, the ice thickness specified in the design of power network, the number of de-icing devices and the ratio of guaranteed resources, are chosen to establish multi-factor model to evaluate power grid risk due to ice disaster. The Pearson type III distribution is utilized in climatic extremes to incarnate factors of disaster, on this basis a fuzzy failure rate modes of unit span, in which the impact of the number of de-icing devices is included, is proposed, and the risk due to ice disaster is composed of the economic loss risk due to the shortage of power supply and the risk due to rehabilitation cost; and a fuzzy model for the impact of the ratio of guaranteed resources in the emergency management on the time of power supply interruption is built. Simulation results of a certain regional power network show that putting de-icing devices into operation and enlarging the specified ice thickness in the design of power network can obviously retard the occurrence of ice disaster and increasing the ratio of guaranteed resources can also lower the risk due to ice disaster considerably.

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