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.
Cai F.,Quanzhou Normal University |
Yu H.,Guangdong Power Grid Company
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.
Liang G.,Guangdong Power Grid Company
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 Company
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 Company
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.