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Wang D.-G.,XJ Group Corporation | Chen Z.,Xuchang Ketop Testing Technology Co. | Yao W.-Z.,XJ Group Corporation | Liu G.,XJ Group Corporation
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

By analyzing and comparative test for LVRT test schemes based on passive-impedance network and the grid simulator, this paper deals with the diversity in terms of the main circuit topology, voltage dip range and accuracy, instantaneous overload ability and control stability etc. The analysis and testing results show that LVRT testing scheme based on the passive-impedance network can be very closer to the actual operation condition with stable output voltage waveforms.


Jin W.,XJ Group Co. | Yang X.,Xuchang Ketop Testing Technology Co. | Yu C.,XJ Group Co. | Zhang H.,XJ Group Co. | Shen Y.,XJ Group Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

The DC transmission power of UHVDC transmission project is set according to the daily power plan made by dispatching system, and the sending and carrying out of the power plan directly influence the stability of the DC system. Based on the in-depth study of IEC60870-5-104/101 and the engineering application of UHVDC transmission project, a function extension of the RCI system and SCADA system are made, a real time transmission, receiving, analysis, display and storing of the power plan are realized based on IEC60870-5-104/101. The automatic power control is realized in the SCADA system, which sends power value automatically to the control systems with high instantaneity and responsibility. The transmission of the power plan and the realization of the automatic power control could improve the efficiency of operators, and there is significance on improving grid security. ©, 2015, Power System Protection and Control Press. All right reserved.


Ding M.,Ningxia Electrical Power Company | Wang H.,Ningxia Electrical Power Company | Shu B.,South China University of Technology | Wu Q.,South China University of Technology | And 3 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2015

In order to analyze the problems of protections and harmonics in the multi-send HVDC system with wind plants, which is a novel power grid, an approach to establish the electromagnetic transient simulation model by PSCAD/EMTDC is presented. After the ±800 kV Ningdong-Zhejiang UHVDC is put into operation, Ningxia grid will be this novel power grid. The winter peak operation mode of Ningxia grid in 2016 is studied. The simulation model is divided into three modules: AC grid, HVDC systems and wind plants. The interfaces between modules are defined. The simulation models of three modules can be established independently. The principle to divide the AC grid into different levels and modules is presented. With interfaces defined, the whole Ningxia grid is connected with the modules. The simulation results of the static performances and fault currents are compared with PSASP, and the validness of the simulation model is testified. The simulation results show that the transient performance of the wind power plants and HVDC/UHVDC can be analyzed in detail. The electromagnetic transient simulation model of the grid is very important to study the problems of protections and harmonics in such grid. © 2015, Power System Protection and Control Press. All right reserved.


Zhuang L.,Xuchang KETOP Testing Technology Co. | Zhang Y.,Xuchang KETOP Testing Technology Co. | Jing X.,XJ Electrical Co. | Li Z.,Xuchang KETOP Testing Technology Co. | And 2 more authors.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2016

A simplified control method for the series side of MMC_UPFC is realized by adopting indirect current control scheme for building simulation model more conveniently. Based on the MMC_UPFC system's phasor model, the process for modeling and simulation of the simplified control strategy is deduced. Some simulation tests are built on the RTDS's microsecond-level module based on one demonstration project of UPFC such as constant voltage phase shift control, active and reactive power flow control, and UPFC dynamic response under power grid disturbance, etc. Simulation results show that the simplified control strategy can make the MMC_UPFC system follow the control instruction fast and effectively and present regulation performance like good voltage control and phase shift and power flow control, etc. © 2016, Power System Protection and Control Press. All right reserved.


Li Y.-P.,Xuchang KETOP Testing Technology Co. | Li Z.-Y.,Xuchang KETOP Testing Technology Co. | Zhou P.-P.,Xuchang KETOP Testing Technology Co. | Wang W.,Xuchang KETOP Testing Technology Co.
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2014

A relay protection dynamic testing system based on new type real-time digital simulation is presented. The system uses RT-Linux and high performance industrial control computer to compute, applies the Matlab/Simulink to develop the model file, adopts PCI interface card to I/O, employs special switch grouping technology to output peer-to-peer data, and uses flexible configuration program to achieve auto-test. It also can solve many problems, such as the calculation time jitter, simulation numerical oscillation, multi bays synchronous output and so on. The system is suitable for real-time dynamic simulation test of conventional protection, intelligent protection and station domain protection.

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