Lin Niu

Optimal Design of Passive Power Filters Based on Pseudo-parallel Genetic Algorithm

The economic costs together with filter efficiency are taken as targets to optimize the parameter of passive filter. Furthermore, the method of combining pseudo-parallel genetic algorithm with adaptive genetic algorithm is adopted in this paper. In the early stages pseudo-parallel genetic algorithm is introduced to increase the population diversity, and adaptive genetic algorithm is used in the late stages to reduce the workload. At the same time, the migration rate of pseudo-parallel genetic algorithm is improved to change with population diversity adaptively. Simulation results show that the filter designed by the proposed method has better filtering effect with lower economic cost, and can be used in engineering.

Study on the Transient Process of 500kV Substations Secondary Equipment

By analyzing on the reason of the lightning accident occur in the substation, the way of lightning incoming surge invading the secondary system is summarized. The interference source acts on the secondary system through various coupling paths. It mainly consists of four ways: the conductance coupling mode, the Capacitive Coupling Mode, the inductive coupling mode, The Radiation Interference Model. Then simulated the way with the program-ATP. At last, from the three aspects of low-voltage power supply system, the impact potential distribution of grounding grid, the secondary system and the computer system. The lightning protection measures is put forward.

Research on Fault Diagnosis Algorithm Based on Multi-Source Data Analysis

Based on multi-source substation equipment inspection data, this article achieve fault diagnosis in the case of incomplete understanding of the mechanism of substation equipment, by establishing fault diagnosis model.This article selected a substation equipment failures and operational information in different conditions as simulation study. The simulation results show the feasibility of the algorithm. Compared with the traditional fault diagnosis model, this method is more flexible , have a stronger ability to handle noisy data and good prospects.

The Online Pattern Recognition Method of SF6 Gas Leakage Based on Image Recognition

Based on image processing of SF6 gas leakage on-line pattern recognition method, this paper achieves gas leakage feature extracting, on-line identification of gas leakage and leakage points, SF6 gas leakage can be on-line automatic identification. The simulation results show the feasibility of the algorithm. Compared with the traditional method, paper provides a more intuitive discrimination basis for field staff , as well as for the depth of the late testing data mining provides a research way of thinking

Research and Application on Successive Action Zone and Dead Zone of Transverse Differential Protection in Parallel Lines

This paper deeply researches on successive action zone and dead zone of transverse differential protection in parallel lines, and improves the existing analysis software for relay protection action. First determine which zone the fault point belongs to, and then analyze the protection action according to the different zone concretely. This improvement will greatly increase the accuracy to analyze the relay protection action, and will be significant to the safe and stable operation of regional networks.

Design and Application of Analysis Software for Relay Protection Action Based on PAS

This paper applies the theory of expert system to analysis for relay protection action based on PAS. And it also summarizes various rules according to the experience of operating personals and relay protection personals for several years. All these rules are suitable for 110kV and 66kV regional networks. This paper not only analyzes three-phase current protection, zero-sequence current protection, distance protection etc, but also discusses some special situations such as under voltage lockout over-current protection for transformer, remote backup protection etc.

Simulation Research on the Transient Characteristics of Permanent Magnet Synchronous Motor Based on the SVPWM

In this paper, the transient characteristics of the permanent magnet synchronous motor based on the space vector pulse width modulation technology are researched in detail. Firstly, the mathematical model of the control system is established. Secondly, the simulation model based on MATLAB/Simulink is built. Thirdly, the transient simulation is implemented by the constructed model. It is proved that the mathematical model is valid and effective, which provides a theoretic base for the design of an actual permanent magnet synchronous motor control system.

Simulation of Secondary Equipment Lightning Protection in EHV Substation Based on ATP

By analyzing the two lightning accidents happening to a 500kV substation situated in the lightning-prone northeastern Guangdong Province, I conclude as follows, there should be some problem in the equipotential earthing of the secondary system of this substation. Specifically, the existing potential difference in the secondary equipment gave rise to the meltdown of it which finally caused the accident. In the context,I build the one-point earthing parallel system simulation model according to ATP graphic pretreatment program, then by using slope-ramp simulation I study the lightning current which leaked into the grounding grids of the substation.In conclusion, the application of high frequency signal mixed low frequency signal earth system in the secondary system and the equipotential bonding is key to preventing accidents.

Research on On-Line Fault Calculation Software for Regional Networks Based on Expert System

This paper researches on a method for on-line fault calculation based on expert system theory. The method improves traditional method of width precedence searching, and applies to form the node impedance matrix, which not only settles loop net but also advances calculation efficiency. To convenient for fault calculation, we process and identify the basic parameters and perform equivalent of 220kV external system. Moreover inbuilt fault calculation software has been realized, which can exchange data with SCADA system on-line.

Infrared Monitoring Studies of Winding Temperature Rise in Electrical Equipment

Winding temperature rise is inevitable for electrical equipment. There is no harm when device is working properly. However, winding temperature rise will be abnormal when equipment failure exists, this will affect the normal operation of equipment even cause electrical accidents. According to the principle of winding temperature rise, we designed an experiment in which the winding temperature rise is real-time monitoring by the thermal infrared imager. Then we get the data and analysis them,after all we simulated the procedure of monitoring and troubleshooting by infrared technology for equipment in electrical system.