Abstract:As on the condition of high orders of harmonics, linear Lagrange interpolation algorithm has oversize errors, while the same situation, parabola Lagrange interpolation algorithm on the condition of low sampled frequency with MU. A new improved algorithm is presented in this paper. According to the characteristics of electric network signal, a weighted function is constructed. The new algorithm with weighted average between the two closed items in the Lagrange interpolation algorithm is formed. According to the calculation thought, the improved algorithm is simulated and modeled by matlab7.0. Compared with the original algorithm, the new algorithm decreases the relative errors of each sampled points greatly and improves the measured accuracy of current, voltage and power magnitudes. By analyzing a typical power harmonic signal, on the condition of high orders of harmonics, the errors of weighted algorithm is improved markedly, and the effect of algorithm with harmonics is compressed availably. The results show that the algorithm has high accuracy, which satisfies the requirement of the novel interface solution to sampled values for substation intelligent electronic device.

Abstract:Compared with the traditional Fourier transform, the wavelet transform has the time-frequency localization features, and the width of the window can adapt to the change of the wavelet automatically, so it has a distinct advantage in the detection of transient signal and unstable signal. A method using the wavelet multi-resolution analysis technology to extract voltage flicker signal is proposed in the paper. According to the characteristics of wavelet function and the demand of analysis, different N values (number of vanishing moments) of the Daubechies wavelet are compared to extract and locate the features of typical transient signal. According to the time-frequency information of amplitude modulation wave, the frequency and the amplitude of transient signal are obtained, and the goal of accurate location of the occurrence and recovery time is achieved. The simulation results show that better performance will be obtained just with the combination of different N values Daubechies wavelet.

Abstract:Through the analysis on the effects of steam seal on the safety and economy of steam turbine units, the importance of the steam seal is introduced in the paper. Based on the research of the features of various steam seal types, the key points and basic principles for the choice of steam seal types are proposed. After the deep analysis of different evaluation methods for the application of steam seal, a more reasonable comprehensive evaluation method is proposed.

Abstract:The 5031 switch will trip, which is caused by the gas generation relay contact point transient on in the process of charging of 500 kV main transformer. The gas protection is the main protection of the winding short-circuits faults and abnormal in transformer oil tank, which the safe and reliable operation is the necessary condition for. This paper gradually rules out the possibility which causes the 5031 switch trip by field survey and analysis. The high inrush current makes winding expanding and contracting when the main transformer is charging, which causes the oil wave. Three conditions for the heavy gas contact closure is concluded from the analysis of the action construct of gas relay. The reason for this fault is explained form the most probability of the heavy gas contact closure is the downward floating ball swing when the oil is waving.

Abstract:When the two-phase-earth-fault occurs to 110 kV power line caused by lightning, the operation of line protection is correct, while transformer differential protection is mal-operation. The main reason confirmed for the mal-operation of transformer differential protection is that the transformer protection does not handle the zero-sequence current caused by external fault. This paper proposes the improved measures to guarantee the power supply reliability.

Abstract:The criterion of the loss of excitation in generators is analyzed in the paper, and the method for the transformation of low excitation limit curve to impedance plane as well as the relationship between impedance circle on the impedance plane and low excitation limit curve is proposed in the paper. Based on the analysis of the relationship between the track of impedance measured during the leading phase experiment and the impedance circle, the method to avoid malfunction is provided.

Abstract:Security-constrained unit commitment (SCUC) and security constrained economic (SCED), which take into account the security and economy of power system operation simultaneously, have caused extensive attention abroad. In recent years, SCUC based on the algorithm Mixed-integer programming (MIP) has procured practical application and rapid development. This paper presents a review of recent advances in SCUC/SCED research, the research situation of the optimization mathematical model and algorithms of SCUC are summarized, the progress of the study on SCUC based on the MIP algorithm is described in category, and the main methods and principles combined with their advantages and disadvantages are analyzed and reviewed, furthermore, some aspects that need to be urgently solved in applying SCUC/SCED to China are proposed.

Abstract:Tianguang ±500 kV HVDC power transmission system is the first HVDC project in the CSG, and the second buck power HVDC transmission project in the China, which made great contributions in the power transmission from west to east and the economics development of the Guangdong province. With the growth of operation time, the trouble in the HVDC control and protection system becomes more and more serious, and has caused Tianguang HVDC transmission system single pole even bipolar pole to block for several times. It is necessary to update the control and protection system of Tianguang HVDC transmission system. The characteristics of PCS-9550 as well as its application in Tianguang HVDC transmission system are introduced in the paper.

Abstract:The artificial fish swarm algorithm,which is combined with the mutation operator and simulated annealing algorithm is researched. We have improved the mutation operator and presented a method to tentative determining of mutation probability,and The economic objective function and security objective function is combined to improve the established optimization models of reactive power distribution network. The artificial fish algorithm which combined the impoved mutation operator and simulated annealing algorithm is applied to the reactive power optimization, the actual system is taken as an example to calculate ,The result shows that the improved algorithm for reactive power distribution network optimization can be reasonable and feasible.

Abstract:This paper discusses the problems in the operation of 220 kV backup lines in Jiangsu power grid, the functions, primary operation modes, protective selection and the application of automatic device configuration of 220 kV backup lines are introduced, and the corresponding solutions and recommendations are proposed. It will greatly improve the quality of power grid operation through the enhancement of the operation management and research of backup lines, giving the backup lines full play to a role, having reliable, fast and flexible stand-by.

Abstract:The protection channels between the power cable and overhead power line are mainly fiber channel and high frequency transmission channel. The right choice between the two channels needs to be made according to the actual power line. Based on the characteristic of mixed power line, this paper expatiates how to make the choice between the fiber channel and high frequency channel, and analyses the application of the two channels on mixed power lines, especially, it discusses the application of high frequency transmission channel in high voltage mixed line, this paper can provide a reference for the feasibility study on the selection for protection channel in mixed power lines.

Abstract:This paper briefly introduces the running situations of 10 kV power cable upgraded to 20kV, interprets the projects of status assessment before boosting, and describes the marks of the assessment. The detection and requirement of the testing items before boosting are introduced; the testing items, requirement, and experimental results after boosting are also presented. This work provides practical application experiences for the operation of 10 kV power cable upgraded to 20 kV.

Abstract:This paper proposes the run-lines to simulate the fault of single-phase earth of 35 kV power network in network test station. There are two connection modes, including neutral insulation and neutral earth with an arc suppression coil. The auto-reclosing current is capacitive and inductive separately. Some desired results are achieved through more than 100 research trials, which can provide practical value data for the normal and reliable operation of 35 kV power network.

Abstract:The implementation process of the scheme of Calibration Capability Verification of Second-Class Standard Mercury Thermometer organized by the National Accreditation Board is introduced in the paper, and the testing results are analyzed. Reasonable proposals are also provided in the paper to reduce the impact of errors. The proposals are useful to the improvement of the calibration capacity of standard mercury thermometer.

Abstract:Whether the selection of 110 kV network structure patterns is reasonable has great effect on the reliability of the whole power grid. Through exploring the scientific and rational assessment index system, the methods of comparison of multi-schemes and quantitative analysis, this paper discusses and demonstrates 110 kV network structures patterns which are suitable for Tai Lake New Town of Wuxi, at last puts forward the proposals.

Abstract:According to the static electromagnetic field theory, the system for the prediction of electromagnetic radiation is developed under the environment of GUI in MATLAB. The system can be used for the prediction of the power-frequency electric-field intensity and the magnetic induction intensity produced by 500 kV or under 500 kV transmission line. In order to analyze the reliability of the system, comparison between predicted data and measured data of typical power transmission lines is made in the paper.

Abstract:In allusion to the traits of consuming randomicity and intermittence of wind farm power contribute, and in order to adapt the requirements of smart grid, this paper proposes the application of EHV controllable reactors in long transmission lines of the station to pool interconnection of wind farm, which can intellectualized regulate reactive power and voltage of transmission line of the station.

Abstract:The information security problems of the current substation automation system are analyzed. In order to guarantee the substation systems safety and stability, this paper proposes the method that combines the border and inside protection, hardware and software protections, and the measures are also put forward.

Abstract:It can supervises and manages the systems based on various operating systems, database and network application effectively through the ITM v6 (IBM Tivoli Monitoring 6.X) of IBM company. In this way, it can availably monitor and analyze the performance of various components applied in enterprises. The technical study on how to apply the ITM to realize the information system supervised management is proposed in this paper, the deployment realization and the application process of the whole architecture of ITM are also introduced, the key points to be noticed for the supervised management in daily operation of power information system are collected, which is combined with the actual ITM application of Wuxi Power Supply Company. This paper can provide a reference for the source of company management and information system operation.

Abstract:The paper introduces the application of sending short messages based on GSM/GPRS on substation monitoring and controlling system, its system architecture is also presented. It describes the implementation processes of GSM/GPRS short messages, at last the message coding is illustrated in detail.

Abstract:The condition that fouling in boiler and salt accumulation on turbine blades occurred under OT condition after one overhaul cycle of a supercritical once-through boiler in Changshu Huarun Power Generation Co. Ltd. is introduced in the paper. Through the analysis on the fouling and salt accumulation, the causes are inferred, and the notes that should be paid attention to under OT condition are discussed. The oxide scale inside the superheater and reheater should also be paid much attention to.

Abstract:According to the experience of 330MW boiler mixed burning anthracite, lean coal and lignite, the effects of mixed radio and mixed mode on the operation safety, economy and the unit output are analyzed. The view that mixed radio and mixed mode should be determined by the characters of the boiler and coal mill is proposed in the paper, and the economy can be improved just by reasonable adjustments.

Abstract:The reasons for the blocking phenomena occurred in the Desulphurization System are analyzed in the paper. The harm of the blocking phenomena to the operation as well as the problems caused by the removal of elements heated in GGH is pointed out, and the solutions for the blocking phenomena are also proposed.

Abstract:Resin leakage takes place in the ion exchange of generator inner cooling water system during the operation process, and this condition has led to a little leakage of resin into the generator stator coil. In order to solve the problem, the reasons for the leakage are analyzed in the paper, and the gas-water resonance method is adopted to wash the generator stator coil. Good results have been achieved.

Abstract:This paper describes grid concepts at home and abroad, the situation of investment and development combined with internal power advantage. Several problems are analyzed and discussed. There are proposed four stages to make the development of smart grid maturity, which are include that the ideal of academic, technical concepts, recommendations for the development of the intelligent network planning and design and construction for reference.