Abstract:The demand for Industrial Ethernet as a real-time control network is increasing as manufacturers realize the benefits of employing a single network technology from the boardroom to the plant floor. Variable speed wind turbines with active pitch control system are most favorable and prevailing nowadays. This thesis makes a research on the feasibility of applying Ethernet in electrical variable propeller pitch system. Based on integrated Ethernet POWERLINK, communication and control advantages of pitch drive are discussed. The test platform of pitch system based on motor load, including the system structure, components and its relevant results is also introduced in the paper.

Abstract:Aiming at attaining the maxim return of power generation in a specific period, this paper establishes a novel probabilistic optimal scheduling model of cascade hydroelectric stations by forecasting probabilities of contingency states and electricity price in the next dispatching period by means of Markov chain. In addition, the influences of time-varying load are analyzed by adopting the load subjected to normal distribution. The detailed representation of cascade hydroelectric stations, which comprise water volume, water discharge, water head and water inflow, is considered in this paper. The forecasting probability of the unit state and optimal scheduling decision-making are close combined in this model. On account of the advantages of differential evolution such as searching efficiency and robustness, this paper applies the algorithm and monte carlo simulation to a cascade hydro plants system. The results demonstrate the rationality and validity of the proposed model.

Abstract:According to the energy-saving and emission-reducing request of our power introductory, a dynamic optimal dispatch model is formulated considering both minimum fuel consumption and minimum exhaust emission during dispatching period. The multi-objective optimal problem is reformulated into single objective problem maximizing satisfaction by means of fuzzy set theory. A series of equations about satisfaction are newly added to the KKT (Karush-Kuhn-Tucker) equations, forming a method suitable for the proposed model. The numerical results on IEEE 30-bus system verify the feasibility and effectiveness of the proposed model and method.

Abstract:The switching protection of steam turbine in zero-power condition, the effect of incomplete import of neutral point branch current on backup protection, the entry mode of rotor voltage prepared for loss of excitation protection, the injection type stator ground protection, the injection type rotor ground protection and the highly sensitive transverse differential protection are researched in the paper. The conclusions can provide valuable reference for the research, development, design and engineering implementation of protection system in oversize power plants.

Abstract:The differential protection can get to work caused by two-phase short circuit fault happened in the pile head of shielding coils. From the waveform during the fault clearing process, the two-phase short circuit fault was changing to the three-phase short circuit. The role of the main transformer shielding coils is introduced, and the on-site failure checking as well as the analysis of differential protection waveforms are presented in detail. The magnitude and angle of fault current flowing through the three-phase winding of the star-side of the main transformer are also analyzed theoretically, when two-phase short circuit occurred in the triangle side of main transformer linked Y0 / △-11. And the analysis results match the actual fault current waveform well. The failure development process can be inferred as basis of correct positioning of failure and main transformer operation.

Abstract:The issues associated with the generator stators, rotors and the accessory systems occurred during the maintenance period in recent years are introduced and analyzed in the paper. The conclusions can provide valuable reference for the operation, maintenance and management of generators in large-scale power plants.

Abstract:Through the study on the feature of fractured core of composite insulator in a certain accident and the sampling test of the imported composite insulator on the same lot operating on 500 kV transmission line, the reason of the core fracture of composite insulator is analyzed. The fracture reason is ascertained that the mechanical performance of core is degraded by acid erosion on account of poor sealing end and unreasonable interface design. At last, the countermeasures of such composite insulator in operation are given to ensure the safety and reliability of power system.

Abstract:To study the audible noise characteristics of UHV Transmission Line, site measurements and statistics of audible noise of UHV test line segment are carried on. And the audible noise level and spectrum characteristics on different weather conditions are also analyzed. The results demonstrate that the audible noise limit of UHV test line segment is 55 dB, which is the same with that of 500 kV AC transmission line.

Abstract:Smart substation will be the developing direction and an inevitable trend of the future substation, which is a great challenge to the traditional substation, though the technology developing process of the smart substation is a gradual perfecting, time consuming, and progressive one. Comparing with the traditional substation, this paper introduced the main design points of the 110 kV smart substation. And the implementations of its process layer, the bay layer, the control layer are described in detail. In the end, the design scheme of 110 kV smart substation is discussed and some proposals are also given.

Abstract:This paper introduces the three typical configurations of the remote tripping. And the advantages and disadvantages of them are analyzed and compared. In the end the differences among the three protection configurations and the problems that should be paid attention to during actual operation are presented.

Abstract:Conventional impedance relay will refuse to trip according to an analysis of measuring impedance by means of impedance locus method when wrong-phase-coupling of traction power supply system occurs. Based on the characteristics of wrong-phase-coupling faults, by means of voltage vector diagram, variations of two power supply voltage and phase voltage are regular. According to this feature combined with current incremental protection, a new protection scheme is developed. The existing simulation results and the analysis of actual data on the faults show that, with its good ability of fault identification, this protection scheme can be equipped in the traction power supply system.

Abstract:This paper introduced particle swarm optimization (PSO) algorithm, which is efficient and quite immune to local optima. The paper applies PSO algorithm to electrical load parameter identification, and the results verify that PSO algorithm is fairly good in both efficiency and global superiority. The load model based on the algorithm is of high accuracy. In the end, simulation experiments of engineering example are carried on, and the results confirm the availability of both PSO algorithm and the load model.

Abstract:The paper analyzes the current situation about the protective relay of double circuit lines on the same tower, and elaborates the judge of different types of protection when faults happen. The advantages and disadvantages of the traditional protection are summed up. And the characteristics of faults and the principle of fault phase selection are studied. Then a practical fault phase selection method is presented. The fault phase selection of a 220 kV double circuit lines on the same tower is carried out using this method. The results of fault analysis, which is the same as the actual fault, verify the feasibility of the proposed method.

Abstract:Unique steady state elimination method is a new method for eliminating resonance in nonlinear system presented recently. Its basic idea is that if there is a normal (non-resonance) solution for the system, and the steady state of system is unique, then the corresponding conditions are the conditions for eliminating resonance. In this paper, this new method is applied to analyze the eliminating of ferroresonance in neutral grounding power system. Based upon Matrix measure technology, the conditions for eliminating this ferroresonance are obtained, which can be determined by the measure of a matrix. The conclusions of this article are proved correct by numerical simulation, and it shows the effectiveness of unique steady state elimination method.

Abstract:Against the construction lag and the necessity to accelerating the development speed of Smart Distribution Grid AVC (SDG AVC), the paper presents the concepts and frame, objective, main components and key technologies on the basis of combining current AVC objectives and features of SDG. Authors hope to play a role in attracting valuable opinions in research and development on SDG AVC, also call for increasing investment in SDG AVC.

Abstract:Based on the survey and monitoring of low-frequency noise pollution caused by indoor distribution transformer installed in high-rise residential buildings, the structure noise in the building caused by the low-frequency noise is analyzed. Then effective measures and implementation plans are selected and proposed. The achieved results are proven to be well and meet the relevant environment standards after the treatments. The paper provides good noise reduction measures for the new built indoor distribution in Jiangyin city, and accumulates some experience in power environmental management.

Abstract:As the international standard exchange format, PQDIF has been widely applied in power quality monitoring system. PQDIF file generation is usually realized only in system side limited to technical difficulty. This paper analyses the structure of PQDIF file, proposes the enabling technologies of realization in embedded hardware platform, and introduces the procedure of realization in PQS-880 series online power quality monitor. The application foreground of PQDIF is also expounded in the end.

Abstract:The choice of system scheme is very essential and important during the construction of large-scale power quality monitoring system. After analyzing the basic functions of the monitoring system and two kinds of interactive system modes, the paper introduces system schemes with two-layer and three-layer logical structure. Based on the analysis and comparison of the two schemes, their application situations are given respectively. In the end, the paper also presents the communication interface and data interchange format of monitoring system.

Abstract:Considering the practical difficulties confronted by coal-fired power plants, there is still a long way for these plants to develop energy saving technology when low-carbon economy was promoted worldwide. To improve the level of energy saving in coal-fired power plants, innovative energy saving management should be carried out as the key, and new technology should also be applied for the continued optimization of equipment and the system.

Abstract:The application of infrared thermal imaging technology is the main content of the paper. The potential hazards of high-and low-voltage electrical equipments, the high temperature and high pressure pipeline of turbine and boiler during the practical operation process can be timely detected and eliminated just using the infrared thermal imaging technology. It's believed that the technology will play an irreplaceable role in the safety operation of thermal power plants and the power grid.

Abstract:According to the air-leakage mechanism of rotary air preheater, the seal reconstruction of air preheater has been conducted in #4 unit. The fundamental measures adopted to reduce the air-leakage as well as the feasibility of the reconstruction project and practical operation condition are also introduced in the paper.

Abstract:The forced draft automatic system is the fundamental part of the combustion automatic control system, and the main difficulty of the air supply technology is the accurate measurement of air flow. It makes the operators be able to monitor the ratio of air and coal momentarily, and can also provide necessary information for the operation of the forced draft control automation system. The issues occurred during the measurement of secondary air and the technical reform experience are also introduced and analyzed in the paper.

Abstract:The drift phenomenon of inverter resistance values leading to the increment of threshold setting value occurred during the long operation process of BORRI E2001 UPS is introduced in the paper, and the harmful consequences as well as the useful preventive measures are also proposed in detail.

Abstract:Due to the features of being fluctuant and intermittent of wind speed, wind power generation has great uncertainty. In order to ensure the safety and stability of power system, it is very necessary to study the influences of wind power integration on power system. The situation at home and abroad of wind power is introduced, and the summaries of the influences of large-scale wind farms integration on power system and the remedial measures are also proposed in this paper.