Abstract:This paper presents a bi-directional interaction based approach for on-line coordination across multiple control centers in the area of reactive power and voltage control. Some results from Jiangsu electric power system demonstrate its real-time bi-directional interaction and show that it has a great performance. The proposed novel method also can be extended to similar applications of smart grid.

Abstract:Represent the purpose and importance of Multiple-Winding High Voltage TV's Second Load Configuration Optimization. Analyze the principle how second loads of various windings affect the error of TV and tests were done to verify it. Guide renovation project executing by theory analyses. The actual error of TV on line is reduced. Safety in production and equity of commercial transaction is assured.

Abstract:The technology and application of Automatic Generation Control (AGC) security constraints control which takes advantage of security constrained dispatch are described in this paper. When the system is in a state of emergency or warning status, AGC performs the corrective and preventive control of stable cross section limit in use of restricting units of AGC to adjust the upper and lower limits or direction based on unit adjustment programs and sensitivity information proposed by the real-time security constrained dispatch. The results show that the AGC security constraints control can effectively eliminate and mitigate the limit of grid stability section, and increase the level of grid security and stability.

Abstract:Based on the guide requirements of grid-connected photovoltaic power station, a control strategy based on low voltage ride through capability of the PV inverter is proposed for the adverse effects caused by photovoltaic power station off the grid when power failure taking place. The increase of active current can be limited, and the reactive current can be given through putting into the control strategy when the power grid voltage drops. Simulation results show that in the case of network voltage dropping deeply and shallowly at the grid-connected point of photovoltaic power station, the control strategy can ensure that the PV inverter output current flow doesn't overcurrent. At the same time, a certain amount of reactive power can be sent out to the grid to support the recovery of voltage at the grid-connected point and achieve low voltage ride through.

Abstract:Power System Stabilizer (PSS) models of application configuration are not the same in the modern power systems. However, the design methods of traditional PSS parameter are limited to the traditional PSS model. The optimization method of generator PSS parameter with multi-model adaption is proposed in this paper to achieve the optimization target that the effect of PSS phase compensation is realized. Particle swarm is used to optimize the PSS parameters of the generator. This method is highly adaptable to a variety of PSS models. It is not only applicable to the traditional PSS model, but also to the new PSS model without the lead and lag part. Examples show that the optimization method of generator PSS parameter with multi-model adaption can effectively enhance the system damping and suppress low frequency oscillation.

Abstract:Infrared thermometric diagnosis techniques can found defects in electric power equipments in time, avoiding a fault to expand into an accident. Based on the analysis of infrared thermometric mapping of 220 kV disconnector, the cause of overheating defects is the poor touching between dynamic and static contacts. The analysis result is verified by cutting power and examination at the scene. It shows that infrared thermometric techniques is valid to detect and diagnose the overheating defects of a disconnector.

Abstract:Typical faults of the operating mechanism in vacuum load switch is introduced in this paper. Based on the category and the theory of the operating mechanism, causes of a fault occuring on it in 10 kV vacuum load switch are analyzed. According to the relevant operating regulations and working experience, some precautions are proposed, offering reference for selecting and debugging similar switch.

Abstract:A secondary voltage loss fault of 220 kV capacitor voltage transformer (CVT) is introduced. The fault was caused by primary lead disconnection in the electromagnetic unit of 220 kV CVT. Possible reasons for the fault phenomena are analyzed. Combined with the structural characteristics of CVT, a method of judging fault causes indirectly by exclusive method and correlation tests is proposed in the case that this kind of equipment can not be checked through disintegration. Discussions are given for improving this kind of equipment.

Abstract:Dynamic Voltage Restorer (DVR) is a voltage type power quality compensator device which is connected in series between grid and load in order to protect the power quality of load side. A new type of cascade multi-level DVR is proposed in this paper. Two H-bridge power unit cascade constitute an inverter unit, which depends on rectifier circuit providing energy to inverter unit DC side capacitor. Capacitor coupling is used to string into the power grid in device. Digital signal processor (DSP), field programmable gate array (FPGA) and complex programmable logic device (CPLD) are chosen to constitute control system. A detailed hardware and software design is carried out. The actual running test results show that the cascade multilevel DVR has fast response, can generate compensation voltage quickly and efficiently, and ensure electric quality of side load.

Abstract:First the polarity verification method of traditional electromagnetic transformers is introduced。 By analyzing the characteristics and working principle of electronic transformers,a polarity verification system of electric transformers is designed which is based on data analyzing software. Also the implementation and authentication method of DC law in polarity verification of different electronic transformers are elaborated, which has provided an effective means of polarity verification of electronic transformers, and ensured the accuracy of application in protection, monitoring, measurement and so on in intelligent substations.

Abstract:The effects that SFC system operating parameters have on fractional harmonic are studied by building Matrix Laboratory (MATLAB) closed-loop simulation model of static frequency converter (SFC). Analysis show that total harmonic distortion (THD) decreases as loop current increases, and increases as supply voltage increases. Fractional harmonic content has the similar law of changes, of which the reason is the change of commutation overlap angle. The times of fractional harmonic are closely related to output frequency of machine bridge. The simplified relation between fractional harmonic and machine bridge output frequency is derived by the method of analogy, and its availability is verified by simulations.

Abstract:A method of detailed static var compensator (SVC) control system simulation model built by PSCAD/EMTDC-MATLAB co-simulation technology is proposed based on the interface components of MATLAB/Simulink and PSCAD/EMTDC. The effective SVC control device algorithm is used by the voltage/reactive power control model of the core component of control system. The control system model is simulated in PSCAD/EMTDC model of SVC dynamic model test system. The compare between Simulation data and the wave recording file of actual SVC control device dynamic simulation test shows that compensation characteristics and dynamic response performance of control model are the same as those of the actual device. The feasibility of simulation modeling methods and the correctness of the simulation model are proved.

Abstract:Combined with network structure diagrams and the symmetrical component method of distribution network with DG, an algorithm is developed. In the algorithm, the fault component of phase to phase current difference is used as a judgement whether a protection acts and can be computed with connected post-fault datas and pre-fault datas. The algorithm is applicable and can identificatethe fault in or out of the protection area accurately. A distribution network model with wind turbine is built in MATLAB to conduct a simulation and verify the algorithm. The simulation results show the algorithm's accurate identification and ability of reducing of the impact to current protection with the access of distributed current to distribution network.

Abstract:Solid state switch insulated gate bipolar transistor (IGBT) is made as main switching elements. The frequency and duty cycle are regulated by microcontroller. High frequency and high voltage square wave voltage is achieved by step-up of pulse transformer and shaping of shaping circuit. The shortcomings of low switching frequency and amplitude with difficult coercion which existing gas switch has are overcome. The frequency of pulse voltage can be adjusted between 1~15 kHz. Voltage amplitude can be continuously adjusted between 0~20 kV. Power has good role on overvoltage and overcurrent protection at the same time.

Abstract:Distribution system state patrolling hand-hold intelligent terminal proposed integrates various technologies and encrypted communication. Besides, it works together with intelligent management system of distribution system patrol. Then it realizes kinds of functions including patrolling management in distribution system, defect management and control of power outage (or charged) management self-healing system. It also serves for other various applications and third-party applications.

Abstract:The climate change has more impacts on load year by year, as well as on accuracy of power system load forecasting. 2011 full-year load level of Nanjing grid is analyzed in detail. The air conditioning load of Nanjing in summer and winter is calculated based on relationship between daily maximum load and temperature. The sensitivity coefficient of highest load and temperature is obtained which provides an effective reference to improve Nanjing load forecasting accuracy.

Abstract:Static var compensator plays an important role in improving the security and stability of power system. On the base of the control theory, nonlinear optimal controller for static reactive power compensation system is designed through exact feedback linearization and nonlinear optimization theory. The designed controller is simulated in an example and then compared with conventional control method. The result shows the designed nonlinear optimal cntroller is superior to the conventional controller.

Abstract:While the new No.2 main transformer in a 220 kV nail substation starts normly and is recovering the running mode, over current protection A protecting neutral point reaches its action value during load growth and then the main transformer CB trip off. They are caused by the inconsistency between three-phase casing CT polarities of public winding in protection A. The fault process and protection's action behavior above are analyzed. Then some suggestions are give to attract more attention of workers responsible for acceptance and transfer to "zero drift" phenomenon and to improve the test method.

Abstract:The modification of exhaust gas temperature influenced by the variation of inlet air temperature is the most important work in the performance test of boilers. However, the difference between ASME code and GB standard always leads to misunderstandings. Based on analysis results of the modification method, it is concluded that the application conditions of this method is that: a good sealing of the air preheater should be maintained; the temperature of the inlet cool air should be adopted and the value of the air leakage ratio before and after modification should keep constant.

Abstract:Effects of coal-quality degradation on the safety and economy of coal-fired power plants are analyzed in this paper. It is advised that, along with the safety pre-warning mechanism, the evaluation model for the safety and economy of power plants facing coal-quality degradation should be developed. Besides, the quantification of these effects on production cost should also be carried out. It is believed that these advised measures will direct the mixture of coal and significantly improve the safety and economy of coal-fired thermal power plants.

Abstract:The platen superheater tubes in one 600 MW supercritical boiler have ruptured for three times. In this paper, the tube rupture processes, field inspection results and the operational features are introduced in detail. Further, analysis on failure reasons is implemented and several precautionary measures are also presented.

Abstract:For the Grade E gas turbine installed in Huadian Yizheng Combined Heat and Power Plant, the features of various types of inlet air cooling technology are analyzed in this paper. According to the performance of different types of cooling technology employed in similar gas turbines, the spray evaporative cooling method is advised for this plant. Besides, the economic performances of this air cooling technology are also proposed in this paper.

Abstract:Focusing on the abnormal issues including unsteady combustion and overlarge speed deviation of the M701DA gas turbine during the first starting procedure, this work firstly introduces the whole analysis process, and then, determines that the unreasonable setting of damping coefficient of the differential pressure transmitter is the main reason for these issues. By using new setting values, it is found that the abnormal issues are effectively avoided.

Abstract:For the boiler feedwater treatment issues, integrated membrane water treatment technology gathering the technology of ultra-filtration (UF), reverse osmosis (RO) and Electrical deionization ionization (EDI) is introduced in this paper. The application of this water treatment technology in the extension project of one thermal power plant, which includes the system flow, main treatment methods and equipment, is also presented. Through comparing the EDI technology adopted in the new treatment method with the traditional mixed bed technology, the advantages of the integrated membrane water treatment technology are further illustrated.