Abstract:In this paper, the principle of user defined modeling of PSS/E is described, while the detailed process of modeling is summarized. The electromechanical transient model of UPFC is established in PSS/E based on equivalent current injection method. Then a test system is used to verify the correctness of the model by simulations. The result shows that UPFC has an excellent capability in regulating power flows and bus voltages. Therefore, UPFC could reduce the power losses of power grid effectively after a three-phase short circuit fault occurred. At the same time, UPFC is able to recover the system to a stable operation state. As a result of the research, the dynamic simulation of power flow and voltage control by UPFC is realized in PSS/E.

Abstract:A full-voltage starting fault in the UHVDC system may cause very high over-voltage on transmission line and other equipment. The over-voltage threatens the safe operation of DC power equipment and system. In this paper, the overvoltage simulation model of ±800 kV Jinping-Suzhou HVDC project is constructed in PSCAD/EMTDC. The over-voltage and over-current caused by full-voltage starting faults under three operation modes in this project are computed. The amplitudes and waves of over-voltage are analyzed and the insulation margins of the equipment are checked. The results show that the highest amplitude of the over-voltage is 1 398.5 kV when full-voltage starting fault occurred in the current arrester configuration in ±800 kV Jinping-Suzhou HVDC project, which meets the requirements of insulation coordination. This study provides a reference for the design, operation and maintenance of UHVDC projects.

Abstract:According to the "highly integrated system, reasonable structure and layout, advanced and applicable equipment, economical, energy saving and environmental protection, support of integrated control" guiding ideology of the new generation of smart substation, and combining the characteristics of a new 220 kV generation of smart substation in Jiangsu province, this paper studies the main electrical connection mode in substations. The optimal design scheme of main electrical connection based on Gas Insulated Switchgears (GIS) equipment is proposed, and technical and economic comparisons to conventional electrical connection are made, which provides some referential significances in the construction of smart substation in future.

Abstract:Final-stage superheater tubes of power plant can fail by overheating, if exfoliated oxide scales were collected in lower tube bends. Using software of workbench, three-dimensional final-stage superheater panel modeling was established, and the temperature distribution of the steam and tube wall of twelve tubes was calculated by utilizing Fluent. Combining with the effect of tube wall temperature on the oxidation rate, the oxide scales growth behavior of superheater was analyzed, which can be used to investigate the thermal deflection of tube panel caused by steam-side oxide scales.

Abstract:Partial discharge testing is one of the most effective methods for inspecting the insulation condition of electrical equipment. Compared with the partial discharge testing of 1000 kV transformer, the partial discharge testing of 1000 kV reactor has the features of large capacity, complicated testing equipment, difficult shielding, and so on. In this paper, the configuration of testing device for 1000 kV shunt reactor, as well as its testing method, principle and calculation, are introduced. The main partial discharge test circuit of 1000 kV shunt reactor is analyzed. The testing parameters, such as test current, capacitance compensation, loss and so on, are calculated. The detecting sensitivity of PD detection circuit and anti-interference are analyzed. According to the testing equipment technical level, the parameters design and selection of main testing equipment's compensation capacitor, frequency conversion voltage, excitation transformer, and trap reactor are carried out. Finally, the basis for equipment development and field testing is provided.

Abstract:In order to solve the difficulty of locating the breakdown spot of UHV gas insulated switchgear (GIS) in field over-voltage withstand testing, this paper summarizes several breakdown spot locating methods, as well as their advantages/disadvantages. Focused on an advanced ultrasonic-wave-detection method, this paper introduces the basic principle and system configuration. Through a practical case, we analyzes the judgment and locating methods of breakdown spot after breakdown discharge occurring in detail. This method offers a reference for breakdown locating method to UHV projects in future.

Abstract:As the most severe assessment method in transformer commissioning testing, partial discharge testing can effectively detect insulation faults inside transformer. In this paper, the adjustable reactor has been firstly proposed and used in the partial discharge commissioning testing of the converter transformers in Jinping-Sunan ±800 kV DC transmission project. The capacitive reactive power of the converter transformer under testing has been analyzed and the inductive compensation has been calculated. The reluctance of the adjustable reactor can be adjusted smoothly, therefore the inductive compensation can be changed continuously in real time and the under-compensation or over-compensation problems of fixed reactor can be avoided. The testing method is validated in the field commissioning testing in Jin-Su UHVDC project and the filed partial discharge testing is completely successful.

Abstract:According to the State Grid's plan, a 6 km long 1100 kV GIL equipment will be adopted in Sutong GIL utility tunnel in 1000 kV "Huainan-Nanjing-Shanghai" UHV AC transmission lines project. This paper gives a detailed introduction to the necessity and effectiveness of UHV GIL over-voltage withstand testing and analyzes some common fault types. The electric field of the free metal particles, the spikes in GIL equipment and the GIL over-voltage withstand testing are implemented. Finally, the suggestions to UHV GIL over-voltage withstand testing are proposed.

Abstract:At present, the solution to the dynamic balance of energy supply and demand of electric power company is based on the experience of controlling power consumption. Because of lacking detailed user consumption records, it is unable to predict the future consumption of power grid based on historical demand data. Intelligent meter reading system is based on wireless sensor network, such as short distance ZigBee network. Therefore, the system has the features of data security and user node scalability. The example model shows that the reasonable capacity planning can realize the automatic and real-time monitoring of remote user's electric meter. The accurate records and real-time data backup reduces the material consumption of paper documents, and the statistical analysis of household consumption data improves the efficiency of management and provides a valuable basis for energy saving.

Abstract:Using nodes stress as maximum stress to evaluate tower component's safety is not accurate. A Lagrange interpolation function method for transmission tower stress calculation is proposed, and a power transmission tower stress calculation software is developed. Firstly, the method uses hybrid truss beam model for transmission tower, and finite element linear analysis and nonlinear finite element analysis are implemented on the structure of rigid and flexible units of tower. Then, the stress of each node is calculated, and through the Lagrange interpolation function the maximum stress can be obtained. Through the developed transmission tower stress calculation software, the process of tower accident is simulated. The simulation calculation results show that the calculation method has a high accuracy and can improve the accuracy of transmission tower structure safety assessment.

Abstract:Battery switching is one of the most important developing modes of electric vehicle. Currently the planning and construction of battery switching network have been carried out in most of the provinces of China. Typical battery switching network should include centralized charging stations for centralized charging and distribution stations for battery switching. In the reference of logistics' relevant contents, the routing problem of logistics team is solved, then according to the needs of distribution stations, on the basis of detailed analysis input and output of distribution stations, logistics teams and large-scale centralized charging station, the integration optimal scheduling model is built.

Abstract:This paper introduces the definition of "three-level grid", dividing method and encoding principle. The whole process of distribution network is sorted with "three-level grid". The "three-level grid" management ideas have been proposed. Finally, an application example is carried out to verify the operability of the distribution network planning method based on "three-level grid". The results show that the method of distribution network planning based on "three level grid" is feasible, and it accords with the actual situation of distribution network in Lianyungang area that has strong practicability.

Abstract:Taking the construction transition period of the power dispatch supporting system of Taizhou' smart grid (D5000) as the background, in the view of the deficiency of traditional verification methods, this paper proposes some reasonable optimization suggestions to safety measurements and remote control testing, etc. Through the application of the power dispatch supporting system in some substations in Taizhou power grid, the monitoring information transmission efficiency is improved, the integration of construction control system is accelerated, and the quality of monitoring information transmission is guaranteed.

Abstract:This paper analyzes the characteristics and manual testing difficulties of FTU. Based on modular hardware design, an automatic testing solution to FTU is proposed. The solution is effective to test FTU devices' binary input channel, binary output channel, AO channel and communication contacts, which ensures the correctness of each channel. At the same time, through analyzing the large-scale and automated produced testing data and using the quality feedback controlled scheme, the production qualification rate and production testing efficiency are improved. The solution effectively solves the problems existing in actual testing of FTU, and the applications show that it has a certain promotion value.

Abstract:This paper studies the feasibility of residual current increment for fault line detecting by analyzing the differential voltage between two stalls of multi-tap arc-suppression coil. Firstly, the differential voltages in the low voltage simulation model of theoretical calculating and from the practical measuring are compared to verify the feasibility of theoretical arithmetic for differential voltage calculation. Then, taking an actual engineering as an example, the change of differential voltage is analyzed, which provides a theoretical and practical basis for practical application of residual current increment.

Abstract:In recent years, coppered steel has been widely using in electrical grounding. The superior performance of coppered steel in corrosion prevention and welding are analyzed firstly. Then, the designing parameters for transmission tower, cable channel and substation engineering are proposed. Last, an actual engineering project is used to interpret the application of coppered steel.

Abstract:The wide-area measurement systems (WAMS) and control/protection systems based on phasor measurement units (PMU) are key technologies of smart grid. The reliability and effectiveness of communication infrastructure play a key role in realizing the functions of WAMS. To address the above issues, this paper first reviews the state of art of PMU/WAMS in terms of scholar research and practical application in the United States. Then, the communication requirements for WAMS according to the corresponding standards and specifications are summarized. Finally, given the developing status and trends of electric power communication in China, this paper proposes specific communication technologies and evolution schemes for WAMS under different scenarios.

Abstract:Reasonable network planning is important to urban distribution network construction. Existing connection modes are compared in terms of reliability, adaptability and economy. Reliability includes power supply, line failure and operational flexibility. Economy includes construction economy, operating economy and annual cost per unit. Adaptability includes network flexibility and resource consumption. The merits and scope of various connection modes are obtained through analyzing and comparing. The Huaian high voltage distribution network is analyzed, and then the problems existed in the network are pointed out. According to the results, the Huaian high voltage distribution network planning scheme is proposed.

Abstract:The fault at the phase A of a 35 kV transformer high voltage winding activated its differential protection. This paper theoretically analyses the short circuit current by using the substation equipment parameters and fault recording data. Also, the short circuit current is calculated by using the derived short circuit current computing formula. It turns out that the theoretical and computational results of the short circuit current are consistent with each other, which confirms the 35 kV transformer differential protection's correct action.

Abstract:The current transformer (TA) may influence the normal operation of measurement and protection devices. In this paper, a transformer protection tripping accident after a fault occurred in the outing line is taken as an example. According to the fault current data, the protection setting data, the TA secondary circuit testing data and the principle and saturation process of CT, their impacts on the protection devices are studied. The analysis shows that the action resistance of the line protection and transformer protection are caused by TA saturation. Therefore, the corresponding countermeasures for this kind of accident are proposed in the paper.

Abstract:Desulfurization agitator blade specimens, which have been used in the repair welding simulation test, were utilized to research the corrosion resistant of their base metal and welds, combining electrochemical corrosion test with immersion corrosion test. The results indicated that the corrosion resistance of the base metal and the welds was extremely strong in the test environment. The circumstance had no obvious effect on corrosion resistance, and corrosion resistance of weld was sufficient to meet the field operation demand.

Abstract:This paper introduced the origin of the flue gas pre washing treatment technology. Base on the field data of one 1050 MW coal-fired power plant, the paper analyzed the problems associated with the operation of flue gas pre washing treatment technology. For example too much water was entrained with gas, which would result in liquid level control disorders of absorption tower and the slurry quality deterioration caused by oil contamination. The influence of such problems was discussed, and then the corresponding suggestions on design and operation regulation were proposed.

Abstract:The stable operation of denitration system is helpful for keeping the exhausted nitrogen oxide under standard. This paper introduced the operating principle and main problems of the selective catalytic reduction system on the #1 unit of one power plant. Through analyzing influencing factors on stable operation of denitration system, measures were taken to ensure the stable working of denitration system, thus the exhausted nitrogen oxide can be under standard for a long period.

Abstract:This paper proposed an on-line data validation diagnostic method on thermoelectric information management system, based on the principle of the conservation of mass and energy. With the relations among parameters of thermal system, the method can diagnose and warn of the on-line acquired abnormal data, then the validation and treatment can be made by professionals. The method proposed was useful to fault diagnose and maintain the measurement instruments of information management system of thermal power units, which has high practical value.