Abstract:Based on the investigation and discussion of district power grid under-frequency and under-voltage load shedding scheme, this paper pointed out that Jiangsu district grids exist problems of serious power shortage and local isolated network under extremely serious chain faults with leveling and districting operation characteristics. Through checking adaptability of Jiangsu district power grid UFLS & UVLS scheme, improvement suggestions of UFLS & UVLS scheme in Jiangsu district power grid was proposed. Finally, considering of UHV grid interconnection, close electric connection, large proportion of power reception, and uncertainties of new energy output in the future, future research direction for setting under-frequency and under-voltage load shedding scheme is prospected.

Abstract:Problems in the development of China power grid were analyzed in this paper, From the viewpoint of dispatch and operation, the project of intensive application of PMU data and the design idea and application function of integrated intelligent alarm were described in detail. The overall framework of integrated smart alarm was proposed ,which was based on information supported platform, to achieve risk pre-alarming, fault analysis and decision support, and then improve dispatchers' online determining and emergency incident handling capabilities.

Abstract:Intelligent state monitoring of substation equipment is an essential factor to realize digitalization of substation information, networking of communication platform and standardization of information sharing. It can also support real-time automatic control, online analysis and decision, cooperative interaction and other advanced features, thus to realize interaction with neighboring substation and dispatching center when necessary. Intelligent state monitoring of electrical equipment can not only ensure proper operation of electrical equipment, but also realize electrical equipment integrated diagnostics using its run state database based on its expert system, so it is the basis of the smart substation. Focused on the present technology of equipment monitoring in substation and combined with the status in this area and the development direction of smart grid in recent years, this paper gave summary of intelligent condition monitoring system for substations.

Abstract:An accident of 10 kV main transformer switch overstep trip was analyzed in this paper, which was caused by 10 kV line switch miss action after permanent faults. The override tripping's cause and process and the on-site analysis and treatment were illustrated in detail. Finally, anti-accident measurements and cautions in on-site operation were proposed based on the analysis of this accident.

Abstract:Review on Nantong area electric transmission line and tower falling incident caused by wind damage, and diagnostic analysis on the cause of tower falling from different points of view of natural calamities and technical equipment, etc., and aiming at the current technology research and design standards, this document further analyzes several possibilities resulting in the tower falling caused by wind damage. Finally it proposes the limited countermeasures and specific measures of the tower falling caused by wind damage, from optimizing the iron tower structure, differentiated designs, comprehensive management and other aspects. It is provided for application reference.

Abstract:Harmonic pollution will be generated when wind power is integrated to power system. For large-scale centralized wind farm, superposition effect generated by harmonic must be considered. This paper analyzed cause of harmonic generated by wind power. Combined with project cases, harmonic current of power grid common connection point were calculated by two kinds of superposition algorithm. It can provide a reliable basis for the construction of wind power.

Abstract:Wuxi 220 kV Xi Jing smart substation will be designed as two networks and three layer which includes control layer, interval layer and process layer. In 220 kV voltage level, bus and transformer protection use 'direct sampling network trip' mode, while line and bus connection protection use 'direct sampling network trip' mode, and process layer network use double configuration. In 110 kV voltage, all protection use 'network sampling network trip' mode, thus we realize network redundancy configuration through unification of three nets: SV sampling GOOSE, IEEE 1588. Protection and control function is integrated in a unit. Station level realize sequence control which is based on master station re-confirmation mechanism, distributed state estimation, intelligent alarm, fault information comprehensive analysis and decision-making intelligent substation advanced feature Etc. Substation is equipped with measurement comparative analysis system, which can realize long-running characteristic comparative analysis of traditional transformer and various electronic transformer under kinds of working conditions.

Abstract:Line optical differential protection of smart substation using optical electric current transformer in one side and traditional electromagnetic TA in the other side. It is necessary to test the synchronization of asymmetric differential protections in order to ensure safety and reliability of the system after optical differential protection put into operation. An experimental method was proposed to test synchronization of the line differential protections based on rise flow under integration test environment. The synchronization test of different differential protections system was carried out by using this method. Comparative analysis of the results indicates that it is important and necessary to test the synchronization for digital line current differential protection.

Abstract:The unit protection devices of Shahe pumped storage power station were imported from the ALSTOM Company along with the main unit, which had some defects in design, protection, operation and other aspects according to the relevant domestic and industry standards. This paper analyzed the problems existing in the protection devices of Shahe station, and illustrated the successful domestic reform which had been improving the protection performance by applying some advanced technologies & principles.

Abstract:With widely utilization of the smart substation, the centralized busbar protection is unable to meet the requirements of high-capacity data exchange when there are more access intervals. So the development of distributed busbar protection for smart substation is the first imperative. A configuration of distributed busbar protection for smart substation was introduced in this paper, and the corresponding solution for high-capacity data transmission and synchronous sampling was proposed.

Abstract:The paper analyzed the problem which the staff faced in the acceptance signal process when new substation put into operation. Based on the basic principles of data acquisition and monitoring system, effective solution was proposed. Through trial operation in practical work, it can improve efficiency of the acceptance work, greatly reduce workload of inspector, provide reliable basis for the improvement of the acceptance process.

Abstract:Inverter with stepless speed regulation changes the operation way of AC asynchronous motor. It is adopted widely because it can save energy strongly when load changes greatly. So frequency control devices are more and more widely used in thermal power plant's air blowers and pump motors. The paper analyzed the characteristics of the power converter used at present. On the basis, problem which should be paid attention to in designing high voltage inverter of thermal plant was summarized.

Abstract:Taking black start power station in northern Jiangsu provinces as an example, this paper presented generator protection configuration and design scheme of black start generator, and introduced the testing process of intra-station start and system black start. Combined with differences between black start test system and the normal operation system, the principles, adjustment situations and operation cautions of some protection and automatic devices were selectively analyzed. Finally, operation requirements of low frequency and low voltage protection were proposed according to the special requirements of black start units.

Abstract:With rapid development of digital substation, IEC 61850 can be widely used. HVDC projects are also in quick developing process, but the digital level of converter station is much lower than substation, mainly reflecting in transmission protocols and transmission network etc. Based on the reconstruction of Tian-Guang HVDC project, this paper illustrated the application of IEC 61850 in the HVDC system from two main sides: device modeling and station-layer communication redundant processing. With the improvement of digital level, IEC 61850 will also be an important cornerstone for the development of automation technology in HVDC systems.

Abstract:Conceptual design of interaction between large-scale electric vehicles and grid (V2G) was proposed. The interactive manners and objectives of large-scale V2G were analyzed. And the interactive market mechanism and coordinated control strategies were designed. Based on the control strategies, conceptual design of the interactive coordinated control system was proposed from two aspects including functions and interactive information. The research could provide methods and ideas for two-way power energy and information interaction of future large-scale V2G applications.

Abstract:Based on the summary of effect on power system production and operation by video monitoring system, this paper analyzed the existing problem and difficulty of realizing regional network of electric video monitoring system. A method adopting multilevel distributed deployment, video streaming transmission, load balance and engineering data synchronization technologies was proposed. This method has characteristics of unified management, distributed deployment, cross-platform application etc, can solve regional and even whole province networking problem of transformer substation's video monitoring system, so as to achieve the requirements of unified monitoring and management. The design and implementation have been successfully utilized in multiple provincial and district levels video monitoring network, and can meet the needs of the users.

Abstract:Voltage stability prewarning based on the PMU technology needs to monitor operation of power transmission lines in real-time. The existing branch voltage stability index only can be used in the case of the constant power factor because it ignores the effect of reactive power. A new index considering branch active and reactive comprehensively was proposed in this paper. The index is applicable to various load power factors. Detailed derivation was made on this index. The index was tested in IEEE14 bus system, and the results indicate that it could reflect branch operation and voltage stability conditions better.

Abstract:There are two different theories about over voltage generated by arc grouding in insulated neutral system, arc extinguishing theories of fundamental frequency and high frequency. With fundamental frequency theory, the over voltage can not endanger the safe operation of equipments because it is only 3.5 times. While with high frequency theory, the over voltage can lead to the system faults because it is 7.5 times than normal one. Two faults had been analyzed to prove the correctness of high frequency act extinguishing theory, one is two phase grounding fault of 10 kV bus and another is C-phase grounding fault of 10 kV oil-minimum breaker.

Abstract:Ultraviolet corona detection technology is a comprehensive technology to judge whether equipment works normally by some information obtained by applying ultraviolet imaging technology. This information is the ultraviolet radiation information when corona, flashover or arc discharging happens in equipment. Current application situation, prospects and typical cases of this technology in power system were presented in this paper. The application of ultraviolet corona detection technology in equipment outer insulation status evaluation is introduced through an example.

Abstract:This paper first deduced the calculation formula of induction voltage and current of multiple loop transmission lines, and concluded that the induction voltage and current of outage line could be calculated by operating lines vector superposition of their separate outcome. Furthermore, induction voltage and current of idle transmission line under different phase arrangement were calculated, which showed that lines induced voltage current could be reduced through reasonable arrangement of running line phase.

Abstract:In order to identify the root reason for the vacuum degradation issues occurred in three 600 MW power plants, field inspection as well as calculation analysis on past operation data has been carried out in this paper. It's concluded that the observed abnormal increment of flow resistance in the condenser may be the main reason. After the implementation of associated measures, the vacuum has been significantly improved. Further, the low speed operation of the circulating pump is considered to have effect on the deposition of the sediment and impurity. The similar plants should pay special attention to this matter.

Abstract:The No.5 and No. 6 steam turbines manufactured by Shanghai Steam Turbine Co.Ltd., were put into operation in November, 2004 and July, 2005 respectively. From then on, the heat consumption of No. 5 has always been approximate 150 kJ/ (kW·h) higher than No.6 steam turbine. The reason for the much higher heat consumption had not been obtained until 4 times of inspection were implemented by the technology researchers. After associated measures were performed, relatively lower heat consumption has been achieved.

Abstract:Supercritical double extraction steam turbine is utilized in 600 MW power plant of Nanjing Thermal Power Generation Company. This type of steam turbines has rarely been adopted in China. The design features of 600 MW supercritical heat supply steam turbine are introduced in this paper, and analysis on reliability of the steam turbine as well as the design scheme and control strategy has also been carried out. Since better economic and social benefits can be achieved using 600 MW supercritical double extraction turbine, it is believed that this type of steam turbine can serve as a valuable alternative.

Abstract:Frequency is one important index of AC system power quality. With the expansion of the regional power grid scale, the existing assessment standard system has a certain limitation. Especially as new energy such as wind power and PV are accessed into grid, the traditional assessment system meets some new requirements. This paper studied national standard and tie-line load control status of five regional power grids. The problems and the reasons were summarized. Finally improvement suggestions were proposed to provide a useful reference for the perfection of the existing assessment system.