Abstract:The statistical analysis for the running condition of protection relays over the years in a Power Grid is carried out in this paper. It is demonstrated that the routine preventive maintenance has not adapted to the need of power grid development under the condition of significant improvement on reliability and flexibility of the microcomputer protection. More, with some practical fault example, the necessity of condition based maintenance is proved. Finally, it is introduced the works about condition based maintenance of protection relay.

Abstract:According to the requirement of constructing super large-scale smart meter automatic verification system by which 8,000,000 smart meters will be verified yearly in Jiangsu province, the construction, software and key design of a smart meter automatic verification system is introduced in this paper. This system is mainly composed of automatic warehouse, AGV, robot, verifying attachment, suitable for constructing super large-scale system. The design of verification task scheduler process is discussed in this paper, including the requirement of the design, two verification task scheduler methods meeting the requirement and a simple scene comparison suitable for the two methods. This paper tries to find a new way of smart meter automatic verification.

Abstract:To analyze fiber optical current transformer (FOCT) error characteristics, the FOCT online test system is established. The system gathers error data of FOCT and compares it with the error data of the standard transformer. It analyzes the error characteristics with the current changing. The result shows that the phase error of FOCT is able to reach 0.2S measurement accuracy, and ratio error can't reach the same accuracy totally.

Abstract:This paper introduces the emissions as well as the utilization condition of FGD gypsum of coal-fired power plants in Jiangsu Province. The emission characteristics, utilization approaches and the main problems of the FGD gypsum in coal-fired power plants are analyzed. Prediction of the FGD gypsum emissions of power industry in Jiangsu province during the "12th Five-year Period" is also made. Finally, considering the effects of various constraints, measures aiming to fully utilize the FGD gypsum are also proposed.

Abstract:Due to massive use of autotransformers, the single phase short circuit current of 220 kV buses is bigger than its three-phase one in 500 kV stations. According to north Lianyungang 500 kV stations of the Jiangsu grid, the effect of current limiting of adding low reactance at neutral point is analyzed by PSASP, proper reactance values are proposed in this paper. Also, the problem of neutral point of main-transformer insulation matching is studied as well.

Abstract:This paper introduces logical structure of communication between communication management workstation of substation and energy management system of main dispatching station in detail, as well as six kinds of typical cases of communication fault analysis and processing. Communication between communication management workstation of substation and energy management system of main dispatching station is very important, in that any communication fault will cause substation exit, which is a serious threat to the safety and stability of power grids operation. The cases which come from practice systematically summarize the fault of communication between communication management workstation and energy management system. The cases have strong practicability, which are able to provide a good reference for quickly and efficiently handling such faults and to enhance the supporting ability for power grid security.

Abstract:This article introduces rotor backwards axial play phenomenon in the process of single-motor test run after motor starting in Guodian Jianbi Power Plant 1 000 MW unit suction fan, presenting using varieties of hypothesis exclusive methods to seek solutions to those problems. With repeated practice, the reasons are ascertained and problems get solved. This paper also provides analysis ideas and methods to equipment defects and fault analysis occurred in the future.

Abstract:As the high voltage level and huge transmission capacity, the influence of DC block caused by incorrect action of protection equipment is great. The existing electric protection and non-electric protection of converter transformer has only one contact, in order to improve the stability of HVDC (high-voltage direct current), the protection of converter transformer should be reformed. Different with the AC transformer reformation, the converter transformer protection is integrated in the PCP (pole protection control) system; the reformation of converter transformer protection includes the modification of the DC control and protection program and external wiring. Based on the reformation of converter transformer protection of Zhengping converter station, this paper analyzed the debugging method of protection equipment and the modification method of the program, and gives the scheme for converter protection testing.

Abstract:This paper analyzes main causes of DC bias of converter transformer, and summarizes electrical characteristics of exciting current during DC bias of converter transformer and the mechanism of DC bias leading to damage of converter transformer. In addition, the principle of saturation protection of converter transformer and the implement method of the protection are introduced. Finally, points for attention in the engineering application of overexcitation protection of converter transformer are discussed.

Abstract:The layout of the outdoor electrical equipment in substation is affected by the fireproof distance. It is extremely necessary for equipment layout to find a balance between the security and economy. But the relevant standard is not unified currently. To improve the situation, the fireproof requirement for outdoor equipment is studied by classification. Besides, to adapt to the requirement better for constructing the "Resource-saving, environment-friendly and industrialized substation", the optimization measures which can guide engineering design is also summarized.

Abstract:High-capacity photovoltaic power generation system connected with grid has some influences on the control of system power exchange and voltage quality in high-voltage power transmission grid. For the safety and stability of power system and improving the quality of power supply, AGC/AVC should be allocated in photovoltaic power station. This paper introduces the structure, control method, control strategy and control flowchart of AGC/AVC in photovoltaic power station. The system has been successfully used in photovoltaic power stations in Ningxia Province and achieves good results.

Abstract:With the increase of non-linear loads and widely usage of power electronic technology in power grid, there have been a large number of harmonics and spread spectrum inter-harmonics in the grid recently. Inter-harmonics have caused more serious hazards than harmonics, such as voltage fluctuation and flicker. Studies of inter-harmonic are still at the stage of characteristic analysis and detective algorithm, without reliable and effective suppression method. This article presents a harmonic suppression technology based on a series of compensation, conducting simulations to demonstrate its effectiveness to suppress the inter-harmonic. The characteristic of voltage fluctuation caused by harmonic is first introduced; then the principle and structure of series compensation are pointed out; finally, by modeling and simulation, series voltage compensator is proved effective to suppress inter-harmonics.

Abstract:Taking advantage of the existing system graphics-database-model integration information, a graphical power grid operation mode preliminary arrangement platform is developed. On this platform, operation mode personnel can easily get relevant information about power cut application from operation information management system (OMS),and set to the corresponding future research state automatically according to the application information. In this study state, operation mode personnel can make preliminary arrangement for operation mode according to their own ideas or call history record of mode operation arrangement. After confirmation, the platform software can automatically call security check experts algorithm for objective evaluation analysis and make anti-misoperation logic check.

Abstract:Optical current transformer has been widely used in Jiangsu Province, but there is not related practical error data with the time going, electromagnetic interference and temperature change. This paper firstly introduces the basic principle of optical current transformer and existing problems, the hardware and algorithm of error comparison device. Then, the device has been installed in Xijing Substation of Jiangsu Province, and proved to be feasible.

Abstract:This article describes the research of a residential area distribution room intelligent operating system solutions and on-site practice. The paper studies various types of equipment for the distribution room, to determine the standard model based on the IEC 61850 protocol, and new developed intelligent information terminal supporting the IEC 61850 protocol, achieving the goal of intelligent transmission and processing of information, plug-and-play of the various types of equipment and information sharing. Development of distributed intelligent operating platform of distribution room for the whole region, including intelligent operation control system and intelligent operation supporting system, solves the problem of safety and economic operation of a large number of unattended power distribution room, getting significant social and economic benefits.

Abstract:This article describes the design and implementation of relay test auto mation system, including the principle and structure of the test system, advantages and features, program analysis and operational processes. Proven, this system compared to the traditional relay test system has notable features, including improvement of efficiency, avoid of human error and reduce of labor costs.

Abstract:According to whether the reference voltage signal, the hot line detecting methods for MOA can be divided into the method with a reference voltage signal (Compensation Act ) and the method without a reference voltage signal. Based on the different ways to set the reference angle, the method without a reference voltage signal can be divided into the angle setting in advance, setting by the current and based on the statistical principle. Through field test, the article compares and analyses the disparities of the measuring results. By summarizing the related laws, this article could provide a reference for the testing personnel in the future to better judge the test results.

Abstract:Due to the randomness and intermittence, a wind power injection power model is built using the wind speed as input. Considering the characteristic of Weibull wind speed distribution, stochastic programming theory is introduced into fault recovery of distribution network including asynchronous wind power generation. A Chance Constrained Programming (CCP) model is used to tackle such optimization. The Clonal Genetic Algorithm with Tabu Search and Memetic local search strategy is used to solve the problem, which could improve the search efficiency. The IEEE 33 buses system is taken as the test case to verify the proposed model and algorithm.

Abstract:The Power Usage Information Acquisition System is an important project of intelligence power grid construction of State Grid. The power usage information acquisition system install a huge number of new customers every day, automatic data analysis ability is required to confirm the correctness of the data, to reduce the artificial debugging and errors. This paper presents a method that contrasts the collecting date under construction debugging process with the marketing system electricity settlement meter reading data to determine the correctness of the collecting date. Principle and decision algorithm are given in this paper, as well as analysis of reasons for difference commonly occurred in terminal installation debugging process. This method significantly reduces the workload of terminal debugging and improves the accuracy of the data gathering, playing a great role in quality management of the power usage information acquisition system construction process.

Abstract:Phase shift is one of the common methods of islanding detection for distributed generation based on synchronous generator. The principle and algorithm of the phase shift method are detailed in this paper. To solve the contradiction problem of reliability and sensitivity of conventional vector shift method, this paper presents a composite islanding detection method utilizing both angle change and frequency variation derived from synchronous generator terminal voltage. Simulations are performed using generic PSCAD/EMTDC. Results show that islanding state can be accurately detected and the non-detection zone can be effectively narrowed down by the composite method on the premise of reliability.

Abstract:Scaling issues occurred in the steam turbine flow passage can lead to the variation of thermal parameters and thus influence the economy and safety of the steam turbines. Through monitoring and utilizing theses thermal parameters, analysis on scaling issues in the steam turbine flow passage is carried out. The equations for incompressible flow, which are verified firstly, are utilized in this paper to analyze the actual conditions of the flow passage of one 630 MW supercritical steam turbine. The scaling issues are preliminarily identified through qualitative analysis focusing on the variation of thermal parameters. Then, quantitative calculation employing the equivalent flow area diagnosis method is performed so as to figure out the location and the severity of the scaling issues. The analysis results are consistent with the inspection results obtained during the maintenance period of the steam turbine.

Abstract:The three kinds of sampling precision check test methods introduced in the national standards of GB 475—2008 entitled "Method for Manual Sampling of Commercial Coal" and GB/T 19494—2004 entitled "Mechanical Sampling of Coal" are analyzed in detail in this paper. Seven kinds of test methods including one replicate-sampling method and six double-sampling methods, which can be implemented more easily, are proposed. According to the practical situations, the customers can make different choices.

Abstract:Since the government paid more attention to the environmental protection, the further processing and comprehensive utilization of coal ash has made great social and economic benefits. However, as the waste of coal-fired power plants, boiler slag has not been fully utilized. This paper presents an approach to develop and use slag in deep processing. That is drying and grinding the wet slag from the plants until its ash granularity meets the national standard. In this way, the boiler slag will have a wider range of use, a higher comprehensive utilization rate and the most effective value in use.

Abstract:The development and study status of wireless power transmission technology are summarized in this paper. Three main technologies of wireless power transmission, including electromagnetic induction method, electromagnetic resonant coupling method, and microwave or laser method, are described briefly. The prospect for application of wireless power transmission technology and the important role of the study of wireless power transmission technology is pointed out.