Abstract:It is a complex process to transform 500 kV substation automation system into a new digital one. This paper introduces a new seamless transformation method which can transform the old system into a new one smoothly, and it can avoid many issues, such as lack data, incomplete anti-maloperation logic, duplicated power cut, duplicated test, and so on. It can ensure the security, stability and continuity of the local monitoring, dispatch communication and remote control operation.

Abstract:Relay protection packet simulation system is basis of function testing of relay protection and is also part of transformer substation automation simulation test system. The relay protection packet simulation system completes the system-level test of the transformer substation automation system with transformer substation automation simulation test system based on PLC module. Firstly, this paper describes the structure of relay protection packet simulation system. It explains the software, hardware and background system. Techniques of this system are also included. The successful research and development of the relay protection packet simulation system provides a good test platform for testing the performances of transformer substation automation system and a good tool for analyzing the transformer substation failure.

Abstract:The gasifier control benchmark problem is an issue associated with the control of the multi-variables, strong coupling and nonlinear system model. A nonlinear degree analysis using the gap metric method and linearization operation is carried out for the model firstly. Considering the dynamic behavior of the system, the paper adopts a modified and practical loop variables pairing rule combined with the RGA method in the decentralized control to determine the relationship between the manipulated variables and the controlled variables. Finally the system control structure is proposed in the paper.

Abstract:To improve power supply reliability and achieve seamless transition between island mode and grid-connected mode, the partition of distributed generation islanding range has been studied. According to the structural characteristics of different voltage level power grid and the fault recovery features, a new islanding control algorithm is proposed, which is based on the combination of pre-planning, dynamic partition and multi-level island. In the pre-planning process, it ensures that the number of islands in a particular fault condition is the least and it does not need to install splitting and synchronous closing devices on all lines. And in a dynamic division process, it guarantees the important loads' power supply and makes the load resection number minimum. Simulation results of IEEE118 node system show that the proposed algorithm can make the island system on stable operation with the minimum cost, and meet the request of the distributed generation island planning and online decision-making.

Abstract:Based on the analysis of the failure of the main transformer differential protection's tripping accident, this paper shows that it is very important to determine the transformer fault properties based on a comprehensive device information collection. Under the situation of there is oil leakage of the on-load tap-changer oil chamber, a method is proposed to exclude the influence of tap-changer's leaky on chromatographic analysis of transformer oil by tracking the chromatographic change trend of the insulating oil.

Abstract:Based on an example of GIS bus fault tripping caused by line fault tripping, solutions and improvement measures for GIS bus fault tripping has been proposed in this paper. Meanwhile, quality of the dispatcher plays an important role in accident procession. And reinforcement on training and professional management of the dispatchers is necessary.

Abstract:The paper introduces the fault conditions happened at the grid-integration gate of a power plant in Jiangsu Province. And it analyzes the effect of the fault on the electric energy measurement as well as the power generation amount to network. The retrieving energy is also calculated in this paper.

Abstract:Traditional reliability evaluation of transmission systems use fixed value to evaluate reliability, but part of the reliability date is usually uncertain because of the impact of objective conditions, which will inevitably lead to inaccuracy of the evaluation. In this paper, a new method based on the theory of connection number and reliability evaluation of transmission systems is presented for evaluating reliability of transmission systems. The method expresses reliability parameters in connection number. The connection number theory is applied to deal with various uncertainties of reliability parameters to calculate the connection number indices with certainty and uncertainty. The method can reflect the influence of original parameters' uncertainty on reliability indices, which give a more refined degree of truth of system reliability. Analyzing results on IEEE-RBTS and IEEE-RTS79 show the rationality and effectiveness of the approach.

Abstract:As the popularization of unattended mode in substations, integrated automation technology has been fully applied. The independent microcomputer's anti-operation has been substituted by integrated automation's anti-operation method step by step. By utilizing these two different anti-operation methods in practice, substation operator found advantages and disadvantages of these two methods.

Abstract:Analysis focused on an abnormal operation mode caused by a trip accident of main transformer of 220kV has been conducted in this paper. And recovery procession of this accident is also given. Analyzed reduced voltage supply mode and potential dangerous nodes, which are caused by the action of automatic switching device on the condition that the switch has not tripped on the 35kV side of the 110kV main transformer in Lukou substation. Solutions and processing thinking for dispatchers when dealing with such special accidents are also summed up.

Abstract:Through the research on software of frequency and voltage emergency control devices, this paper presents an implement method of configuration of function setting, data acquisition and processing, fixed value management, and export control etc. This method is based on the principles of software modularization, hierarchical abstraction and data isolation from logic procedures. Configuration engineering software has been developed in the SCS-200A frequency and voltage emergency control device and its type test has been completed. The proposed software facilitates standardization of frequency and voltage emergency control device configuration, flexibility of manufacturing, maintenance and upgrade, and reliability of frequency and voltage emergency control device.

Abstract:Focusing on an incorrect operation of 220kV circuit-breaker failure protection in Licheng substation, this paper analyzes its causes in-depth. Based on upgrading the reliability and normalization of circuit-breaker failure protection, some measures of configuration, grouped screens, circuits are given for new construction, reconstruction and expansion of substations. For the circuits in-service of circuit-breaker failure protection, this paper puts forward a "point by point measurement of voltage" test method which can ensure the credibility of test results. Practical operation and fault analysis verify the correctness and effectiveness of the measures.

Abstract:CIM (Common Information Model) is an object-oriented public model established by UML (Unified Modeling Language) in order to realize the power system information sharing. According to the characteristic of the CIM and the object-oriented technology, a power system graphic platform based on CIM is developed in the Visual C++ 6.0 environment. The graphic system can use the universal information, one advantage of CIM, and the associated characteristic between the classes in the topological package and line package in CIM, through adding geometric properties to the corresponding class in topological package, the connective relation can be set up automatically after the finished main electrical power system writing drawing.

Abstract:In power distribution unbalanced three-phase voltage is a reflection of abnormality and failure of power system. There are various of causes, mechanism and phenomenons. The reasons of various phenomenon of unbalanced three-phase voltage are analyzed and the solutions are summarized in this paper. Technicians should be able to efficiently and accurately solve the unbalanced three-phase voltage based on this paper.

Abstract:This paper establish the model for paint film of grading ring and grading capacitor. The conclusion of model is according with the measuring data, which verify valid of the model. It indicates that paint film has obvious affection to measuring grading capacitor's dielectric loss according to calculating the test date. Thus measuring line should connect with the naked metal of grading capacitor to avoiding affection of the paint film.

Abstract:Compound voltage locking overcurrent protection is the backup protection for transformer. Different transformer backup protection devices have different protecting function, some devices only have high voltage side backup protection. In certain operation modes, there will be dead-zone in such backup protection. If short fault occurs in this dead-zone, the backup protection device will refuse to trip, so the short fault can't be cleared, and then transformer would be destroyed. This thesis analyses the logic of compound voltage locking, it finds the reasons of the backup protection dead-zone, and then it puts forward several simple improvement methods according to different instance.

Abstract:This paper presents the principle and configuration of the GPS real-time monitoring system of substation, analyzes the problems exiting in practice and summarizes solutions. The results show that this monitoring system can realize the target of GPS real-time monitoring the whole power grid, which can improve the operation and management level of power grid's stability and security.

Abstract:Starting from the unusual appearance of the test when simulating reverse fault during the check of the connection between the new-built optical fiber connector GXC-01 and the bypass breaker protection WXB-11C. This paper analyses the reason for the opposite carrier current protection malfunction when there is a fault at the adjacent line, as bypass breaker operating. It also analyses the cooperation between the carrier current protection and the transceiver by permissive logic or blocking logic when normal operation and bypass breaker operation. The related signals from the debugging job is also discussed and summarized.

Abstract:As the development of new technologies such as pure optical transformer, IEEE1588 clock synchronization technology, IEC61850-9-2 network construction etc. in recentyears, these new technologies have been preliminarily explored to be applied in some digital substations. It is a prominent problem to systematically evaluate the performance of digital substation. This paper introduces the project's scheme and practical experience of digital interval test in east Suzhou (Yushan substation), proposes the content and measure of the digital substation test, and concludes some problems in the test.

Abstract:At present, power system interconnection has brought new challenges to the safety and stability of power system operation. In the event that a large-scale and long-duration fault occurs in the interconnected system, the power fault recording and monitoring system (PFRMS) should be able to meet the requirements of fault analysis. The Paper elaborates a power fault recording and monitoring system with the type of DPR-2E. In order to improve system reliability and anti-jamming, the hardware device of DPR-2E adopts a twin CPU system made up of Motorola PowerPC and ADI BlackFin DSP and the software adopts Linux embedded real-time operating system . Based on the platform of synchrophasor measurement and the synchronous clock signal, DPR-2E can supply large-scale original data .Constant-temperature crystal oscillator with good stability and time keeping technique with high precision ensures the veracity of one Pulses Per Second (1PPS) at any time and the synchronous analysis of large-scale fault. The improved prony algorithm identifies the power system low frequency oscillation quickly and exactly. The high accuracy location technology can commendably adapt to the ranging fault due to the variation of line parameters. The system realizes consecutive recording over a long period of time and uniform analysis of the steady,synchrophasor,dynamic and transient data, providing reliable data sources for analysis of the ultra-long, large-scale and developing fault.

Abstract:At present, series reactor is adopted to control the close inrush current of reactive power compensation capacitor bank. From both theory and case, this paper has elaborated that harmonic will be enlarged if reactance rate of series reactor is set improperly and thus serious incidents may be caused.

Abstract:Based on Rapid computations of DSP, the differences of frequency, voltage, angle between waiting-synchronization side and network are sampled and calculated on time. And the adaptive sampling of the voltage on waiting-synchronization side is realized. By using external interruption to response to the Phase-difference change, and least-square method of curve fitting to calculate the Phase-difference change rate, and also using specific mechanism, the accuracy and rapidity of synchronous switching can be ensured.

Abstract:Detailed control strategies for the quick grid connection with the boiler and the turbine still being in operation after load rejection tests are introduced in the paper, and the reasons for the formulation of the control strategy are also proposed just using various charts. It can provide valuable reference for the quick grid connection of other ultra-supercritical power plants.

Abstract:Suggestions for the equipment selection and system design of 650 MW steam turbine units are proposed in the paper, and schemes for the optimization of the system design with some of them already put into effect are also introduced. Moreover, the paper includes the proposal that energy-saving equipment should be adopted during the equipment selection period to avoid the unnecessary investment caused by the energy-saving retrofit.

Abstract:To improve the browsing efficiency and meet the demand for experimental data, the asynchronous refresh mode is adopted for the data transmission from WEB servers to the client just using Ajax engine. Based on B/S mode, the management database of power generators is built to realize the data sharing of leading phase operation.

Abstract:Due to the leakage of the main steam drainage pipes, the efficiency as well as the personal safety and the normal operation of the equipment in one power plant has been seriously affected. The excessively high secondary stress is considered to the main reason for the issue, so instead of fixed bearings, sliding bearings are adopted to make sure that the secondary stress is in the allowable range. No leakage accidents happen again after the technical renovation.

Abstract:Hardness is a main performance to ensure the wear resistance for silver plating layer of High-voltage switchgear, and the State Grid Corporation has made clear their requirements. The silver plating layer thickness characteristic and the principles of hardness testing have been analyzed. And a microhardness testing approach on silver plating layer without affected from the substrate has been proposed. A testing load force for microhardness testing has been also recommended.