With the increasing expansion of AC/DC transmission system scale, the research on Available Transfer Capability (ATC) for AC/DC transmission systems has important academic and practical significances to AC/DC transmis...
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With the increasing expansion of AC/DC transmission system scale, the research on Available Transfer Capability (ATC) for AC/DC transmission systems has important academic and practical significances to AC/DC transmission system planning, operation and reliability evaluation. Most of the existing ATC calculation methods are mainly based on deterministic techniques and suitable for AC transmission system. In practical powersystems, there are large amount of uncertainties which can effect the operation of AC/DC transmission system, and powersystem is dynamic and time-varying. A novel approach is proposed to analyze relevant features of ATC and calculate ATC based on sequential Monte Carlo-Frequency and Duration (FD) considering uncertainties and time variation of AC/DC transmission systems. The algorithm MATLAB6.5 is developed. Modified IEEE-14 node test system is used to verify the presented approach.
In this paper, concerning the limitations of this method which can not meet the current needs of the development of large-scale powersystem, a new electromechanical transient simulation model based on dynamic equival...
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ISBN:
(纸本)9781424480807
In this paper, concerning the limitations of this method which can not meet the current needs of the development of large-scale powersystem, a new electromechanical transient simulation model based on dynamic equivalent is proposed. It develop a new vision for the electromechanical transient and electromagnetic transient hybrid simulation, which presents the application of dynamic hybrid simulation equivalent in hybrid simulation. Two cases are studied, electromechanical Simulation of IEEE14 nodes system, and hybrid simulation of electromagnetic transient and electromechanical transient on RTDS was developed, in the condition that the electromagnetic transient part is an actual DC system. The simulation results show that dynamic equivalence presented in the paper is valid and effective. On this basis, hybrid simulation based on dynamic equivalence is realized, thereby expanding the simulation size of AC system.
With the expansion of the powersystems, DC power transmission has been increasingly applied in interconnection of grids. The determination of Available Transfer Capability (ATC) for the AC/DC transmission systems is ...
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With the expansion of the powersystems, DC power transmission has been increasingly applied in interconnection of grids. The determination of Available Transfer Capability (ATC) for the AC/DC transmission systems is significant to the system planning and operation. So far, most studies have been focused on ATC determination for AC transmission systems, few are on the AC/DC system ATC determination. In this paper, the ATC determination model for the AC/DC systems is proposed. Multi-terminal DC (MTDC) system is considered in ATC computation model. Conventionally, the power injection variations are determined by load variations and generation dispatch, both of them are nonlinear. To model these nonlinear variations, an alternate iterative continuation power flow (CPF) method with multiple load variations and generation economic dispatch patterns is presented to solve the proposed model. The MTDC system configurations, the converter control strategies and the transformer's tap adjustment strategies are incorporated to this modified CPF algorithm. The modified IEEE 30-bus test system is used to verify the presented approach.
Previous blackouts demonstrate that the safe and stable operation of backbone-grid plays a key role in preventing large-scale blackouts caused by cascading failures. Based on binary particle swarm optimization, a nove...
Previous blackouts demonstrate that the safe and stable operation of backbone-grid plays a key role in preventing large-scale blackouts caused by cascading failures. Based on binary particle swarm optimization, a novel method is proposed to identify the backbone-grid in power grid. First, the concept of the backbone-grid is defined for mathematically describing the critical lines and important topology structure which are crucial for powersystem to prevent the blackout caused by cascading failures. On this basis, the problem of exploring backbone-grid is further formulated as a mixed integer nonlinear programming problem which is to be solved with binary particle swarm optimization. The problem just needs to be optimized only once. The backbone-grid essential to the safe and stable operation of power grid can be obtained. Simulation on IEEE RTS-79 system verifies that the proposed method can identify backbone-grid with high computational efficiency.
The issue of power quality in the distribution system is always in sense of the concern. With the high penetration of distributed generation (DG) currently, it tends to be more complicated. This paper presents a new a...
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For digital distance relays, in order to get the correct measuring impedance, phase selector is widely used to identify the fault phases first. However, when a fault occurs at the line during powersystem swings, the ...
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For digital distance relays, in order to get the correct measuring impedance, phase selector is widely used to identify the fault phases first. However, when a fault occurs at the line during powersystem swings, the traditional sequence component based phase selector might not identify the fault phase correctly, which leads to mal-operation of distance relays. Therefore, how to improve the existing sequence component based phase selector, especially at the condition of powersystem swings, is crucial. The relationship between the relative phase and amplitude of the sequence component of various asymmetric faults is analyzed. An improved asymmetric fault phase selector during power swings is proposed according to the corresponding relationship between the zero, negative sequence current components and the asymmetric fault types. The simulation results have shown the effectiveness of the method under power swings. Combining with fault component phase selector in no power swing, this method can perfectly solve the phase selection problem of transmission lines.
In order to overcome some disadvantages of the conventional adjacent matrix method, the relationship between the elements of the adjacent matrix and the connected routes among nodes is analyzed as the fundamental intr...
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ISBN:
(纸本)9781424480807
In order to overcome some disadvantages of the conventional adjacent matrix method, the relationship between the elements of the adjacent matrix and the connected routes among nodes is analyzed as the fundamental introduction. Subsequently, the graphic characteristic of the main electrical connection in power plant or substation is extracted as three types: single branch, two branches in-parallel and multi-branches in-parallel, and an unified principle for the formulation of connected routes among arbitrary two nodes in wiring connection is also proposed as the cornerstone for the novel method. Thirdly, a novel method of substation configuration is established based on the set of connected routes among arbitrary two nodes, and by mean of taking the route state as variables, the value of connected routes set is used to directly determine the element in corresponding place of the adjacent matrix. Finally, the example results show that the new method is able to finish the original topology analysis and track the state status of switches more accurately and rapidly.
This paper briefly introduces the first project in China using a Static Var Compensator (SVC) to damp Sub-Synchronous Oscillations (SSO) excited by fixed series compensation. Since the SVC function of this project is ...
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This paper briefly introduces the first project in China using a Static Var Compensator (SVC) to damp Sub-Synchronous Oscillations (SSO) excited by fixed series compensation. Since the SVC function of this project is to damp SSO, it is necessary to study its side-effects on the ac system when damping SSO. A real time digital simulator (RTDS) model for this project is developed and a closed-loop test platform is established, which is comprised of an RTDS and a physical SVC controller. Based on the platform, this paper studies the side-effects of the SVC including transformer overload, ac system transient stability and relay malfunction. Simulation and theoretical results show that all these side-effects are acceptable and will not effect the operation of the ac system.
The faults in electric powersystem can not be completely avoided. When powersystem operates from normal state to failure or abnormal operates, its electric quantities may change significantly. Our researches indicat...
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The faults in electric powersystem can not be completely avoided. When powersystem operates from normal state to failure or abnormal operates, its electric quantities may change significantly. Our researches indicate that the variable with the biggest coefficient in principal component usually corresponds to the fault. Therefore, utilizing real-time measurements of PMU, basing on principal components analysis technology, we have completed the fault location of electric powersystem. Of course, because of the complexity of different types of faults in powersystem, there still exists enormous problems need a close and intensive study.
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