This paper puts forward a TCR module based new type shunt high voltage reactor, which consists many small capacity thyristor controlled reactor modules and via three-windings transformer connecting to system. The seco...
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This paper puts forward a TCR module based new type shunt high voltage reactor, which consists many small capacity thyristor controlled reactor modules and via three-windings transformer connecting to system. The secondary windings of transformer adopt duplex winding structure and each has multi-bank TCR modules being in delta connection. In this topology, the harmonic current injected into the power system is limited remarkably. A 500 kvar/10 kV industrial prototype was developed, and digital simulation based on EMTDC/PSCAD and field test were carried out to verify the characteristics of topology proposed.
How to compare the wind power generation and traditional power generation in aspect of capacity is essential of power system expansion. The capacity credit is a convenient and effective way to compare these two differ...
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How to compare the wind power generation and traditional power generation in aspect of capacity is essential of power system expansion. The capacity credit is a convenient and effective way to compare these two different types of power generation. Unfortunately, the definition of capacity credit of wind farms is not clear and generally acknowledged. In this paper, a more clear definition of wind farms' capacity credit based on well-known concept of effective load carrying capability (ELCC) is presented. As well as a calculation method of wind farms' capacity credit based on non-sequential Monte-Carlo simulation, this method considered the failure of transmission lines. The secant method is used at capacity credit calculation process, and the modified direct current optimal power flow method is adopted in power flow calculation. Several different influence factors of capacity credit of wind farms such as the cut-in, cut-out and rated wind speed and the rated capacity of the wind turbine generator, transmission capacity of transmission lines and different integration solutions are analyzed in IEEE-RTS79 case studies.
To avoid undesired operation of backup protection caused by load encroachment under cascading failures, the methodology for vulnerability assessment of backup protection is studied. In this paper, the vulnerability as...
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To avoid undesired operation of backup protection caused by load encroachment under cascading failures, the methodology for vulnerability assessment of backup protection is studied. In this paper, the vulnerability assessment of backup protections is formulated as a mixed integer nonlinear programming problem, which is solved by the binary particle swarm optimization approach. The measurement index for assessing the vulnerability of backup protection is given as well. The simulation results on New England 39-bus system demonstrate that the proposed method can effectively assess the vulnerability of backup protection under cascading failures.
A three-phase unbalanced system will reduce mechanical and electrical energy interaction and thus, to some extent, inhibit subsynchronous resonance (SSR). Based on this principle, a compensation method using a single-...
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A three-phase unbalanced system will reduce mechanical and electrical energy interaction and thus, to some extent, inhibit subsynchronous resonance (SSR). Based on this principle, a compensation method using a single-phase static synchronous series compensator (SSSC) is proposed. In this method, only one phase employs an SSSC to replace part of the fixed series capacitor, while the other two phases have fixed series compensation (FSC). By controlling the SSSC, the three-phase reactance at power frequency is balanced, while at sub-synchronous frequencies, the system is unbalanced and thus inhibits SSO. A single-phase SSSC model based on a cascaded H bridge topology is built for time-domain simulations. The damping effect and the minimum degree of compensation required from the SSSC are analyzed by transient simulations. Simulation results show the method can effectively restrain SSO and has little effect on the three-phase voltage unbalance factor. Compared with employing SSSC in all three phases, this method is more economical.
The instrument transformer is the necessary equipment which connects the primary power system and PMU. Therefore, the measurement accuracy of PMU is directly affected by the transfer accuracy and the transient respons...
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The instrument transformer is the necessary equipment which connects the primary power system and PMU. Therefore, the measurement accuracy of PMU is directly affected by the transfer accuracy and the transient response of instrument transformer. In this paper, the dynamic signal models are abstracted from the phenomena of practical power systems. Under such kinds of dynamic signal models, the impact of instrument transformer on PMU is analyzed in detail, especially for the saturation problem of the current transformer and the ferromagnetic resonance and transient response of capacitor voltage transformer. Based on the analysis, the suggestions for the evaluation criteria of PMU dynamic behavior can be provided. Moreover, the principles of choosing instrument transformers in the wide-area measurement systems are suggested as well.
With the widely installation of Phasor Measurement Units (PMUs) in power system and the increasing requirement of the real-time monitoring and control, a novel power system topology analysis algorithm is proposed with...
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ISBN:
(纸本)9781424480807
With the widely installation of Phasor Measurement Units (PMUs) in power system and the increasing requirement of the real-time monitoring and control, a novel power system topology analysis algorithm is proposed with high precise information from PMUs to improve the performance of current network topology analysis. First of all, a method of identifying switch status is established to correct the state mistake of circuit breakers (CB) relying on the analog data acquired by PMUs. Subsequently, a topology analysis in substation combined with the PMUs information (including the digital data of CBs state and the phasor of voltage and current) is advanced in this paper. And then an efficient topology analysis algorithm introduces into topology search process using Cotree-to-Bus structure array. Finally, simulation results based on the PSCAD and MATLAB software have validated the efficiency and accuracy of the novel method introduced in this paper.
A novel wide-area fault location algorithm is proposed in this paper. Fault model is developed in super-imposed network, and then based on network correlation coefficient matrix (NCCM), location function is defined. F...
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A novel wide-area fault location algorithm is proposed in this paper. Fault model is developed in super-imposed network, and then based on network correlation coefficient matrix (NCCM), location function is defined. Finally search technique with adaptive step is used to locate fault branch and fault distance. This method requires few PMUs, avoids modifying node admittance matrix and NCCM. It has less calculation burden, and is easy to achieve. Simulation results based-on PSCAD show that the algorithm can locate fault branch accurately and fault distance precisely in condition of limited measurement points. And fault location results are not affected by fault type or fault resistance.
Microgrid technologies are highly developed in low voltage networks, improving the power supply reliability and energy efficiency. Therefore, in this paper, the concept, including the configuration, principle and oper...
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Microgrid technologies are highly developed in low voltage networks, improving the power supply reliability and energy efficiency. Therefore, in this paper, the concept, including the configuration, principle and operation of microgrid, will be specified, comparing the microgrid with the prior distributed generation. Additionally, in order to justify the feasibility, the economical benefit analysis of the application will be identified via some methodological viewpoints which are advised to regulate the operation of the microgrid in an economical approach. At the end, the costs, benefit and the share of the microgrid and micro-generation are discussed by analyzing the test case.
Wind power penetration to power systems is increasing rapidly in the recent years due to its environmental benefit, while wind power fluctuation also brings some problems to power system operation which impacts the tr...
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ISBN:
(纸本)9781424480807
Wind power penetration to power systems is increasing rapidly in the recent years due to its environmental benefit, while wind power fluctuation also brings some problems to power system operation which impacts the transmission company's willingness to accept wind power. The most serious conflict influencing wind power development is that the currently adopted price of wind power on-grid does not take this fluctuation or the impact on the system operation into account. Currently, quotas and enforcing access is broadly used in wind power regulation. It is now required that all wind power output should be accepted by the grid, and is rewarded with a guided rate. But with the increase of wind power penetration to power grid, a more effective price regulation to wind power should be set up with wind output uncertainty into account. This paper takes wind farms in different areas in China as the research objects and uses accounting cost analysis approach to calculate wind power costs, which enables the wind farms in different areas to get the same rate of return on investment as that of thermal power plants. These tariffs will be derived as a basic price for the reference by the power grid then. The basic wind power prices are multiplied by a penalty factor which is an innovative as the final prices paid to the wind farms. The penalty factor is related to the accuracy of wind power output. If the accuracy of the wind farm output is higher than that of the regional average one, the penalty factor will be greater than one, so that the really paid wind power price is higher than the base value and the income of the wind farm will be increased, otherwise the earnings will be reduced. To illustrate the problem, an example is given. The use of this penalty factor will eventually help stimulate wind farms to improve the accuracy of wind power output, and improve the stable operation of the systems with large wind power penetration, and promote the sustainable development of wind
In this paper, a static synchronous series compensator (SSSC) combined with a fixed capacitor, which is called hybrid series compensation (HSC), is proposed to avoid subsynchronous oscillation (SSO) in a series compen...
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In this paper, a static synchronous series compensator (SSSC) combined with a fixed capacitor, which is called hybrid series compensation (HSC), is proposed to avoid subsynchronous oscillation (SSO) in a series compensated transmission system and its characteristic is studied based on IEEE first benchmark model for SSO analysis. By employing the complex torque coefficient method and time-domain simulation, the performance of HSC on damping SSO is analyzed in the aspects of component proportion of HSC, installation location and control strategy mode. A supplementary sub-synchronous damping controller (SSDC) for SSSC is also designed to increase the damping performance of HSC at critical oscillation frequency.
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