A good Black-Start scheme is important and necessary to resume power supply fast and efficiently after black out, and how to choose black-start power is the first thing to consider in the scheme. In this paper, the ad...
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A good Black-Start scheme is important and necessary to resume power supply fast and efficiently after black out, and how to choose black-start power is the first thing to consider in the scheme. In this paper, the advantages of VSC-HVDC as black start power are analyzed. The ability of VSC-HVDC to soft energize major power system equipment is proved through simulation by software PSCAD/EMTDC. Simulation waveforms during soft energization are illustrated. These plots have described the good voltage and frequency characteristics of VSC-HVDC. Furthermore, the transition from black start control to normal power flow control is discussed. Simulation results indicate that by using soft energization, VSC-HVDC is an ideal black start power.
Wide area measurement system (WAMS) has been widely used in power system dynamicmonitoring and control, such as low frequency identification and control, stability assessment and preventive control, etc. However, as ...
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Wide area measurement system (WAMS) has been widely used in power system dynamicmonitoring and control, such as low frequency identification and control, stability assessment and preventive control, etc. However, as a measurement tool, phasor measurement unit (PMU) has the measurement error and bad data unavoidably. If the raw measurements are applied in power system analysis and control directly, the unexpected consequence might be resulted in. Aiming at this problem, a novel dynamic state estimator for generator state variables is proposed in this paper. The corresponding mathematical model is given in detail. Bad data detection and elimination approach is presented as well. The simulation results show that the proposed method can provide the estimated trajectories of the generators in real-time, which eliminates the impact of measurement error and bad data and could give the backbone for WAMS based dynamic applications and real-time control.
In the control of the wind generation, the maximal power point tracking (MPPT) control plays important role in the efficiency. This paper presents the simulation results of the MPPT control with RTDS-based DFIG model....
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In the control of the wind generation, the maximal power point tracking (MPPT) control plays important role in the efficiency. This paper presents the simulation results of the MPPT control with RTDS-based DFIG model. At first, it analyzes the vector-control scheme for the MTTP, which results in independent control of active and reactive power of the generator. And then, it develops the MPPT controller implemented on the rectifier and inverter based on PI control strategic. Furthermore, it builds the DFIG model based on the RTDS with the corresponding technology. And the simulation result with the proposed model verified the control strategy.
In this paper, we adopt a novel topological approach to fault diagnosis. In our researches, global information will be introduced into electric power system, we are using mainly BFS of graph theory algorithms to resol...
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In this paper, we adopt a novel topological approach to fault diagnosis. In our researches, global information will be introduced into electric power system, we are using mainly BFS of graph theory algorithms to resolve fast and exact discrimination of faulty components and faulty sections, and finally accomplish fault diagnosis. Graph theory algorithms can be used to model many different physical and abstract systems such as transportation and communication networks, models for business administration, political science, and psychology and so on. In the study of fault diagnosis in electric power system, especially the fault diagnosis for mechanically-driven sections of equipments in power plant, graph theory algorithms must also have a good prospect of application.
Establishing an effective performance evaluation method and market driven incentive mechanism is an important subject that the electric power utilities are currently facing with. By aid of Data Envelopment Analysis (D...
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Establishing an effective performance evaluation method and market driven incentive mechanism is an important subject that the electric power utilities are currently facing with. By aid of Data Envelopment Analysis (DEA) method which is widely used in other industries' performance evaluation, three DEA based models are proposed to evaluate electricity distribution utilities' performances, the relative efficiency scores are then given. In addition, the improvement schemes are presented for those relative less efficient utilities. At last, an approach of sensitivity analysis with respect to evaluation indices and a method to simplify evaluation indices are presented. The empirical study shows that the proposed performance evaluation method for electricity distribution utilities is effective and straightforward.
Expanding the extra high voltage AC/DC hybrid transmission system and improving the transfer capability of the network are the primary tasks of the power network in China. With the increasing expansion of AC/DC transm...
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ISBN:
(纸本)9781424449347
Expanding the extra high voltage AC/DC hybrid transmission system and improving the transfer capability of the network are the primary tasks of the power network in China. With the increasing expansion of AC/DC transmission system scale, the super large scale hybrid network has taken shape in china, then the systematic research on ATC calculation model and algorithm for AC/DC systems is urgently needed. A new ATC computation model for AC/DC hybrid transmission system is proposed in this paper. In this model the effect of multiterminal DC system can be considered. CPF algorithm is presented to solve this model, then the ATC value of AC/DC hybrid transmission system can be gained. The algorithm based on MATLAB6.5 is developed. IEEE 14-bus test system is used to verify the presented approach.
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. However, most of the present researches on the ATC calculation are only suitable for AC transmission system, few is about the ATC analysis for AC/DC systems. In this paper a novel ATC calculation model for AC/DC transmission systems is proposed, and alternate iterative continuation power flow algorithm is presented to solve this model. ATC of an AC/DC transmission system is computed considering the impacts of DC control system on ATC and compared to one of the AC system. The algorithm based on MATLAB6.5 is developed. The modified IEEE 14-bus test system is used to verify the presented approach.
Islanding detection and protection is an important concern for grid connected photovoltaic (PV) power generation system due to personnel and equipment safety. Over/under voltage protection (OVP/UVP) and over/under fre...
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Islanding detection and protection is an important concern for grid connected photovoltaic (PV) power generation system due to personnel and equipment safety. Over/under voltage protection (OVP/UVP) and over/under frequency protection (OFP/UFP) are basical inverter resident passive islanding detection method (IDM) for detecting an islanding condition by monitor parameters in point of common coupling (PCC) such as voltage amplitude and frequency and then cause the inverter to shut down when there is sufficient transition from normal specified conditions. The real and reactive power equations and Non-Detection Zone (NDZ) of OVP/UVP and OFP/UFP methods for grid connected PV system are derived and analyzed in this paper. Analyses show that the behavior of the system at the time of disconnection will depend on the imbalance power at the instant before the switch opens to form the island, these results also indicate the NDZ of OVP/UVP and OFP/UFP methods is considerable large and the reaction times for these protective methodologies may be variable or unpredictable.
When a fault occurs on a transmission line, fault-generated high-frequency signals contains a lot of information about fault. This paper proposes a protection scheme for phase-to-phase fault in transmission line based...
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When a fault occurs on a transmission line, fault-generated high-frequency signals contains a lot of information about fault. This paper proposes a protection scheme for phase-to-phase fault in transmission line based on spectrum characteristic of fault-generated high-frequency signals. The difference of fundamental natural frequencies in both ends of transmission line is used to determine whether a fault is internal or external. The scheme can reduce trip time if the fault is an internal fault and does not misoperate if the fault is external. It also can identify chose-up faults. The scheme performance was proven using power System Computer Aided Design (PSCAD) in 500-kV power system considering critical fault cases.
Recent years, technologies for new energy have developed rapidly since the energy crisis and the environmental pollution got worse. And the solar energy generation technology tends towards the stage of a large number ...
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Recent years, technologies for new energy have developed rapidly since the energy crisis and the environmental pollution got worse. And the solar energy generation technology tends towards the stage of a large number of applications in engineering from the research stage. This paper designed a grid-connected PV system firstly, then introduced the operation principle of the various parts as well with the control strategy of the power flow. The design of energy storage is of great significance as the output power of PV cells array is greatly affected by the light intensity and the temperature change. Battery is used as the energy storage device normally in the traditional energy storage system. In this paper, it used the Ultracapacitor as the energy storage device after comparing with the battery, and designed the charge-discharge control strategy according to the characteristics of the ultracapacitor. Finally it verified the feasibility of the energy storage control strategy through the simulation models which was built based on the PSCAD/EMTDC platform.
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