This paper studies the dynamic operation of a residential electric energy system with distributed renewable generation. Energy streams among the power grid, local renewable plant, storage unit, and demand are consider...
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ISBN:
(数字)9789881563903
ISBN:
(纸本)9781728165233
This paper studies the dynamic operation of a residential electric energy system with distributed renewable generation. Energy streams among the power grid, local renewable plant, storage unit, and demand are considered; the temporal volatility of renewable generation is described by an uncertainty set, and the optimal operation problem gives rise to a multi-stage robust optimization. To deal with the non-anticipativity issue, the robust model is solved via robust dual dynamic programming (RDDP) approach. The the cost-to-go function is approximated by iteratively updating the upper and lower bounds, which can be obtained from forward-pass and backward pass procedures. Case studies validate the performance and advantage of the proposed method.
A novel active damping control scheme is developed to eliminate stability problems arisen in the current control of a three-phase voltage source active rectifier (VSR) with LCL-filter. A converter side inductance volt...
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A novel active damping control scheme is developed to eliminate stability problems arisen in the current control of a three-phase voltage source active rectifier (VSR) with LCL-filter. A converter side inductance voltage feedback loop is introduced in the traditional voltage oriented control to stabilize VSR. A simplified discrete model including the current control loop and LCL-filter is established with one sample delay, considering time delays induced by S/H (sampling and holding), processing and modulation. The amplification coefficient of the converter side inductance voltage feedback loop is tuned up to change the unstable poles of LCL-filter. Parameter estimate methods are used to remove unnecessary sensors. simulation and experiment of VSR with LCL-filter demonstrate the proposed active damping control scheme and the stability analyses.
Non conventional instrument transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in curr...
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Non conventional instrument transformer (NCIT) and IEC 61850 are crucial technologies in digital substations. But they bring some new uncertainties to protection IEDs, especially the time synchronization issue in current differential protection. The paper analyzes the time delay of transferring sampled values from NCIT to current differential relay in NCIT and IEC61850 based digital substation, then finds out the delay-non-deterministic problem, at last presents a novel current differential protection scheme by using phase-locked loops (PLL ) technology.
Regarding the power transmission mode from energy base to load center as the heart of the matter, a joint optimal operating model for both sending- and receiving- end power grids is established. In this model, the car...
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The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential differenc...
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The prediction method based on the partition of weather types has been widely used in photovoltaic prediction. Here, the temporal characteristics of PV data is studied, the physical meaning of the sequential difference sequences is analysed, and a characteristic index system including sequential characteristics index is proposed. The weather types are partitioned based on self-organising map neural network algorithm. Case study shows that the partition method is helpful to improve the discrimination of weather types and to improve prediction accuracy.
This paper presents a new practical backup power supply connection scheme for distribution line non-communication protection (DNCP). simulation tests have been conducted using the alternate transient program (ATP) wit...
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This paper presents a new practical backup power supply connection scheme for distribution line non-communication protection (DNCP). simulation tests have been conducted using the alternate transient program (ATP) with respect to a typical single circuit breaker multi-section system. The results prove that the new scheme is able to not only recover the power supply of loads on healthy lines automatically, but also create disturbances in favor of accelerated over current (AOC) criterion. Aiming at the failure of directional under voltage (DUV) criterion derived from high voltage and large capacity induction motor load, a novel criterion using the increment of reactive power is proposed.
Energy crisis and environmental concerns have led to the rapid development of renewable energy sources(RES). However, the fluctuating and unpredictable nature of RES reduce the reliability of the powersystems. Using ...
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Energy crisis and environmental concerns have led to the rapid development of renewable energy sources(RES). However, the fluctuating and unpredictable nature of RES reduce the reliability of the powersystems. Using compressed air energy storage(CAES) is one of the main solutions to this problem. In this paper, three typical operation modes of CAES are adopted to improve the flexibility of the wind-CAES hybrid system, and a risk-constrained economic dispatch model considering the uncertainty of wind power and the part-load characteristics of CAES is proposed. Scenario generation and reduction technique is applied to model the uncertainties and a piecewise linearization method is used to incorporate the part-load features into the mixed integer linear programming model. The effectiveness of the proposed methodology is studied in a modified IEEE RTS 24-bus system.
Compared with other conventional energy sources, renewable energy, which results in less pollution and has numerous resources, is a significant factor in addressing the current issues of the serious environmental poll...
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Compared with other conventional energy sources, renewable energy, which results in less pollution and has numerous resources, is a significant factor in addressing the current issues of the serious environmental pollution and the resource depletion. Large-scale renewable energy connected to the grid could lead to a the change of the morphological structure and the operation modes of energy transmission. While current power grid evolution models did not consider the characteristics of renewable energy in the evolution strategy. The expansion mechanism of the future transmission network with a high proportion of renewable energy is studied in this paper. The operation cost including renewable energy curtailment are optimized using the production simulations, where the stochastic and intermittent of wind and solar energy are modeled. And the dual variable information is adopted to drive the grid upgrading. The expansion strategies for power grid of Zhejiang province in China are analyzed to balance the construction cost and curtailment cost of renewable energy.
A risk based method is proposed to design under voltage load shedding (UVLS) scheme. Different with traditional methods, the proposed one employs a series of risk indices, which are obtained based on a full-scale cont...
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A risk based method is proposed to design under voltage load shedding (UVLS) scheme. Different with traditional methods, the proposed one employs a series of risk indices, which are obtained based on a full-scale contingencies analysis, to determine the operating parameters of load shedding. According to this method, the load bus, in which the UVLS can exert itself with the highest efficiency to prevent voltage collapse, is selected as the first candidate to execute load shedding. And the amount of loads to be shed is identified though a relationship between risk values and shedding amount. The selection of shedding time conforms to the principle that the compound risk brought by failed shedding and unexpected shedding must be the minimum. Experiments conducted for IEEE 39-bus system reveal that the proposed method redound to identify the location, amount and time of load shedding more accurately and reasonably due to taking into account a great deal of uncertain factors.
In order to make up the deficiency of traditional analytical method used in the research of voltage stability problem, we need to know the probability information concerned with voltage instability. Therefore, this pa...
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In order to make up the deficiency of traditional analytical method used in the research of voltage stability problem, we need to know the probability information concerned with voltage instability. Therefore, this paper proposes a method to calculate the probability of voltage instability based on the stochastic characteristic of load margin index. This method firstly determines the stochastic characteristic of load margin index through an analysis about the randomicity of parameters which tie up with the tracing of critical point in continue power flow computation, and then figures out the probability of voltage instability by using moment and cumulate method. Owing to take into account more uncertain factors' influence on the voltage stability, the result acquired by this method is much more accurate and reasonable. A numerical simulation based on IEEE 39-bus system reveals that the proposed method works properly.
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