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Conventionally power flow of transmission and distribution network is calculated separately. With the increasing penetration level of distributed generation (DG), such as photovoltaic and wind power, voltage and power characteristics of tie bus become complicated. The tight coupling problem appears between transmission and distribution network. As a consequence, the power flow calculation must be...
In this paper, a new method for reference network considering network topology optimization is proposed. The actual operation mode optimization and the correction control with transmission switching under the contingency situation are taken into account in the proposed method. Based on the forecasted load values of each period in predictive multi-time scale and candidate transmission line schemes...
Wind generation forecast approaches are typically based on fixed model structures, which might fit well with existing data but fall short in forecasting out-of-sample data. The reason lies in that predetermined models cannot always capture the actual dynamic features of wind farms, resulting in unavoidable model errors. In this paper, a novel ultra-short-term wind generation forecast approach based...
For controlling distributed controllable units in radial distribution networks, a method based on alternating direction method of multipliers (ADMM) for dynamic distributed optimal power flow (DOPF) is designed. The convex DistFlow model for power flow is spitted into two layers. Based on power flow of distribution networks, distribution system operators (DSOs) in the upper layer calculate shadow...
With the diversified development of electrical loads, and the large-scale integration of volatile renewable generations, power system operation, control and planning face the challenge of increasing injection uncertainties. In this paper, a new method for reference network considering nodal injection uncertainties is proposed. The actual operation mode optimization and reserve configuration of power...
For the randomness and asynchronous characteristics of wind power and photovoltaic (PV) generation, large-scale integration of renewable generations into power grid, especially when the electric network topology is fixed, has brought the problems of transmission congestion and voltage security in power system operation. In order to make better use of existing network to promote security and economy...
Reference network model determines the optimal transmission line capacities by minimizing the generation cost and investment cost of transmission lines, in which line flow constraints under contingency events should be respected. However, the number of these constraints is tremendous and this makes the impediment when reference network model is applied for real large power systems. In this paper a...
Generation schedule must not only meet the forecasting load, but also be capable of coping with uncertainty. Traditionally, the ability to provide adequacy generation under uncertainty is just required in each period, namely certain reliability criteria must be satisfied. However, because the inner period variability and uncertainty brought by renewable generation such as wind power increase greatly,...
Inefficient utilization of electricity business expanding data in State Grid Companies related departments still exist. It is because of their excessive attention on the speed of electricity supply and the quality of service, but ignores the potential useful information of the data implied in the future electricity sale market. With this regard, this paper proposes a novel analysis and forecast method...
Dynamic thermal rating (DTR) is an effective technique to improve the ampacity of overhead power transmission lines based on the monitoring of real-time environmental conditions. With DTR technology being introduced, the thermal rating of transmission line is no longer constant but time-dependent. To fully utilize the transfer capability of transmission lines, it is necessary to provide operators...
To evaluate the operational flexibility of power system can accurately grasp the regulating capacity of power system, which is helpful to deal with the variability and uncertainty of wind power. Energy storage brings new opportunities for power system operation. In the day-ahead dispatch stage, energy storage can be used to optimize the scheduling and improve the economic performance of power system...
The penetration level of distributed generation (DG) grows rapidly bringing more frequency fluctuation nowadays. Besides, the power system grows in size day by day; the assumption that the frequencies are the same across the grid is no longer valid. These all bring out problems to the frequency control mechanism currently used. The recently proposed rotor angle control strategy may solve these problems...
A reference network is topologically identical to the existing network in which the generators and loads are not changed while the transmission line capacity will be optimized. By applying a reference network, the optimal transmission capacities of each line could be identified, as it takes annual operational and transmission costs into consideration. A reference network provides a standard to evaluate...
Effect of voltage hasn't been considered reasonably in existing loss allocation methods. Aiming at the problem, the impact of voltage on the loss allocation method based on circuit theory is deeply discussed in this paper. Firstly, the two node equivalence modes and principles of the branch loss allocation method are investigated. Then the relationship between voltage and the loss under different...
Power grid tries to maximize its profit by reducing generation cost, supply costs and operation costs while sustaining its required reliability. Developing maintenance strategies is one of the most effective methods. The condition-based maintenance approach is a key method in providing optimal maintenance strategies in theory. It considers the tradeoffs between the system maintenance risk and the...
Probabilistic wind generation forecast results are crucial for power system operational dispatch. In this paper, a nonparametric approach for short-term probabilistic wind generation forecast based on the sparse Bayesian classification (SBC) and Dempster-Shafer theory (DST) is proposed. This approach is composed by the following four steps: Firstly, a spot forecast of wind generation is performed...
Customer baseline load (CBL) is widely used as an evaluation tool in demand response (DR) programs. Due to uncertainty of load, it is difficult to establish an accurate CBL model and the calculation error is inevitable. Therefore, calculation error of CBL must be estimated, so that DR programs can be evaluated effectively. Consumers' load changes with periodic pattern of production and life, meanwhile,...
A static security preventive control approach considering thermal inertia of overhead line is proposed in this paper. Combined with dynamic thermal rating (DTR) technology, the approach considers temperature as overhead lines' thermal limit, introduces heat balance equation (HBE) and thermal inertia time constraint of overhead line in preventive control model. Accordingly, the model is more realistic...
For the time being, the absolute rotor angle of every generator is changing from time to time, so it's less likely to improve transient stability by use of rotor angle measurement. Things are no longer so after absolute rotor angle controllers are deployed across the power system. The frequency of the power system will remain constant, and the absolute rotor angle of every generator will be kept at...
As the regulating range is limited in the real-time dispatch, the security improvement is more prominent than the economic improvement for the real-time dispatch. Based on the preemptive goal programming and the steady-state security region estimation methods, this paper proposed a model for the real-time dispatch, in which the base-points and the participation factors of the AGC (Automatic Generation...
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