Power-flow study

About: Power-flow study is a research topic. Over the lifetime, 8091 publications have been published within this topic receiving 155053 citations. The topic is also known as: load-flow study.

Coordinated Day-Ahead Reactive Power Dispatch in Distribution Network Based on Real Power Forecast Errors

Abstract: Reactive power outputs of DGs are used along with capacitor banks to regulate distribution network voltage. However, reactive power capability of a DG is limited by the inverter ratings and real power outputs of the DG. In order to achieve optimal power flow, minimize power losses, and minimize switching of capacitor banks, a day-ahead coordinated dispatch method of reactive power is proposed. Forecast errors of DG real power in every period are used to estimate the probability distribution of DGs reactive power capacity. Considering different output characteristics and constraints of reactive power sources, a dynamic preliminary-coarse-fine adjustment method is designed to optimize DG and shunt compensator outputs, decrease the switching cost, and reduce loss. The preliminary optimization obtains initial values, and multiple iterations between the coarse and fine optimizations are used to achieve a coordinated result. Simulations studies are performed to verify the proposed method.

Load Supplying Capability of Generation-Transmission Networks

Abstract: This paper describes an extension of the power transfer capacity calculation to the calculation of maximum power system loading. This loading capability is a function of the generation and transmission capacity of the power system. The dc power flow equations provide a basis for the development of constraint equations necessary in the linear programming optimization of the generation-transmission system. An example is provided to illustrate the concepts of the load supplying capability of the power system, and the application to assessment of network adequacy and long range planning is discussed.

A processing unit for symmetrical components and harmonics estimation based on a new adaptive linear combiner structure

Abstract: Symmetrical components as well as harmonic tracking are of great importance in many applications in power systems such as power quality and protection. This paper introduces a novel Adaptive linear combiner (ADALINE) structure for symmetrical components estimation. This structure is capable of dealing with multi-output systems for parameter tracking/estimation rather than the existing ADALINE, which deals only with single output systems. As the new topology deals with Multi-Output systems, it is called MO-ADALINE. Moreover, the paper presents a new processing unit, which can estimate symmetrical and harmonic components from the measured current signals. The advantages of this proposed unit are its independence of the voltage waveform and its ability to give information about the reactive component of the resolved current. Simulation results are given to validate the proposed algorithms.

Distribution system short circuit analysis-A rigid approach

Abstract: A rigid approach to short circuit analysis for large-scale distribution systems is introduced. The approach uses an individual (a-b-c) phase-based system representation, a nontrivial transformer model, and includes the contribution due to load. The method can, therefore, be applied to balanced or unbalanced, radial, network, or mixed-type distribution systems. This approach is oriented toward applications in distribution system operation analysis rather than the more typical planning-oriented analysis. The solution method is an iterative compensation method, which uses a single optimally ordered factorization of the bus admittance matrix (Y/sub Bus/), commonly used in power flow analysis, to simulate the fault condition. The use of this method in a short circuit analysis program enables a factorized Y/sub Bus/ solution, resulting in many advantages. Using a common factorization, both power flow and short circuit analyses are possible in a single execution. Since the factorization is unchanged, multiple faults of various types can be simulated in one run of the program. >

Optimal Design of a Push-Pull-Forward Half-Bridge (PPFHB) Bidirectional DC–DC Converter With Variable Input Voltage

Abstract: This paper presents a low-cost bidirectional isolated dc-dc converter, derived from dual-active-bridge converter for the power sources with variable output voltage like super capacitors. The proposed converter consists of push-pull-forward circuit half-bridge circuit (PPFHB) and a high-frequency transformer; this structure minimizes the number of the switching transistors and their associate gate driver components. With phase-shift control strategy, all the switches are operated under zero-voltage switching (ZVS) condition. Furthermore, in order to optimize the converter performance and increase efficiency, optimal design methods and criteria are investigated, including coupled inductors design, bidirectional power flow analysis, harmonics analysis, and ZVS range extension. Based on all the optimal parameters, higher efficiency can be achieved. Finally, prototypes are built in laboratory controlled by digital signal processor for comparison purpose. Detailed test results verify the theoretical analysis and demonstrate the validity of optimization design method.