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.

Estimation Algorithms for Large-Scale Power Systems

Abstract: The operation of large-scale power systems demands that the real-time monitoring, security, and control procedures can draw on a consistent and reliable set of data representing the measurements and the network parameters. This paper considers the enhancement of this data base through advanced estimation programs for the states and parameters of the network. The role of such programs and the different forms they can take are presented in a comprehensive and unified manner. This will assist the designer in the task of selection and development of a suitable algorithm for his system from a set of possible approaches.

Power supply adaptive feedforward control circuit

Abstract: A power supply system is disclosed. In one embodiment the power supply system includes a source of DC power that provides a DC bus voltage between a pair of DC bus terminals, and a power supply that receives power from the DC bus terminals and delivers power to a load. An output measurement circuit measures output parameters delivered by the power supply and provides a corresponding set of feedback signals. A feedback regulator connected receives the feedback signals and provides a feedback output signal operative to regulate the output of the power supply to achieve a desired voltage, current, or power level specified by a setpoint signal. An adaptive feedforward circuit connected to the feedback regulator and to the DC bus terminals provides a combined regulation signal to the power supply that minimizes perturbations in the output of the power supply due to DC bus ripple voltage.

Passivity-based control of a wound-rotor synchronous motor

Abstract: This study presents a new non-linear passivity-based controller for a wound-rotor synchronous machine, acting as a motor drive. The control objectives are stated in the dq-frame, and the port-controlled Hamiltonian model is also obtained. A power flow analysis allows to state the control goals in terms of ohmic losses reduction, and motivates the use of the field current for the reactive power compensation. From the Hamiltonian structure, the simultaneous interconnection and damping assignment technique is used to compute the control action, which results in a controller with a simpler architecture than the standard one for this class of machines, able to cope with both positive and negative external mechanical loads and having thus bidirectional power capabilities. The robustness of the control action is also taken into account in the design procedure. Finally, the computed controller is validated via numerical simulations.

Power flow analysis of multi-terminal HVDC networks

Abstract: Availability of suitable converter technologies added with increasing demands for HVDC connection, especially in the North Sea area, opens the potential for establishing multi-terminal HVDC grid. Such dc network requires a separate power flow analysis method as opposed to the conventional method employed for ac network problems. This paper discusses a numerical iteration method based upon the Newton-Raphson approximation for analysing power flow in multi-terminal HVDC networks. The method was tested to analyse the power flow of a five terminal HVDC grid. It was observed that even with poor initial guesses of the unknown nodal voltages; the iterative method was giving a convergent solution of the required error margin within few iteration steps.

Power System Transients

Abstract: The steady state load limits of a power network may be examined by familiar methods of analysis. However, the instability of a system with one or more elements working close to these limits sets lower values of power at which the system can be expected to give satisfactory operation under the sudden changes in load or connections which it must successfully sustain in operation. This paper presents methods for the analysis of power systems under transient conditions. A qualitative discussion of the problem is given, followed by an outline of a point-by-point scheme of analysis which takes into account the inertia of machines, field transients, etc. The value of this scheme depends upon having available rapid methods of analysis applicable to conditions prevailing at a given instant during the transient. Therefore, there is also included a description of the methods which have been found advantageous, notable among which is a superposition method of solving systems by means of charts. This is a powerful means of attacking complicated systems. The method of point-to-point analysis is applied to specific types of networks as examples. There is also given an extension of approximate methods of analysis presented previously. The paper is confined to the exposition of the methods of analysis which we have found convenient and powerful.