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.

A performance comparison between extended Kalman Filter and unscented Kalman Filter in power system dynamic state estimation

Abstract: Dynamic State Estimation (DSE) is a critical tool for analysis, monitoring and planning of a power system. The concept of DSE involves designing state estimation with Extended Kalman Filter (EKF) or Unscented Kalman Filter (UKF) methods, which can be used by wide area monitoring to improve the stability of power system. State estimation with EKF and UKF methods can be used for monitoring and estimating the dynamic state variables of multi-machine power systems, which are generator rotor speed and rotor angle. This paper uses Powerfactory to solve power flow analysis of simulations, then a non-linear state estimator is developed in MatLab to solve states by applying the unscented Kalman filter (UKF) and Extended Kalman Filter (EKF) algorithm. Finally, a DSE model is built for a 14 bus power system network to evaluate the proposed algorithm for the networks. This article will focus on comparing and studying the advantages and disadvantages of both methods under transient conditions. It is demonstrated that UKF is easier to implement and accurate in estimation.

Integrated electrical power distribution system using common building blocks

Abstract: An electrical power distribution system includes a data bus, separate from the main aircraft data bus, internal to the aircraft electrical power distribution system and an electric power control unit (EPCU) in communication with the internal data bus. Primary and emergency power distribution subsystems include line replaceable modules (LRM) connected in the aircraft electrical power distribution system as electrical load control units (ELCU), each having a common supervisory control interface in communication with the internal data bus, while a secondary power distribution subsystem includes LRMs connected in the aircraft electrical power distribution system as solid state power control (SSPC) units, each having the common supervisory control interface in communication with the internal data bus. The common supervisory control interfaces all execute a common supervisory control logic for receiving commutation commands from the EPCU and providing status back to the EPCU.

Metering and protection system for an A.C. power system

Abstract: A system for electronically metering an A.C. electrical power system to derive performance parameters such as real and reactive power useful in revenue metering and fault protection applications. Voltage and current sensors associated with the power system provide isolated output signals proportional to the voltage and current in the system. From these signals finite-duration impulse-response filters periodically determine Walsh function correlation coefficients by integrating the voltage and current signals at least once during each period of the power system and periodically sampling and holding the integrated signal in sequence with the integration. The present and a plurality of immediately preceding correlation coefficient values are stored in memory, and by combination of the correlation coefficients by addition, subtraction or multiplication, power system performance parameters, such as real power, reactive power, voltage, current, or power factor, are obtained for utilization in revenue metering or overload protection applications. Related methods are also disclosed.

Generating Capacity Reliability Evaluation in Interconnected Systems using a Frequency and Duration Approach Part I. Mathematical Analysis

Abstract: Equations for computing the frequency and duration of various capacity outages were first given by Halperin and Adler1. The application to the generation area was subsequently extended by the publication of a recent series of papers2-6 which presented a far more general approach to the problem. The general method is extremely powerful and can be applied to a wide range of problems7-9. This paper utilizes the basic concepts previously presented2,3 and extends them to develop a frequency and duration approach to interconnected system reliability evaluation. Equations are developed for one system connected to another system and are subsequently extended to the case of a system connected to two or more systems. The application of the theoretical technique is illustrated in Part II of this paper entitled "System Applications".

Distributed generator and load-side secondary frequency control in power networks

Abstract: We design a distributed secondary frequency control scheme for both generators and controllable loads. The proposed scheme operates via local sensing and computation, and neighborhood communication. Equilibrium and stability analysis of the closed-loop system is performed with a power network model including turbines and governors of generators and nonlinear AC power flows. After a change in power supply or demand, the proposed scheme is able to stabilize the system, restore bus frequencies and net inter-area power exchanges, and minimize total generation cost minus user utility at equilibrium.