t is the time of discharge, expressed in h. k is the Peukert constant, dimensionless. I is the discharge current, expressed in A.
Cp = I k tĬp is the capacity according to Peukert, at a one-ampere discharge rate, expressed in Ah. As the rate increases, the battery’s available capacity decreases. It expresses the capacity of a battery in terms of the rate at which it is discharged. There is an important equation for the capacity of all lead-acid batteries, called ”Peukert’s law” (1). It depends on the application case which model will be used. A simple electric equivalent for a battery together with a more complex equivalent with parasitic path is shown in Figure 2.1. The battery is fully loaded if the SOC is one and it is zero if Battery Energy Storing Systems (BESS) The State of Charge corresponds to the current loading state of the battery. A battery model should depict the terminal voltage and the internal resistance which are a function of several intern-related variables such as the Battery State of Charge (SOC), the age and temperature of the battery. Different approaches could be found in, and. To design a good model for a battery is a science on itself. Each type has its own assets and drawbacks. But there are also a lot of other types like nickelcadmium (NiCd), nickel-metal hybrid (NiMH) and several lithium-ion types. Common batteries in the industry are often lead-acid batteries. Only a model with appropriate parameters could deliver good results. The second problem is to get the parameters from manufacturers or own measurements needed for the model. The first problem is to get a model that is not too complex but accurate enough. There are two main challenges with battery models. So there is no easy, accurate model, valid for all batteries. The problem with batteries is the huge diversity of the technologies and also the variety inside one technology. The storing part in this case a rechargeable battery is an element that depends on the actual application.
This element is well known and available in PowerFactory. The rectifier/inverter is normally based on a voltage sourced converter (VSC) with a pulse width modulation (PWM). Secondly a rectifier/inverter that could transform the DC-voltage from the storing part to the AC-voltage needed for the grid and vice versa. Firstly a storing part that could store/restore energy in an electrochemical process. So the reader could use the document in parallel with the PowerFactory project of the BESS.Ī battery energy storing system (BESS) consists of two parts. For a better usability are the names of the study cases of the project as well as the important steps in PowerFactory given. Finally, different cases are simulated and results discussed. Secondly, all required dynamic models, including the battery and the shunt VSC controller models, are presented and verified. In the first part of this application guide describes the relevant characteristics of the test network and discusses all modelling and project organisational issues that must be taken into account when setting up the model in PDF. This BESS application becomes significantly important in small or island power system, with rather low spinning reserve, where load perturbations have a considerable effect on the network frequency.
DESCARGAR DIGSILENT 15.2 FULL HOW TO
The document gives the reader guidance on how to perform the analysis in the simulation tool PowerFactory (PDF). This document describes the assessment of a BESS to replace the spinning reserve/primary reserve in a test network. These applications include different FACT controllers, where the storage devices are interfaced with the power system through either shunt- or series-connected voltage sourced converters (VSC). Large Battery Energy Storage Systems (BESS) are being increasingly used in Flexible AC Transmission Systems (FACTS) applications as a way to improve the voltage, frequency, oscillatory and/or transient stability of the system and hence enhance the reliability of power supply. Ĥ.2 Replacement of Primary Control Energy (Generator Outage). Ĥ Application Case 1: Frequency RegulationĤ.1 Replacement of Primary Control Energy (Load Change). Battery Energy Storing Systems (BESS)Ģ.1 Battery Model.
No part of this document may be reproduced, copied, or transmitted in any form, by any means electronic or mechanical, without the prior written permission of DIgSILENT GmbH. Copyright of this document belongs to DIgSILENT GmbH. DIgSILENT PowerFactory Application ExampleĭIgSILENT GmbH Heinrich-Hertz-Str.
0 kommentar(er)
