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Battery management system for power plants

IP.com Disclosure Number: IPCOM000201636D
Publication Date: 2010-Nov-17
Document File: 8 page(s) / 100K

Publishing Venue

The IP.com Prior Art Database

Related People

Yoann Roux: AUTHOR

Abstract

A battery management system is proposed applicable to power plants. By the use of data collected by a battery monitoring system, computations are directly used for maintenance, operation, and engineering. The system allows energy management with automatic actions. Functions are enabled such as automatic load shedding of the no-longer required consumers, automatic indication of battery states, and accurate indication of the earliest restart possibility.

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Battery management system for power plants

Abstract

A battery management system is proposed applicable to power plants. By the use of data collected by a battery monitoring system, computations are directly used for maintenance, operation, and engineering. The system allows energy management with automatic actions. Functions are enabled such as automatic load shedding of the no-longer required consumers, automatic indication of battery states, and accurate indication of the earliest restart possibility.

Introduction

The following pertains to power plants with battery-supplied consumers ensuring safe shutdown on normal AC loss (blackout)

Many types of power plants use battery-supplied essential consumers.

These essential consumers are, depending on their function, required to run for a time measured from a few seconds to several hours.

On-line information about the battery energy content would allow different automatic actions to reduce design margin, reduce maintenance work, reduce the risk of undetected failure and finally increase machine availability. The process of executing such automatic actions based on battery status data is here referred to as a battery management system, where battery monitoring may be considered the keystone for such battery management system.

Conventionally, battery banks are sized based on an estimate of the power demand of each connected consumer, over the minimum time the last required consumer shall run, with estimated correction factors linked to an estimated average room temperature () and to the battery aging impact (). See figure 1.

Battery Energy content:

Battery capacity (example): f (,)

Figure 1: Current battery sizing basics

These various assumptions as a whole jeopardize the precision of the sizing calculation. This may lead to a costly over-sizing of the battery bank and can furthermore introduce hazards, while the battery bank is not able to supply a safety-related consumer over the required time.

This status being known, the following four good practices mitigate the risk of such hazard:

  • At engineering level:

The sizing calculation normally considers a high design margin: the equipment is oversized; most of the consumer are permanently connected to the battery and remain on.

In fact, the lack of precise information on discharge status does not allow a secured decision to switch-off non-essential but useful consumers: a time-based automatic action would not fit with any special case, while an operator decision is to be excluded in a exceptional stressful situation.

  • At maintenance level:

Battery cells are manually monitored. This manual monitoring requires work important effort, as being done cell by cell (acid-density meter, voltage measurement) and is requiring outage (discharge test).

  • At operation level:

The down-time between a battery partial discharge (due to a blackout) and a restart of the power plant is calculated based on full recharge time or based on a basic estimate of the SoC (state of c...