Battery monitoring in Nuclear Power Plants

Batteries are widely used in Nuclear Power Plants to ensure that the facility is operable even in the event of a failure or disturbance in the utility power grid.

Large number of batteries

One Nuclear Power Plant can have as many as 100 batteries of various sizes. Some of them being of extreme importance for the safety of the Plant in case of an emergency situation. A large battery can comprise 200 cells that are connected in series.

Safe Battery Monitoring

A Battery Monitoring System can greatly increase the reliability of the batteries. However, the system must be selected with care since a poorly designed battery monitoring system will have the opposite effect.

Batscan = Safety

Batscan is jointly developed by TechTrade, Sweden and Bell Labs, USA. The system was designed for maximum safety and reliability without compromising performance and user friendliness. Batscan is used with the famous AT&T Round Cells (the world's most reliable lead/acid battery) in the most mission critical battery installations.

Current Limiting Resistor

Batscan makes no direct connections to the battery, instead, a high ohmic protective resistor is fitted between each battery cell and the measuring leads. The specifications of this resistor are extreme; Resistance is 2MΩ, and surge pulse capability is in excess of 10kV.

The high resistance ensures that maximum short circuit current is limited to a safe level under all circumstances.

What is 'Safe Level'?

For human protection a circuit is considered to be safe if the current is limited to 0.7mA.

Batscan is setting a new standard for reliability by using the same level for protection of the monitored battery.

Note! This is the limit in worst case condition, such as short circuit. Normally the measuring current is in the µA range.

Safe connection to a battery cell with
a high ohmic protective resistor.

Forsmark Nuclear Power Plant
in Sweden.

Separate Power Supply

Obviously, the monitoring system must be powered separately in order to work independently of the monitored battery.

Fiber optic communication

A common computer in the control room may be used for monitoring of both safety classified and unclassified batteries within the facility by using fiber optic cables between the battery rooms.

User friendly software

The graphical user interface allows for a large number of batteries to be monitored at the same time.

Graphical presentation gives
a good overview..

With a well thoughtful graphical user interface the operator can quickly get a good overview of the condition of the batteries simultaneously, without that the detailed information gets lost.

See example with a 10 battery monitoring system: Arlanda ATCC.

Service & Maintenance

Batscan is also a great tool for periodic battery discharge tests to produce documentation and logging of battery data. See example of Battery Discharge Test.

Batscan Battery Monitoring System

Batscan is an advanced battery monitoring system of batteries where the safety is the most important.

Monitoring unclassified and safety classified batteries.

A computer collects measuring data with high speed from the measure modules that are connected to the batteries. Batscan evaluates the collected values and saves the changed values on the computer's hard drive. Abnormal measuring vales will send an alarm to the superior alarm system.

Flexible bus network

A network combines the computer with the batteries for monitoring. The network is a combination of bus topology with copper wire and ring topology with a fiber optic cable. With the copper wire the measuring modules can receive its current from the network.

Isolated local bus network

Every battery cell is monitored one by one via a current measuring module and one or more cell voltage modules that are connected to a local bus network via transformators with high isolation voltage (6kV).

The current measuring module connects to Batscan’s network, either directly or through an optical fibre adapter.