Battery Test; Figure 5.7-1 Battery Test Timing Diagram - Siemens 7SR224 Technical Manual

7SR224 Argus Description of Operation
5.8

Battery Test

The DC battery voltage is constantly monitored by the relay. The output function Battery Healthy is provided to
indicate that the battery charging system is connected and functioning correctly by measurement of the 'Float
Charge' voltage level and comparison with the minimum float voltage based on the Battery Nominal Voltage
setting.
In addition to this, the relay can be used to apply a loading test to the battery system at a settable periodic
interval. The test sequence is shown below.
If a protection Pickup occurs at any time during the test, the test will be abandoned and the charging system re-
connected. The battery voltage level will be maintained such that the Recloser will be capable of normal operation
throughout the duration of the test. Battery tests can be executed at manual request from a binary input or from
the Control Menu of the relay. If the time elapsed since the previous battery test is less than 12 hours, the test will
not execute and Test Aborted will be displayed on the Battery Condition meter.
Figure 5.8-1 Battery Test timing diagram
When the test is required, the output Battery Test is raised to interface with external equipment. This signal is
used to disconnect the charging system and the battery is allowed to settle for a fixed period of 30 minutes. The
battery voltage with no load is then measured (V1) and the output Battery Load Test is then raised. This is used
to connect the resistive load to the battery and the voltage is measured again after 500ms (V2). This voltage is
used to asses the battery internal resistance and the resistance of connections. If V1-V2 (ΔV) is greater than the
Battery Volts Drop setting the test will be considered as a failure and the test stopped, otherwise voltage is
measured again after a further 5 seconds with the load resistance connected. This voltage, (V3), is compared to
V2 and must not differ by more than 2 volts or the test will be stopped and recorded as a fail. The load is then
disconnected, by the drop-off of the Battery Load Test output and a 10 minute recovery time applied before the
voltage is measured again (V4). This voltage must not differ from the pre-test voltage by more than 0.5 volts or
Recovery Fail output will be raised. The Battery Test output is now cleared which will reconnect the charging
system to allow the system to return to normal. The quiescent voltage monitoring will resume after 30 minutes.
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