ABB Relion 630 Series, Technical Manual

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Timer 2
Once activated, the timer activates
ST_UHIGH
for overvoltage condition. When the
operate timer has reached the value set by the Alarm delay time setting, the
AL_UHIGH
output is activated. If the voltage returns to normal value before the
module operates, the reset timer is activated. If the reset timer reaches the value set by
Reset delay time , the operate timer resets and the ST_UHIGH output is deactivated.
The activation of the
BLOCK
input signal resets the timer and deactivates the
ST_UHIGH
and
AL_UHIGH
outputs. The activation of
BLK_ST
and
BLK_AL
blocks
the individual alarm and operate outputs respectively.
5.1.5 Application
Usually, the load on the DC system is a constant resistance load, for example, lamps,
LEDs, electronic instruments and electromagnetic contactors in a steady state
condition. A transient RL load exists when breakers are tripped or closed.
The battery voltage has to be continuously monitored as the batteries can withstand
moderate overvoltage and undervoltage only for a short period of time.
• If the battery is subjected to a prolonged or frequent overvoltage, it leads to the
ageing of the battery, which may lead to the earlier failure of the battery. The other
occurrences may be the thermal runaway, generation of heat or increased amount
of hydrogen gas and the depletion of fluid in case of valve regulated batteries.
• If the value of the charging voltage drops below the minimum recommended float
voltage of the battery, the battery does not receive sufficient charging current to
offset internal losses, resulting in a gradual loss of capacity.
•
If a lead acid battery is subjected to a continuous undervoltage, heavy
sulfation occurs on the plates, which leads to the loss of the battery capacity.
5.1.6 Signals
Table 243: SPVNZBAT Input signals
Name Type Default Description
U_BATT_IN REAL 0.00 Battery terminal voltage
BLOCK BOOLEAN 0 Block of function
BLK_AL BOOLEAN 0 Blocks the alarm signals
BLK_ST BOOLEAN 0 Blocks the start signals
1MRS757256 F
Section 5
Supervision functions
PML630/Compact Load-Shedding Solution 193
Technical Manual