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17. CAPACITIVE VOLTAGE INDICATORS
Each module of switchgears is equipped with a capacitive
voltage indicator in accordance with either IEC 61958 (VPIS)
or IEC 61243-5 (VDS).
17.1 VOLTAGE INDICATORS VPIS
VPIS indicators are used to indicate the presence of service
medium voltage.
WARNING
The indication of VPIS alone is not sufficient to pro-
ve that the system is dead: if operating procedures
make it mandatory, relevant voltage detectors
according to IEC 61243-1, IEC 61243-2 and IEC
61243-5 shall be used.
The energized state of the unit is indicated by a flashing light
with frequency of repetition of at least 1 Hz.
NOTE
Under very bright lighting it may be necessary to
improve visibility by additional means.
OPERATING TEMPERATURE
The VPIS will operate reliably over a temperature range of
–25° to +50°C.
PHASE COMPARISON AND TESTING OF VPIS
Each phase of the integrated voltage presence indicating
system has a connection point on the front panel, which can
be used to perform phase comparison and to test the voltage
presence indicator.
THRESHOLD VALUES FOR VOLTAGE PRESENCE
INDICATION
The indication corresponding to “voltage present” appears
when the actual line-to-earth voltage is between 45% of the
nominal voltage and the rated voltage. The indication corres-
ponding to “voltage present” does not appear when the actual
line-to-earth voltage is less than 10% of the nominal voltage.
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