ABB PQFA, Instruction Manual

Page: 86 / 98

PQFA Instructions Manual
Asea Brown Boveri Jumet S.A.
86
10.8.2. Alarm contact
The PQFA is fitted with a normally open alarm contact (voltage free contact)
allowing remote supervision of the unit. It is open if one of the following
conditions is met:
? ? The filter is in error condition
? ? The filter is off
When it is closed the filter is working properly.
The exterior alarm has to be connected to connection points X12-1 and X12-2
of terminal X12.
10.9. Protections
The PQFA is fitted with two types of protection:
? ?
Slow protection
? ?
Fast protection
The role of the slow protection is to change on-line the way the filter is
working according to the filter stress and programmed levels. This ensures
that the filter is never overloaded and always has an optimal filtering effect.
The fast protection is only activated in case of abnormal working conditions
and ensures the integrity of the filter.
The fast protection means include:
1. Preventing the main breaker from closing in the event that the filter
– cannot synchronise to the supply network (e.g. wrong phase rotation
order)
– detects a permanent AC undervoltage on one of the feeding phases
– detects a permanent internal error generated by e.g. a wrong internal
flat cable connection, an excessively high level measured on the voltage
or current input channels, a faulty IGBT-module etc.
2. A blocking system of the IGBT-bridge in case of one occurrence of the
following events
– AC overvoltage on the mains detected by the hardware protection
system
– DC overvoltage on the DC capacitors detected by the hardware
protection system
– Filter overcurrent detected by the hardware protection system
– IGBT Overcurrent detected by the IGBT’s internal control logic
– IGBT Overtemperature detected by the IGBT’s internal control logic