AUTOMATION 2000 DGPT2-IB - 3- Electrical Operation; 3.2.1 Gas Discharge Operation

3– ELECTRICAL OPERATION
3.1 Preamble
All DGPT2
®
monitoring functions come with change-over contacts (a Normally
Opened contact, a Normally Closed contact and a Common point).
3.2 Operating diagram
3.2.1 Gas discharge
Gas discharge is usually due to an electrical defect in the transformer active part,
creating an electrical arc not strong enough to cause an instantaneous pressure
increase.
G2 G1
(as an option)
When the gas volume inside the gas accumulation tank reaches a certain value
(depending on the dielectric density), the Reed contact changes position.
Dielectric density < 1  Volume < 140 cm
3
Dielectric density = 1  Volume = 140 cm
3
(±5 cm
3
)
Dielectric density > 1  Volume > 140 cm
3
Reed
Gas accumulation tank
Triggering float
In the following diagrams, the contacts are shown unpowered
(dead), meaning not under the influence of any defect for
their respective monitoring functions.
NORMAL LEVEL
Reed contact(s)
Indicator float
Terminal
block
NO
C
3’
2’
1’
NC NO
C
3
2
1
NC
AUTOMATI ON 20 0 0
TECH. INSTRUCTIONS
Page
N° T/NOT-0021 Date: 28/09/16
Rev.
7
DGPT2
®
5