Main applicationBuchholz relay type QJ is a kind of protective device used for oil immersed transformer with conservator and on-
load tap changer. If a fault generated inside the transformer(or the on-load tap changer), cause gases
generated from oil decomposed. When the amount of gas accumulate up to a stated level, the signal contact of
buchholz relay turns on and send alarm signal. When a serious fault generates inside transformer or on-load
tap changer, the transformer oil surge will happen, oil flow heavily in the pipeline and result in the operation of
baffle plate of buchholz relay leads to the trip contact turning on, so trips the transformer. If the oil level is low
due to the oil losses, the alarms is also initiated.
assembling method |
the relay's pipe axis should be parallel to the transformer case cover,and it is allowed for the end leading to the conservator is highter,however the inclination between the axis and level surface may not exceed 4% |
structure of the gas relay |
the relay's core structure is shown in fig.1 and the relay's upper core consist of gas lock1,gas lock nut 2,probe 3,blocking 4,snap ring(float) 5,weight drop6,guard board 7,magnet 8, connecting terminal 9,spring 10,regulating rod11 and dry reed contact12.formin a flow device that acts on tripping,gas lock 1 in the cover is used for exhaustion in the case of assembly and extracting gas out of order. probe 3 is used to check flexibility and reliability of the tripping mechanism. |
Application The Gas relay series QJ is protective device for oil immered transformer. If a fault causes gas to be generated
in the transformer or a heavy surge of insulating oil the Gas relay shall be in operation, thealarm signal is
initeated and/or the transformer is tripped automatically.
Principle of designWhen the transformer is operating normally, the Gas relay is completely filled with insulating oil .If a fault causes
gas to be generated in the transformer, the bubble will filter along towards the conservator and accumulated at
the highest point in the Gas relay. As the amount of gas coquette increases and the oil level in relay fall as a
result, the cup also falls and eventually reaches point where it actuates the magnetic switch with the permanent
magnet and so initiated the alarm signal. If the oil loses, the alarm signal is also initiated A violent generation of
gas accompanied by a heavy surge of insulating oil results in operation of baffle plate. the magnetic is actuated
by the permantmagnet on the baffle plate so it trips the transformer.
Technical data(1) Working temperature: -30°C~95°C
(2) Switch Capacity: AC 220V 0.3A COSφ≤0.6
DC 220V 0.3A S≤5×10-3S
(3) Operation Character:Table
Type |
QJ-80 |
QJ-50 |
QJ-25 |
Range of flow(m/s) |
0.7~1.5 |
0.6~1.2 |
1.0 |
Gas accumulation (ml) |
250~300 |
<250 |
(4) Sealing character: filling transformer oil into the relay, Pressurizing normal temperature 200kPa,Continued
20 min and without any leakage.
(5) Insulation Character:Table
Test item |
Voltage between contacts |
Voltage between terminal and earth |
Voltage between signal and trippingterminal |
Bring to bear on industry voltaye |
2000v /1 min |
2000v /1 min |
2000v /1 min |
(6) Antivibration capacity
When acceleration is 4g at vibration frequency of 4~20Hz,the relay shall not do any.
Installation and applicationThe overall size of QJ4-25 Relay is shown as Fig. A. The overall size of QJ1-50 ,80,QJ4-50,80 Relay is shown
as Fig. B. Seeing Table 3 for the size.
The Gas relay is fitted in pipeline between the tank and conservator. pay special attention to the arrow on the
housing the conservator.
For filling oil, please all valves in the pipeline between the tank and conservator, blled the housing via the
bleeder and then ciosed.
Air pumped form the air plug, the reliability of "Signal" contacting motion can bechecked.
Cover twisted down, pinprossed, the reliability of "Trip" contacting motion can bechecked.
NoteBefore the newly-produced relay installed and used, the relay chip must be taken out and the locked banding
used during the transportation should be demolished.
The Gas relay must be checked by special device, then can mounted.
The spring on the baffle plate can changed the length, adjusting the value for tripping. The other parts of the
Gas relay can`t change at will.
Replacing or adding some parts near the permanent magnet and magnetic switch, the non-magnetic material
must be used.
The permanent magnet can be not intensely vibratied or in strong magnetic field, The permissible operating
temperature is from -40°C to 100°C.
The magnetic switch can`t dismantle and the end of leads can`t bend at will.
Structure outline and dimensions:Table
No. |
Type |
Connection pipe(mm) |
Gas Volume (ml) |
Set oil flow speed range (m/s) |
Magnet contact tube |
Connection diagram |
1 |
QJ4-25 |
25 |
250 |
1.0 |
Single signal; Single trip |
4 |
2 |
QJ4G-25 |
|
Single trip |
5 |
3 |
QJ6-25 |
Double trips |
6 |
4 |
QJ1-50 |
50 |
250~300 |
0.6~1.2 |
Single signal; Double trips |
7 |
5 |
QJ1-80 |
80 |
0.7~1.5 |
6 |
QJ2-50 |
50 |
0.6~1.2 |
7 |
QJ2-80 |
80 |
0.7~1.5 |
8 |
QJ3-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
8 |
9 |
QJ3-80 |
80 |
0.7~1.5 |
10 |
QJ4-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
7 |
11 |
QJ4-80 |
80 |
0.7~1.5 |
12 |
QJ5-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
8 |
13 |
QJ5-80 |
80 |
0.7~1.5 |
14 |
QJ6-50 |
50 |
0.6~1.2 |
15 |
QJ6-80 |
80 |
0.7~1.5 |
16 |
QJ7-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
7 |
17 |
QJ7-80 |
80 |
0.7~1.5 |
18 |
QJ8-50 |
50 |
0.6~1.2 |
Double signal; Double trips |
9 |
19 |
QJ8-80 |
80 |
0.7~1.5 |
20 |
QJ9-50 |
50 |
0.6~1.2 |
21 |
QJ9-80 |
80 |
0.7~1.5 |
22 |
QJ10-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
7 |
23 |
QJ10-80 |
80 |
0.7~1.5 |
24 |
QJ11-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
8 |
25 |
QJ11-80 |
80 |
0.7~1.5 |
26 |
QJ12-50 |
50 |
0.6~1.2 |
27 |
QJ12-80 |
80 |
0.7~1.5 |
28 |
QJ13-50 |
50 |
0.6~1.2 |
29 |
QJ13-80 |
80 |
0.7~1.5 |
30 |
QJ14-50 |
50 |
0.6~1.2 |
Double signal; Double trips |
9 |
31 |
QJ14-80 |
80 |
0.7~1.5 |
32 |
QJ15-50 |
50 |
0.6~1.2 |
Single signal ;Double trips |
8 |
33 |
QJ15-80 |
80 |
0.7~1.5 |
34 |
QJ16-50 |
50 |
0.6~1.2 |
Double signal; Double trips |
9 |
35 |
QJ16-80 |
80 |
0.7~1.5 |
36 |
QJ17-50 |
50 |
0.6~1.2 |
Double signals ;Single trip |
10 |
37 |
QJ17-80 |
80 |
0.7~1.5 |
38 |
QJ18-50 |
50 |
0.6~1.2 |
39 |
QJ18-80 |
80 |
0.7~1.5 |
40 |
QJ19-50 |
50 |
250~300 |
0.6~1.2 |
Double signals ;Double trips |
11 |
41 |
QJ19-80 |
80 |
0.7~1.5 |