Gas Relay for Transformer

Gas relay
QJ1G
Product Description
Main application
Buchholz 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.

 
 
1 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, the alarm signal is initeated and/or the transformer is tripped automatically.

 
Principle of design
When 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.
3,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 application
The 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.

5,Note
Before 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			0.6~1.2	Single signal ;Double trips	8
13	QJ5-80			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
42	QH