Claims:1. A Real Time Surge Detector (RTSD) comprising of a main housing 1, a top plate 2 and the operating flap 3 as major parts; the said operating flap 3 is assembled with the top plate 2 with help of the rotary shaft 4, brass bushes 11 and stopper plate 12; the relative movement between operating flap 3 and rotary shaft 4 is locked with help of locking pin 5; a position sensor 6 is mounted on main housing 1 to facilitate rotary movement monitoring of the operating flap 3 in response to abnormal flow rate of oil in both the directions; during normal operation of electrical transformer, oil doesn’t exhibits any force on the operating flap 3 so, the operating flap 3 remains vertical and this home position is monitored by a proximity sensor – home 7; during heavy internal arching oil flows rapidly from the transformer tank 15 and pushes the operating flap 3 towards right and generates analogue signal with help of position sensor 6 about its angular position; this device also generates a digital signal with help of a proximity sensor – surge 8 when operating flap 3 reaches extreme right position; during oil pump switching oil flows rapidly towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position; this device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position; during oil leakage from transformer tank 15, the oil flows towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position; this device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position.

2. The real time surge detector (RTSD) as claimed in claim 1, wherein the monitoring means for monitoring the position of the operating flap 3 can be selected from group of position sensor, magnetic sensor, proximity sensor, magnetic switch, or combination thereof.

3. The real time surge detector (RTSD) as claimed in claim 1, wherein the circuit used for monitoring the position of the operating flap 3 is normally close (NC) circuit.

4. The real time surge detector (RTSD) as claimed in claim 1, wherein the operating flap 3 is kept free to move in either direction in response to the increase in the flow of the oil.

5. The real time surge detector (RTSD) as claimed in claim 1, wherein the rotary mechanism is completely submerged in dielectric oil eliminating the need of separate lubrication means.

6. The real time surge detector (RTSD) as claimed in claim 1, used alone and or in combination of bladder flange and or conservator tank and or any other such mechanism and or device to prevent and or protect the electrical transformer from explosion and or fire. , Description:Technical field of the Invention:

The present invention relates to the field of monitoring the working of rotating mechanical components, and more particularly, to real time surge detector (RTSD) for electrical transformers which is used to detect the oil surge generated in the transformer tank due to short circuit.
Background and prior art:

In electrical transformers, heavy arching due to short circuit transfers complete electrical energy from an arc to the dielectric oil which generate maximum volume of gas and increases the dynamic pressure causing turbulent surge or pressure wave which last for few milliseconds.

If this process is not prevented and controlled, it explodes the electrical transformer and in turn hot oil and gases are released to the surrounding environment. When released gases comes in contact with oxygen, it ignites spontaneously and spreads fire to nearby valuable assets like human being, equipment’s, buildings etc.

In order to deal with such situations, there are number of transformer protection systems developed, which safeguard the electrical transformers by reacting to different input signals from various control units, sensors, switches etc. However, these systems exhibit certain delay in action for protecting the electrical transformer due to their limitations in timely identifying electrical faults and its effects.

Electrical faults are identified by transformer’s internal protection system which generate trip signals based on differential relay pre-set values. The immediate effect of electrical faults is oil surge generation which should be detected precisely in shortest time to effectively prevent and protect electrical transformer from explosion and fire and minimize the damage to electrical transformer and surrounding environment.

The available transformer protection systems receive oil surge signal from Buchholz Relay fitted by transformer manufacturer. Buchholz Relay when used along with electrical transformer, gives the combination of signals like alarm in case of slow accumulation of gas generated due to decomposition of dielectric oil, alarm in case of oil leakage, circuit breaker in case of rapid oil flow i.e. oil surge from transformer tank to conservator tank.

The Buchholz Relay provides signals in case of hazardous conditions, but it also has some major limitations in identifying surge because it gives trip signal only in case of intensive laminar / steady oil flow.

However, heavy arching due to short circuit transfers complete electrical energy from arc to the oil which generate maximum volume of gas and increases the dynamic pressure causing turbulent surge or pressure wave which last for few milliseconds (about 5ms). The mechanical construction of the Buchholz Relay fails to detect turbulent flow and or medium intensity surge and generate digital signal at set steady flow rate only. So, the Buchholz Relay alone is not specialized fool- proof surge detecting device.

Therefore there is a need to design and develop a specialized device which can overcome the drawbacks of the prior art and detect any kind of oil surge precisely in shortest time.
Objectives of the invention:

The primary objective of the present invention is to provide a real time surge detector (RTSD) for an electrical transformer to detect the rapid flow of dielectric oil from transformer tank in response to the oil surge generated in the transformer tank due to short circuit caused because of the heavy arching inside the electrical transformer.

Another objective of the present invention is to provide a real time surge detector (RTSD) for an electrical transformer to detect the rapid flow of dielectric oil towards transformer tank in response to vacuumization caused during oil cooling, pump switching and transformer tank leakage.

Another objective of the present invention is to provide a real time surge detector (RTSD) for an electrical transformer wherein the response of the operating flap is achieved with respect to increase in flow rate of oil in either direction.

Another objective of the present invention is to provide a real time surge detector (RTSD) for an electrical transformer wherein the position of the operating flap in response to change in the flow rate of the oil is monitored on a continuous basis thereby providing additional alerts related to mechanical or electrical failures like loose contact or wire break.

Another objective of the present invention is to provide a real time surge detector (RTSD) for an electrical transformer which continuously monitors the position of the operating flap by means of proximity sensor connected in normally closed (NC) circuit to facilitate the identification of mechanical or electrical failures like loose assembly, loose electrical contact, wire break etc.

Summary of the invention:

The present invention describes the real time surge detector (RTSD) for an electrical transformer which should be exceptionally used to detect positive and or negative surge of the oil in transformer tank. The present invention addresses the disadvantages associated with the prior art patent by using the real time surge detector (RTSD).

The present invention discloses the Real Time Surge Detector (RTSD) which comprises of three major parts such as main housing 1, top plate 2 and operating flap 3. An operating flap 3 is assembled with top plate 2 with help of rotary shaft 4, brass bushes 11 and stopper plate 12. The relative movement between operating flap 3 and rotary shaft 4 is locked with help of locking pin 5. A position sensor 6 is mounted on main housing 1 to facilitate rotary movement monitoring of the operating flap 3 in response to abnormal flow rate of oil in both directions. In normal operation of electric transformer oil doesn’t exhibits any force on the operating flap 3 so, the operating flap 3 remains vertical and this home position is monitored by a proximity sensor – home 7.

During heavy internal arching, the oil flows rapidly from the transformer tank 15 and pushes the operating flap 3 towards right and generates analogue signal with help of the position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – surge 8 when operating flap 3 reaches extreme right position.

During oil pump switching, the oil flows rapidly towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position.

During oil leakage from transformer tank 15, the oil flows towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position.

Brief Description of the Drawings

FIG.1 illustrates the schematic representation of the electrical transformer along with real time surge detector (RTSD).
FIG.2 illustrates the three dimensional image of the real time surge detector (RTSD).
FIG.3 illustrates the position of the real time surge detector during normal operation (RTSD).
FIG.4 illustrates the position of the real time surge detector (RTSD) during oil surge condition.
FIG.5 illustrates the position of the real time surge detector (RTSD) during oil pump switching and or oil leakage condition.

Reference numbers used in figures
1) Main Housing
2) Top Plate
3) Operating Flap
4) Rotary Shaft
5) Locking Pin
6) Position Sensor
7) Proximity Sensor - Home
8) Proximity Sensor - Surge
9) Proximity Sensor - Vacuum
10) Side Cover Plate
11) Brass Bush
12) Stopper Plate
13) Air Release Bolt
14) Oil Drain Bolt
15) Transformer Tank
16) Inlet Pipe
17) Outlet Pipe
18) Bladder Flange
19) Oil Drain Pit

Detailed description of the invention:

The present invention is described below.
The present invention describes a Real Time Surge Detector (RTSD) which is used to detect the oil surge caused due to heavy internal arching in electrical transformer.
As illustrated in FIG. 1, the real time surge detector (RTSD) is mounted between the transformer tank 15 and bladder flange 18 with help of an inlet pipe 16 and outlet pipe 17. The bladder flange 18 is in connection with the oil drain pit 19. The Buchholz Relay (BR) along with Conservator Sequester Valve (CSV) is also in connection with the transformer tank 15.

FIG. 2 describes the real time surge detector (RTSD) in assembled three dimensional view.

Referring to FIG. 3, the real time surge detector (RTSD) during normal operation is illustrated. In normal working condition, the operating flap 3 is in home position and free to move in either direction as per the oil flow.

FIG. 3 illustrates the Real Time Surge Detector (RTSD) which comprises of a main housing 1, top plate 2 and operating flap 3 as three major parts. An operating flap 3 is assembled with top plate 2 with help of rotary shaft 4, brass bushes 11 and stopper plate 12. The relative movement between operating flap 3 and rotary shaft 4 is locked with help of locking pin 5. A position sensor 6 is mounted on main housing 1 to facilitate monitoring the rotatory movement of the operating flap 3 in response to the abnormal flow rate of oil in both the directions.

In normal operation of electrical transformer, oil doesn’t exhibit any force on the operating flap 3. This makes the operating flap 3 to remain vertical and this home position is monitored by a proximity sensor – home 7.

The operating flap 3 of the present invention is designed to move in both the directions in response to direction of flow of oil in any hazardous conditions which results into increase in flow rate of oil. In this position the top plate 2 has kept the operating flap 3 in a pendulum position where it can move in response to the increase in the flow rate of the oil.

This device is designed to facilitate free movement of the operating flap 3 in response to oil flow by means of guiding the oil flow to exhibit maximum force at right portion of the operating flap 3 and ensuring minimum frictional losses in rotary mechanism. Due to pendulum concept, the resultant weight of the operating flap 3 determines the threshold of the flow rate of oil to which its movement is triggered.

The real time surge detector (RTSD) comprises of a top plate 2 which is provided with stoppers on both the sides to limit the rapid movement of operating flap 3 during oil surge or vacuumization. The RTSD is also provided with an air release bolt 13 and an oil drain bolt 14 for releasing air and oil respectively. The said air release bolt 13 and an oil drain bolt 14 can be used during the installation and maintenance of real time surge detector (RTSD).

Referring to FIG 4, the real time surge detector (RTSD) is described in oil surge condition. In this condition, the operating flap 3 is automatically moved in anticlockwise direction in response to rapid flow of oil from transformer tank 15. During heavy internal arching, the oil flows rapidly from the transformer tank 15 and pushes the operating flap 3 towards right and generates analogue signal with help of position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – surge 8 when operating flap 3 reaches extreme right position.

Referring to FIG 5, the real time surge detector (RTSD) is described in vacuum generation. In this condition, the operating flap 3 is automatically moved in clockwise direction in response to rapid flow of oil towards transformer tank 15. During oil pump switching, the oil flows rapidly towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position.

Also during oil leakage from transformer tank, the oil flows towards the transformer tank 15 and pushes the operating flap 3 towards left and generates analogue signal with help of position sensor 6 about its angular position. This device also generates a digital signal with help of a proximity sensor – vacuum 9 when operating flap 3 reaches extreme left position.

The position sensor 6 which is present in the Real Time Surge Detector (RTSD) is used in continuous monitoring of the angular position of the operating flap 3 in real time and generates the analogue signal to transformer protection system. In addition to the position sensor 6, three numbers of proximity sensors are used to detect the operating flap 3 position during normal operation, oil surge and vacuum.

The combination of signals received from position sensor 6 and three proximity sensors 7, 8 & 9 helps the transformer protection system to identify the kind of fault at real time and execute the necessary transformer safety and or protection measures. The proximity sensor – home 7 is mounted on the main housing 1 of the real time surge detector (RTSD) and it is connected through normally closed (NC) circuit. The NC circuit continuously monitors the home position of the operating flap 3 and triggers immediate signal to the transformer protection system if the contact breaks. Thus the real time surge detector (RTSD) identifies the operating movement of operating flap 3 in all the cases and also during mechanical or electrical failures like loose assembly, loose electrical contact, wire break etc.

Advantages of the invention

The present invention has several advantages. The primary advantage of the real time surge detector (RTSD) disclosed in the present invention is its exceptional speciality in identifying the oil surge precisely at real time and supporting transformer protection system in safeguarding the electrical transformer from hazardous situations like explosion and fire.

Yet another advantage of this real time surge detector (RTSD) is its ability to differentiate the negative surge during oil pump switching and transformer tank oil leakage to avoid misguiding the transformer protection system.

Yet another advantage of this real time surge detector (RTSD) is its ability to identify any kind of surge like laminar, turbulent etc.

Yet another advantage of the real time surge detector (RTSD) is the ability of the detector to continuously monitor the position of the operating flap 3 which ensures the generation of alerts in the event of abnormal flow rate of oil and also in the event of mechanical or electrical failures like loose assembly, loose electrical contact, wire break etc.

Yet another advantage of the real time surge detector (RTSD) is that it prevents the false trigger or emergency signals created due to minor increase in the flow rate of the oil wherein such increase in the flow rate is below the threshold limit.

Yet another advantage of the real time surge detector (RTSD) is that as the system has self-lubricated rotary mechanism. As rotary mechanism is submerged in oil there is no need of external lubrication.

Yet another advantage of the real time surge detector (RTSD) is that the horizontal angle of installation which is seen in the system, eliminates the need of maintaining the complex angle during installation.