Today it is impossible for anyone to imagine a world without Electrical Power. The importance of Transformers in this electrical world cannot be undermined. The breakdown of transformer leads to huge production and financial losses to the industry.

So as to maintain the transformers to provide trouble free service, various schedules have been laid down by various national and international standards. Various safety equipments have also been in service since long so as to monitor the health of the transformers and its protection. But ironically, still the transformers do breakdown. The breakdown of a transformer can be due to many reasons such as Electric Fault, Thermal Fault, Internal Fault, Ageing Fault, Material Failure, Improper Loading, and Operating Environment etc. The existing techniques of monitoring the health of the transformer are such that by the time one comes to know about the transformer failure, sufficient damage has already been done to the transformer. It has been a long time desire of the transformer manufactures and operators that only if there could be such an equipment that would warn much before too much damage is done to the transformer, so that there would be minimum down period and maximum mean time between repairs (MTBR).

M/s New Delhi Laboratories Pvt. Ltd. and ERDA have introduced a latest technology for sensing the birth of a fault in the transformers. The technology, on-line fault monitoring of transformers is presently being marketed under the Brand name Sensofast and is based on the principle of measuring the evolved Hydrogen Gas from the oil of the Transformer.

Why measure the evolved Hydrogen Gas?
Transformer Oil being Hydro Carbons under any fault condition of transformers, hydrogen is produced in 60% to 70% quantities out of various other fault gases. However, while other gases get dissolved slowly back into the oil, the hydrogen gas remains undissolved to the extent of 95%. Hence to expedite the sensing of a fault, non-other gas is more important than hydrogen. A popular foolproof method, known as Dissolved Gas Analysis (D.G.A.), detects the other gases but this is a periodic process. Normally DGA of Transformer Oil is carried out once in a year. So fault occurring in a transformer immediately after DGA shall not be immediately detected.

The Buchholz relay mounted on the transformer is also important safety equipment. But Buchholz requires about 165 cc of total gases to be produced for operations, which are, produced only the actual breakdown of the transformer.

Working of Sensofast:
Sensofast On-Line Fault Monitoring System is a 24 hours online system that monitors the Transformers for any defect Internal Fault e.g. Electric Fault, Thermal Fault. The sensor is installed on the air vent of the Buchholz relay, which is the most likely place for the evolved gases to get collected. Out of all the gases, the Sensor will sense Key fault gas i.e. hydrogen in PPM levels. The equivalent electrical signal from the sensor is passed on to a processing unit, installed locally near the transformer via a shielded cable. The output of the processing unit is used to drive a remote monitor unit (processing indicating and warning unit). The remote monitor unit is installed at any convenient place inside the Central Control Room or any other location.

The system provides for two warning levels. The two warning levels are user programmable using a hand held programmer. The lower warning (yellow-audio-visual) warns the user of the beginning of a fault in the transformer. The upper warning (Red-audio-visual) confirms the defect.

We supervise the complete installation of Sensofast. The installation of Sensofast comprises of installing the Sensofast sensor on the air vent of Buchholz Relay using appropriate Matching adaptors. The processing unit is installed in the marshalling box. Assistance is expected from the customers in this installation. The processing unit is connected to the sensor using a two core shielded wire. A 230 volts supply of 25 watts is required at this point for operation of processing unit. The electrical output of the processing unit is conveyed to the Remote monitor Unit via an up to eight core cable. The laying of this cable from Transformer to the place where the customers do Remote monitor Unit is to be installed. A 230 Volts supply is required at the place of installation of Remote Unit. The final stage of Installation is the commissioning of Sensofast and making various settings.

Prior to commercialization of the product, it was field trial tested by ERDA at various capacities of transformers in different industries and utilities all over India such as BSES Ltd., KPCL, RSEB, and PGCIL etc.

It is highly encouraging that Sensofast is the recipient of Best Product Award in ELECRAMA-2002 held in Mumbai in January 2002, where over 10,000 products were on display from over 1000 different national & international industries of the world.

Sensofast On-Line Fault Monitoring System is currently installed at some of the highly prestigious companies of India such as TISCO, HPCL, Hindalco, Kajaria Ceramics etc. and is the process of installation at many more such as Tata Power- Mumbai, Indal, Asahi Safety Glass, Necular Power Corporation- Kota, NALCO etc.

Sensofast has now grown up to be compatible with different versions of system such as SCADA and PC compatible software. Further, improvements are in pipeline so as to provide compatibility with PLC system also. Our innovative Multiple Transformer Monitoring Software “Analyst Software” is currently using Sensofast as one of its four Inputs. The analyst Software provides for the On-Line, real time Monitoring of 64 Transformers for 04 Parameters – Fault, Winding Temperature, Oil Temperature and Load.

As a conclusion, one would say that Sensofast functions as a watch dog for the precious Transformers that warn the users of the birth of any fault in the transformer, before it is too late or any irreversible damage is alone to the transformers.

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