Description:
TECHNICAL FIELD OF THE INVENTION

[001] The present subject matter described herein, in general, relates to transformer breather monitoring field, specifically a kind of transformer breather supervisory system that can also be used in any plant/equipment having a breathing system.

BACKGROUND OF THE PRESENT INVENTION

[002] Silicagel breather is the only component of a transformer that prevents external moisture to enter inside the main tank during breathing process. Therefore, its healthiness must be ensured to ensure a healthy and reliable transformer with high operational life. However, no system is available to monitor the healthiness of the breather remotely or locally.

[003] Most of the transformer breathers are equipped with silicagel or envirogel adsorbent with blue or orange colour pigments respectively. Under normal condition moisture saturated silicagel turns into pink and saturated envirogel turns into deep green. By monitoring the adsorbent colour one could assess the condition of the breather. However, condition assessment of breathers with colourless adsorbent was impossible.

[004] In addition to this, it was impossible to assess the following conditions which may cause potential damage to the transformer. Moisture can pass through any weak or leaky joints of a pipe line. The breather itself can be choked causing high pressure or vacuum pressure inside main tank. The atmoseal fitted inside main tank can be damaged causing direct contact between insulating oil and atmospheric oxygen. On the contrary, most of the stations were unmanned stations. This made physical inspection of the breather unit impossible. Having no available solution for local or remote monitoring, the asset management team stepped into a gravely difficult situation.

[005] Therefore, to eliminate the above mentioned problem, the inventors of the present invention have felt a dire need to provide a better and more efficient system for the purpose of monitoring of transformer breathers.

SUMMARY OF THE INVENTION

[006] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[007] An objective of the present invention is to provide a remote monitoring of breather condition of transformers, that overcome the drawbacks of the prior art.

[008] Another objective of the present invention is to monitor leakage in breather pipeline.

[009] Still another objective of the present invention is to monitor condition of conservator air bag / atmoseal.

[0010] Yet another objective of the present invention is to monitor choking in the breather pipeline can be identified remotely.

[0011] As for one aspect, the present invention provides a monitoring system to remotely monitor an aggregate condition of a transformer breather and a conservator tank, said system comprising: a plurality of sensor means configured to measure air temperature, humidity and pressure value; at least one controller means communicably coupled to said plurality of sensors to receive measured values of air temperature, humidity and pressure, from said sensors, said controller is configured to activate an alarm if the measured values exceed a pre-set limit; at least a gateway means configured to fetch data from the at least one controller and send the fetched data to a remote data center; and at least one display unit communicably coupled to the controller, to display the absolute measured values locally.

[0012] In one implementation, the controller means is selected from a microcontroller unit, and the conservator tank is a atmoseal fitted conservator tank.

[0013] In one implementation, the sensor means is a combined digital temperature, humidity and pressure sensor.

[0014] In one implementation, one sensor means of the plurality of sensor means is fitted in series with breather pipeline, to measure the air temperature, humidity and pressure value inside said breather pipeline and another sensor means of the plurality of sensor means is fitted in any location open to the atmosphere to measure ambient temperature, humidity and pressure.

[0015] In one implementation, the system further comprises an alarm unit communicably coupled to said controller means, consists of potential free NO – NC contacts that changes its normal status is case of any abnormalities.

[0016] In one implementation, gateway means is required to fetch data from the sensor means fitted in the in series with the breather pipeline, and the sensor means fitted in any location open to the atmosphere, and send the data to the data centre.

[0017] In one implementation, an analytical unit is configured to: compare the field data from both the sensor means; determine whether the breather and the conservator tank are operating normally; determine the moisture absorbent inside the breather saturated beyond a threshold limit; determine atmospheric air passing through a leak point in the breather or the breather pipeline or the conservator tank; determine whether atmoseal / air bag inside the conservator tank is leaked / damaged; and determine whether the breather unit is choked.

[0018] In one implementation, the system is for remote monitoring of an aggregate condition for oil filled transformers being used in LV/MV/HV/EHV/UHV electrical system.

[0019] According to the various implementations of the present invention, in depth condition of the breathing system of a transformer is achieved.

[0020] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0021] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0022] Figures 1A-B illustrate a monitoring system to remotely monitor an aggregate condition of a transformer breather and a conservator tank, according to one implementation of the present invention.

[0023] Figure 2 illustrates the graphical illustration of humidity inside breather of a conventional conservator tank (Blue), humidity inside breather of an atmoseal fitted conservator (Red) and ambient humidity (Pink) plotted with 24hrs data, according to one implementation of the present invention.

[0024] Figure 3 illustrates the graphical representation of humidity inside breather (Red) and ambient humidity (Pink) plotted with 24 hrs data, according to one implementation of the present invention.

[0025] Figure 4 illustrates sensor position in a sealed housing box, according to one implementation of the present invention.

[0026] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0027] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0028] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0029] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0030] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0031] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0032] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0033] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0034] In one implementation, the present invention discloses monitoring system to remotely monitor an aggregate condition of a transformer breather and a conservator tank. The system is a combination of one combined digital temperature, humidity and pressure sensor, one micro controller, and one display unit for local monitoring and one gateway for remote monitoring. It provides an in depth condition of the breathing system of a transformer.

[0035] In one implementation, the monitoring system is designed for oil filled transformers being used in LV/MV/HV/EHV/UHV electrical system. However, this can also be used in any plant/equipment having a breathing system.

[0036] Reference is made to figures 1 which shows block diagram of a transformer breather system. The components of the system are as follows:
1. First Sensor: combined digital temperature, humidity & pressure sensor fitted in series with a breather pipeline, measures temperature, humidity and pressure value inside the breather system.
2. Second Sensor: combined digital temperature, humidity & pressure sensor fitted in open air, measures temperature, humidity & pressure of ambient. This is required for comparison purpose.
3. A Microcontroller takes the values from the sensors for processing. It sends data to local display unit & to RS-485 (Modbus) port and generates an alarm is the value exceeds the pre-set limit.
4. A Local Display Unit may be a 4X16 LCD display unit that displays absolute values locally.
5. An Alarm Unit consists of potential free NO – NC contacts that changes its normal status is case of any abnormalities.
6. Provision for remote communication is given by providing a RS-485 (Modbus) connectivity.

[0037] In one implementation, the breather monitoring system is equipped with a combined digital temperature, humidity and pressure sensor. The combined sensor along with its housing box is fitted in series with the breather pipeline. Now being fitted inside the breather pipeline itself, the sensor output helps to monitor the temperature, humidity and pressure inside the breather.

[0038] The humidity level inside the breather pipeline depends on the type of conservator tank. For atmoseal fitted conservator tank, it illustrates the sole condition of the breather only. Normally this value lies in-between 1-15%. Any higher value is an indication of defective breather and a high humidity level despite a healthy breather means damaged / defective atmoseal. This facility allows the asset managers to monitor the atmoseal condition remotely. Earlier identification of damaged / defective atmoseal was a troublesome job even for an expert at site.

[0039] For conventional conservator tanks (without atmoseal) the humidity level is a resultant value of breather condition and moisture inside the tank oil. Under normal cases, the value is primarily influenced by the moisture inside the oil only. For transformers with poor condition of breather, humidity level will increase to acquire the value close to ambient humidity level. It is also expected that in future with sufficient database of humidity level and temperature; it would be possible for us to remotely presume the moisture content of the transformer with conventional conservator tank.

[0040] The pressure and humidity inside the main tank vis a vis inside the breather pipelines, can no way be sensed or measured in an objective manner. There are other temperature sensing arrangements fitted with a transformer which reflect gradual changes in the temperature and gives alarm. Hence the signals coming from the humidity and pressure sensors are the features which improves upon the existing process of sensing pressure and humidity and for this we cannot bank on human skills.

[0041] In one implementation, reference is made to the figure 2, which shows graphical illustration of humidity inside breather of a conventional conservator tank (Blue), humidity inside breather of an atmoseal fitted conservator (Red) & ambient humidity (Pink) plotted with 24hrs data. Referring to Figure 2, the blue graph shows the controlled level of humidity inside the breather pipeline, the conservator for which does not have atmoseal / air-bag fitted with it; but the conservator is smaller in size as compared to the main conservator. While the red graph shows the controlled humidity inside the breather pipeline of the main conservator fitted with breather and atmoseal. And the pink graph shows variation of ambient humidity. These graphs delineate good control of humidity inside breather pipelines with healthy condition of breathers fitted with conservator tanks even if there is variation of humidity of ambient air.

[0042] The pressure inside the breather pipeline must be equal to the ambient pressure with a -5 to +5 mbar tolerance. However, in case of breather choking during breath-in process will create vacuum condition (low pressure with respect to ambient) and choking during breath-out process will create high pressure condition inside. Heavy vacuum-pull inside main tank initiates bubble formation leading to buchholz operation and heavy pressure inside increases possibility of Pressure Release Valve (PRV) operation. Ultimately in both cases it will lead to tripping with a chance of transformer damage. By monitoring the pressure inside breather pipeline it is possible to prevent such possibilities.

[0043] In one implementation, reference is made to figure 3, which illustrates the Graphical representation of humidity inside breather (Red) & ambient humidity (Pink) plotted with 24 hrs data. It shows the variation of humidity inside the breather pipeline where the breather is not in healthy condition – may be due to saturated silica-gel or leakage in the pipeline or breather.

[0044] Generally, the output temperature is 5-6 degree less than the top oil temperature. So in case of fault inside that tank (main tank / cable box tank / OLTC tank) the temperature output should rise with the rise of oil temperature. In other words, it should indicate the possibility of fault inside the tank. Fortunately, or unfortunately, no such case has been recorded till date.

[0045] In one implementation, reference is made to figure 4, which shows the position of sensor. First sensor may be placed inside a sealed housing box (marked using yellow circle in the figure 4) in series with the breather pipeline. The output temperature, humidity and pressure value of this sensor represents the condition inside conservator / atmoseal and breather pipeline. Another housing box (marked using blue circle in the above picture) contains the second sensor, the microcontroller, local display unit, alarm unit and RS-485 port fitted inside it.

[0046] Some of the non-limiting advantages of the present invention, are as follows:
• Remote monitoring of breather condition is possible through this system.
• Not only looks after the breather, it looks after the entire breathing system.
• Leakage in breather pipeline can also be identified.
• Condition of conservator air bag / atmoseal can be monitored.
• For conventional conservator tank type transformers, overall moisture content in oil can be assumed.
• Any kind of choking in the breather box can be identified remotely.

[0047] Although the transformer breather monitoring system has been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described. Rather, the specific features are disclosed as examples of implementations of the transformer breather monitoring system.
, Claims:
1. A monitoring system to remotely monitor an aggregate condition of a transformer breather and a conservator tank, said system comprising:
a plurality of sensor means configured to measure air temperature, humidity and pressure value;
at least one controller means communicably coupled to said plurality of sensors to receive measured values of air temperature, humidity and pressure, from said sensors, said controller is configured to activate an alarm if the measured values exceed a pre-set limit;
at least a gateway means configured to fetch data from the at least one controller and send the fetched data to a remote data center; and
at least one display unit communicably coupled to the controller, to display the absolute measured values locally.

2. The system as claimed in the claim 1, wherein said controller means is selected from a microcontroller unit, and the conservator tank is a atmoseal fitted conservator tank.

3. The system as claimed in the claim 1, wherein said sensor means is a combined digital temperature, humidity and pressure sensor.

4. The system as claimed in the claim 3, wherein one sensor means of the plurality of sensor means is fitted in series with breather pipeline, to measure the air temperature, humidity and pressure value inside said breather pipeline and another sensor means of the plurality of sensor means is fitted in any location open to the atmosphere to measure ambient temperature, humidity and pressure.

5. The system as claimed in the claim 1, further comprises an alarm unit communicably coupled to said controller means, consists of potential free NO – NC contacts that changes its normal status is case of any abnormalities.

6. The system as claimed in the claim 1, wherein said gateway means is required to fetch data from the sensor means fitted in the in series with the breather pipeline, and the sensor means fitted in any location open to the atmosphere, and send the data to the data centre.

7. The system as claimed in claim 6, wherein the data centre comprises: a memory unit configured to store historical data; and an analytical unit configured to ascertain the physical condition of the transformer breather and a conservator tank.

8. The system as claimed in claim 7, wherein the analytical unit is configured to:
compare the field data from both the sensor means;
determine whether the breather and the conservator tank are operating normally;
determine the moisture absorbent inside the breather saturated beyond a threshold limit;
determine atmospheric air passing through a leak point in the breather or the breather pipeline or the conservator tank;
determine whether atmoseal / air bag inside the conservator tank is leaked / damaged; and
determine whether the breather unit is choked.

9. The system as claimed in claim 1, wherein the system is configured to remotely monitor the aggregate condition for oil filled transformers being used in LV/MV/HV/EHV/UHV electrical system.