Description:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the field of electrical engineering and more particularly, a smart health monitoring system for transformers in electric power distribution system for monitoring a plurality of transformer operating parameters, including temperature, transformer oil level, humidity, electrically live enclosure door status and the like.

BACKGROUND OF THE INVENTION
Because electric energy plays more and more important role in the productive life of people, for guaranteeing the safe and reliable of transmission system, with regard to needing, effective monitoring is in real time carried out to the indices of transformer station. At present, major power transformer station of man of China adopts the method for off-line monitoring, Utilities Electric Co. needs special staff to carry out regular maintenance to substation equipment, its workload is comparatively large, human cost is higher, in addition, each maintenance all needs power failure work, affects power supply reliability, bring loss and inconvenience to the productive life of people, and power failure work may bring risk to power grid security. Along with the quick propelling that domestic intelligent substationization is built, power transformer station develops some on-line monitoring systems, but is all the local individual event supervisory control system based on wired.

Current electrical power generation systems and electrical power supply systems use a wide variety of transformer designs to transform electrical power from a primary voltage (e.g., input voltage) to a secondary voltage (e.g., output voltage). Electrical transformers are typically used to transfer electrical energy between circuits through inductively coupled conductors. Transformers generally include a core, wound conductors (i.e., a winding assembly), and a housing, The housing may include a tank that contains transformer liquid, such as, e.g., mineral oil, to insulate and absorb heat from the core and winding assembly, which may be immersed in the transformer liquid. The external walls of the tank and/or housing may include a plurality of vanes to transfer heat to the ambient environment. Currently, monitoring systems are implemented to monitor transformer operations, and to detect faults.

The document JP5973716 B2 is directed to provide a method, system and computer program product for determining the health of a transformer. A method for determining the health includes a step of computing an effective turns ratio based on a primary electrical parameter associated with a primary winding of the transformer and a secondary electrical parameter associated with a secondary winding of the transformer. The method further includes a step of computing an operational magnetizing current based on the effective turns ratio and primary and secondary currents of the transformer or primary and secondary voltages of the transformer. Finally, the method includes a step of determining an inter-turn winding health indicator based at least in part on the operational magnetizing current. The system includes a turns ratio modeler for computing an effective turns ratio of a transformer. Further, the system also includes an operating state modeler for computing an operational magnetizing current. The system also includes a diagnostic module for determining an inter-turn winding health indicator.

The document US20170011612 A1 discloses a system, a method and a computer program to monitor a plurality of transformer operating parameters, as well as to accurately control one or more of the transformer operating parameters. Also, the system and method may calculate loss of life and give diagnosis for recovery and provide maintenance notification, along with monitoring the operation of the LTC.

The document CN104716741 A discloses a transformer substation remote monitoring system and method. All indexes of a transformer substation can be monitored online in real time, wherein the indexes include all monitoring data in a transformer, a breaker and an arrester; when a certain index of the transformer substation becomes abnormal, an alarm sound can be sent out in time, failure data and failure devices are displayed on a display screen of a monitoring module, workers are reminded, the data monitoring accuracy and timeliness are improved, and the data transmitting safety and reliability are improved. Meanwhile, the monitoring data of the transformer substation are analyzed and processed in real time at a remote monitoring center, failure reasons and failure sources are found, a maintenance reference scheme is generated, and maintainers of the transformer substation are guided to remove failures in time. In addition, the maintenance records of routing inspection personnel can be recorded, monitored and fed back in time, and the routing inspection personnel are reminded to complete conventional maintenance in time.

Power Transformers (PTRs) and distribution transformers (DTRs) are the most vital assets creating the main backbone for any power distribution network and hence require special care and attention. Monitoring of critical health related parameters of these transformers is essential for defining the life and performance of the units. Supervisory Control and Data acquisition (SCADA) System are in use since long back for monitoring and control of the Substations covering hundreds of switchgears and PTRs. Extending the SCADA system for online monitoring of these DTRs is not viable largely because of the prohibitive cost factor. However, these Distribution Transformers are metered with AMR energy meters and GSM/GPRS modems for remote energy auditing and monitoring electrical data (e.g. energy, voltage, current, power factor).

The above described prior art systems suffer from many disadvantages, which the instant invention effectively eliminates. Since improper performance or transformer failure can result in power disruption, fluctuating power supply, or power outage, loss of transformer life, it is important to provide accurate measurement, analysis and monitoring of transformer parameters, so as to facilitate timely intervention. For this reason, there is a dire need to provide an improved health monitoring system for transformers in electric power distribution system.

SUMMARY OF THE INVENTION
The following disclosure 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.

An object of the present invention is to overcome the problems of prior arts.

An object of the present invention is to provide an agnostic health monitoring system for transformers in electric power distribution system.

An object of the present invention is to provide a health monitoring system for transformers in electric power distribution system which provides health status of multiple distribution transformers on real time basis.

Yet another object of the present invention is to provide a low cost health monitoring system for transformers in electric power distribution system.

Yet another object of the present invention is to provide a low cost health monitoring system for transformers in the distribution system which prevents failure and fire hazards thereby improving / safeguarding lifecycle of the distribution assets.

Yet another object of the present invention is to provide a health monitoring system for transformers in the distribution system which provides proactive measures for preventing damage of the equipment.

Yet another object of the present invention is to provide a health monitoring system which is self-sufficient and uses a battery backed power supply to assure data communication during local low tension (LT) supply failure.

One aspect of the present disclosure is to provide a health monitoring system for transformers in the distribution system. It discloses a smart and vendor agnostic Health Monitoring System for Transformers in electric power distribution network using a low cost lightweight infrastructure with a set of simple sensors, connected in IIoT over MQTT protocol. In the present disclosure, the system, a hardware software duo works in synchronization to reflect any anomaly in the transformers. The head-end application has been designed and developed with a philosophy that supports smooth integration of the products (field devices) from different vendors with the proposed health monitoring system and thus establishes a vendor agnostic system which is most desired by any implementer of today. The analytics used in the head-end software also helps user to take proactive measures for preventing damage of the equipment

The objectives of this disclosure is primarily to improve the life cycle of the DTRs, the most vital and costly assets creating the backbone of the power distribution network, by monitoring the critical health parameters of the same through a low cost home-grown central monitoring system and taking necessary measures to prevent damage due to catastrophic failure of the equipment. It provides health status of multiple distribution transformers on real time basis. It primarily focuses on oil filled DTRs for proactive immediate response at the equipment beyond tolerable threshold. This will help averting failures and fire hazards thereby also improving / safeguarding lifecycle of the distribution assets.

In one implementation, present invention provides a Distribution Transformer Health Monitoring System, the system comprises at least one temperature sensor configured to measure temperature in the transformer and to output a temperature signal, at least one oil level sensor configured to measure level of transformer oil and to output an oil level signal, at least one humidity sensor configured to measure moisture in the transformer oil and to output a moisture content signal and at least one door status sensor configured to provide electrically live enclosure door status and to output a door status signal, an Industrial internet-of-things (IIoT) gateway housing a microcontroller module in communication with the sensors; wherein the sensors and the IIoT gateway are mounted on the distribution transformer and the microcontroller module of the IIoT gateway comprises a firmware to orchestrate the sensor readings and a communication module sends the sensed and processed data to a distribution transformer head-end application (DTHMS) through a built-in GSM/GPRS modem via a cloud based MQTT broker wherein the DTHMS resides in on-premise server which collects data from Automated Meter Reading (AMR) database and correlates the same with the data received from the IIoT gateway and updating the data on a custom made Dashboard at Human Machine Interface (HMI) with built-in analytical tools.

In one implementation of the present invention generates alerts which are automatically sent to the stakeholders through push notification.

In one implementation of the present invention the IIoT gateway comprises a power supply with battery backup configured to assure data communication during a Low Tension (LT) supply failure.

In one implementation of the present invention the data generated in the process are stored in a Relational Database Management System (RDBMS).

In one implementation of the present invention the custom made DTHMS Dashboard at Human Machine Interface (HMI) with built-in analytical tools displays the anomalies of parameters across the entire system.

The system of the present invention discloses a built-in watchdog in the field devices which helps in resetting the device automatically in case of temporary snaps of the communication due to hanging of the device. Both the watchdog feature and the remote configuration provide great relieve from resetting/ configuring the devices physically at site, particularly for the devices mounted on the pole mounted DTRs and it does not call for any shutdown of the DTRs for the above purposes.

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 ACCOMPANYING DRAWINGS
The above and other aspects, features and advantages of the embodiments of the present disclosure will be more apparent in the following description taken in conjunction with the accompanying drawings, in which:

Figure 1 Shows the block diagram of the DTHMS depicting flow of data from sensor to the central head-end application, according to one of the embodiments of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may not have 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
The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding, but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the various embodiments described herein can be made without departing from the scope and spirit of the present disclosure. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.

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 present disclosure. Accordingly, it should be apparent to those skilled in the art that the following description of various embodiments of the present disclosure is provided for illustration purpose only and not for the purpose of limiting the present disclosure as defined by the appended claims and their equivalents.

The present invention provides a health monitoring system for transformers in the distribution system. It discloses a smart and vendor agnostic Health Monitoring System for Transformers in electric power distribution network using a low cost lightweight infrastructure with a set of simple sensors, connected in IIoT over MQTT protocol. In the present disclosure, the system, a hardware software duo works in synchronization to reflect any anomaly in the transformers. The head-end application has been designed and developed with a philosophy that supports smooth integration of the products (field devices) from different vendors with the proposed health monitoring system and thus establishes a vendor agnostic system which is most desired by any implementer of today. The analytics used in the head-end software also helps user to take proactive measures for preventing damage of the equipment.

It is to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, a reference to "a component surface" includes a reference to one or more of such surfaces.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments belong. Further, the meaning of terms or words used in the specification and the claims should not be limited to the literal or commonly employed sense, but should be construed in accordance with the spirit of the disclosure to most properly describe the present disclosure.

The terminology used herein is for the purpose of describing particular various embodiments only and is not intended to be limiting of various embodiments. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising" used herein specify the presence of stated features, integers, steps, operations, members, components, and/or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, members, components, and/or groups thereof. Also, Expressions such as "at least one of," when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.

Figure- 1 of the present disclosure shows the block diagram of the DTHMS depicting flow of data from sensor to the central head-end application. Different sensors (1, 2, 3, 4) such as temperature, humidity, oil level, door status etc. have been fixed in different parts of the DTR. One IIoT Gateway (5), mounted on the transformer collects data from the different sensors (1, 2, 3, 4) (fitted with the DTR) through physical connections and send the sensed and processed data to the home-grown head-end application (DTMHS) through a built-in GSM/GPRS modem via a cloud based MQTT broker. The DTHMS residing in the on-premise server collects data (Voltage and Current) from AMR data base, correlates the same with data received directly from the IIoT gateways (5) and reflects the same in the Dashboard (9) having sundry visualization screens.

Each Distribution Transformer (DTR) is provided with an IIoT Gateway (5) which receives the data of parameters such as temperature, humidity, oil level etc. from the various high industrial grade sensors to be fitted with the DTR and finally sends the same to the on-premise server through a cloud-based broker using MQTT protocol, one of the prime standard protocol used in the IoT technology. The sensors are installed at different sensitive and strategic positions of the transformers. This is obviously scalable (add new sensors at any point of time on demand) and re-configurable.

The IIoT Gateway (5) houses the microcontroller, power supply with battery backup (6) and the wireless communication module. The microcontroller of the Gateway is embedded with a firmware to orchestrate the sensor readings and the communication module to flow information to the head-end for data warehousing. The lightweight MQTT protocol for data transport is chosen to establish a flexible data bridge to the head-end.

The system of the present invention discloses a built-in watchdog in the field devices which helps in resetting the device automatically in case of temporary snaps of the communication due to hanging of the device. Both the watchdog feature and the remote configuration provide great relieve from resetting/ configuring the devices physically at site, particularly for the devices mounted on the pole mounted DTRs and it does not call for any shutdown of the DTRs for the above purposes.

In order to achieve a uniform look and feel of the Dashboard (9) at the Human Machine Interface (HMI) with a goal to accommodate different vendors through seamless integrations of their products (IIoT Gateway) with the above DTHMS, the head-end Software application for the system is developed in-house after standardizing all the requirements (e.g. parameters, data structure, Protocol etc.) and hosted the same in company’s on-premise Server. The software application (8) is responsible for interacting with IIoT Gateways (5) from different manufacturers (to be fitted on Distribution Transformers in-situ) via cloud based MQTT Brokers of the respective manufacturers and updating the data on a custom made Dashboard with built-in analytical tools. The data generated in the process are stored in a Relational Database Management System (RDBMS) which can share the same to other applications, if required in future for further analytics within the company.

In one implementation, present invention provides a Distribution Transformer Health Monitoring System, the system comprises at least one temperature sensor configured to measure temperature in the transformer and to output a temperature signal, at least one oil level sensor (4) configured to measure level of transformer oil and to output an oil level signal, at least one humidity sensor (2) configured to measure moisture in the transformer oil and to output a moisture content signal; and
at least one door status sensor (3) configured to provide electrically live enclosure door status and to output a door status signal, an Industrial internet-of-things (IIoT) gateway (5) housing a microcontroller module in communication with the sensors; wherein the sensors (1, 2, 3, 4) and the IIoT gateway (5) are mounted on the distribution transformer and the microcontroller module of the IIoT gateway (5) comprises a firmware to orchestrate the sensor readings and a communication module sends the sensed and processed data to a distribution transformer head-end application (DTHMS) (8) through a built-in GSM/GPRS modem (7) via a cloud based MQTT broker wherein the DTHMS (8) resides in on-premise server which collects data from Automated Meter Reading (AMR) database and correlates the same with the data received from the IIoT gateway (5) and updating the data on a custom made Dashboard at Human Machine Interface (HMI) (9) with built-in analytical tools.

In one implementation of the present invention generates alerts which are automatically sent to the stakeholders through push notification.

In one implementation of the present invention the IIoT gateway comprises a power supply (6) with battery backup configured to assure data communication during a Low Tension (LT) supply failure.

In one implementation of the present invention the data generated in the process are stored in a Relational Database Management System (RDBMS).

In one implementation of the present invention the custom made DTHMS Dashboard (9) at Human Machine Interface (HMI) with built-in analytical tools displays the anomalies of parameters across the entire system.

The head-end system, beside the data parsing and warehousing, supports user interfaces for data visualization and alert visualization. Apart from generating alerts for parameters beyond tolerable threshold on real time basis, the head-end software also supports analytics for predicting sundry protective measures to be done proactively. The analytic modules draw required correlations with the parameters including those measured directly from the field through IoT sensors (e.g. Temperature, Humidity, Oil level etc.) and some parameters measured through AMR system (e.g. phase and line voltages, currents etc.) for the purpose of analysis and thus enabled us refer curves/plots like load vs. temperature, load vs. humidity etc. to pin point the problem areas, if any and take measures to protect the equipment from damage proactively.

Sensing the LT and HT cable Box door status (open/ close) from remote using proximity sensors at the field has been done to prevent electrocution and ensures human safety. The battery backed power supply (6) used in the IIoT Gateway (5) assures data communication during local LT supply failure.

The system of the present invention has been designed in such a way that the manufacturers of field devices (IoT based) can easily comply with our requirements and get integrated with the system seamlessly. Further, the change of sampling frequency of the sensor data at field devices can be done remotely, if required for specific analysis.

In present disclosure, the visualization of data in software application shows plots and curves of parameters in relation with time. The tool tip shows all measured parameters in textual form at the pointed time on the curve. Users can remove or add parameters to the display as needed to have a focused view on certain parameters or for comparison purpose for inferring certain anomalies. Further, the visualization of alert in software application shows graphical representation of alerts/ anomalies covering all the integrated equipment/sensors. The screen shows a set of bubbles with a few bigger bubbles containing small bubbles with parameters beyond the threshold values out of all the sensors used in the entire system. If all parameters undergo normal range of values, all bubbles representing individual parameters will be uniform in size and form a circle. Operators looking at this screen can see the anomalies of parameters across the entire system. It has a provision to set threshold values by the user and visualize alerts to care seasonal influences of the parameters. The tool tip on the individual small bubble will show values with date and time of the last registered abnormality.

The system has undergone a good number of developmental stages before reaching into the final one, it is expected that the present system is quite matured to be deployed in large scale roll out. Moreover, as the head-end software has been developed in-house and finally hosted into a company’s on-premise server, the manipulation of the system as the need arises can be done comfortably. It also helps us to reduce operational expenses due to cloud hiring. The present system comprising state-of-the-art technologies and requiring 2-way always-on mode of communication infrastructure performs well with GSM/GPRS based wireless communication medium.

Stages of Development:
The invention has been undergone following stages of developments and trials before coming to the present system.

Stage 1: One DTR has been equipped with sensors such as temperature, humidity, oil level in the conservator tank etc. connected with an IoT gateway which processes the data from the sensors and send the same wirelessly to a cloud-based application via MQTT broker. This kind of model has a benefit that we get a readymade frontend application upfront. But, this also poses vendor dependence for making any addition/ modification of features.

Stage 2: In order to achieve a vendor agnostic solution for the above system, a specification for the field device (IoT Gateway) has been made where things like sensors, communication medium, communication protocol and data formats have been standardized to the extent possible to achieve smooth integration of devices from different vendors.

Stage 3: The head-end application for displaying runtime data from all the above sensors in graphical as well as tabular form through a dashboard has been developed in-house and finally hosted into our on-premise server. It also supports sundry analytical tools for analyzing the archived and runtime data and generating alerts on the dashboard for prompt response. The application also enabled us to achieve a uniform look and feel of dashboard thus enhancing the ease of the operators.

Stage 4: A table-top proof of concept (PoC) was conducted in the laboratory with products from two out of four potential vendors where it was found that the data of both the products have been successfully communicated in the stipulated format as par specification at a 15-minute data sampling frequency. The availability factor was also found highly satisfactory.

Stage-5: After successful completion of the table-top PoC, planning has done to test the system with live equipment. Accordingly, two DTRs have been equipped with sensors in-situ and integrated with the newly developed head-end application. The result of this test was found quite satisfactory.

Stage 6: After development of the hardware modules as per prescribed specification by two different vendors, the units were tested are fitted at 25 different oil filled type distribution transformers. The system is operational till date as a pilot project model.

Stage 7: Considering the constraint of getting shut down permission for maintenance of the intelligent field devices on the pole mounted DTRs as experienced after the installation, following things have been incorporated within the field devices with the help of respective vendors for minimizing the need for getting shutdown.

1. Incorporate remote configuration of certain features like sampling frequency etc. so that physical local connection is not required for frequently
2. Incorporation of software watchdog for automatic resetting of the device in case of communication failure.

Some of the non-limiting advantages of the present invention are as follows:
1. Reduction of AT&C losses of the utility by preventing damage/burnt out of the costly assets through proactive measures based on the analysis of the system.
2. Improvement of the availability factor due to reduction of failures
3. Customer delight through quality power with higher availability
4. Improvement of efficiency of the distribution network
5. Building a data repository for future development of AI based model on Transformer health.

Those skilled in the art will recognize other use cases, improvements, and modification to the embodiments of the present disclosure. All such improvements and other use-cases are considered within the scope of the concepts disclosed herein.

Claims:1. A Distribution Transformer Health Monitoring System, the system comprising:
at least one temperature sensor (1) configured to measure temperature in the transformer and to output a temperature signal;
at least one oil level sensor (4) configured to measure level of transformer oil and to output an oil level signal;
at least one humidity sensor (2) configured to measure moisture in the transformer oil and to output a moisture content signal; and
at least one door status sensor (3) configured to provide electrically live enclosure door status and to output a door status signal;
an Industrial internet-of-things (IIoT) gateway (5) housing a microcontroller module in communication with the sensors;
wherein the sensors (1, 2, 3, 4) and the IIoT gateway (5) are mounted on the distribution transformer and the microcontroller module of the IIoT gateway (5) comprises a firmware to orchestrate the sensor readings and a communication module sends the sensed and processed data to a distribution transformer head-end application (DTHMS) (8) through a built-in GSM/GPRS modem (7) via a cloud based MQTT broker;
wherein the DTHMS (8) resides in on-premise server which collects data from Automated Meter Reading (AMR) database and correlates the same with the data received from the IIoT gateway (5) and updating the data on a custom made Dashboard at Human Machine Interface (HMI) (9) with built-in analytical tools.

2. The system as claimed in claim 1, wherein the system generates alerts which are automatically sent to the stakeholders through push notification.

3. The system as claimed in claim 1, wherein the IIoT gateway comprises a power supply (6) with battery backup configured to assure data communication during a Low Tension (LT) supply failure.

4. The system as claimed in claim 1, wherein the data generated in the process are stored in a Relational Database Management System (RDBMS).

5. The system as claimed in claim 1, wherein the custom made DTHMS Dashboard (9) at Human Machine Interface (HMI) with built-in analytical tools displays the anomalies of parameters across the entire system.

6. The system as claimed in claim 5, wherein the DTHMS Dashboard (9) at Human Machine Interface (HMI) provides provision to set threshold values by user.