FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
An integrated system for automatic voltage regulation and health monitoring of transformers using shared memory architecture.
APPLICANTS (S)
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company.
INVENTOR (S)
Pasumarthi Umamahesh and Pardeshi Suraj; both of Crompton Greaves Ltd, Electronic Design Centre, CG Global R&D Centre, Crompton Greaves Limited, Kanjur Marg, Mumbai 400 042, Maharashtra, India; both Indian Nationals.
PREAMBLE TO THE DESCRIPTION:
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF THE INVENTION:
This invention relates to the field of transformers and systems and methods for transformer monitoring.
Particularly, this invention relates to an integrated system for automatic voltage regulation and health monitoring of transformers using shared memory architecture.
BACKGROUND OF THE INVENTION:
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors — the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is called inductive coupling.
Power transformer is a transformer that is used to transform AC power in power system networks, radio apparatus, and automatic systems. A power transformer operates with a constant effective voltage. The frequency of power-transformer current in most countries, including the USSR, is 50 hertz (Hz); in the USA and some other countries it is 60 Hz. Power transformers are the most common class of transformers.

A transformer tap is a connection point along a transformer winding that allows a certain number of turns to be selected. This means, a transformer with a variable turns' ratio is produced, enabling voltage regulation of the output. The tap selection is made via a tap changer mechanism.
For many power transformer applications, a supply interruption during a tap change is unacceptable, and the transformer is often fitted with a more expensive and complex on-load tap-changing (OLTC, sometimes LTC) mechanism. On-load tap changers may be generally classified as mechanical, electronically assisted, or fully electronic.
OLTC relates to on-load tap changer. The function of OLTC is to change the voltage level of secondary side of transformer according to change in load to meet the requirement of constant voltage and to keep the voltage constant within the limits and also act as a safety device.
Firstly, for a transformer or a power transformer, a voltage regulation system and method is required.
For automatic voltage regulation, the output voltage of the transformer is sensed by voltage transducer and On-line tap controller (OLTC) position is changed using digital output card. Changing the OLTC position increases / decreases the output voltage of the transformer. This method is useful for tracking the voltage change due to sudden changes in load. In this system and method, there is a main controller which utilizes the memory for capturing the voltage samples, storing and comparing with the reference voltage. The reference voltage is tracked by

changing the OLTC position through a digital output card. OLTC position is typically sensed by a 4-20mA sensor.
The processor main memory is fully utilized for voltage regulation purpose only, which is a limiting feature.
Secondly, for a transformer or a power transformer, a health monitoring system and method is required.
For health monitoring of transformer, the main controller receives the input from various sensors such as gas, temperature, pressure. Also, inputs from transducers such as voltage and current signals are given to main controller. The main controller captures the inputs from various sensors and determines the health of the transformer through systems and methods given in accordance with IEEE standards. After computing certain parameters, various trip commands are given to the relay.
The processor main memory is fully utilized for health monitoring of the transformer, which is a limiting feature.
Reliability is a key issue in transformers. Various parameters need to be continually measured or sensed and actions in accordance with the measured of sensed parameters need to be adequately taken in order to maintain optimum transformer working conditions.

OBJECTS OF THE INVENTION:
An object of the invention is to provide a shared memory-architecture for voltage regulation purpose of a transformer along with health monitoring of a transformer.
Another object of the invention is to provide a shared processor-architecture for voltage regulation purpose of a transformer along with health monitoring of a transformer.
Yet another object of the invention is to provide a hybrid interface for voltage regulation purpose of a transformer along with health monitoring of a transformer.
SUMMARY OF THE INVENTION:
According to this invention, there is provided an integrated system for automatic voltage regulation and health monitoring of transformer using shared memory architecture, said system comprises:
A) voltage transducer adapted to sense voltage parameters of a transformer to obtain voltage values;
B) current transducer adapted to sense current parameters of a transformer to obtain current values;
C) processor means adapted to receive said sensed voltage values and said sensed current values;

D) shared memory means adapted to communicate with said processor means, for
storing and communicating said sensed voltage values and said sensed current
values in relation to time;
E) hybrid interface comprising sensor input card, digital input card, digital output
card, first communication means between said processor means and said sensor
input card, second communication means between said sensor input card and
said digital input card, third communication means between said digital input
card and said digital output card, wherein
a) said sensor input card is adapted to receive on-load tap changer sensed position from an on-load tap changer position sensor;
b) said digital input card is adapted to receive various pre-defined parameter values in relation to pre-defined transformer equipment;
c) said digital output card is adapted to output actuation signals to an on-load tap changer to change tap position in accordance with sensed load condition which is depicted in terms of change in sensed current parameter by current transducer and / or in terms of change in sensed voltage parameter by voltage transducer,
thereby achieving dual functions of automatic voltage regulation and health monitoring by using shared memory architecture with a hybrid interface.
Typically, said first communication means comprises a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.
Typically, said second communication means comprises a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.

Typically, said third communication means comprises a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.
Typically, said hybrid interface is a a bi-directional interface which is used by the said processor means to receive said sensed current values and said sensed voltage values and is also used to give command to said digital output card.
Typically, said processor means uses a shared memory architecture using SRAM (static RAM) and flash memory interface.
Typically, said system includes an RJ45 port at said processor means in order to monitor health of the transformer, remotely.
Typically, said system includes a serial port at said processor means for providing communication between various such processor means of other transformers.
According to this invention, there is also provided an integrated method for automatic voltage regulation and health monitoring of transformer using shared memory architecture, said method comprises the steps of:
I) sensing voltage parameters of a transformer to obtain voltage values;
II) sensing current parameters of a transformer to obtain current values;
III) receiving said sensed voltage values and said sensed current values at a processor means;
IV) storing and communicating said sensed voltage values and said sensed current values in relation to time, at a shared memory means in communication with said processor means;

V) providing a hybrid interface comprising sensor input card, digital input card, digital output card, first communication means between said processor means and said sensor input card, second communication means between said sensor input card and said digital input card, third communication means between said digital input card and said digital output card, wherein said hybrid interface comprises the steps of: i. receiving on-load tap changer sensed position from an on-load tap changer
position sensor, by means of said sensor input card; ii. receiving various pre-defined parameter values in relation to pre-defined
transformer equipment, by means of said digital input card;
iii. outputting actuation signals to an on-load tap changer, by means of said
digital output card, to change tap position in accordance with sensed load
condition which is depicted in terms of change in sensed current parameter
by current transducer and / or in terms of change in sensed voltage
parameter by voltage transducer,
thereby achieving dual functions of automatic voltage regulation and health
monitoring by using shared memory architecture with a hybrid interface, such that
when said processor means is given command for automatic voltage regulation
from an external interface, said processor means dedicates a portion of said shared
memory for automatic voltage regulation and stores said sensed voltage values and
sensed current values and depending on the command sent to said digital output
card for changing tap position of said on-load tap changer and when said processor
means is given command for health monitoring, said processor means receives said
sensed voltage values and sensed current values and processes pre-defined
modules for monitoring health of said transformer.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a voltage regulation system and method for a transformer, according to the prior art; and
Figure 2 illustrates a health monitoring system and method for a transformer, according to the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 3 illustrates a schematic of an integrated system for automatic voltage regulation and health monitoring of transformers using shared memory architecture.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a voltage regulation system and method for a transformer, according to the prior art.
For this automatic voltage regulation, an OLTC (on-load tap changer) position sensor (OLTC-PS) is employed to sense instantaneous OLTC position of the transformer. This sensed information is provided to a main processor (MP1). The main processor also receives voltage readings from a voltage transducer (VT) employed at the transformer. The main processor is adapted to check sensed position in correlation with sensed voltage in order to check whether correct

position of OLTC is provided in accordance with current load. With change in load, sensed voltage changes, and hence, OLTC position should change. This change is effected by means of a relay (RL) actuated by signals received from the main processor (MP1).
Figure 2 illustrates a health monitoring system and method for a transformer, according to the prior art.
For this health monitoring, a gas sensor (GS), a temperature sensor (TS), and other such sensors (OS) are employed which provide its sensed readings to a main processor (MP2). Further, readings relating to sensed current related values from a current transducer (CT) and sensed voltage related values from a voltage transducer (VT) are provided to the main processor (MP2). This provides parameters relating to the health and working parameters of the transformer. The main processor is adapted to check sensed readings and sensed values in correlation with pre-defined stored threshold readings and threshold values. Appropriate pre-defined action is effected through mechanisms such as cooling control module (CC) and relays (RL) which receive actuation signals from the main processor (MP2).
According to this invention, there is provided an integrated system for automatic voltage regulation and health monitoring of transformers using shared memory architecture.
Figure 3 illustrates a schematic of the system.

In accordance with an embodiment of this invention, there is provided a voltage transducer (VT) adapted to sense voltage parameters of a transformer. Voltage is continuously monitored by means of this voltage transducer at discrete time intervals and recorded.
In accordance with another embodiment of this invention, there is provided a current transducer (CT) adapted to sense current parameters of a transformer. Current is continuously monitored by means of this current transducer at discrete time intervals and recorded.
In accordance with yet another embodiment of this invention, there is provided a main processor (MP) adapted to receive the sensed voltage values and the sensed current values.
In accordance with another embodiment of this invention, there is provided a shared memory means (MM) adapted to communicate with the main processor. The main processor is adapted to store sensed parameters such as sensed voltage parameters and sensed current parameters in relation to time. The main processor is adapted to fetch the stored sensed parameters as and when required.
In accordance with still another embodiment of this invention, there is provided a sensor input card (SIC) adapted to receive OLTC sensed position from an OLTC position sensor (OLTC-PS).

In accordance with an additional embodiment of this invention, there is provided a digital input card (DIC) adapted to receive various pre-defined parameter values in relation to actuators, contactors, and the like transformer equipment.
In accordance with yet an additional embodiment of this invention, there is provided a digital output card (DOC) adapted to output actuation signals to an OLTC or a relay of an OLTC to change the tap position in accordance with sensed load condition which is depicted in terms of change in current (sensed current parameter by current transducer) and / or in terms of change in voltage (sensed voltage parameter by voltage transducer).
In accordance with still an additional embodiment of this invention, there is provided a first communication means (CM1) between the main processor (MP) and the sensor input card (SIC).
In accordance with still an additional embodiment of this invention, there is provided a second communication means (CM2) between the sensor input card (SIC) and the digital input card (DIC).
In accordance with still an additional embodiment of this invention, there is provided a third communication means (CM3) between the digital input card (DIC) and the digital output card (DOC).
Typically, each of the first communication means (CM1), the second communication means (CM2), and the third communication means (CM3) comprises a RS485 dual bus, a CAN, and a GPIO. RS485 relates to a standard

defining the electrical characteristics of drivers and receivers for use in balanced digital multipoint systems. It essentially aids in full duplex communication between nodes. CAN relates to Controller-area network which is a bus standard designed to allow microcontrollers and devices to communicate with each other without a host computer. GPIO relates to General Purpose Input/Output which is a generic pin on a chip whose behaviour (including whether it is an input or output pin) can be controlled (programmed) through software. The communication is effected through the RS485 bus. If the communication is jammed due to any reason, the CAN interface is invoked as a back-up. If the CAN interface also fails, then GPIO pin is activated by the main processor. The GPIO pin, herein, is pre-configured to reset communication on that communication means if there is transmission interruption or transmission jam. Thus, identification of communication means' jam location is also possible.
The main processor (MP) captures the voltage and current values and stores the same in a shared memory (MM). The hybrid interface, which interacts with the main processor (MP), is a bi-directional interface which is used by the main processor to receive the sensed current and voltage values and is also used to give command to the digital output card (DOC). The main processor uses a shared memory architecture using SRAM (static RAM) and flash memory interface. When the main processor is given command for automatic voltage regulation from external interface through display or fiber optic serial port or through Ethernet, the main controller dedicates a portion of memory for automatic voltage regulation and stores the voltage and current samples and depending on the command sent to digital output card (DOC) for changing the tap position of OLTC. In case of health

monitoring, the main processor (MP) receives data from the current and voltage transducers and processes algorithms for monitoring the health of transformers
In accordance with another additional embodiment of this invention, there is provided an RJ45 port at the main processor (MP) in order to monitor health of the transformer, remotely. Remote operation is possible through the port.
In accordance with another additional embodiment of this invention, there is provided a serial port (SP) at the main processor (MP). This is preferably a fibre optic serial port. The serial port is used for connecting multiple serial ports of other such main processors of other such transformers. Thus, handshaking between multiple such processors is possible, through this port.
Therefore, this invention provides a system for achieving dual functions of automatic voltage regulation and health monitoring by using shared memory architecture with a hybrid interface.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. An integrated system for automatic voltage regulation and health monitoring of transformer using shared memory architecture, said system comprising:
A) voltage transducer adapted to sense voltage parameters of a transformer to obtain voltage values;
B) current transducer adapted to sense current parameters of a transformer to obtain current values;
C) processor means adapted to receive said sensed voltage values and said sensed current values;
D) shared memory means adapted to communicate with said processor means, for storing and communicating said sensed voltage values and said sensed current values in relation to time;
E) hybrid interface comprising sensor input card, digital input card, digital
output card, first communication means between said processor means and
said sensor input card, second communication means between said sensor
input card and said digital input card, third communication means between
said digital input card and said digital output card, wherein
a. said sensor input card is adapted to receive on-load tap changer sensed
position from an on-load tap changer position sensor;
b. said digital input card is adapted to receive various pre-defined
parameter values in relation to pre-defined transformer equipment;
c. said digital output card is adapted to output actuation signals to an on
load tap changer to change tap position in accordance with sensed load
condition which is depicted in terms of change in sensed current

parameter by current transducer and / or in terms of change in sensed
voltage parameter by voltage transducer, thereby achieving dual functions of automatic voltage regulation and health monitoring by using shared memory architecture with a hybrid interface.
2. A system as claimed in claim 1 wherein, said first communication means comprising a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.
3. A system as claimed in claim 1 wherein, said second communication means comprising a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.
4. A system as claimed in claim 1 wherein, said third communication means comprising a RS485 dual bus, a CAN, and a GPIO, said GPIO adapted to reset corresponding communication link.
5. A system as claimed in claim 1 wherein, said hybrid interface is a a bidirectional interface which is used by the said processor means to receive said sensed current values and said sensed voltage values and is also used to give command to said digital output card.
6. A system as claimed in claim 1 wherein, said processor means uses a shared memory architecture using SRAM (static RAM) and flash memory interface.

7. A system as claimed in claim 1 wherein, said system includes an RJ45 port at said processor means in order to monitor health of the transformer, remotely.
8. A system as claimed in claim 1 wherein, said system includes a serial port at said processor means for providing communication between various such processor means of other transformers.
9. An integrated method for automatic voltage regulation and health monitoring of transformer using shared memory architecture, said method comprising the steps of:

I) sensing voltage parameters of a transformer to obtain voltage values;
II) sensing current parameters of a transformer to obtain current values;
III) receiving said sensed voltage values and said sensed current values at a processor means;
IV) storing and communicating said sensed voltage values and said sensed current values in relation to time, at a shared memory means in communication with said processor means;
V) providing a hybrid interface comprising sensor input card, digital input card, digital output card, first communication means between said processor means and said sensor input card, second communication means between said sensor input card and said digital input card, third communication means between said digital input card and said digital output card, wherein said hybrid interface comprising the steps of:
i. receiving on-load tap changer sensed position from an on-load tap changer position sensor, by means of said sensor input card;

ii. receiving various pre-defined parameter values in relation to predefined transformer equipment, by means of said digital input card; iii. outputting actuation signals to an on-load tap changer, by means of said digital output card, to change tap position in accordance with sensed load condition which is depicted in terms of change in sensed current parameter by current transducer and / or in terms of change in sensed voltage parameter by voltage transducer, thereby achieving dual functions of automatic voltage regulation and health monitoring by using shared memory architecture with a hybrid interface, such that when said processor means is given command for automatic voltage regulation from an external interface, said processor means dedicates a portion of said shared memory for automatic voltage regulation and stores said sensed voltage values and sensed current values and depending on the command sent to said digital output card for changing tap position of said on-load tap changer and when said processor means is given command for health monitoring, said processor means receives said sensed voltage values and sensed current values and processes pre-defined modules for monitoring health of said transformer.