A) TECHNICAL FIELD
[0001] The present invention generally relates to energy meter like watt-hour meter and particularly to a tamper detection device in energy meter. The present invention more particularly relates to detect the tampering of energy meter due to extra high voltages.
B) BACKGROUND OF THE INVENTION
[0002] An energy meter is a device that measures the amount of electrical energy supplied to residence, industries, business, machine etc. Most meters are capable of monitoring steady-state or contmuous parameters such as voltage imbalance, under voltage or over voltage. The voltage fluctuations can be monitored remotely using sensors or voltage sensing devices in order to prevent it from tampering.
[0003] The meters for measuring single phase energy are also available. It also provides capabilities like Maximum demand with date & time and kWh Backups. The modem electricity meters operate by continuously measuring the instantaneous voltages and current in amperes and iinding the product of these two to give an instantaneous electrical power in watts which is then integrated against time to compute the total energy used (in joules, kilowatt-hours etc). The meters fall into two basic categories, like electromechanical meter and electronic meter.
[0004] The meters may be manipulated so as to make them under-register or even run backwards, effectively allowing usage of power without paying for it.

[0005] All electrical equipment can be monitored, by using sensors fed to devices monitoring the necessary parameters. Each type of equipment has sensors and devices suited specifically to the application facilitating remote commimication. Sensors for current and voltage provide the basic input to devices used for protection and/or metering and monitoring, as well as status of the power system. Intelligent remote monitoring and power management systems use voltage, current, status and temperature to derive hundreds of usefiil parameters to help plant managers stay on top of what their electrical systems are doing.
[0006] Almost all Electronic equipments incorporate an in-built high voltage detection schemes. In general, the function of the high voltage sensing devices is to alert the controller when a voltage limit is exceeded. Continuous voltage monitoring schemes have been applied to monitor and interrupt the process once the high voltage is detected.
[0007] The currently available high voltage detection and measurement methods deploy a contact type high voltage detection circuit. Hence there is a need to develop a high voltage detection circuit which can also be used to sense the EHT tampering at any point of the instrument in a non contact maimer easily and efficiently.
[0008] The Prior art Patent No. US3991367 discloses a method for detection of potential on a high-voltage transmission lines. It includes a suspension insulator used on the tower of a high-voltage traramission line with a capacitive voltage dividing pickup plate placed to pickup a low-power indication of the potential carried by the line. In order to detect the potential on the plate, the potential difference between the plate and the tower is limited, rectified and applied to a neon lamp in a photo coupler.

[00091 The prior art patent No. US4870343 provides a Hi^ voltage detection device. It includes a high voltage detecting test stick. The high voltage test stick produces both a visual and an audible signal in response to a broad range of transmission and distribution voltages. It includes two independent chcuits. The two independent circuits in the test stick provide a positive indication of the presence of high voltage over a broad range of transmission and cUstribution applications.
[0010] Thus none of the currently available high voltage detection and measurement device is non contact type and can detect weak and high electrical fields. Hence there is a need to develop a high voltage detection and measurement device to detect and measure extra high voltages and weak electrical fields easily and efficiently in a non contact manner. Also there is a need to detect the tampering of energy meters due to extra high voltages.
C) OBJECT OF THE INVENTION
[0011] The primary object of the present invention is to develop a high voltage tamper detection device to detect the tampering of an energy meter due to extra high voltages in a non contact manner.
[0012] Another object of the present invention is to develop a high voltage detection device to detect extra high voltages in a non contact manner easily and efficiently.

[0013] Yet another object of the present invention is to develop an extra high voltage detection device to provide electrical isolation between the source, sensmg coil and transduction circuit in a non contact manner.
[0014] Yet another object of the present invention is to develop an extra high voltage detection device provided with a sensing coil which is designed not based on current or voltage transfer ratios.
[0015] Yet another object of the present invention is to develop an extra high voltage detection device to detect even the weakest electrical field which may cause corona discharge from the source to the instrument to detect the tampering of energy meters.
[0016] Yet another object of the present invention is to develop an extra high voltage detection device provided with a single transducer and associated circuit to sense the EHT tampering at any point of the instrument.
[0017] Yet another object of the present invention is to develop an extra high voltage detection device to detect the extra high voltages based on the electrical field agitation principle.
[0018] These and other objecte and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

D) SUMMARY OF THE INVENTION
[0019] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.
[0020] The various embodiments of the present invention provide an extra high voltage detection device and method to detect the tampering of energy meter due to high voltages in a non contact manner easily and efficiently. According to one embodhnent of the present invention, the extra high voltage detection device is provided with a conducting coil arranged to surround a device such as energy meter to act as proximity sensor. A Neon bulb is connected to the proximity sensor. A light dependent resistor is arranged opposhe to the Neon bulb and is coupled to a transistor connected to a control circuit. When an extra high voltage source is brought near the device, an arcing is generated from the source of the device. The electric field generated by the arcing is picked up the conducting coil in the proximity sensor. As a result of the electric field picked by the coil in the proximity sensor, the neon bxilb is made to glow. The glow in fee neon bulb is detected by the LDR. Whenever the neon bulb glows, the resistance of the LDR is decreased to make the transistor to conduct. As a result, the collector voltj^e of the transistor is reduced. A control circuit carries out suitable action based on the low collector vohage of the transistor. The tampering of the energy meter by the high vohage is detected and stored for fiiture reference and corrective action.

[0021] These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.
E) BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0023] FIGURE. I shows a block circuit diagram of an extra high voltage detection device for detecting the tampering of the energy meter.
[0024] Although specific features of the present invention are shown m some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0025] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and h is to be understood that the logical, mechanical and other changes may be made without

departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0026] The various embodiments of the present invention provide an extra high voltage detection device and method to detect the tampering of energy meter due to high voltages in a non contact manner easily and efficiently. According to one embodiment of the present invention, the extra high voltage detection device is provided with a conducting coil arranged to surround a device such as energy meter to act as proximity sensor. A Neon bulb is connected to the proximity sensor. A light dependent resistor is arranged opposite to the Neon bulb and is coupled to a transistor connected to a control circuit. When an extra high voltage source is brought near the device, an arcing is generated from the source of the device. The electric field generated by the arcing is picked up the conducting coil in the proximity sensor. As a result of the electric field picked by the coil in the proximity sensor, the neon bulb is made to glow. The glow in the neon bulb is detected by the LDR. Whenever the neon bulb glows, the resistance of the LDR is decreased to make the transistor to conduct. As a result, the collector voltage of the transistor is redxiced. A control circuit carries out suitable action based on die low collector voltage of the transistor. The tampering of the energy meter by the high vohage is detected and stored for future reference and corrective action.
[0027] FIGURE. 1 shows a block cfrcuit diagram of an extra high voltage detection device for detecting the tampering of the energy meter. With respect to FIG-1, the extra high voUage detection device is provided with a conducting coil arranged to surround a device such as energy meter to act as proximity sensor. The conducting

coil is arranged inside the device. The device may be an energy meter. A Neon bulb is connected to the proximity sensor.
[0028] A hght dependent resistor (LDR) Rl is arranged opposite to the Neon bulb and is coupled to a transistor connected to a control circuit. In the LDR, the resistance of the resistor Rl is varied with respect to the light, when the LDR is irradiated with a light. When an extra high voltage source is brought near the device, an arcing is generated from the source of the de\4ce. The electric field generated by the arcing is picked up the conducting coil in the proximity sensor. As a result of the electric field picked by the coil in the proximity sensor, the neon bulb is made to glow. The glow in the neon bulb is detected by the LDR. Whenever the neon bulb glows, the resistance of the LDR Rl is decreased to make the transistor to conduct. As a result, the collector voltage of the transistor is reduced, A control circuit carries out suitable action based on the low collector voltage of the transistor. The tampering of the energy meter by the high voltage is detected and stored for future reference and corrective action.
[0029] The neon bulb and LDR should be placed in a box which blocks the ambient light to prevent the exposure of the LDR to the ambient light to improve the sensitivity of the measurement. The neon bulb glows mainly due to the agitation by electric field and not due to the conduction of current in the coil wire. The purpose of the coil is just to minimise the number of neon bulb and the LDR. In the absence of the coil, multiple neon bulbs, LDRs and associated circuits are requu-ed. Also the neon bulb need not be coimected in a closed loop as the neon bulb glows due to the electric field and not due to the flow of current.

G) ADVANTAGES OF THE INVENTION
[Q030] Thus the various embodiments of the invention provide a device and method to detect the extra high voltages (EHV) in a device like energy meter in a non contact manner to detect the tampering of the energy meter due to the extra high voltage. The extra high voltage detection device detects the extra high voltages in a non contact type and provided electrical isolation between the source, the sensing coil, and transduction circuit. The sensing coil circuit is not designed based on the current and voltage transfer ratios. The EHV detection device is able to detect even the weakest electric field which may cause corona discharge from the source to the instrument such as energy meter so that the tampering of the energy meter due to EHV is detected and recorded. The cost of the device is reduced as a single transducer and associated circuit is sufficient to sense the EHT tampering at any point. The neon bulb glows only due to the agitation of the gases by the electric field and not due to the conduction of current through the electrodes thereby preventing the erosion of the electi\)des. As a result the life of the neon life may be even increased beyond that of the semiconductors used in the instrument. The device may be improved to measure the extra high voltages by standardizing the neon lamp characteristics and by calibrating the light sensing circuit.
[0031] Although the invention is described with various specific embodiments, it will be obvious for a person skilled in the art to practice the invention with modifications. However, all such modifications are deemed to be withm the scope of the claims.

[0032] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the present invention described herein and all the

CLAIMS
What is claimed is:
1. An extra high voltage tamper detection device for energy meter, the device
comprising:
a conducting coil placed around a device used for power measurement;
a neon bulb connected to the conducting coil;
a light dependent resistor arranged opposite to neon bulb;
a transistor connected to the light dependent resistor;
Wherein the neon bulb glows when an extra high voltage source is brought
near the device used for power measurement.
2. The device according to claim 1, wherein the light dependent resistor detects the glow in the neon bulb.
3. The device according to claim 1, wherein the light dependent resistor (LDR) is exposed to the neon glow so that the resistance of the LDR is decreased to make the transistor to conduct.
4. The device according to claim 1, further comprises a control circuit connected to the LDR and transistor.
5. The device according to claim 1, wherein the transistor is made to conduct to activate a control circuit to register a tamper detection event.

6. The device according to claim 1, wherein the coil is placed inside the device
used for power measurement.
7. The device according to claim 1, wherein the neon bulb and the LDR are
placed inside the box to protect the LDR from the ambient light.
8. The device according to claim 1, wherein the device used for power
measurement is an energy meter.