GB2416851A

GB2416851A - Remote and isolated measurement of current on a high voltage line by radio or infra-red transmission

Info

Publication number: GB2416851A
Application number: GB0417111A
Authority: GB
Inventors: Sanjaya Singhal; Kaushik Ghosh
Original assignee: Polymeters Response International Ltd
Current assignee: Secure Meters UK Ltd
Priority date: 2004-07-30
Filing date: 2004-07-30
Publication date: 2006-02-08
Also published as: GB0417111D0

Abstract

A system to be utilised with a high voltage circuit, the system including a unit adapted: to operate in an ungrounded condition and comprising: a current transformer 1 for detecting a signal indicative of the current of the circuit; a sampling means 2 for sampling the signal defected by the current transformer; a transmission means 3 arranged to transmit the sampled signal via wire communication to a reception means 4 located at a remote location to the transmission means, and a signal processing means remote from the unit and adapted to the convert sampled signal into the signal indicative of the current in the circuit. The transmission may be via radio or by an infra-red optical transmission.

Description

241 685 1

DETECTION SYSTEM FOR A HIGH VOLTAGE CIRCUIT

The present invention relates to high voltage circuits. In particular, the present invention relates to a system utilised in conjunction with a high voltage circuit.

High voltage circuits typically utilise current transformers for measurement of the current. Conventional high voltage current transformers use a coil type configuration to measure the current in the circuit. However, this type of current transformer is required to be insulated in order to provide isolation to ground and due to the high voltages present in the circuits, a large degree of insulation is necessary.

For example, whereas a current transformer utilised in 240V circuit may be of a low cost to produce due to the degree of insulation required, a current transformer for use in a high voltage circuit such as an 1 lkv circuit will require considerably more insulation and this increases the production costs.

The present invention attempts to overcome the problems by utilising a high voltage current transformer system which requires less insulation and reduces costs.

In particular, the present invention provides a system to be utilised with a high voltage circuit, the system including a unit adapted to operate in an ungrounded condition and comprising: a current transformer for detecting a signal indicative of the current of the circuit; a sampling means for sampling the signal detected by the current transformer; and a transmission means arranged to transmit the sampled signal via wireless communication to a reception means located at a remote location to the transmission means; and a signal processing means remote from the unit and adapted to convert the sampled signal into the signal indicative of the current in the circuit.

After the sampled signal has been converted into the signal indicative of the current, further processing may be carried out if necessary.

The current transformer, the sampling means and the transmission means are at a high voltage since they are not connected to ground. As the current transformer does not need to be grounded no or very little insulation is required by the current transformer thus reducing insulation costs.

In order that the present invention be more readily understood, a preferred embodiment thereof will be described by way of example with reference to the accompanying figure which represent a schematic view of the system according to the preferred embodiment of the present invention.

The system comprises two main sections: a transmission section 10 and a reception section 20 located remote from the transmission section lO. The transmission section lO comprises a current transformer l, digital sampler 2 and transmitter 3 and is located in close proximity to a high voltage circuit l for which measurements are required and is not grounded. The reception section 20 is located at a remote location from the high voltage circuit l and is preferably grounded. Communication between the sections lO and 11 is achieved in a wireless form using either radio frequency signals or light pulses such as IR.

An analogue waveform representing the current is picked off from the high voltage circuit l by a current transformer (not shown). The waveform is sampled by a digital sampler 2 to obtain a digital form of the detected analogue signal. The digital signal is sent to a transmitter 3 connected to the digital sampler 2.

Power for the transmission section 10 is provided by a storage device such as a battery and/or a capacitor or rechargeable battery connected to a charging circuit which is inductively coupled to the voltage circuit.

The receiver 4 forms part of the reception section 20 which is preferably grounded and is located at a distance away from the transmission section lO to enable digital signal to be sent over a radio frequency communication channel. It will be appreciated that another type of communication may be utilised which is capable of transferring the digital signal in a wireless manner.

The digital signal received by the receiver 4 is then converted into an analogue signal in a reconstruction unit 5 thus reproducing the analogue waveform signal picked off from the high voltage circuit. In addition, measurements In relation to the waveform can then be carried out in a processing unit 6 if required.

It will be appreciated that the reconstruction unit 5 may form part of the receiver 4 and does not necessarily have to be a separate unit. Moreover, the reception section 20 may be in the form of one embedded unit.

The advantage of such an arrangement is that the insulation costs which are normally associated with conventional high voltage current transformers can be substantially reduced as the signal measured by the current transformer is transferred to a remote location through wireless communication before being further utilised.

Accordingly, current transformers require no or very little insulation thereby reducing insulation costs.

Claims

CLAI1\IS: 1. A system to be utilised with a high voltage circuit, the

system including a unit adapted: to operate in an ungrounded condition and comprising: a current transformer for detecting a signal indicative of the current of the circuit; a sampling means for sampling the signal detected by the current transformer; a transmission means arranged to transmit the sampled signal via wireless communication to a reception means located at a remote location to the transmission O means, and a signal processing means remote from the unit and adapted to convert the sampled signal into the signal indicative of the current in the circuit.
2. A system according to claim 1, wherein the transmission means includes a radio frequency transmitter.
3. A system according to claim 1, wherein the transmission means includes an infra red transmitter.
4. A system according to claim 1, 2 or 3 wherein the transmission means includes a source of power in the form of a battery and/or capacitor.
5. A system according to claim 4, wherein the source of power is connected to an inductive coupling arrangement whereby to supply power to the source from the high voltage circuit.