WO2006113945A1

WO2006113945A1 - Power line communication system

Info

Publication number: WO2006113945A1
Application number: PCT/ZA2006/000056
Authority: WO
Inventors: Roland Baridon Hill
Original assignee: Roland Baridon Hill
Priority date: 2005-04-21
Filing date: 2006-04-18
Publication date: 2006-10-26
Also published as: ZA200801579B

Abstract

An electrical system communication device 10 is provided which includes an interface 12, an impedance modulator 14, and a processor 16. The interface 12 includes an impedance 18, the interface 12 providing a connection to an electrical power line, in use. The impedance modulator 14 is arranged in communication with the interface 12, which modulator 14 is for modulating the impedance 18. The processor 16 is arranged in communication with the modulator 14, the processor 16 being configured to automatically and independently control the modulator 14, in use, so that the impedance of the interface 12 is able to be modulated to automatically generate a signal which includes information about the line and/or an appliance connected to the line. This signal is superimposed on the line via the interface 12 so that the signal is detectable by a remote receiver monitoring the line.

Description

POWER LINE COMMUNICATION SYSTEM

FIELD OF THE INVENTION

This invention relates to an electrical system communication device.

BACKGROUND TO THE INVENTION

Communications over electrical power distribution lines and systems are known. These communication systems generally superimpose a communications signal on an existing electrical power line with the communications signal having a higher frequency than the power signal of the line, also known as ripple communication. These known communication systems typically require complex filtering circuitry to realise this superimposition and subsequent retrieval of the higher frequency signal. This generally allows the communications signal to travel on the line without interfering with the power signal. In this manner, communication over conventional power lines is possible.

Furthermore, the existing systems typically comprise duplex communication systems where a monitoring station polls remote communication devices to transmit information via a power line. A disadvantage of these systems is that they are complicated and require specialized set-up procedures in order to function properly.

This invention proposes a possible solution to the above problems.

SUMMARY OF THE INVENTION

According to an aspect of the invention there is provided an electrical system communication device which includes an interface which includes an impedance, which interface is for connecting the device to an electrical power line, in use; an impedance modulator arranged in communication with the interface, which modulator is for modulating the impedance of the interface; and a processor arranged in communication with the modulator, which processor is energized via the interface and which processor is configured to automatically and independently control the modulator, in use, so that the impedance of the interface is able to be modulated in order to automatically generate a signal which includes information about the line and/or an appliance connected to the line, which signal is superimposed on the line via the interface so that the signal is detectable by a remote receiver monitoring the line.

It is to be appreciated that the device automatically and independently generates the signal without requiring polling, an interrogation request, or the like from a remote location. It is further to be appreciated that the device is powered from the line, e.g. a parallel connection between the line and neutral, or the like.

It is to be appreciated that the interface is understood to refer to any means for connecting the device to an existing electrical power line to enable the signal to be superimposed in the line to allow communication between the device and the remote receiver.

The signal may have a higher frequency than a power signal on the electrical line to minimize interference between the signal and the power signal, e.g. 125 kHz with the frequency of the power signal in the range of 50-60Hz, or the like. The signal may be superimposed once the device is supplied with electrical power from the line, i.e. once the interface has a voltage potential applied to it. It is to be appreciated that the signal may be generated according to any suitable protocol or standard suitable for transmitting information via a line and, as such, the processor is configurable to control the modulator accordingly.

The device may include a sensor for sensing electrical characteristics of the line, e.g. voltage levels, current levels, power consumption, supply frequency, and/or the like. Accordingly, the signal may include information about the sensed electrical characteristics of the line.

The device may include a sensor for sensing operational conditions of the electrical device connected to the line, e.g. voltage levels, current levels, power consumption, number of times the device has been activated over a predetermined period, period of power consumption, and/or the like. Accordingly, the signal may include information about the sensed operational conditions of the device.

The device may include a sensor for sensing general conditions at a point where the device is interfaced with the line, e.g. ambient temperature, humidity, light intensity, and/or the like. Accordingly, the device may include a sensor for sensing general conditions of the appliance connected to the line, e.g. ambient temperature, humidity, light intensity, and/or the like. Accordingly, the signal then includes these sensed general conditions of the line and/or appliance.

It is to be appreciated that the sensor may be configured to sense any suitable variable of the line and/or appliance which the device is then able to include in the signal superimposed on the line.

Furthermore, the processor may be configured to accept an input from a sensor of the electrical appliance connected to the line, e.g. an existing power meter, or the like.

The processor may be configured to control the modulator so that the superimposed signal includes redundancy to minimize errors when the signal is detected by the remote receiver.

The processor may be configured to store a log of the signals transmitted via the interface on a suitable memory arrangement. As such, the processor may include a data connection which enables the stored log to be transmitted to a remote location. The data connection may include a modem connection, or the like. The processor may be configured to transmit the stored log via the data connection after a predetermined number of signals have been generated, or maintain a first-in-first-out data log for random access as required.

The interface impedance may include a protection impedance for limiting the current through the interface, e.g. a resistor. The interface impedance may include a capacitive storage impedance for storing electrical energy in the interface, e.g. a capacitor, which minimizes supply fluctuations, or the like. The interface impedance may include a voltage regulator, e.g. a Zener diode, or the like. It is to be appreciated that the voltage regulator may supply the processor and/or sensor with electrical power as regulated from the electrical line.

The modulator may include a transistor arranged in parallel electrical connection with the voltage regulator with the transistor controlled by the processor.

Accordingly, if the transistor is activated by the processor, the regulator is short-circuited which, by activating and deactivating the transistor, superimposes the signal on the line via the interface.

The processor may also be configured to control a switch in response to a sensed condition, e.g. to interrupt the line if a fault is sensed, for protection purposes, safety considerations, consumption control, or the like.

It is to be appreciated that the processor generally performs its various tasks and configurations by executing a specific set of instructions, e.g. software instructions, or the like.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of non-limiting example, with reference to the accompanying drawings wherein

Figure 1 shows, in diagrammatic view, a circuit diagram of an electrical system communication device, in accordance with the invention;

Figure 2 shows, in diagrammatic view, one embodiment of the device shown in Figure 1 , in use;

Figure 3 shows, in diagrammatic view, a further embodiment of the device shown in Figure 1 , in use; and

Figure 4 shows, in diagrammatic view, a further embodiment of the invention shown in Figure 1.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the accompanying drawings, an electrical system communication device, in accordance with the invention, is generally indicated by reference numeral 10. The communication device 10 includes an interface 12, an impedance modulator 14, and a processor 16.

The interface 12 includes an impedance 18 which connects the device 10 to an electrical power line 20. In the embodiment shown, the impedance 18 consists of a resistive protection impedance in the form of a resistor 18.1 for limiting the current from the line 20 through the interface 12, and a capacitive storage impedance 18.2 in the form of a capacitor for storing electrical energy to minimize supply fluctuations. The resistor and capacitor are generally connected in series. The interface impedance 18 also includes a voltage regulator 18.3 in the form of a Zener diode in series with the resistor and capacitor. The voltage regulator 18.3 supplies electrical power to the active components of the device 10.

The impedance modulator 14 is arranged in communication with the interface 12 for modulating the impedance 18 of the interface 12. In the embodiment shown, the modulator 14 is a transistor arranged in parallel electrical connection with the voltage regulator 18.3 with the transistor controlled by the processor 16.

The processor 16 is typically a conventional microprocessor. The processor 16 is arranged in communication with the modulator 14 which processor 16 automatically and independently controls the modulator 14, in use, so that the impedance 18 of the interface 12 is modulated to automatically generate a signal which includes information about the line 20 and/or an appliance 22 connected to the line 20. The generated signal is then superimposed on the line 20 via the interface 12 so that the signal is detectable by a remote receiver (not shown) monitoring the line 20.

In use, the device 10 is connected in parallel via the interface 12 to the existing power line 20. The device 10 is generally connected between the live wire and neutral wire. It is to be appreciated that the device can be connected in parallel across the appliance, or to the line 20 independently of an appliance. If there is a voltage potential between the live wire and the neutral connection, the device is able to function. The protection impedance 18.1 limits the current through the interface 18, so that the voltage regulator Zener diode 18.3 produces a regulated output, e.g. 10V, or the like. The regulated output of the Zener diode provides a power supply for the processor 16. A diode and capacitor provide further stability of supply for the processor 16.

In one embodiment of the invention, when the interface 12 is connected to a line 20 which is powered, the processor 16 is able to control the modulator 14. If the transistor is activated by the processor 14, the regulator 18.3 is short-circuited which produces a signal across the interface 12. This signal is then superimposed onto the line 20. By the processor 16 activating and deactivating the transistor, a specific signal can be superimposed on the line 20 via the interface 12.

It is to be appreciated that the device 10 automatically and independently generates a signal without requiring polling, an interrogation request, or the like from a remote location, e.g. the remote receiver, or the like. It is further to be appreciated that the device 10 is powered from the line 20, e.g. a parallel connection between the line and neutral, or the like. It is further to be appreciated that the device 10 does generally not use bulky and expensive coupling transformers or inductors as is common practice.

The signal superimposed on the line 20 generally has a higher frequency than a power signal on the electrical line 20, e.g. 125 kHz with the frequency of the power signal in the range of 50-60Hz, or the like.

It is further to be appreciated that the device 10 enables communication as soon as the line 20 has a voltage potential applied thereto. For example, the device 10 is able to alert when the line 20 is activated, or the device 10 can report every 10 minutes if the line 20 is still active, or the like.

The signal generated by the modulation of the transistor by the processor 16 includes a unique identifying code which tells the remote receiver which device 10 is sending the signal. It is to be appreciated that a plurality of devices 10 is able to function on a single line. Accordingly, each device 10 will have its own unique code.

In further embodiments, the device 10 includes a sensor 24 for sensing electrical characteristics of the line 20, e.g. voltage levels, current levels, power consumption, supply frequency, and/or the like. Accordingly, the signal then includes information about the sensed electrical characteristics of the line 20.

The device 10 may also include a sensor 24 for sensing operational conditions of the electrical appliance 22 connected to the line 20, e.g. voltage levels, current levels, power consumption, number of times the appliance 22 has been activated over a predetermined period, period of power consumption, and/or the like. Accordingly, the signal then includes information about the sensed operational conditions of the appliance 22.

The device 10 may include a sensor 24 for sensing general conditions at a point where the device 10 is interfaced with the line 20, or general conditions of the appliance connected to the line 20, e.g. ambient temperature, humidity, light intensity, and/or the like. Accordingly, the signal then includes information about these general conditions as measured by the sensor 24.

It is to be appreciated that the device 10 may include any sensor 24 for sensing any suitable variable of the line 20 and/or appliance 22 which the device 10 is then able to include in the signal superimposed on the line 20.

Furthermore, in other embodiments of the invention, the processor 16 may be configured to accept an input from a sensor of the electrical appliance 22 connected to the line 20, e.g. an existing power meter output, or the like.

For example, in one embodiment of the invention the device 10 is used to report energy consumption registered by metering units. The processor 16 determines the amount of energy used by a particular connection and modulates the voltage regulator to impose the signal on the line 20. The remote receiver is able to uniquely identify the specific device 10 and assigns the energy used to an account associated with that specific device 10.

Accordingly, it is to be appreciated that the processor 16 is typically configured to control the modulator 14 so that the superimposed signal includes redundancy to minimize errors when the signal is detected by the remote receiver. The remote receiver is also then configured to analyze the received signal using suitable statistical methods to extrapolate required information from the generated signal.

For example, the processor 16 can include the unique identifying code along with information relating to the hourly energy consumption of the appliance 22 which signal includes quadruple redundancy. It is to be appreciated that such redundancy maximizes the safe receipt of the signal by the remote receiver as the device 10 is never polled or subjected to an interrogating signal. Furthermore, where multiple devices 10 superimpose signals on the line 20, some signal interference may occur which can cause deterioration of such signals. This deterioration of signals is minimized by using redundancy and is acceptable.

The device 10 is then able to report on a large number of parameters of the line 20 and/or appliance 22. For example, activities such as amount of minutes which the line 20 and/or appliance 22 has been activated, the number of times the appliance 22 has been activated, the supply voltage on the line 20, the current of the line 20, the temperature, the energy consumption, any errors in operation, an occurrence of an electrical fault, light intensity, humidity, and/or the like.

Accordingly, the remote receiver is then able to interpret and/or act on the received information. For example, remote metering, fault reporting, electrical system protection, demand side management, and/or the like.

In addition, the processor 16 can also be configured to operate a switch in response to a sensed condition, e.g. to interrupt the line 20 if a fault is sensed, shut down an appliance if a specific condition is sensed, and/or the like.

With reference to Figure 4, an embodiment is shown wherein the processor 16 is generally configured to store a log of the signals transmitted via the interface 12 on a suitable memory arrangement (not shown). It is to be appreciated that this memory arrangement is typically realised as non-volatile memory forming part of the processor 16, or the like.

As such, the processor 16 includes a data connection 26 which enables the stored log to be transmitted to a remote location. The data connection 26 typically includes a modem connection, or the like. The processor 16 is also configured to transmit the stored log via the data connection 26 after a predetermined number of signals have been generated, e.g. every thousand signals generated on the interface 12 results in the stored log being transmitted via Bluetooth modem, or the like.

In one embodiment of the invention, the stored log is stored on a suitable register, such as a FIFO (first-in-first-out) register, or the like.

It is to be appreciated that the device 10 does not follow the conventional practice of signal superimposition by energy injection via an impedance matched coupling mechanism, such as a transformer or an inductor. Instead, the device 10 makes use of energy absorption techniques via the impedance modulator 14 to establish or generate the communication signal.

Accordingly, conventional systems typically require a separate power supply in order to inject a communications signal onto a line via an inductive coupling to such line, such as a transformer or inductor. The current invention, on the other hand, includes a capacitive element in the interface 12 for absorbing energy directly from the existing line, which provides for a more elegant and efficient technique to accomplish such communications over a power line.

In addition, the device 10 does generally not include user configurable or settable parts in order to establish node maps or address details. In this manner, the installation and maintenance logistics are substantially simplified. For example, each device 10, when arranged in a larger system, typically includes a unique identification code transmitted together with the generated signal, or the like.

Furthermore, the capacitive storage impedance 18.2 enables signal transmission before and after the voltage zero crossing point, and thus avoids non- linear distortions generally present in typical distribution systems which require transmissions synchronized to the voltage zero crossing on the line.

It shall be understood that the examples are provided for illustrating the invention further and to assist a person skilled in the art with understanding the invention and is not meant to be construed as unduly limiting the reasonable scope of the invention.

The Inventor regards it as an advantage that the device enables information relating to a power line and/or appliance connected to the line to be automatically and independently transmitted along the power line to a remote receiver.

The Inventor regards it as a further advantage that the device does not require any polling or interrogation to transmit the information. The Inventor regards it as a further advantage that the device is simple and inexpensive and that the device may be retro-fitted to an existing appliance or line without unnecessary effort.

Claims

1. An electrical system communication device which includes an interface which includes an impedance, which interface is for connecting the device to an electrical power line, in use; an impedance modulator arranged in communication with the interface, which modulator is for modulating the impedance of the interface; and a processor arranged in communication with the modulator, which processor is energized via the interface and which processor is configured to automatically and independently control the modulator, in use, so that the impedance of the interface is able to be modulated in order to automatically generate a signal which includes information about the line and/or an appliance connected to the line, which signal is superimposed on the line via the interface so that the signal is detectable by a remote receiver monitoring the line.

2. A device as claimed in claim 1 , wherein the signal has a higher frequency than a power signal on the electrical line to minimize interference between the signal and the power signal.

3. A device as claimed in either one of claims 1 or 2, which includes a sensor for sensing electrical characteristics of the line.

4. A device as claimed in claim 3, wherein the signal includes information about the sensed electrical characteristics of the line.

5. A device as claimed in any one of claims 1 to 4, which includes a sensor for sensing operational conditions of an electrical device connected to the line.

6. A device as claimed in claim 5, wherein the signal includes information about the sensed operational conditions of the device.

7. A device as claimed in any one of claims 1 to 6, which includes a sensor for sensing general ambient conditions at a point where the device is interfaced with the line.

8. A device as claimed in any one of claims 1 to 7, which includes a sensor for sensing general ambient conditions of an appliance connected to the line.

9. A device as claimed in either one of claims 7 or 8, wherein the signal includes information about the sensed general ambient conditions.

10. A device as claimed in any one of claims 1 to 9, wherein the processor is configured to accept an input from a sensor of an electrical appliance connected to the line.

11. A device as claimed in any one of claims 1 to 10, wherein the processor is configured to control the modulator so that the superimposed signal includes redundancy information to minimize errors when the signal is detected by a remote receiver.

12. A device as claimed in any one of claims 1 to 11 , wherein the processor is configured to store a log of the signals transmitted via the interface on a suitable memory arrangement.

13. A device as claimed in claim 12, wherein the processor includes a data connection which enables the stored log to be transmitted to a remote location.

14. A device as claimed in claim 13, wherein the data connection includes a modem connection.

15. A device as claimed in claim 13, wherein the processor is configured to transmit the stored log via the data connection after a predetermined number of signals have been generated.

16. A device as claimed in any one of claims 1 to 15, wherein the interface impedance includes a resistive protection impedance for limiting the current through the interface.

17. A device as claimed in any one of claims 1 to 16, wherein the interface impedance includes a capacitive storage impedance for storing electrical energy in the interface to minimize power supply fluctuations.

18. A device as claimed in any one of claims 1 to 17, wherein the interface impedance includes a voltage regulator for supplying the processor with electrical power as regulated from the electrical line.

19. A device as claimed in claim 18, wherein the modulator includes a transistor arranged in parallel electrical connection with the voltage regulator with the transistor controlled by the processor.

20. A device as claimed in claim 19, wherein if the transistor is activated by the processor, the voltage regulator is short-circuited which, by activating and deactivating the transistor, superimposes the signal on the line via the interface.

21. A device as claimed in any one of claims 1 to 20, wherein the processor is configured to control a switch in response to a sensed condition so as to interrupt the line for protection purposes.

22. A device as claimed in claim 1 , substantially as herein described and illustrated.

23. A new device substantially as herein described.