WO2012130509A1

WO2012130509A1 - A method for detecting an association between an electrical device and a power meter, a power supply system and a monitoring system

Info

Publication number: WO2012130509A1
Application number: PCT/EP2012/052021
Authority: WO
Inventors: Juergen Quittek; Dominique Dudkowski; Marcus Brunner
Original assignee: Nec Europe Ltd.
Priority date: 2011-03-31
Filing date: 2012-02-07
Publication date: 2012-10-04

Abstract

For allowing an efficient and reliable association bet ween an electrical device and a power meter a method for detecting an association bet ween an electrical device and a power meter within a power supply system is claimed, wherein the power 5 meter measures a power value of the power consumption o f the electrical device, wherein a working condition of the electrical device will be monitored and wherein a change of the working condition will be detected and correlated with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter. Further, an according power supply system and monitoring system is claimed, preferably f or carrying out the above mentioned method.

Description

A METHOD FOR DETECTING AN ASSOCIATION BETWEEN AN ELECTRICAL DEVICE AND A POWER METER, A POWER SUPPLY

SYSTEM AND A MONITORING SYSTEM The present invention relates to a method for detecting an association between an electrical device and a power meter, wherein the power meter measures a power value of the power consumption of the electrical device, wherein a working condition of the electrical device will be monitored and wherein a change of the working condition will be detected and correlated with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter.

Further, the present invention relates to a power supply system, preferably for carrying out the above mentioned method, comprising at least one electrical device and at least one power meter, wherein the association between an electrical device and a power meter will be detected and wherein the power meter measures a power value of the power consumption of the electrical device, further comprising means for monitoring a working condition of the electrical device and for detecting a change of the working condition and means for correlating the change of the working condition with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter.

Further, the present invention relates to a monitoring system, preferably for carrying out the above mentioned method, wherein an association between an electrical device and a power meter will be detected and wherein the power meter measures a power value of the power consumption of the electrical device, comprising means for monitoring a working condition of the electrical device and for detecting a change of the working condition and means for correlating the change of the working condition with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter. Metering the power and energy consumption of an electrical device requires hardware that conducts the measurement. For cost reasons and other reasons, many devices are not instrumented with such hardware. Often power of such devices is measured with external power meters, for example, built into a power distribution unit (PDU, aka smart power strip). When using such an external power meter, it is often not clear for which device power is measured, because cabling of power cords between the meter and the device to be measured may change frequently through physical movement, re-cabling, etc. Also a meter may measure power at a single power outlet, but this outlet may be connected to another power strip that allows multiple electrical devices to be supplied from this outlet. Then the meter measures the sum of the power of all connected devices.

The problem is to find out which devices are supplied with a power line at which a meter is measuring power, i.e. which electrical device is associated to which power meter. Known methods addressing this problem include

• Artificial generation of load on a certain device at a certain point in time. For example, an energy management creates high load on a PC for a certain amount in time and checks which meter shows an increase and subsequent decrease in power at the same times. This method has the problem that the energy management system must have the ability and authorization to generate artificial load on concerned devices. For several kinds of devices this is very hard. For example, the load on a router or switch cannot be generated by accessing the switch itself, but rather by other devices that create network traffic passing the switch.

• Pattern recognition for detecting "power signatures". Many devices have power signatures, such as a refrigerator with recurring cooling actions or a washing machine with heating, washing and tumbling phases. Their power signatures can be subject to pattern matching in order to detect that the power of such a device is measured by a certain power meter. However, this method has the problem that it only identifies a kind of device, not a particular one. There is no problem with detecting a single washing machine in a home. But in a datacenter there may be thousands of identical servers all with the same power-on and power-off signature. Even if there are only two very similar devices measured by two meters, this method will not be useful for finding out which device is connected to which meter. It is an object of the present invention to improve and further develop a method for detecting an association between an electrical device and a power meter, a power supply system and a monitoring system for allowing an efficient and reliable association between an electrical device and a power meter. In accordance with the invention, the aforementioned object is accomplished by a method comprising the features of claim 1 , by a power supply system comprising the features of claim 27 and by a monitoring system comprising the features of claim 28.

According to the invention it has been recognized that it is possible to allow for an efficient and reliable association between an electrical device and a power meter by a simple proceeding. First of all a working condition of the electrical device has to be monitored and a change of the working condition has to be detected. If such a change of the working condition, which is including a variation or fluctuation of the working condition or of a parameter of the working condition, has been detected, such a change will be correlated with a respective change of the measured power value and an indication of association between the electrical device and the power meter can be provided, if there is a correlation between the change of the working condition and the change of the measured power value. This will provide a hint that the electrical device and the power meter are associated and that the power meter is measuring the energy and power consumption of the electrical device.

This method for detecting which electrical device is metered or measured by which power meter is non-intrusive, i.e. no artificial load has to be generated on the electrical device in order to map it to a power meter. Further, the method is providing the advantage that multiple electrical devices can be mapped to a single power meter and that multiple identical electrical devices connected to a single power meter or to multiple power meters can be mapped correctly. Within a preferred embodiment the power meter could be integrated in or be part of a power supply system. Within a further preferred embodiment the working condition could be characterized by at least one dynamic property of the electrical device. In this case a power measurement can be matched with the measurement of a dynamic device property in order to get an indication which electrical device receives the power that is measured at a power meter. Concretely and very easily a significant increase and/or decrease of the at least one dynamic property within a definable time interval could be monitored. The time interval comprising the significant increase and/or decrease of the at least one dynamic property could be defined in dependence on individual applications of the electrical device. For example, the dynamic property could be a processor load of the electrical device. For example, if a steep increase of processor load is monitored and at the same time a steep increase of power at one of different power meters, then this is an indication that the processor load is measured by this power meter.

Instead of or additionally to a significant increase and/or decrease of the at least one dynamic property, lengths of peaks and/or bursts or frequencies of periodic time series of the at least one dynamic property within a definable time interval could be monitored. The selection of such a monitored parameter could be depending on the individual application of the electrical device. Within a further preferred embodiment the working condition could be characterized by the occurrence or termination of a definable event or process generated by the electrical device. In other words, instead of detecting, for example, steep increases or decreases of dynamic properties of electrical devices, also events generated by the devices could be used to match with increases and decreases, respectively, of power values.

Within a preferred and concrete embodiment the event could be the start or the completion of a computing job or program. For example, a notification from a server that computing jobs were started or completed could be matched with power fluctuations or changes at the same point in time.

The change of the measured power value could be a significant increase and/or decrease of the power value within a definable time interval. Such a time interval could be defined depending on an individual application situation.

Within a very simple embodiment the working condition could be monitored by the electrical device itself. Thus, implementation of further separate entities is not necessary. Alternatively, the working condition could be monitored by a separate monitoring entity.

Within a further preferred embodiment information about the working condition or about a change of the working condition could be transmitted from the electrical device or from the monitoring entity to a system entity for performing the correlation of a detected change of the working condition with a respective change of the measured power value. In a further preferred and very compact realization of a power supply system the system entity and the monitoring entity could be realized within a single monitoring and system entity.

Within a further preferred embodiment a system entity performing correlation could generate indication of an association between an electrical device and a power meter each time there is a strong correlation between a detected change of the electrical device's working condition and a power value measured by the power meter.

It may happen that a change of a device's working condition and a change of the measured power at a meter occur coincidentally at the same time without the meter measuring the device's power. Thus, a single indication of synchronous events at meter and electrical device may not be sufficient to reliably detect an association between them. Thus, for providing a reliable statement with regard to a possible association between an electrical device and a power meter the indications of associations observed within a definable time interval with regard to a definable pair of electrical device and power meter could be collected or counted. Then, if a number of collected or counted indications would exceed a definable threshold, it could be assumed that the electrical device is associated with the power meter and that the power consumption of the electrical device is at least a part of the power consumption measured by the power meter. Within a concrete and preferred embodiment the collecting or counting process and/or the assuming process could be performed by the above mentioned system entity. In this case a very compact power supply system could be realized.

For providing a very efficient and reliable association between the electrical device and a power meter the method for detecting corresponding or associated pairs of electrical devices and power meters could be performed continuously. In this case changes can be detected, for example, when an electrical device is plugged into another socket for which power is metered by a different power meter. Within another preferred embodiment the method for detecting corresponding or associated pairs of electrical devices and power meters could be performed periodically, preferably depending on how often a change is expected. For example, the method could be performed once per hour, per day or per week. In this case, processing capacity could be saved.

Within another preferred embodiment the method for detecting corresponding or associated pairs of electrical devices and power meters could be repeated when triggered by an event on the electrical device that is an indicator for a potential change of cabling. An example could be a re-boot of a system.

Within a further preferred embodiment a mapping or an association of an electrical device to a power meter could be invalidated by an event that is an indicator for a potential change of cabling. Further preferred, the method for detecting corresponding or associated pairs of electrical devices and power meters could be performed offline or independent from monitoring activities. For example, log files of a server could be processed. For providing high association reliability all dynamic properties of an electrical device could be monitored. As an electrical device could have many dynamic properties, high computational capacity could be necessary for monitoring all said dynamic properties. For reducing computational load at least one predefinable dynamic property could be monitored. This could be possible, if it is known by, for example, the monitoring system, that there are dynamic properties which have only a small influence on the electrical power value of the electrical device. Such dynamic properties could be ignored. A further reduction of the amount of data and processing capacity could be realized, if the electrical device or the monitoring entity would preprocess the information about the working condition or about a change of the working condition by providing and/or reporting only correlation relevant information, preferably to a remote entity. Within a concrete and preferred embodiment the preprocessing could comprise extracting times of increases and/or decreases of a dynamic property and preferably reporting or providing only them. Additionally or alternatively the preprocessing could comprise extracting times of occurrence or termination of a definable event or process generated by the electrical device. Generally, such a preprocessing could also be executed offline, for example, by processing log files of a server.

Within a further preferred embodiment cascaded power meters could be detected, when a single electrical device can be mapped or associated to two power meters. If indications are detected of an association between an electrical device and two power meters then it can be assumed that power meters are cascaded and that the power measured by both power meters includes the power of the electrical device. Within a further preferred embodiment the method could be used for validating existing wiring plans for metered electrical devices.

Important aspects of preferred embodiments of the present invention can be summarized as follows: matching power measurements with measurements of other dynamic device properties in order to get an indication which electrical devices receive the power that is measured at a power meter,

matching a significant increase or decrease of a dynamic device property in a short time with a significant increase or decrease, respectively, of measured power at a power meter for getting an indication on which electrical device's power is metered by which power meter,

assuming that the device's power is a part of the power measured by the power meter if for a pair of power meter and electrical device the number of indications observed within a given time frame exceeds a given threshold, running the process of mapping electrical devices to power meters continuously instead of stopping it once an electrical device has been mapped,

monitoring all properties of an electrical device in order to map it to a power meter,

only monitoring properties of an electrical device that are known to have a significant influence on the electrical power value of the electrical device, monitoring only one of a set of highly correlated properties,

not monitoring properties that are constant or almost constant,

selecting parameters of the mapping process, including the time frame in which the number of indications is collected and the threshold that needs to be exceeded for assuming that an electrical device corresponds to a power meter,

using indirect methods of monitoring device properties instead of receiving them directly from the electrical device,

having the monitored electrical devices or an intermediate device between the monitored electrical devices and the energy management system or system entity preprocessing the time series of values of their properties in order to reduce the amount of data to be transferred and to reduce the processing load on the energy management system - preprocessing may, for example, include extracting times of steep increases or decreases and reporting only them -, • running the mapping process offline instead of online, for example, one per hour or per day,

• matching other input from the electrical device with increases or decreases of power values, for example, notifications on computing jobs to be started or completed,

• conducting processing of event notifications offline, for example by processing log files,

• using other characteristics of time series than decreases or increases for matching with power measurements, for example peak/burst length, frequencies of periodic time series, etc.,

• detecting cascaded power meters when a single electrical device can be mapped to two power meters,

• using the method for validating existing wiring plans for metered electrical devices,

• invalidating a mapping of an electrical device to a power meter after receiving an event that is an indicator for a potential change of cabling of the electrical device, for example, a re-boot event of an electrical device that might have been the result of changing the power supply line for the electrical device.

There are several ways how to design and further develop the teaching of the present invention in an advantageous way. To this end, it is to be referred to the patent claims subordinate to patent claim 1 on the one hand and to the following explanation of preferred examples of embodiments of the invention, illustrated by the drawing on the other hand. In connection with the explanation of the preferred embodiments of the invention by the aid of the drawing, generally preferred embodiments and further developments of the teaching will we explained. The only drawing

Fig. 1 shows schematically an embodiment of a power supply system according to the invention.

Fig. 1 shows schematically an embodiment of a power supply system according to the invention. The power supply system comprises two power sources each having a power supply cable. Each power supply cable is connected to a power meter, so that the power supply system in Fig. 1 comprises two power meters. The first power source provides energy to electrical devices 1 , 2 and 3. The second power source provides energy to electrical devices 4, 5 and 6. The electrical devices report individual working conditions to a power monitoring system. Both power meters report power values to the same power monitoring system. The power monitoring system comprises a monitoring entity and a system entity for performing the correlation of a detected change of the working condition with a respective change of the measured power value.

The present invention provides a non-intrusive method to identify a single electrical device or multiple electrical devices connected to a power source or a power outlet or a power cord at which power is measured as shown in Fig. 1. One idea is to match power measurements with measurements of other working conditions or dynamic device properties in order to get an indication which electrical devices receive the power that is measured at a power meter.

For this purpose, monitoring of working conditions or dynamic properties of the electrical devices is needed. One idea is matching a significant increase or decrease of a dynamic device property in a short time with a significant increase or decrease, respectively, of measured power at a power meter. For example if we observe at a PC or computer a steep increase of processor load and at the same time a steep increase of power at one of the power meters, then this is an indication that the PC's or computer's power is measured by this power meter.

A power monitoring system would correlate power measurements and observations of dynamic properties of electric devices and collect such indications resulting from timely correlated increases or decreases, respectively, of power values and dynamic device properties. There are many methods known for detecting increases and decreases of average values in time series of values including, for example, MCMC Methods (see Paper: 31. Lavielle, M., Lebarbier, E.: An Application of MCMC Methods for the Multiple Change-Points Problem, Signal Processing, 81 (2001 ), 39-53) or Multiresolution and Hybrid Bayesian Algorithms (see Paper: 32. MacDougall, S., Nandi, A.K., Chapman, R.: Multiresolution and Hybrid Bayesian Algorithms for Automatic Detection of Change Points, IEEE Proceedings - Vision, Image and Signal Processing, 145(1998)4, 280-286.). If for a pair of power meter and electrical device the number of indications observed within a given time frame exceeds a given threshold, then the power management system assumes that the device's power is a part of the power measured by the power meter. The process of detecting corresponding pairs of power meters and electrical devices can run continuously. This way, changes can be detected, for example when an electrical device is plugged into another socket for which power is metered by a different power meter. Some electrical devices have many dynamic properties that can be monitored. A simple approach is to monitor all dynamic values that are available and detect steep increases and decreases of their values. But this needs more processing at the power monitoring system. There are several ways to reduce the required effort. If it is known by the energy monitoring system which of these properties have a significant influence on the electrical power value of the electrical device, monitoring can be restricted to these values. If two or more values usually show increases and decreases simultaneously, then they are apparently highly correlated and the energy monitoring system may just monitor one of them instead of all. On the other hand, if properties show almost constant values for a very long time, the energy monitoring system can save effort by ignoring them.

If the energy monitoring system has knowledge about the kind of a monitored electrical device, it may also select the parameters of the method for mapping electrical devices to corresponding power meters including the time frame in which the number of indications is collected and the threshold that needs to be exceeded for assuming that an electrical device corresponds to a power meter. Deviating from Fig. 1 , the energy monitoring system may receive information about dynamic properties of an electrical device indirectly from another entity that has access to information on these properties. Monitored electrical devices or intermediate devices between the monitored electrical devices and the energy management system may preprocess the time series of values of their properties in order to reduce the amount of data to be transferred and to reduce the processing load on the energy/power management system. Preprocessing may, for example, include extracting times of steep increases or decreases and reporting only them.

The detection of indications that an electrical device is associated to a power meter may be conducted offline. Instead of continuously monitoring dynamic properties of an electrical device, the energy monitoring system may periodically map electrical devices to power meters, for example once per hour, per day or per week, depending on how often changes are expected.

Instead of detecting steep increases or decreases of dynamic properties of electrical devices, also events generated by the electrical devices can be used to match with increases and decreases, respectively, of power values. For example, a notification from a server that computing jobs was started or completed can be matched with power fluctuations at the same point in time. This method can as well be executed offline, for example, by processing log files of a server. Instead of using occurrences of steep increases or decreases of dynamic properties of electrical devices and measured power values, also other characteristics of time series can be used, for example, lengths of peaks and bursts, frequencies of periodic time series, etc. If indications of an association between an electrical device and two power meters are detected then the energy monitoring system can assume that power meters are cascaded and that the power measured by both power meters includes the power of the electrical device. Within an embodiment of the present invention a power monitoring system or an energy monitoring system could monitor a number of computers and use a few power meters installed in the power supply system according to Fig. 1. The embodiment can match power measurements with measurements of other dynamic device properties in order to get an indication which electrical devices receive power that is measured at a power meter. A significant increase or decrease of a dynamic device property in a short time can be matched with a significant increase and decrease, respectively, of measured power at a power meter for getting an indication on which device's power is metered by which power meter.

The embodiment is providing a method for the detection of what electrical device is associated with a certain power meter. Observed dynamic device properties can be matched with metered time series of power values.

Many modifications and other embodiments of the invention set forth herein will come to mind the one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing description and the associated drawing. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

C l a i m s

1. A method for detecting an association between an electrical device and a power meter, wherein the power meter measures a power value of the power consumption of the electrical device, wherein a working condition of the electrical device will be monitored and wherein a change of the working condition will be detected and correlated with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter.

2. A method according to claim 1 , wherein the power meter is integrated in or is part of a power supply system.

3. A method according to claim 1 or 2, wherein the working condition is characterized by at least one dynamic property of the electrical device.

4. A method according to claim 3, wherein a significant increase and/or decrease of the at least one dynamic property within a definable time interval will be monitored.

5. A method according to claim 3 or 4, wherein the dynamic property is a processor load of the electrical device.

6. A method according to one of claims 3 to 5, wherein lengths of peaks and/or bursts or wherein frequencies of periodic time series of the at least one dynamic property within a definable time interval will be monitored.

7. A method according to one of claims 1 to 6, wherein the working condition is characterized by the occurrence or termination of a definable event or process generated by the electrical device.

8. A method according to claim 7, wherein the event is the start or the completion of a computing job or program.

9. A method according to one of claims 1 to 8, wherein the change of the measured power value is a significant increase and/or decrease of the power value within a definable time interval.

10. A method according to one of claims 1 to 9, wherein the working condition will be monitored by the electrical device or a monitoring entity.

1 1. A method according to one of claims 1 to 10, wherein information about the working condition or about a change of the working condition will be transmitted from the electrical device or from the monitoring entity to a system entity for performing the correlation of a detected change of the working condition with a respective change of the measured power value.

12. A method according to one of claims 1 to 1 1 , wherein a system entity performing correlation generates indication of an association between an electrical device and a power meter each time there is a strong correlation between a detected change of the electrical device's working condition and a power value measured by the power meter.

13. A method according to one of claims 1 to 12, wherein indications of associations observed within a definable time interval with regard to a definable pair of electrical device and power meter will be collected or counted.

14. A method according to claim 13, wherein, if a number of collected or counted indications exceeds a definable threshold, it will be assumed that the electrical device is associated with the power meter and that the power consumption of the electrical device is at least a part of the power consumption measured by the power meter.

15. A method according to claim 13 or 14, wherein the collecting or counting process and/or the assuming process will be performed by the system entity.

16. A method according to one of claims 1 to 15, wherein the method for detecting corresponding or associated pairs of electrical devices and power meters will be performed continuously.

17. A method according to one of claims 1 to 15, wherein the method for detecting corresponding or associated pairs of electrical devices and power meters will be performed periodically, preferably depending on how often a change is expected.

18. A method according to one of claims 1 to 15, wherein the method for detecting corresponding or associated pairs of electrical devices and power meters will be repeated when triggered by an event on the electrical device that is an indicator for a potential change of cabling.

19. A method according to one of claims 1 to 15, wherein a mapping or an association of an electrical device to a power meter will be invalidated by an event that is an indicator for a potential change of cabling.

20. A method according to one of claims 1 to 19, wherein the method for detecting corresponding or associated pairs of electrical devices and power meters will be performed offline.

21. A method according to one of claims 3 to 20, wherein all dynamic properties or at least one predefinable dynamic property will be monitored.

22. A method according to one of claims 1 to 21 , wherein the electrical device or the monitoring entity preprocesses the information about the working condition or about a change of the working condition by providing and/or reporting only correlation relevant information, preferably to a remote entity.

23. A method according to claim 22, wherein the preprocessing comprises extracting times of increases and/or decreases of a dynamic property.

24. A method according to claim 22 or 23, wherein the preprocessing comprises extracting times of occurrence or termination of a definable event or process generated by the electrical device.

25. A method according to one of claims 1 to 24, wherein cascaded power meters will be detected, when a single electrical device can be mapped or associated to two power meters.

26. A method according to one of claims 1 to 25, wherein the method will be used for validating existing wiring plans for metered electrical devices

27. A power supply system, preferably for carrying out the method according to any one of claims 1 to 26, comprising at least one electrical device and at least one power meter, wherein the association between an electrical device and a power meter will be detected and wherein the power meter measures a power value of the power consumption of the electrical device, further comprising means for monitoring a working condition of the electrical device and for detecting a change of the working condition and means for correlating the change of the working condition with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter.

28. A monitoring system, preferably for carrying out the method according to any one of claims 1 to 26, wherein an association between an electrical device and a power meter will be detected and wherein the power meter measures a power value of the power consumption of the electrical device, comprising means for monitoring a working condition of the electrical device and for detecting a change of the working condition and means for correlating the change of the working condition with a respective change of the measured power value for providing an indication of association between the electrical device and the power meter.