Patent Application
20130110424
The subject matter disclosed herein relates to a power meter to detect power and a power detection system. In particular, power meters monitor power usage in structures connected to a power grid. However, customers often are unaware of abnormal power usage or the differences between peak and non-peak times that correspond to different rates for power usage.
According to one aspect of the invention, a method to detect power comprises detecting power consumed in at least a portion of a building over a plurality of predetermined periods of time; calculating a representative value of the power consumed during each predetermined period of time; comparing the representative value to a threshold value; determining whether the detected power consumed is abnormal based at least upon the comparison of the representative value to the threshold value; and generating an alert when it is determined that the consumed power is abnormal.
According to another aspect of the invention, a power meter comprises a power detection unit to sense a level of consumed power in at least a portion of a building and to output sensed power level data; and an analysis unit to receive the sensed power level data and to determine whether the level of consumed power is abnormal by generating a representative value representative of the level of consumed power over a predetermined period of time, comparing the representative value to a threshold value, and outputting an alert to a remote device when it is determined that the consumed power is abnormal based at least on the comparison of the representative value to the threshold value.
According to yet another aspect of the invention, a power detection system comprises a power meter including a power detection unit to sense a level of power consumption in at least a portion of a building over a predetermined period of time, and an analysis unit to generate a representative value based on the sensed level of power over the predetermined period of time, to compare the representative value to a threshold value, to determine that the level of power consumption is abnormal based at least upon the comparison of the representative value with the threshold value, and to generate an alert when it is determined that the level of power consumption is abnormal; and a remote device to receive from the power detection device the alert.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The following detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
In alternative embodiments, the building that receives the power from the power provider is one of a commercial building, such as an industrial facility or office building, an apartment building, an office or series of offices, an apartment, condo, or townhome, or a series of apartments, condos, or townhomes, etc.
The binned data is processed according to rules stored in the rules unit 16. Based on the results of the rules processing, an alert is generated by the alert generating unit 17. The alert generating unit 17 transmits alert data to a communication unit 19, which transmits the alert data to a power provider and to a remote device 20. The remote device 20 is a device operated by a user of the house 2. In the present embodiment, the remote device 20 is a smart phone. According to alternative embodiments, the remote device is a laptop, a personal computer, or any other handheld device capable of receiving personal text messages, rich-content messages, links, and other alerts.
The power meter 10 also includes a display unit 18 to display power data and to receive user input to control options of the power meter.
Both a user and a power provider access the power meter 10 to control display operations, to alter rules, and to set alert options. A user accesses the meter 10 directly via the display unit 18, such as a touch-screen display or LCD display having a separate keypad. The user selects and alters threshold values, as discussed below, to set rule options. The user also alters alert settings, such as a destination device.
In addition, both the user and the provider access the power meter 10 via the communication unit 19, which includes data communication modules, such as a cable data connection and an antenna to communicate wirelessly.
The power meter 10 includes a case 31 and a control unit 40 including a processor 41 and memory 42. The memory 42 stores commands and data. The commands control the processor to perform operations, and the data is operated upon. For example, the data is stored, deleted, and altered, according to the operations performed by the processor 41.
The power detection unit 11 of
The temperature detection unit 12 of
According to another alternative embodiment, the power meter 10 does not include the temperature detection unit 12, and instead temperature data is received from an external source, such as the power provider, via the communication unit 19. For example, temperature data from weather stations in a same geographical area as the house 2 may be used to provide temperature information to the processor 41.
The timing unit 13 includes a clock 34 and a counter 35. The clock 34 includes data including date and time data to the control unit 40. The counter 35 provides duration data to the control unit 40. According to an alternative embodiment, the processor 41 executes one or more programs from memory 42 to track date, time, and to track a duration. According to yet another alternative embodiment, date and time data is provided from an external source, such as from the power provider 3 via the communication unit 19. According to one example embodiment, the data and time data is stored in memory 42 and executed by the processor 41, and updated at predetermined intervals by an external source, such as by the power provider 3.
The display unit 18 includes a display 36 and a display processor 37. The display unit 18 receives data from the control unit 40 to display, processes the data, and displays the data on the display 36. According to an alternative embodiment, the processor 41 prepares the data for display and transmits the processed data directly to the display 36. According to various embodiments, the display 36 is any one of an LCD display, LED display, and a rotating dial.
The analysis unit 14 of
According to one embodiment, the representative value is a z-value, which is a unitless value that compares the detected power level to a standard deviation of a plurality of normalized plurality of power levels. The processor 41 analyzes the representative value from the predetermined period of time and calculates the z-value of the representative value when compared with a plurality of values. According to one embodiment, the plurality of values includes values from a predetermined number of previous time periods. According to alternative embodiments, the plurality of values is obtained from a same hour of each day for a predetermined number of previous days, or from a plurality of predetermined time periods of a same category as the elapsed predetermined time period. For example, if the elapsed predetermined time period is in a “peak” time, as determined by the power provider, then the plurality of the predetermined number of previous time periods is obtained from previous “peak” time periods and excludes “non-peak” or “off-peak” time periods. Similarly, if the predetermined time period is designated as “non-peak,” the representative value may be compared with a plurality of previous non-peak time periods to determine the z-score. Calculation of the z-score is described below in additional detail with reference to
According to another embodiment, instead of generating a representative value to represent the power generated during the entire elapsed predetermined time period, the processor 41 generates representative values of detected power in real-time. The processor 41 receives the power usage data, converts the power level data to a z-score, and compares the z-score to the threshold value. The threshold value varies among different predetermined periods of time. As discussed above, according to various embodiments, the z-score is determined by analyzing the detected power usage data together with power usage data from a predetermined number of previous time periods, including periods corresponding to a same hour of previous days and same categories of hours, such as “peak” and “non-peak” power usage hours, as determined by the power provider.
According to one embodiment, when the representative value is generated in real-time, a duration of time within the predetermined period of time is determined during which the z-scores of the detected power levels exceeded a threshold z-score. At the end of the predetermined time period, it is determined whether to generate an alert based on the detected duration of time within the predetermined period of time during which the z-scores of the detected power levels exceeded a threshold z-score. By waiting unit the end of the predetermined period of time to generate the alert, false alerts and alerts based on fleeting power spikes are reduced or eliminated.
According to one embodiment, another factor that is used to determine whether power usage during the predetermined period of time was abnormal is temperature. The processor 41 receives the temperature data from the temperature sensor 33 and compares the received temperature data to a predetermined temperature threshold. Temperature data from a previous predetermined time period is stored in memory 42. The processor 41 calculates a change in temperature between the previously-stored temperature data and the temperature data received from the temperature sensor 33 corresponding to the most recently-elapsed predetermined time period. The processor 41 compares the difference to a predetermined threshold to determine whether the change in temperature is greater than a predetermined change in temperature. The comparison of the sensed temperature data and the temperature threshold is another factor that is used to determine whether power usage during the predetermined period of time was abnormal.
Although an embodiment is disclosed in which the temperature threshold corresponds to a predetermined difference between two temperatures, according to an alternative embodiment, the temperature threshold corresponds to a target temperature, and the temperature data is compared to the target temperature.
According to various embodiments, the temperature data corresponds to one of a maximum temperature during the predetermined period of time, an average temperature, a mean temperature, a starting temperature, and an ending temperature during the predetermined period of time.
According to one disclosed embodiment, when the processor 41 determines that the representative value is greater than the threshold value, the processor determines a duration of time within the elapsed predetermined period of time that the sensed power level exceeded a power level corresponding to the threshold value. The determined duration is compared with a predetermined threshold duration stored in memory 42. The result of the comparison between the determined duration and the threshold duration is another factor that is used to determine whether a sensed power usage during the predetermined period of time was abnormal.
Based on the power, temperature, and time durations, the processor 41 determines whether to generate an alert. The determination whether to generate the alert occurs at the end of the predetermined period of time based on data collected during the entire predetermined period of time. A program is stored in memory 42 that generates a text or email and inserts into the text or email data regarding the sensed power usage. The processor 41 transmits the alert to the communication unit 19 to transmit to an external or remote device 20.
The communication unit 19 includes a circuit or structure to transmit a signal to a remote device 20. According to a disclosed embodiment, the circuit or structure includes at least one of an antenna 43 and a wired input/output port 44. Embodiments of a wired input/output port 44 include a USB port, a copper cable, a telephone cable, an Ethernet cable, and a fiber optic cable. The communication unit 19 further includes a signal processor 45 to process signals transmitted to and from the power meter 10. The signal processor 45 receives the alert from the processor 41 and processes the signal to be transmitted via at least one of the antenna 43 and the wired input/output 44.
According to an alternative embodiment, the power meter 10 transmits data to and from the power provider over the power line.
According to one embodiment, alert data is transmitted to the power provider, which in turn transmits the alert data to a remote device, such as a handheld device of a user associated with the power meter 10.
In operation 401, a span of time is divided into a plurality of predetermined periods of time. According to one embodiment, each day is divided into twenty-four one-hour periods of time. In operation 402, power consumed by at least a portion of a building is detected.
In operation 403, it is determined whether an end of a predetermined period of time has been reached. If not, power is continually detected in operation 402, and the detected power levels are stored. If the end of the period of time has been reached, the process continues to operation 404.
According to one embodiment, in operation 404, once the predetermined period of time has elapsed, a representative value, Value1, is generated. The representative value, Value1, is a value representative of the power usage sensed during the entire elapsed predetermined period of time. According to various embodiments, the representative value, Value1, is representative of an average power value during the predetermined period of time, a mean power value during the predetermined period of time, and a power level measured at a particular point in time. According to one embodiment, the representative value is a z-value, or a measure of the sensed power value relative to a standard deviation from a mean value from among a plurality of power values. The plurality of power values are taken from power values of previous predetermined periods of time. According to various embodiments, the predetermined periods of time correspond to a same hour of a different day as the elapsed predetermined period of time, a same category of a period of time, such as a plurality of previous “peak” periods or “non-peak” periods, and a plurality of periods of time immediately preceding the elapsed period of time. For example, if the elapsed period of time corresponds to a Wednesday, between 3 PM and 4 PM, according to one embodiment, the plurality of periods of time corresponds to a plurality of previous Wednesdays, between 3 PM and 4 PM. According to another embodiment, the plurality of periods of time corresponds to a plurality of previous peak hours, such as weekdays between 9 AM and 5 PM.
According to one embodiment, an average of the power consumed during the predetermined period of time is calculated, and a z-score is generated to compare the calculated average power consumed to averages of previous periods of time.
According to an alternative embodiment, a z-score comparing the detected power level to previously detected power levels is continually generated in operation 404 as the consumed power is detected in operation 402, and no average of the power consumed during the predetermined period of time is generated.
In
In
According to the above-described embodiment in which all of the measured power of a predetermined time period, e.g. P2, are represented by a representative value, the power consumption between approximately 24 kWh and 34 kWh are averaged to generate a z-score. The average power usage during period P2 is approximately 26 kWh, which corresponds to a z-score between +0 and +1. In operation 405, it is determined whether the representative value, Value1, is greater than the threshold value, THvalue. Since the z-score, or the representative value, Value1, of the power usage during the period P2 is less than the threshold value +2, or THvalue, no alert is generated, and no further analysis regarding temperature and duration is performed.
According to one embodiment, the mean power consumption values and corresponding z-scores during peak and non-peak times are determined by the power provider. For example, the power provider determines that the mean power level during a peak time is 25 kWh and the mean power level during a non-peak time is 30 kWh. The power provider may provide mean power usage levels for peak and non-peak times to attempt to influence users to consume relatively less power during peak times and relatively more power during non-peak times.
According to one embodiment, when it is determined in operation 405 that the representative value, Value1, is greater than the threshold value, THvalue, a current temperature, Temp1, is detected in operation 406. In operation 407, a change in temperature is detected between the current temperature, Temp1, and a previously-stored temperature, such as a temperature from a same hour of a previous day.
In operation 408, the change in temperature is compared with a threshold value, ΔTH. If it is determined that the change in temperature is less than or equal to a threshold value, ΔTH, no alert is generated. In particular, since higher temperatures lead to increased power usage, if the temperature has dropped with respect to a previous temperature by a predetermined degree, then an increase in power usage in the current time period would not correspond to “peak” power usage, and no alert needs to be generated. However, if it is determined in operation 408 that the temperature has not dropped by a predetermined amount from previous temperature, then the method proceeds to operation 409 to calculate a time duration based on the representative value, Value1.
According to an alternative embodiment, a sensed temperature is compared to a threshold temperature. If the detected temperature is less than the threshold temperature, no alert is generated.
According to yet another embodiment, the detected temperature is compared to a range of temperatures. The temperature range may be determined by the power provider according to power grid data corresponding to customer power usage in each range. For example, the power provider may determined that if a temperature is above a first threshold or below a second threshold lower than the first threshold, then the process of determining whether to issue an alert continues.
In operation 409, a time duration is measured corresponding to the duration T1 at which the detected power usage was greater than a power usage corresponding to the threshold value, THvalue. In other words, referring to
For example, with reference to
In operation 411, an alert is generated. The alert includes a text or email message including power consumption data.
In
In particular, in operation 301, a predetermined period of time is set, such as an hour. Then, power usage is detected in operation 402. In operation 404, a representative value, Value1, is generated for each power measurement within the predetermined period of time as the predetermined period of time elapses. According to the present embodiment, the representative value, Value1, is a z-score of the measured power usage value compared with prior power usage values.
Each representative value, Value1, is compared to a threshold value, THvalue in operation 405. As illustrated in
If it is determined that the representative value, Value1, is greater than the threshold value, THvalue, the power data is stored in operation 412. According to the present embodiment, the power data includes the measured power usage level. After the representative value, Value1, is compared to the threshold value, THvalue, in operation 405, and after the power data is stored in operation 412, it is determined in operation 403 whether the end of the predetermined time period is detected. If the end of the predetermined period of time is detected in operation 403, then, in operation 409, the stored data from the predetermined period of time is analyzed regarding the duration of time T1 that the representative value, Value1, exceeded the threshold value, THvalue. As discussed above with respect to
According to the embodiment illustrated in
However, even though the representative values are generated in real-time, false alerts are avoided, because a determination of whether to generate the alert is made only after the predetermined period of time has elapsed, and a duration of high power consumption is determined to be above a threshold duration. Thus, in each predetermined period of time, it is determined whether an abnormal power usage occurred by determining if a high power usage occurred for at least a predetermined duration within the predetermined period of time.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
