Apparatus and method for data preservation and power loss recovery in an electric meter

Abstract

An electric meter configured to regenerate meter state data after a loss of power includes a memory having at least one volatile and non-volatile memory device, and a processor connected to the memory. The processor is configured to retrieve a backup copy of meter state data and a plurality of meter input data samples from the non-volatile memory device, the plurality of meter input data samples generated after the backup copy of meter state data and before the loss of power. The processor is configured to regenerate the meter state data by updating the backup copy of meter state data with the plurality of meter input data samples to regenerate the meter state data at a time of a last meter input data sample before the loss of power.

Description

[0001] This is a divisional application. The parent application is entitled "Apparatus and Method for Data Storage and Power Loss Recovery in Electricity Meters", filed on May 7, 2019, with application number 201980046048.7. Technical Field

[0002] This disclosure generally relates to electric meters, and more particularly to electric meters that minimize data loss in the event of a power failure without the use of an uninterruptible power supply. Background Technology

[0003] An electricity meter is a device that measures and / or measures aspects of the energy supplied to a load. The load may be part of a residence, business, or even a larger power distribution system. Commonly available meters include electromechanical meters and electronic meters. Electromechanical meters employ a rotating disk that rotates in response to the electric and magnetic fields induced by the electricity delivered to the load. As is known in the art, the speed of rotation of the disk is a function of the amount of electricity delivered to the load. A mechanical counter accumulates the number of disk rotations, indicating the energy consumed by the load. In some cases, electromechanical meters may employ processing circuitry to perform additional operations using the consumption information provided by the rotating disk.

[0004] Electronic meters typically use processing circuitry instead of rotating discs and mechanical counters. In such meters, sensors within the meter detect the voltage and current delivered to the load. The circuitry within the meter converts the sensed voltage and current into digital values. The processing circuitry then uses digital signal processing to calculate, among other things, the energy consumed based on these digital values. Electronic meters offer greater flexibility in terms of the types of energy consumption information they can calculate, track, and store.

[0005] Electricity meters that measure the power flowing through a power line typically use a small fraction of that power to power the circuitry, processors, and other components within the meter itself. Of course, in some cases, the flow of power to the meter is interrupted due to a power outage. Some simple electricity meters (such as electromechanical panel meters) stop operating when the power supply is interrupted and resume operation when power is restored. However, more complex electricity meters generate measurement results and billing data based on power measurements over longer periods, and the loss of power means the meter loses a significant amount of data. More sophisticated existing electricity meters use a form of uninterruptible power supply (UPS) with independent energy storage devices, such as batteries or large capacitors (sometimes called "supercapacitors"), which enables the meter to: maintain operation during short interruptions in the power flow through the power line; or, in the event of a longer interruption, transfer information stored in the meter's memory to an external monitoring system before the energy storage in the UPS is depleted.

[0006] While existing UPS implementations reduce the likelihood of data loss in electricity meters due to unexpected power loss, these devices increase the cost and complexity of the meters, while also increasing power consumption and potentially reducing reliability. In some cases, the possibility of battery or other component failure in the UPS can actually increase the likelihood of the meter failing to monitor power, which is counterproductive since the underlying reason for including a UPS is to improve meter reliability. Therefore, it would be beneficial to improve the meter to mitigate the impact of power loss without requiring existing UPS implementations. Summary of the Invention

[0007] In one embodiment, an electricity meter is configured to regenerate meter status data after a power loss has occurred. The electricity meter includes: a memory storing at least one volatile memory device and at least one non-volatile memory device; and a processor operatively connected to the memory. The processor is configured to: retrieve a backup copy of the meter status data from the at least one non-volatile memory device after the electricity meter resumes operation following a power loss; retrieve multiple meter input data samples from the at least one non-volatile memory device after the electricity meter resumes operation following a power loss, the multiple meter input data samples being associated with a time period after the backup copy of the meter status data is stored in the at least one non-volatile memory device and before the power loss; and regenerate the meter status data by updating the backup copy of the meter status data using the multiple meter input data samples, thereby regenerating the meter status data at the time of the final meter input data sample among the multiple meter input data samples before the power loss, the meter status data being stored in the at least one volatile memory device.

[0008] In another embodiment, a method for operating an electricity meter to regenerate meter status data after a power loss has occurred has been developed. The method includes: using a processor in the electricity meter to retrieve a backup copy of the meter status data from at least one non-volatile memory device in the electricity meter after the meter resumes operation following a power loss; using the processor to retrieve a first plurality of meter input data samples from the at least one non-volatile memory device after the meter resumes operation following a power loss, the first plurality of meter input data samples being associated with a time period after the backup copy of the meter status data is stored in the at least one non-volatile memory device and before the power loss; and using the processor to regenerate the meter status data by updating the backup copy of the meter status data using the first plurality of meter input data samples, thereby regenerating the meter status data at the time of the final meter input data sample in the first plurality of meter input data samples before the power loss, the meter status data being stored in at least one volatile memory device in the electricity meter. Attached Figure Description

[0009] The foregoing aspects and other features of the electricity meter are explained in the following description taken in conjunction with the accompanying drawings.

[0010] Figure 1This is a schematic diagram of an electricity meter configured to handle interruptions in service conditions without losing measurement data and without requiring an uninterruptible power supply.

[0011] Figure 2 It is used for operation Figure 1 A block diagram of the process for an electricity meter, which is used to handle interruptions in the operation of the electricity meter without the need for an uninterruptible power supply.

[0012] Figure 3 It describes in Figure 2 During the process Figure 1 A timeline of an example of the operation of an electricity meter.

[0013] Figure 4 It is a diagram depicting multiple electricity meters, including a main electricity meter that receives meter input data from one or more auxiliary electricity meters. Detailed Implementation

[0014] Reference has been made to the accompanying drawings to provide a general understanding of the environment and details of the device disclosed herein. In the drawings, similar reference numerals denote similar elements.

[0015] As used herein, the term "metrology circuit" refers to any suitable circuit that detects, measures, and determines one or more electrical and / or energy consumption values ​​based on the energy flowing between the terminals of an electricity meter, the terminals of which are connected in series (in-line) to a power line between a power source and a load receiving the power. In a common configuration, the mains or other power source is connected to one set of terminals, and the power-receiving load is connected to another set of terminals. The power in the power line flows through the electricity meter, and the metrology circuit measures various aspects of the electrical signal, including but not limited to voltage and current.

[0016] As used herein, the term "meter input data" refers to any digital information that a processor in an electricity meter receives from sensors in the meter, other devices within the meter, or from other electricity meters via a network device, and records it to a non-volatile memory device to maintain the meter input data record in the event of power loss. One form of meter input data is meter sensor data (also referred to as "sensor data"), which includes raw or processed information from current and voltage sensors, and optionally other sensors within the electricity meter. Another form of meter input data includes relay status information that records the status of one or more relays included in or connected to the electricity meter. Yet another form of meter input data includes meter input data received from other electricity meters connected via a data network, configured such that a single meter stores meter input data from multiple electricity meters.

[0017] As used herein, the term "meter status data" refers to status information generated by one or more processors in an electricity meter through further processing of one or more samples of meter input data recorded over time. Examples of meter status data include, for example, billing record data generated at least in part based on measured energy consumption levels determined based on meter sensor data and other meter input data. Other examples of meter status data include records of alarms and other events of interest recorded by the meter based on input data. In the illustrative embodiments described herein, meter status data is stored in a tabular data structure that includes fields for storing billing register data, including usage time data. Meter status data further includes: load profile interval data, primary and secondary loggers, daily maximum / minimum demand data, dial-out reasons, and internal data structures supporting the above data. In particular, dial-out reasons refer to alarms and other events of interest that the electricity meter has detected but has not yet transmitted to an external monitoring system using a modem or other data networking device.

[0018] Some electricity meter implementations optionally store meter status data in data tables conforming to the ANSI C12.19 standard. A non-limiting list of these tables according to the ANSI C12.19 standard includes: Table 23 – Current Register Data Table, Table 24 – Previous Quarter Data Table, Table 25 – Previous Demand Reset Data Table, Table 26 – Self-Read Data Table, Table 63 – Load Profile Status Table, Tables 64-67 – Load Profile Data Settings I / II / III / IV Tables, Table 74 – Historical Log Data Table, and Table 76 – Event Log Data Table. Although tables conforming to the ANSI C12.19 standard are described in conjunction with meter status data for illustrative purposes, electricity meters can store meter status data in an alternative format that does not require conformity to the ANSI C12.19 standard.

[0019] Figure 1 An electrical meter 100 is depicted, which includes a meter base 104 and a metering circuit 150. Although Figure 1 The meter base 104 and the metrology circuitry 150 are depicted as separate components, but in some embodiments, the meter base 104 and the metrology circuitry 150 are combined into a single printed circuit board or other substrate. Figure 1 The illustrative embodiment of the electricity meter 100 depicts the components necessary to implement the power loss recovery operation described herein, and does not necessarily depict every component of the electricity meter in more detail, and any omission of a particular electricity meter component from the specification is not exclusionary unless expressly stated herein.

[0020] In the electricity meter 100, the meter base 104 includes two terminals 108A and 108B connected together via a conductor 112. Terminals 108A and 108B extend from the housing of the electricity meter 100 to engage a socket formed in a power line 116, thereby placing the conductor 112 and the power line 116 in series. For illustrative purposes, Figure 1 The meter base 104 depicts a single power line 116 and a single terminal set 108A and 108B, but other electrical meter embodiments include additional terminal sets for monitoring multiple power lines, such as in a multiphase power line system. Although in Figure 1While not explicitly depicted, the meter base 104 may optionally include additional analog or digital sensor components that enable the components of the metrology circuitry 150 to monitor the flow of electrical power through the power line 116 and conductor 112. Examples of additional components incorporated into the meter base include, but are not limited to: induction coils and magnets used in various embodiments of the current sensor; resistors for a voltage divider used to measure the voltage level in the power line 116; and isolation elements to prevent high voltage or high current from affecting the components of the metrology circuitry 150.

[0021] In some embodiments, the meter base 104 or other structures within the meter include signal controls for operating an external relay (such as a solid-state or electromechanical relay) operable to connect and disconnect individual loads or load groups from conductor 112 and power line 116. This relay is used in power load shedding operations, in which some embodiments of the electricity meter 100 operate the relay to disconnect appliances and other energy-consuming devices individually connected to power line 116 via the relay, thereby reducing the overall level of power consumption during peak demand periods. Information regarding the relay status (open, to disconnect power to the load, or closed, to connect power to the load) is encoded as relay sensor data, which forms part of the meter input data in the electricity meter 100, and load shedding is otherwise well known in the art and will not be discussed further in detail herein.

[0022] Another use of relay sensor data in electricity meters refers to the KYZ pulse generated by the relay whenever the electricity meter measures a predetermined amount of electrical energy consumption (e.g., 1 pulse = 1 kWh consumption, although other configurations generate pulses for different amounts of energy). As is known in the art, when two relays (Y and Z) connected to the common line K are switched between opposite closed and open configurations (e.g., (Y...)...)... 断开的 →Y 闭合的 Z 闭合的 →Z 断开的 ) or (Y 闭合的 →Y 断开的 Z 断开的 →Z 闭合的The relays generate KYZ pulses. The relays perform alternating switching operations after the load has consumed a predetermined amount of energy, and the duration of the pulses from the closed relays indicates the amount of time it took for the load to consume that predetermined amount of energy. In the electricity meter 100, the duration of each pulse is approximately one second when the load draws the maximum expected power level, although instantaneous spikes in load power consumption may produce shorter pulses over short periods. Different embodiments of the electricity meter 100 record pulses corresponding to the relay states of the Y and Z relays as part of a process for recording meter input data, which supplements or replaces the data received from the DSP 158.

[0023] In the electricity meter 100, the metering circuit 150 includes: one or more electricity meter sensors 154, a digital signal processor (DSP) 158, one or more data output devices 162, a data input bus 164, an auxiliary meter network device 166, a relay sensor 168, a processor 180, a memory 182, and a power supply 192. Figure 1 The electricity meter sensor 154 in the embodiment includes at least one current sensor and a voltage sensor. The current sensor detects the current level in the power line 116, and the voltage sensor detects the voltage level in the power line 116 relative to a ground wire or another grounded reference. In the electricity meter 100, the electricity meter sensor 154 is coupled to a conductor 112 in the meter base 104 to sense the current and voltage levels flowing through the power line 116 and the conductor 112. The electricity meter sensor 154 may optionally include other sensors, including, for example, a zero-crossing sensor, an arc detection circuit, a temperature sensor, etc.

[0024] A DSP 158 in the metrology circuit 150 is connected to a meter sensor 154 and generates a set of data output elements based on sensor data at regular intervals. In some embodiments, the DSP 158 includes analog-to-digital circuitry that converts the analog sensor signal from the sensor 154 into a digital form for additional processing in the DSP 158 and processor 180. The DSP 158 receives sensor data from the meter sensor 154 at high rates (e.g., hundreds of hertz or thousands of hertz). The DSP 158 may optionally apply filters and other signal processing techniques to remove noise from the sensor data and generate a digitized sample of meter sensor data that integrates measurements of current and voltage signals over a predetermined time period (e.g., a one-second interval, although longer or shorter intervals may be used). Examples of meter sensor data generated by the DSP 158 include, but are not limited to, total current and voltage levels (including RMS current / voltage or IT). 2 / V2 Measurement results include voltage distortion measurements, volt-ampere (VA) measurements, phase angle measurements, measurements of the hourly energy consumption rate of the power line proportionally distributed over a one-second time interval, power factor ratio values, and other suitable meter sensor data. Different embodiments of the DSP 158 can also generate meter sensor data samples from other sensors in the electricity meter 100, including, for example, temperature sensors, magnetic sensors, and any other suitable sensor devices.

[0025] The data output device 162 in the metering circuit 150 is a device that provides output monitoring data generated in the electricity meter 100 to any one or both of an external monitoring system and a human-readable output device (such as a gauge, indicator light, display screen, and audible alarm) via a data transmission device. In one embodiment, the data output device 162 includes: a data transmission device, such as a modem, wireless transmitter, USB, or serial port; or a wired network adapter, such as an Ethernet or power line network, which transmits the collected meter data to an external computing device for storage and further analysis. In some embodiments, the external computing device is part of a grid monitoring system operated by an electricity utility. In another embodiment, the data output device 162 provides human-readable output at the location of the electricity meter 100. During operation of the electricity meter, the networked data output device 162 typically transmits meter status data at relatively long time intervals (such as hourly intervals) and optionally transmits meter input data to a remote monitoring system.

[0026] In the metering circuit 150, an input data bus 164 connects the DSP 158, the auxiliary metering network device 166, and the relay sensor 168 to the processor 180. For example, the input data bus 164 is a shared digital data bus implemented using a shared or point-to-point wired connection employing any suitable data exchange protocol that enables the processor 180 to receive metering input data from each of the DSP 158, the auxiliary metering network device 166, and the relay sensor 168. Specifically, the auxiliary metering network device 166 is a wired or wireless network data transceiver that optionally connects the electricity meter 100 to one or more additional electricity meters, enabling the electricity meter 100 to receive additional metering input data from other electricity meters (referred to as auxiliary meters). Some power monitoring systems use groups of multiple meters, where one meter in the group receives and records metering input data from the other meters in the group. In some embodiments, the network data transceiver implementing the auxiliary meter network device 166 also serves as the data output device 162, with one functional difference being that the auxiliary meter network device 166 communicates with other electricity meters, while the output device 162 communicates with an external monitoring system.

[0027] Relay sensor 168 detects the transition between open and closed states of relays (if any) in electricity meter 100 and generates meter input data for processor 180 indicating the transition between the open and closed states of a particular relay. For example, relay sensor 168 includes: electrical continuity circuitry that determines whether a relay is in an open or closed state; and output circuitry that transmits digital data to processor 180 to indicate the transition in the state of the relay, and, in embodiments of electricity meter 100 including more than one relay, identifies the relay. Processor 180 uses relay state information to monitor the open or closed state of relays that provide load shedding over time, and, in embodiments monitoring KYZ pulses, measures the energy usage of the load based on the duration of each pulse from the Y and Z relays. In some embodiments, processor 180 also controls load shedding relays, although in other embodiments, an external control device controls the state of the relays independently of processor 180. Electricity meter 100 includes separate control circuitry (not shown) that enables processor 180 to operate the relays to place each relay in an open or closed state during load shedding operations.

[0028] In the metrology circuit 150, the processor 180 is operatively connected to the DSP 158, the data output device 162, the auxiliary meter network device 166, the relay sensor 168, and the memory 182. The processor 180 in the metrology circuit 150 is a digital logic device, including, for example, one or more microprocessors, microcontrollers, field-programmable gate arrays (FPGAs), programmable logic controllers (PLCs), application-specific integrated circuits (ASICs), etc. The processor 180 also includes a real-time clock (RTC) that provides time data with sufficient accuracy and precision for accurately measuring the time of power consumption. This real-time clock, such as... Figure 1 The embodiment provides an accurate RTC accurate to one second. When properly synchronized with an external time source, the RTC enables the processor 180 to record the time of receiving various samples of meter input data, which is useful for many applications, including systems monitoring a large number of electricity meters in a power grid or other distributed system. Although Figure 1 The RTC is depicted as being integrated with the processor 180, but in alternative embodiments, the RTC is a separate device connected to the processor 180. Although Figure 1 The diagram depicts an electricity meter 100 in which the DSP 158 is a separate device from the processor 180; however, in some embodiments, the DSP 158 is integrated with the processor 180. In addition to the specific functions described herein, the processor 180 also implements metrological routines, display routines, and communication routines typically associated with the operation of the electricity meter.

[0029] In the electricity meter 100, the memory 182 includes at least one volatile memory device and at least one non-volatile memory device. The terms "volatile" and "non-volatile" are given their common meanings to those skilled in the art. More specifically, a volatile memory device is a memory device that reliably retains data only when power is provided and rapidly loses data in the event of power loss. Embodiments of volatile memory suitable for use in the electricity meter 100 include, but are not limited to, static and dynamic random access memory (SRAM and DRAM) devices. The volatile memory device also includes a memory cache incorporated into some embodiments of the processor 180. A non-volatile memory device uses power to read and write stored data, but can retain stored data for extended periods without power. Embodiments of non-volatile memory suitable for use in the electricity meter 100 include, but are not limited to, solid-state memory devices, including, for example, EEPROM, NAND and NOR flash memory, phase-change solid-state memory devices, and the like.

[0030] In memory 182, one or more non-volatile memory devices store stored software / firmware instruction code 184, a data buffer 186 for meter input data, and periodic backups 188 of two or more copies of meter status data. Processor 180 uses the stored software / firmware data 184 to perform operations in the electricity meter 100 and implement the functions described herein. As described in more detail below, processor 180 stores meter input data received from DSP 158, auxiliary meter network device 166, and relay sensor 168 in the non-volatile meter input data buffer 186 for a limited period of time (e.g., 30 minutes of sensor data samples) and periodically makes backups of meter status data in non-volatile memory 188 so that the electricity meter can recover from power loss with minimal data loss. Memory 182 also includes one or more volatile memory devices 190 that store and process meter sensor data received from DSP 158, meter input data from other sources, and meter status data.

[0031] In the electricity meter 100, the power supply 192 is a switched capacitor power supply or other suitable power supply connected to the power line 116 via conductor 112 and terminals 108A / 108B. The power supply 192 converts the alternating current (AC) signal in the power line 116 into a direct current (DC) output at one or more predetermined power supply voltage levels (e.g., 12V, 5V, 3.3V, etc.) to supply power to the meter sensor 154, DSP 158, data output device 162, processor 180, memory 182, and other components in the electricity meter 100 that consume DC power. While the electricity meter 100 measures AC power in the power line 116, another electricity meter embodiment measuring the DC power line employs a DC-to-DC power supply to convert the DC current in the power line into appropriate voltage and current levels for use in the electricity meter 100. In either embodiment, the power supply 192 supplies power to the components in the electricity meter only when power is available from the power line 116.

[0032] The electricity meter 100 does not require an uninterruptible power supply (UPS) to minimize the loss of measurement data and meter status data in the event of a power loss from power line 116. This power loss is typically caused by a power outage from the power source supplying power to power line 116, but can also occur due to a disconnection of the electricity meter 116 from power line 116, or due to a failure of power supply 192 or another component within the electricity meter 100. Instead, as described in more detail below, the electricity meter 100 is configured to store meter input data to non-volatile memory at a rate substantially the same as the rate at which input meter data samples are generated (e.g., once per second) to prevent any significant loss of recorded meter input data (e.g., greater than one second); and to regenerate the meter status data of the electricity meter using the recorded meter input data. Additionally, in the event of a power loss, the electricity meter 100 does not require a battery or capacitor to maintain the state of the real-time clock. Although electricity meter 100 does not require a UPS, another embodiment of electricity meter 100 can be configured to use a UPS without preventing the operation of the processes described herein that enable electricity meter 100 to recover from unexpected power loss. For example, another embodiment of an electricity meter including a UPS may still experience unexpected power loss due to a failure of a component in the UPS itself, and that electricity meter implements the structures and methods described herein to recover from unexpected power loss.

[0033] Figure 2 A process 200 for operating an electricity meter is described, which aims to reduce or eliminate data loss due to power loss events without the need for a UPS. In the following description, references to process 200 performing a function or action refer to a processor device executing stored program instructions to perform that function or action in conjunction with other components of the electricity meter. For illustrative purposes, [the following is a continuation of the previous sentence]. Figure 1 Meters 100 and Figure 3 The illustrative timeline 300 describes process 200.

[0034] During process 200, the electrical meter 100 receives meter input data at predetermined time intervals (e.g., one meter input data sample per second), and stores each sample of the meter input data in a non-volatile meter input data buffer 186 (box 204) at the same or similar time intervals as the time intervals at which the meter input data is received. Figure 1In the illustrative embodiment, meter sensor 154 generates current and voltage measurements corresponding to the current flowing between terminals 108A and 108B. Processor 180 receives the digitized meter sensor data from DSP 158 and, among other processing operations, stores the sensor data in a non-volatile meter input data buffer 186 with a latency as small as the actual latency given the hardware capabilities of a given electricity meter 100. In a practical embodiment of the electricity meter 100 using an embedded processor 180 and a solid-state non-volatile storage device, processor 108 can store each set of meter sensor data within 100 milliseconds of receiving data from DSP 158 or other meter input data via input bus 164. Since DSP 158 generates new samples of meter input data every second, processor 180 stores each new sample in the non-volatile memory buffer 186 at one-second intervals. Processor 180 uses RTC to generate an accurate timestamp for each sample of meter input data, and processor 180 stores the timestamp in association with the meter input data in a non-volatile meter input data buffer 186.

[0035] As described above, the meter input data also includes meter input data received from one or more additional meters from the auxiliary meter network device 166. Figure 4 An example of an electricity meter network is depicted, wherein electricity meter 100 is the primary electricity meter, which receives meter sensor data from three auxiliary meters 404A-404C and optionally receives other meter input data. Electricity meters 100 and 404A-404C communicate via channel 406, which may be, for example, a wired communication network or a wireless communication channel. In one embodiment, electricity meter 100 also receives meter input data from the auxiliary meters 404A-404C at one-second intervals to minimize the potential for data loss, which could occur in electricity meter 100 or in the event of power loss in one or more of the meters 404A-404C. Memory 182 includes a single instance of meter input data buffer 186 that stores meter input data received from each of the auxiliary meters 404A-404C, which transmit meter input data to electricity meter 100. For illustrative purposes, Figure 4 A total of four electricity meters are depicted, but other embodiments may include a different number of auxiliary meters. Additionally, electricity meter 100 may perform process 200 without receiving auxiliary meter input data from any other electricity meter.

[0036] exist Figure 1In one embodiment, the non-volatile meter input data buffer 186 is implemented as a ring buffer that stores a fixed number of samples of sensor data and other meter input data corresponding to a predetermined time period during the operation of the meter 100. In one configuration, the non-volatile meter input data buffer 186 stores meter input data for the most recent 30 minutes, which corresponds to 1800 samples given a sensor sample generation rate of one sample per second. After the data buffer 186 is full, the processor 180 overwrites the oldest entry in the data buffer to maintain a constant record of the sampled meter input data for the previous 30 minutes in the non-volatile memory device. Each meter input data sample stored in the meter input data buffer 186 is associated with a timestamp corresponding to the time when that meter input data sample was generated. In an embodiment of an electrical meter that receives meter input data from an auxiliary electrical meter via an auxiliary meter network device 166, the memory 182 includes an additional non-volatile meter input data buffer 186 for each of the auxiliary electrical meters that transmits meter input data to the electrical meter 100. The electrical meter 100 also uses a copy of the meter input data stored in volatile memory for additional processing to update the meter status data of the electrical meter 100 and for reporting via the data output interface 162.

[0037] During process 200, processor 180 also receives meter input data from relay sensor 168. In an embodiment of the electricity meter 100, processor 180 receives relay status data corresponding to the actual state (open or closed) of one or more external relays at one-second intervals as part of the meter input data. Additionally, in an embodiment using KYZ pulses, the relay data includes the states of the Y and Z relays in each sample of input meter data to track the pulse duration and the energy usage of the load over time. Processor 180 stores the relay status data along with other samples of meter input data in a non-volatile meter input data buffer 186.

[0038] During process 200, the electricity meter 100 also generates and continuously updates the meter status based on the meter input data, while periodically backing up the meter status data to non-volatile memory 188 at predetermined time intervals (block 208). As described above, the processor 180 generates and updates the meter status data based on multiple samples of meter input data recorded over time. For embodiments of the electricity meter 100 that records meter input data from one or more additional electricity meters via auxiliary meter network device 166, the processor 180 also generates meter status data comprising meter input data samples received from each monitored electricity meter to generate a single set of meter status data corresponding to the meter input data received from each monitored electricity meter. Figure 4 The total amount of meter input data received from all electricity meters in the network configuration. Meter status data typically occupies a much larger amount of memory (e.g., tens of thousands of bytes) compared to each sample of meter input data, which typically occupies only a few hundred bytes (e.g., 512 bytes) to a few thousand bytes of data. Therefore, in electricity meter 100, processor 180 typically stores meter status data in volatile RAM 190 during normal operation and stores backup copies of the meter status data in meter status backup data 188 at relatively long intervals to reduce the overall requirement for non-volatile memory. In one embodiment, meter 100 stores backups of meter status data at 15-minute intervals, and as described above, non-volatile meter input data buffer 186 stores the sensor data recorded in the most recent 30 minutes at much shorter one-second intervals, corresponding to the sampling rate of the meter input data.

[0039] Other meter embodiments may perform backups of meter status data to non-volatile memory at longer or shorter time intervals, and store meter input data in longer or shorter buffers. Generally, the electric meter stores meter input data in a meter input data buffer 186, which covers a longer time period than the time interval between meter status backups 188. For example, in a configuration that stores meter status data to non-volatile meter status data backup data 188 every 2 minutes, a meter input data buffer 186 storing 120 minutes of meter input data is used. Additionally, system 100 stores more than one copy of meter status data corresponding to two or more time intervals in the meter status data backup data 188. Figure 1In one embodiment, system 100 stores a total of thirty copies of meter status data (covering sixty minutes) at two-minute intervals in non-volatile meter status data backup data 188. In other embodiments, the non-volatile memory device stores at least two copies 188 of meter status data corresponding to two most recent time intervals to ensure that at least one valid backup copy 188 of the meter status data is stored in the non-volatile memory device. Storing at least two copies of the meter status data ensures that if a power loss occurs while the electricity meter 100 is in the process of writing a new backup copy 188 of the meter status data, at least one valid copy 188 of the previously stored meter status data is available, because a power loss typically corrupts meter status data that has not yet been fully written to the non-volatile memory device before the power loss. These examples employ a storage size for the meter input data buffer 186 that covers a time period at least twice the length of the time interval between backups 188 of the meter status data. This ensures that the meter input data buffer 186 can store sufficient meter input data to regenerate the meter status data during playback starting from the oldest valid backup copy of the meter status data, thereby regenerating the meter status after a power loss event. However, alternative embodiments may use a larger ratio between the time period stored in the meter input data buffer 186 and the time period between the meter status data and the backup storage of the non-volatile meter status backup 188.

[0040] like Figure 3 As depicted in the timing diagram 300, the operation of the electricity meter 100 to perform meter state backup 304 is shown, in which the processor 180 writes the meter state to the non-volatile meter state data backup 188. The electricity meter 100 continues to store additional backup meter input data to the non-volatile meter sensor buffer 186, as depicted in time region 308.

[0041] Refer again Figure 2Referring to the processes in boxes 204 and 208, the electricity meter 100 continues its operation as described above until a power loss occurs (box 212). In the scenario of process 200, a power loss occurs at an unexpected time, resulting in the loss of all data stored in the volatile memory of the electricity meter 100. The power loss prevents the operation of the processor 180 and other components in the electricity meter. Data in the volatile memory device 190 storing sensor data and meter status is lost after the power loss occurs, although the contents of the non-volatile device of memory 182 remain intact and are accessible after power is restored. In particular, the meter input data buffer 186 and the most recent backup 188 of the meter status data are stored in non-volatile memory and are available after power is restored.

[0042] After power is restored, the electricity meter 100 resumes monitoring the current flowing through the power line 116 (box 216). The meter sensor 154 generates sensor data, and the DSP 158 provides this data to the processor 180 within a relatively short period of power restoration (e.g., less than 10 seconds). Additionally, the processor 180 receives additional meter input data from the auxiliary meter network device 166 and the relay sensor 168 via the input bus 164. Combined with the sensor data stored in the meter input data buffer 186 and other meter input data, the electricity meter 100... Figure 1 In one embodiment, up to one second of recorded meter input data may be lost because meter 100 stores each sample of meter input data into the non-volatile meter input data buffer 186 within one second of generating the meter input data. Other embodiments that record and store meter input data at different intervals due to power loss may lose several seconds of recorded meter input data corresponding to different time periods, such as for an electrical meter that stores samples of meter input data at a lower rate than electrical meter 100. However, because the RTC resets upon power loss, electrical meter 100 cannot generate accurate timestamp information upon initial restart. In one embodiment, processor 180 generates relative timestamp information starting from a first meter data sample generated after electrical meter 100 restarts operation. This relative timestamp information has a data flag indicating that the meter input data sample was not stored with a normal timestamp. This relative timestamp is also referred to as a "placeholder" timestamp because processor 180 uses this placeholder timestamp until the RTC is resynchronized as described below. The processor 180 also stores the meter input data generated after the electricity meter 100 restarts operation in the meter input data buffer 186 in a manner similar to that described in reference box 204 above.

[0043] During process 200, the electricity meter 100 also regenerates the meter state immediately preceding the time of power loss when power to the meter is restored (box 220). To regenerate this meter state, the processor 180 first retrieves the most recent backup of the meter state from the non-volatile meter state data 188 back to the volatile memory 190. The processor 180 identifies the timestamp associated with the backup copy of the meter state and then regenerates the meter state at an earlier time (e.g., the time of power loss) in a “playback” operation. The retrieved meter input data samples form a time series that begins with a sample having a timestamp immediately following the backup of the meter state data and continues to the final sample of meter input data stored in the non-volatile buffer 186, which was stored in the non-volatile memory device before the power loss.

[0044] System 100 only replays previously stored meter input data to update the meter status if previously stored meter input data has been generated using a correctly synchronized RTC. In cases where system 100 experiences a power loss sequence with brief power recovery periods (during which a complete resynchronization of the RTC is not permitted), system 100 performs replay using the most recent copy of backup meter status data 188 and stored meter input data from buffer 186 (generated using a correctly synchronized RTC timestamp). In some embodiments, the electricity meter 100 applies a default billing rate (also referred to as the "Standby Rate") to samples of meter input data collected during brief operational periods between power losses (during which the electricity meter 100 cannot resynchronize the RTC) and calculates accurate billing information for these meter input data samples.

[0045] Processor 180 regenerates the meter status using the same sequence of operations used by processor 180 during normal operation to update the meter status. In one example, where a power loss occurs at 12:04:41, processor 180 retrieves the most recent backup 188 of the meter status data with a timestamp of 12:00:00. Processor 180 identifies the time of the power loss by searching meter input data buffer 186 to identify each record of stored meter input data, each record starting from 12:00:00 up to the most recently stored record immediately preceding the power loss at 12:04:41. Processor 180 uses each of the 281 meter input data records in meter input data buffer 186 to regenerate meter status data up to the time of the power loss event, these 281 meter input data records corresponding to one record per second within the 4:41 (281 seconds) elapsed from the most recent backup until the power loss. This playback process enables the electricity meter 100 to regenerate the same meter status data stored in the volatile memory 190 based on the meter input data most recently stored in the buffer 186 before the power loss, including energy usage and billing information generated by the electricity meter 100 up to the time of the power loss. Additionally, in embodiments of the electricity meter 100 that receives relay status data from a relay sensor 168 for external relays providing load shedding, the processor 180 regenerates the meter status data based on playback of a sample of meter input data in the non-volatile meter input data buffer 186 to ensure that the meter status accurately reflects the history of how long each relay has been open and closed at different time periods in the meter input data. The recorded history of the open or closed states of relays may affect the billing information in the regenerated meter status data for a specific load connected to different relays for different durations in a time-of-use billing configuration. In some embodiments, if a relay is in a different open / closed state after the power loss compared to its state before the power loss, the processor 180 also operates one or more relays to return the relay to its state before the power loss.

[0046] like Figure 3As depicted in the timing diagram 300, a power loss event is portrayed, which begins at time reference 312 when the power loss occurs and ends at time reference 316 when the power is restored. Once the power is restored, the electricity meter 100 resumes generating sensor measurement data and other input meter data with placeholder timestamps, as depicted in time region 320, and simultaneously performs a playback operation in time region 324 to regenerate the meter state based on the most recent meter state backup 304, the final meter input data sample stored in non-volatile memory up to immediately before the power loss. Specifically, the processor 180 can use all the backed-up meter input data samples 308 to perform the playback operation to regenerate the meter state data, thereby regenerating the state data of the electricity meter 100 immediately before the power loss at time 312. During the time period 320 prior to RTC synchronization at time 328, processor 180 uses placeholder timestamps to continue recording meter input data generated by DSP 158 after power recovery 316, as well as any other meter input data received via input bus 164.

[0047] In an embodiment of the electricity meter 100 that uses an auxiliary meter network device 166 to record meter input data from other electricity meters, the processor 180 also regenerates the meter state up to the time of the power loss event based on the meter input data, using the same process as described above from additional monitored electricity meters (such as...). Figure 4 The meter 100 receives the meter input data from the auxiliary meters (meters 404A-404C). Additionally, the meter 100 uses the auxiliary meter network device 166 to receive meter input data from the auxiliary meters after power loss, and the auxiliary meters either assign placeholder timestamps to the additional meter input data samples, or the processor 180 assigns placeholder timestamps before RTC resynchronization. In cases where the meter 100 loses power but one or more of the auxiliary meters 404A-404C do not lose power, the auxiliary meters that did not lose power can retransmit all meter input data generated during the power loss event to ensure that the meter 100 accurately regenerates the meter state for each auxiliary meter.

[0048] Refer again Figure 2During process 200, processor 180 continues to use placeholder timestamps for the meter input data until meter 100 completes the clock synchronization process of setting the RTC in processor 180 to the correct time (box 224). In meter 100, processor 180 receives clock synchronization data from an external time source. Examples of processes used to synchronize the RTC include, for example, Network Time Protocol (NTP), time synchronization messages used in SCADA system protocols (such as Distributed Network Protocol (DNP)), or the use of a radio receiver that can receive time synchronization signals from various transmission sources, including the National Radio Time Transmission Service, cellular telephone towers, navigation satellites including Global Positioning System (GPS) satellites, etc. In some embodiments, the source of the RTC synchronization data is another meter (e.g., Figure 4 In some embodiments, the auxiliary electricity meter (one of 404A-404C) has not experienced a power loss event, or has previously performed time synchronization operations after a power loss event. Some electricity meter embodiments also provide a manual interface for synchronizing the RTC.

[0049] exist Figure 2In the illustrative embodiment, processor 180 determines the duration of the power loss event based on the difference between the final timestamp of the meter input data generated before the power loss event and the calculated timestamp of a first sample of meter data after RTC resynchronization. As described above, electricity meter 100 stores each meter input data sample in association with a placeholder timestamp. During resynchronization, processor 180 calculates the actual time of the first placeholder timestamp based on the time elapsed from when electricity meter 100 resumes operation after the power loss until RTC resynchronization. For example, if electricity meter 100 resynchronizes RTC to time (13:20:00) after collecting 300 seconds of meter input data using placeholder timestamps, processor 180 calculates the power recovery time as 13:15:00 (300 seconds before the current time). Processor 180 identifies the duration of a power loss event based on the difference between the time of restart operation and the last valid timestamp of the meter input data sample associated with the power loss (e.g., a 600-second power loss event that begins immediately after 13:05:00 and lasts until 13:15:00). In cases where meter 100 experiences a series of power losses—where there are only brief operational periods between power losses during which RTC resynchronization is not possible—meter 100 measures the duration of the power loss event as the total time elapsed from before the first power loss until sufficient time has passed for power recovery to allow meter 100 to resynchronize the RTC. In addition to other meter status data, meter 100 also transmits the duration of the power loss event to an external monitoring system using data output device 162.

[0050] Process 200 continues with the processor 180 performing another playback procedure to update the meter status data (box 228) for the period after the electricity meter 100 restarts operation, based on the meter input data stored in the meter input data buffer 186, after power recovery following a power loss to meter 100. In meter 100, the processor 180 performs a second playback operation after the RTC has been resynchronized to ensure that the meter status is correctly updated to the current time using the correct timestamp information for each sample of the meter input data. A non-limiting example of a meter status update operation relying on the correct absolute time from the RTC is generating billing information based on meter input data in cases where electricity tariffs change between multiple tariff periods or other time periods within a single day. Processor 180 uses the synchronized RTC and placeholder timestamps in the meter input data to calculate the timestamp for each meter input data sample after power loss during the second playback process, based on the synchronized RTC and the relative placeholder timestamps of each meter input data sample. For example... Figure 3 As depicted, processor 180 uses additional meter input data 320 recorded by the meter after power recovery at time 316 to perform a second playback operation 332 following clock synchronization 328. After the second playback process, the electricity meter 100 has generated an updated meter state that has lost at most one second of recorded meter input data due to the power loss event. After the second playback process is completed, the electricity meter 100 restarts the operation described in reference boxes 204 and 208 above. This includes continuing to store additional meter input data with the correct RTC timestamp in non-volatile meter input data buffer 186, and storing backups of the meter state data in non-volatile meter state backup data 188 at predetermined intervals.

[0051] As described above, the embodiments described herein provide specific improvements to electricity meters, including a list of non-limiting improvements described below. One improvement is an embodiment of an electricity meter that reduces or eliminates the loss of meter input data and meter status data due to unexpected power loss. Another improvement is that the electricity meter reduces or eliminates the loss of meter input data and meter status data due to unexpected power loss without requiring the use of a UPS or other battery / capacitor energy storage device in the electricity meter. Yet another improvement includes the ability to operate the electricity meter 100 for extended periods without loss of recorded data fidelity due to a playback process that allows the electricity meter to regenerate the meter status based on meter input data recorded in non-volatile memory after the RTC clock is synchronized, and the electricity meter 100 can calculate the time value for each recorded sample of meter input data. As described above, in one embodiment, the non-volatile meter input data buffer 186 stores meter input data for an extended period (e.g., up to two hours before RTC resynchronization), while only losing up to one second of recorded meter input data due to power loss. Therefore, the electricity meter described herein operates with little or no loss of data fidelity and avoids operation in a less accurate "standby" mode even when the meter experiences a power loss event.

[0052] It will be appreciated that the above disclosure, along with variations or alternatives to other features and functions, can be desirablely combined into many other different systems, applications, or methods. Various alternatives, modifications, variations, or improvements that are not currently foreseen or anticipated by those skilled in the art can subsequently be made, and these are also intended to be covered by the appended claims.

Claims

1. A method for operating an electricity meter, comprising: After the power loss, the electricity meter resumes operation and before the electricity meter's clock is resynchronized; The processor in the electricity meter receives multiple meter input data samples; wherein the meter input data samples are generated by the electricity meter at a sample generation rate and include one or more of current data samples and voltage data samples. In response to receiving each meter input data sample, the meter input data sample is stored in a non-volatile memory device, and a placeholder timestamp is associated with the stored meter input data sample, wherein the placeholder timestamp indicates the time relative to the first of the plurality of meter input data samples received after the electricity meter resumes operation following a power loss. During clock resynchronization: The power recovery time is determined using the following methods: Determine the time associated with clock resynchronization; Determine the number of meter input data samples received after the electricity meter restarts operation following a power loss. as well as The power recovery time is determined based on the time associated with clock resynchronization, the number of meter input data samples received after the meter resumes operation following the power loss, and the sample generation rate for the meter input data samples. The duration of the power loss is determined by the difference between the power recovery time and the final timestamp of the meter input data sample associated with the power loss stored in the non-volatile memory device prior to the power loss. as well as A timestamp is associated with each stored meter input data sample, wherein the timestamp is based on the placeholder timestamp associated with the stored meter input data sample and the duration of power loss.

2. The method according to claim 1, further comprising: After the electricity meter restarts operation following a power loss and before the electricity meter's clock is resynchronized: Retrieve a backup copy of the meter status data from a non-volatile memory device, wherein the backup copy of the meter status data was stored prior to power loss based on a periodic backup schedule; Retrieve a second plurality of meter input data samples from a non-volatile memory device, wherein the second plurality of meter input data samples are stored after a backup copy of the meter status data is stored and before power loss; as well as The backup copy of the meter status data is updated using a second set of meter input data samples to generate updated meter status data, which corresponds to the time after the backup copy of the meter status data is stored in a non-volatile memory device and before power loss.

3. The method according to claim 2, further comprising: Retrieve the plurality of meter input data samples from a non-volatile memory device, including an associated timestamp for each of the plurality of meter input data samples; as well as The updated meter status data is updated using samples of the multiple meter input data received after the electricity meter resumes operation following a power loss, to generate meter status data corresponding to the time following clock resynchronization.

4. The method according to claim 1, further comprising: After the electricity meter restarts operation following a power loss: Receive multiple meter input data samples from the auxiliary electricity meter corresponding to the time of power loss; Retrieve a backup copy of the meter status data for the auxiliary electricity meter from a non-volatile memory device, wherein the backup copy of the meter status data was stored prior to power loss based on a periodic backup schedule; as well as The backup copy of the meter status data for the auxiliary electricity meter is updated using multiple meter input data samples from the auxiliary electricity meter to generate updated meter status data for the auxiliary electricity meter corresponding to the time following the power loss.

5. An electricity meter, comprising: Current sensor; Voltage sensor; The memory includes at least one volatile memory device and at least one non-volatile memory device; Clock, and A processor, operably connected to receive current data samples based on the output of a current sensor and voltage data samples based on the output of a voltage sensor, and to store and retrieve information from memory, the processor being configured to: Multiple meter input data samples are received over a first time interval, wherein the multiple meter input data samples include current data samples generated at a current sample generation rate and voltage data samples generated at a voltage sample generation rate. In response to receiving each meter input data sample: The meter input data sample is stored in the at least one non-volatile memory device, and a timestamp is associated with the stored meter input data sample. The meter input data sample is used to generate updated meter status data; as well as The updated meter status data is stored in the at least one volatile memory device; Periodically, backup copies of updated meter status data are stored in the at least one non-volatile memory device, wherein the meter input data samples stored in the at least one non-volatile memory device cover a longer period than the time between consecutive backup copies of the updated meter status data. In the event of power loss, the at least one non-volatile memory device stores at least a sample of meter input data and a backup copy of the updated meter status data associated with the period after a backup copy of the updated meter status data is stored in the at least one non-volatile memory device and before the power loss. After the electricity meter resumes operation following a power loss and before clock resynchronization, the processor is further configured to: The processor in the electricity meter receives input data samples from a second or more meters, and In response to receiving each of the second plurality of meter input data samples, the meter input data sample is stored in the at least one non-volatile memory device, and a placeholder timestamp is associated with the stored meter input data sample, wherein the placeholder timestamp indicates a time relative to the first of the second plurality of meter input data samples received after the electricity meter resumes operation following a power loss, and wherein, upon clock resynchronization, the processor is further configured to: Determine the power recovery time; The duration of the power loss is determined by the difference between the power recovery time and the final timestamp of the meter input data sample associated with the power loss stored in the at least one non-volatile memory device prior to the power loss. as well as The timestamp is associated with each of the stored meter input data samples in the second plurality of meter input data samples, wherein the timestamp is based on the placeholder timestamp associated with the stored meter input data sample and the duration of power loss.

6. The electricity meter according to claim 5, wherein the processor is further configured to: After the electricity meter restarts operation following a power loss: Retrieve a backup copy of the updated meter status data from the at least one non-volatile memory device; retrieve a sample of meter input data associated with the period after the backup copy of the updated meter status data was stored in the at least one non-volatile memory device and before the power loss; and The updated backup copy of the meter status data is further updated using a sample of meter input data associated with a period of time after the backup copy of the updated meter status data is stored in the at least one non-volatile memory device and before the power loss, to generate meter status data corresponding to the time after the backup copy of the meter status data is stored in the at least one non-volatile memory device and before the power loss.

7. The electricity meter according to claim 5, further comprising: A digital signal processor (DSP) is operatively connected to the output of a current sensor, the output of a voltage sensor, and the input of the processor, wherein the DSP generates samples of the plurality of meter input data based on the outputs of the current sensor and the voltage sensor.

8. The electricity meter of claim 5, wherein the processor is further configured to determine the power recovery time in such a manner as: Determine the time associated with clock resynchronization; The number of meter input data samples received after the meter resumes operation following a power loss is determined; and the power recovery time is determined based on the time associated with clock resynchronization, the number of meter input data samples received after the meter resumes operation following a power loss, the current sample generation rate, and the voltage sample generation rate.

9. The electricity meter according to claim 5, further comprising: A network device configured to receive meter input data from an auxiliary electricity meter external to the main electricity meter, wherein the processor is operatively connected to the network device and is further configured to: Use a network to receive at least one meter input data sample from an auxiliary electricity meter; Before power loss, at least one meter input data sample from the auxiliary electricity meter is stored in the at least one non-volatile memory device; Meter status data for the auxiliary electricity meter is generated using at least one meter input data sample from the auxiliary electricity meter. The meter status data for the auxiliary electricity meter is stored in the at least one volatile memory device; as well as A backup copy of the meter status data for the auxiliary electricity meter is periodically stored in the at least one non-volatile memory device.

10. The electricity meter of claim 5, wherein, in the event of power loss, the at least one non-volatile memory device further stores a sample of meter input data associated with a time period prior to the time when a backup copy of the updated meter status data was stored in the at least one non-volatile memory device.

11. A method for operating an electricity meter, comprising: The processor of the electricity meter receives multiple meter input data samples over a first time interval, wherein the multiple meter input data samples include current data samples generated at a current sample generation rate and voltage data samples generated at a voltage sample generation rate. Ah, it should receive a sample of input data from each meter: The meter input data sample is stored in the non-volatile memory device of the electric meter, and a timestamp is associated with the stored meter input data sample. Use a sample of recorded meter input data to generate updated meter status data, and The updated meter status data is stored in the volatile memory device of the electricity meter; as well as Periodically store backup copies of the updated meter status data in a non-volatile memory device, wherein the meter input data samples stored in the non-volatile memory device cover a longer period of time than the time between consecutive backup copies of the updated meter status data. In the event of power loss, the non-volatile memory device stores at least the meter input data sample and the backup copy of the updated meter status data associated with the period after the backup copy of the updated meter status data was stored in the non-volatile memory device and before the power loss. The power recovery time is determined by the following steps after the electricity meter restarts operation following a power loss and during the resynchronization of the electricity meter's clock: Determine the time associated with clock resynchronization; Determine the number of meter input data samples received after the electricity meter restarts operation following a power loss. as well as The power recovery time is determined based on the time associated with clock resynchronization, the number of meter input data samples received after the meter resumes operation following power loss, the current sample generation rate, and the voltage sample generation rate.

12. The method of claim 11, further comprising: After the electricity meter restarts operation following a power loss: Retrieve a backup copy of the updated meter status data from a non-volatile memory device; A sample of meter input data is retrieved from a non-volatile memory device and associated with the period after a backup copy of the updated meter status data is stored in the non-volatile memory device and before the power loss. as well as The updated backup copy of the meter status data is further updated using a sample of meter input data associated with the time period after the backup copy of the updated meter status data was stored in the non-volatile memory device and before the power loss, to generate meter status data corresponding to the time period after the backup copy of the meter status data was stored in the non-volatile memory device and before the power loss.

13. The method of claim 11, further comprising: After the electricity meter restarts operation following a power loss and before the electricity meter's clock is resynchronized: The processor in the electricity meter receives input data samples from a second or more meters. as well as In response to receiving each of the second plurality of meter input data samples, the meter input data sample is stored in a non-volatile memory device, and a placeholder timestamp is associated with the stored meter input data sample, wherein the placeholder timestamp indicates the time relative to the first of the second plurality of meter input data samples received after the electricity meter has resumed operation following a power loss.

14. The method of claim 11, further comprising: In the event of power loss, the non-volatile memory device further stores a sample of meter input data associated with a time period prior to when a backup copy of the updated meter status data was stored in the non-volatile memory device.

15. The method of claim 13, further comprising: The duration of the power loss is determined using the difference between the power recovery time and the final timestamp of the meter input data sample associated with the power loss stored in the non-volatile memory device prior to the power loss. The timestamp is associated with each of the stored meter input data samples in the second plurality of meter input data samples, wherein the timestamp is based on the placeholder timestamp associated with the stored meter input data sample and the duration of power loss.

16. The method of claim 11, further comprising: A network device configured to receive meter input data from an auxiliary electricity meter external to the main electricity meter, wherein the processor is operatively connected to the network device and is further configured to: Use a network to receive at least one meter input data sample from an auxiliary electricity meter; Before power loss, at least one meter input data sample from the auxiliary electricity meter is stored in a non-volatile memory device; Meter status data for the auxiliary electricity meter is generated using at least one meter input data sample from the auxiliary electricity meter. The meter status data for auxiliary electricity meters is stored in a volatile memory device; as well as Periodically store backup copies of meter status data for auxiliary electricity meters in a non-volatile memory device.

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