Electric meter with service break switch

Abstract

An electricity meter includes: an actuator coupled to a switch, the actuator configured to output a switching signal to the switch; and a processor arranged to output a control signal to the actuator to cause the output of the switching signal; wherein the processor is configured to: determine a switching state of the switch to be changed; use a switch characterization tool to determine an estimated switching time period between (i) the output of the control signal and (ii) the change of the switching state; monitor a waveform; determine an output time for the control signal such that the switching state changes when the waveform reaches a target point; output the control signal to the actuator at the output time; monitor a load-side waveform to detect the actual switching time period; and modify the switch characterization tool based on the actual switching time period.

Description

Technical Field

[0001] This disclosure pertains to the field of electricity meters for measuring electricity consumption, such as those used in residential and commercial settings. In particular, this disclosure relates to electricity meters with a service disconnect switch. Background Technology

[0002] An electricity meter (also known in the art as a power meter, electricity meter or electrical instrument) is a device that measures the electrical power consumed by one or more electrical devices over a time interval, such as in a residential or commercial setting.

[0003] Electricity meters are typically installed in homes for billing and monitoring consumption. In some examples, the meter can be read manually and periodically to determine the level of electricity consumption. In other examples, advanced meters, referred to in the art as "smart meters," can be configured to communicate (e.g., wirelessly) with utility providers to provide electricity consumption information and / or receive billing information and / or control signals.

[0004] Electricity, such as electrical power, can be delivered to homes through a range of available service types, such as: single-phase three-wire commonly used in US residential homes; three-phase four-wire Y-connected commonly used in US commercial homes; and three-phase three-wire delta-connected commonly used in US industrial facilities. Different service types have associated meter configurations, such as 2S, 3S, 5S, etc., as are known in the art and are described in further detail below.

[0005] One technique for automatic or remote power service disconnection is to use a service disconnect switching device within the meter. A service disconnect switch is a relay or other switching device between the load side and the grid side of the meter, used to selectively disconnect the power supply from the grid side to the load side.

[0006] The load side of an electricity meter can refer to the connection between the meter and the power-consuming load. The grid side of an electricity meter can refer to the connection between the meter and the power line from the utility provider (e.g., from the power grid).

[0007] In some cases, the service disconnect switch is tripped by a remote device that communicates with the meter circuit via a modem, radio, or other means. Alternatively, for example, in prepaid situations, the meter itself can be programmed to disconnect and reconnect electrical service under certain circumstances. In some cases, the meter can disconnect and restore electrical service through a combination of local programming and remote commands. Summary of the Invention

[0008] To reduce wear and tearing of the switch contacts in servicing circuit breakers, it is desirable to make or break the mechanical contact of the switch contacts when the electrical power to be switched (e.g., AC power such as AC voltage and / or AC current) is not at its peak, thereby at least reducing or even preventing arcing. The randomness of servicing disconnection operations results in a flat distribution of the probability of the switch operating and the likelihood and severity of arcing that may occur during actuation. Arcing discharge leads to wear of the circuit breaker contacts during maintenance.

[0009] Known electricity meters use service disconnect switches with at least two contacts per phase to provide redundancy due to wear. The inventors have determined that having these multiple contacts increases the complexity of meter assembly and increases the size of the meter.

[0010] According to one aspect of this disclosure, an electricity meter is provided, comprising: a grid-side input terminal and a load-side output terminal; and a switch coupled between the grid-side input terminal and the load-side output terminal.

[0011] An actuator coupled to the switch, the actuator being configured to output a switching signal to the switch to change the switching state of the switch; and a processor arranged to output a control signal to the actuator to cause the output of the switching signal; wherein the processor is configured to: determine at a predetermined time that the switching state of the switch is to be changed; and, using a switch characterization tool, determine an estimated switching time interval between (i) the processor outputting the control signal to the actuator and (ii) the change in the switching state of the switch;

[0012] Monitor the waveform of the meter; determine the output time of the output control signal based on the waveform and the estimated switching time period, such that the switching state of the switch will change when the waveform reaches the target point; output the control signal to the actuator at the output time so that the switching signal is output from the actuator to the switch; monitor at least one load-side waveform of the meter on the connection between the switch and the load-side output terminal to detect the actual switching time period between (i) the output of the control signal and (ii) the change in the switching state of the switch; and modify the switch characterization tool based on the actual switching time period.

[0013] In embodiments of this disclosure, the processor monitors and then characterizes the actuator's operation over time, and then adjusts the timing of the output of a control signal for changing the switching state of the switch to ensure that the switching state of the switch changes when the waveform reaches a target point. The target point may be a point that will reduce or eliminate contact wear due to proper timing (i.e., will reduce the amount or severity of arcing observed during switching operation). For example, embodiments of this disclosure may advantageously avoid changing the switching state of the switch when the AC power (such as AC voltage and / or AC current) is at its peak, instead ensuring that the switching state of the switch changes at or near a zero-crossing of the waveform.

[0014] Reduced wear means that the thickness of the contacts in each service circuit breaker can be reduced, or one or more service circuit breaker contacts used in known meters can be eliminated entirely (because there is no need for redundancy of multiple contacts in each service circuit breaker). This advantageously leads to reduced complexity in meter assembly and a smaller meter size.

[0015] Known methods for mitigating the aforementioned arcing involve using a material (e.g., a silver-cadmium alloy) on the contacts of the service circuit breaker to protect the service circuit breaker from arcing damage for its required lifespan. Damage to the service circuit breaker is reduced by controlling the switch to change its switching state when the waveform reaches a target point, thereby allowing for the reduction (or elimination) of this material or its replacement with a different material.

[0016] The waveform of the meter can be the grid-side waveform present on the connection between the grid-side input terminal and the switch.

[0017] The processor can be configured to monitor the grid-side waveform of the meter when the switch is closed. The grid-side waveform can be either a grid-side voltage waveform or a grid-side current waveform.

[0018] The grid-side waveform can be the grid-side voltage, and the processor can be configured to monitor the grid-side waveform of the meter when the switch is in the open state.

[0019] The waveform of the meter can be a load-side waveform present on the connection between the switch and the load-side output terminal. The load-side waveform can be a load-side voltage waveform or a load-side current waveform.

[0020] At least one load-side waveform of the meter may include one or both of the load-side voltage waveform and the load-side current waveform.

[0021] Actuators can include electric motors. Compared to other technologies such as relays and solenoids, electric motors are advantageously more reliable and less susceptible to tampering.

[0022] Actuators may include solenoids and / or relays. Solenoids and relays advantageously offer more repeatable operation than motors, but delays still exist associated with these circuits because they are electromechanical.

[0023] The processor can be configured to use the temperature associated with the switch at the determined time to determine the estimated switching time period.

[0024] The processor can be configured to use the lifespan of the switch to determine the estimated switching time period.

[0025] The processor can be configured to determine the estimated switching time period using the number of switch actuations performed by the switch.

[0026] In some embodiments, the switch representation tool is a lookup table. In other embodiments, the switch representation tool is an equation. In still other embodiments, the switch representation tool is a machine learning model.

[0027] The target point can be the zero-crossing point of the waveform.

[0028] According to another aspect of this disclosure, a method of operating an electricity meter is provided, the method comprising: determining at a predetermined time that a switching state of a switch of the electricity meter is to be changed, the switch being coupled between a grid-side input terminal and a load-side output terminal of the electricity meter; using a switch characterization tool to determine an estimated switching time interval between (i) outputting a control signal to an actuator coupled to the switch and (ii) the change in the switching state of the switch; monitoring a waveform of the electricity meter; determining, based on the waveform and the estimated switching time interval, an output time of the output control signal such that the switching state of the switch will change when the waveform reaches a target point; outputting the control signal to the actuator at the output time to cause a switching signal to be output from the actuator to the switch; monitoring at least one load-side waveform of the electricity meter on the connection between the switch and the load-side output terminal to detect an actual switching time interval between (i) the output of the control signal and (ii) the change in the switching state of the switch; and modifying the switch characterization tool based on the actual switching time interval.

[0029] According to another aspect of this disclosure, a non-transient computer-readable storage medium is provided, comprising instructions for operating an electricity meter, which, when executed by a processor of the electricity meter, cause the processor to: determine at a predetermined time that a switching state of a switch of the electricity meter is to be changed, the switch being coupled between a grid-side input terminal and a load-side output terminal of the electricity meter; use a switch characterization tool to determine an estimated switching time interval between (i) outputting a control signal to an actuator coupled to the switch and (ii) the change in the switching state of the switch; monitor a waveform of the electricity meter; determine, based on the waveform and the estimated switching time interval, an output time of the output control signal such that the switching state of the switch will change when the waveform reaches a target point; output the control signal to the actuator at the output time to cause a switching signal to be output from the actuator to the switch; monitor at least one load-side waveform of the electricity meter on the connection between the switch and the load-side output terminal to detect the actual switching time interval between (i) the output of the control signal and (ii) the change in the switching state of the switch; and modify the switch characterization tool based on the actual switching time interval.

[0030] The specification may be provided on one or more carriers. For example, one or more non-transient memories may be present, such as random access memory (RAM), read-only memory (ROM), optical disk, flash memory, hard disk storage, and other memory devices that can use magnetic, optical, and other technologies to store instructions and other data. The memory / multiple memories may be integrated into and / or separated from the corresponding processing chip. The code (and / or data) used to implement embodiments of this disclosure may include source, object, or executable code in a conventional programming language (interpreted or compiled) such as C, or assembly code, code for setting up or controlling an ASIC (Application-Specific Integrated Circuit) or FPGA (Field-Programmable Gate Array), or code for a hardware description language.

[0031] The above description of the invention is intended to be exemplary only and not restrictive. This disclosure includes one or more corresponding aspects, embodiments, or features, individually or in various combinations, whether specifically stated (including claimed) in such combination or individually. It should be understood that features defined above according to any aspect of this disclosure or features hereinafter relating to any particular embodiment of this disclosure may be used alone or in combination with any other defined features for any other aspect or embodiment or to form another aspect or embodiment of this disclosure. Attached Figure Description

[0032] These and other aspects of this disclosure will now be described by way of example only with reference to the accompanying drawings, in which:

[0033] Figure 1 A block diagram of a prior art electricity meter connected in series with a load, having a 2S form, is depicted.

[0034] Figure 2 Another example of a conventional electricity meter is depicted;

[0035] Figure 3 The multiple contacts used in the service disconnect switch are depicted;

[0036] Figure 4 An electricity meter according to an embodiment of the present disclosure is depicted;

[0037] Figure 5 A flowchart depicts a method for generating switch characterization tools; and

[0038] Figure 6 A flowchart depicts the methods for using and modifying switch characterization tools. Detailed Implementation

[0039] Figure 1 A block diagram of a prior art electricity meter 100 is depicted. For illustrative purposes, the prior art electricity meter 100 is configured as a Form 2S service type meter, which is a meter configured for use with single-phase three-wire service.

[0040] In the prior art, the electricity meter 100 is installed in series with the load 105. For the purpose of illustrating a residential load, the load 105 is depicted as a house.

[0041] In use, the high-voltage power line 110 can provide power from the grid (i.e., from the utility company). The transformer 115 can reduce the voltage on the power line 110 to a voltage suitable for the load 105, such as 240 volts or 110 volts.

[0042] In the example meter 100, a first input terminal 120a is connected to a power supply voltage from a transformer 115 having a first phase, and a second input terminal 120c is connected to a power supply voltage from a transformer 115 having a second phase. The second phase is out of phase with the first phase. For example, the second phase can be reversed, for example, 180 degrees out of phase with the first phase. The first input terminal 120a may be referred to in the art as the "A-phase" input. The second input terminal 120c may be referred to in the art as the "C-phase" input.

[0043] The first output terminal 140a and the second output terminal 140c are connected to the load 105, and thus power can be supplied to the load 105.

[0044] Example meter 100 includes a first actuated switch S1 and a second actuated switch S2. The first actuated switch S1 can selectively disconnect / connect the first input terminal 120a on the grid side to the first output terminal 140a on the load side. The second actuated switch S2 can selectively disconnect / connect the second input terminal 120c on the grid side to the second output terminal 140c on the load side.

[0045] In use, the first actuated switch S1 and the second actuated switch S2 can be collectively referred to as "service disconnect switches" and can be configured to selectively connect / disconnect the load side and the grid side of the meter 100. That is, the first actuated switch S1 can selectively couple the first input terminal 120a to the first output terminal 140a, and the second actuated switch S2 can selectively couple the second input terminal 120c to the second output terminal 140c.

[0046] An exemplary electricity meter 100 includes a measuring circuit 130. The measuring circuit 130 includes an analog front end, in Figure 1 The term "AFE" is used here. Measurement circuitry 130, particularly the AFE, may include an analog-to-digital converter, an anti-aliasing filter, etc. The analog front end may be communicatively coupled to control circuitry and / or processing circuitry (not shown). The analog front end may be configured to perform analog measurements of grid-side voltage and / or load-side voltage and / or current, and to convert such measurements into digital signals for transmission to the control circuitry, as further described below.

[0047] The input voltage level at the first input terminal 120a of “A phase”, for example on the grid side of the first startable switch S1, can be measured by the measuring circuit 130, for example by sensing the voltage at a series of resistors (not shown) coupled to the first node 135a of the first input terminal 120a.

[0048] The input voltage level at the second input terminal 120c of “C phase”, for example on the grid side of the second actuable switch S2, can be measured by the measuring circuit 130, for example by sensing the voltage at a series of resistors (not shown) coupled to the second node 135c of the second input terminal 120c.

[0049] The output voltage level at the first output terminal 140a of “A phase”, for example on the load side of the first actuable switch S1, can be measured by the measuring circuit 130, for example by sensing the voltage at a series of resistors (not shown) coupled to the third node 145a of the first output terminal 140a.

[0050] The output voltage level at the second output terminal 140c of “C phase”, for example on the load side of the second actuable switch S2, can be measured by the measuring circuit 130, for example by sensing the voltage at a series of resistors (not shown) coupled to the fourth node 145c of the second output terminal 140c.

[0051] The meter 100 also includes a first current transformer 150a for providing a signal to the measuring circuit 130 corresponding to the “A-phase” current on the load side of the first startable switch S1.

[0052] The meter 100 also includes a second current transformer 150c for providing a signal to the measuring circuit 130 corresponding to the C-phase current at the load side of the second actuable switch S2.

[0053] Figure 2 A more detailed example of a prior art electricity meter 200 is depicted, typically corresponding to Figure 1 The Form 2S meter 100 is shown, but specific components of the meter 200 are shown in more detail.

[0054] In the prior art, the electricity meter 200 is installed in series between the power grid 215 and the load 205.

[0055] In the example meter 200, a first input terminal 220a is connected to a supply voltage with a first phase from the power grid 215, and a second input terminal 220c is connected to a supply voltage with a second phase from the power grid 215, wherein the second phase is out of phase with the first phase.

[0056] The first input terminal 220a and the second input terminal 220c can be set at the service entrance of the meter 200.

[0057] The first input terminal 220a may be referred to in the art as the "A-phase" input. The second input terminal 220c may be referred to in the art as the "C-phase" input.

[0058] The first output terminal 240a and the second output terminal 240c are connected to the load 205, and thus power can be supplied to the load 205.

[0059] Example meter 200 includes a service disconnect switch 295, which can selectively disconnect / connect the power grid 215 to the load 205.

[0060] The meter 200 includes an actuator 265, which may include, for example, a solenoid for actuating the service disconnect switch 295.

[0061] An exemplary electricity meter 200 includes measurement circuitry 230. Measurement circuitry 230 includes an analog front-end 270. Measurement circuitry 230, particularly analog front-end 270, may include an analog-to-digital converter, anti-aliasing filters, etc. In this example, analog front-end 270 is communicatively coupled to digital circuitry 275. Analog front-end 270 can be configured to perform analog measurements of grid-side voltage and load-side voltage and current, and convert such measurements into digital signals for processing by digital circuitry 275. In some examples, data corresponding to the processed measurement results can be transmitted via digital circuitry 275 to a remote device, such as another meter in a mesh network; digital circuitry 275 may include communication circuitry such as a transceiver.

[0062] A grid voltage sensing circuit 280G, denoted as V_SENSEGRID, is configured to determine the voltage at each of the first input terminal 220a and the second input terminal 220c, thereby providing a grid-side voltage measurement. The grid voltage sensing circuit 280G can be implemented using a relatively expensive resistor string (not shown), which will be referenced below. Figure 3 To describe in more detail. This expensive resistor string can tolerate considerable voltage spikes and current surges, such as those that may occur due to lightning strikes. Such a resistor string can substantially reduce the overall cost of manufacturing the meter 200. The grid voltage sensing circuit 280G is coupled to the analog front end 270, enabling the measurement of the grid-side voltage.

[0063] Similar to Figure 1 The meters 100 and 200 also include a load voltage sensing circuit 280L, denoted as V_SENSELOAD, for sensing the voltage across the load 205 on the load side of the service disconnect switch 295. The load voltage sensing circuit 280L is also coupled to an analog front end 270, enabling the measurement of the load-side voltage. The load voltage sensing circuit 280L can also implement a relatively expensive resistor string.

[0064] A first current sensing circuit 290a (denoted as I_SENSEPHASE_A) can be used to measure the current flowing from the first input terminal 220a to the load 205 to determine the power consumption of the load 205. The first current sensing circuit 290a may include a current transformer. The first current sensing circuit 290a is coupled to a measurement circuit 230, for example, coupled to one or more ADC channels of the analog front end 270.

[0065] A second current sensing circuit 290c (denoted as I_SENSEPHASE_A) can be used to measure the current flowing from the second input terminal 220c to the load 205 to determine the power consumption of the load 205. The second current sensing circuit 290c may include a current transformer. The second current sensing circuit 290c is coupled to the measurement circuit 230, for example, to one or more ADC channels of the analog front end 270.

[0066] The meter 200 includes a power supply 260. The power supply 260 receives power from the power grid 215 via a first input terminal 220a and a second input terminal 220c. The power supply 260 provides power to components of the meter 200. In this example, the power supply 260 provides power to the actuator 265. The power supply 260 also provides power to the measuring circuit 230. In this example, the power supply 260 may include at least one rectifier and / or regulator circuit configured to supply power to the measuring circuit 230 and the actuator 265. For example, the power supply 260 may include a rectifier, such as a bridge rectifier, configured to provide a DC output from an AC input at the input of the power supply 260. The power supply 260 may include one or more regulators configured to provide a voltage range suitable for the operation of different components of the smart meter. As an example, power supply 260 can be configured to provide 24 volts DC power to actuator 265, 5 volts DC power to analog front end 270, and 3.3 volts DC power to microprocessor circuitry within digital circuitry 275.

[0067] Figure 3 A portion of a service disconnect switch 295 comprising multiple contacts is depicted. Specifically, the service disconnect switch 295 is shown as having two contacts 296a, 296b per phase (which may be made of silver and / or other suitable materials) to provide redundancy due to the aforementioned wear. In other examples, three contacts per phase may be implemented in the service disconnect switch 295. As will be described in more detail below, embodiments of this disclosure are able to eliminate the need for providing multiple contacts in the service disconnect switch 295 and / or reduce the thickness of the contacts used in the service disconnect switch 295.

[0068] Figure 4 An electricity meter 400 according to an embodiment of the present disclosure is depicted. The electricity meter 400 includes components of the electricity meter 200, and therefore corresponding reference numerals are used where appropriate. For clarity, reference numerals have been drawn from... Figure 4 Some features (such as power supply 260) have been omitted.

[0069] like Figure 4As shown, meter 400 includes processor 402 coupled to memory 403. Processor 402 may correspond to a microprocessor within the digital circuitry 275 mentioned above. The functionality of processor 402 described herein can be implemented using code (software or firmware) stored in memory (e.g., memory 403) comprising one or more storage media, and arranged to execute on a processor comprising one or more processing units. The storage media may be integrated into and / or separate from processor 402. The code is configured to perform operations consistent with the embodiments discussed herein when retrieved from memory and executed on the processor. Alternatively, it is not excluded that some or all of the functionality of processor 402 may be implemented in dedicated hardware circuitry or configurable hardware circuitry (such as an FPGA).

[0070] Processor 402 is coupled to memory 403 so that processor 402 can store data in memory 403 and retrieve data from memory 403.

[0071] The processor 402 is also coupled to a temperature sensor 404. The temperature sensor 404 is configured to sense the temperature in the environment surrounding the meter 400, and thus the temperature in the environment surrounding the service disconnect switch 295a and service disconnect switch 295b. The temperature sensor 404 is configured to output a temperature signal to the processor 402, indicating the temperature in the environment surrounding the meter 400.

[0072] like Figure 4 As shown, a service disconnect switch 295a is provided on the connection between the first input terminal 220a and the first output terminal 240a, and a service disconnect switch 295b is provided on the connection between the second input terminal 220c and the second output terminal 240c.

[0073] Processor 402 is coupled to actuator 265. Actuator is coupled to both service disconnect switches 295a and 295b.

[0074] exist Figure 4In the example, processor 402 is configured to output a first control signal to actuator 265 at connection 406 between processor 402 and actuator 265. Actuator 265 is configured to output a switching signal at connection 408 between actuator 265 and service disconnect switch 295a according to the value of the first control signal, to change the switching state of service disconnect switch 295a. Furthermore, processor 402 is configured to output a second control signal to actuator 265 at connection 410 between processor 402 and actuator 265. Actuator 265 is configured to output a switching signal at connection 412 between actuator 265 and service disconnect switch 295b according to the value of the second control signal, to change the switching state of service disconnect switch 295b. Although two separate connections 406, 410 are shown between processor 402 and actuator 265, it should be understood that this is merely an example, and a single connection may exist between processor 402 and actuator 265. Actuator 265 can be configured to convert a low-power control signal received from processor 402 into a high-power control signal to control service disconnect switches 295a and 295b.

[0075] Actuator 265 may include an electric motor. It should be understood that temperature affects the operation of the electric motor. Optionally, actuator 265 may include a gearbox coupled to the electric motor. The gearbox contains grease (or other lubricant), which will have different coefficients of friction (viscosity) based on temperature. Motor actuation may take tens of milliseconds and is unpredictable due to temperature variations and other factors, including mechanical variations such as friction, lubricant viscosity, etc. Therefore, the timing of the processor 402 outputting control signals to actuator 265 when the monitored waveform reaches a target point (causing a change in the switching state of the switch) cannot be simply encoded into the firmware / software running on processor 402.

[0076] Actuator 265 may include a solenoid or a relay. It should be understood that temperature affects the operation of both the solenoid and the relay.

[0077] The processor 402 can be coupled to the analog front end 270.

[0078] The electricity meter 400 includes a mains voltage sensing circuit 280G ( Figure 4(Not shown in the diagram) to determine the voltage on each of the first input terminal 220a and the second input terminal 220c. A mains voltage sensing circuit 280G, configured to output the measured voltage on each of the first input terminal 220a and the second input terminal 220c, is shown as "line-side voltage sensing". A processor 402 is arranged to receive the measured voltage on each of the first and second input terminals 220a, 220c from the mains voltage sensing circuit 280G or from an AFE 270 (in an embodiment where the processor 402 is coupled to an AFE 270).

[0079] The meter 400 includes a first current sensing circuit 290a ( Figure 4 (Not shown in the diagram) is used to measure the "A-phase" current flowing from the first input 220a to the load 205. A first current sensing circuit 290a is configured to output the measured "A-phase" current, illustrated as "A-phase current sensing". A processor 402 is arranged to receive the measured "A-phase" current from the first current sensing circuit 290a or from the AFE 270 (in an embodiment where the processor 402 is coupled to the AFE 270).

[0080] The meter 400 includes a second current sensing circuit 290c ( Figure 4 (Not shown in the diagram) is used to measure the "C-phase" current flowing from the second input 220c to the load 205. A second current sensing circuit 290c is configured to output the measured "C-phase" current, illustrated as "C-phase current sensing". A processor 402 is arranged to receive the measured "C-phase" current from the second current sensing circuit 290c or from the AFE 270 (in an embodiment where the processor 402 is coupled to the AFE 270).

[0081] The electricity meter 400 includes a load voltage sensing circuit 280L ( Figure 4 (Not shown in the diagram) for sensing the voltage across load 205 on the load side of service disconnect switches 295a and 295b. Load voltage sensing circuit 280L is configured to output the measured voltage on the load side of service disconnect switches 295a and 295b. Processor 402 is arranged to receive the measured voltage on the load side of service disconnect switches 295a and 295b from load voltage sensing circuit 280L or from AFE 270 (in embodiments where processor 402 is coupled to AFE 270).

[0082] In embodiments of this disclosure, processor 402 uses a switch characterization tool to determine an estimated switching time period between (i) the processor 402 outputting a control signal to actuator 265 and (ii) a change in the switching state of service disconnect switch 295. Processor 402 then adjusts the timing of its control signal output to actuator 265 (to control the switching state of service disconnect switch 295) to attempt to change the switching state of the switch when the monitored waveform reaches a target point. Processor 402 monitors at least one load-side waveform to determine the actual switching time period, such that each switch operation provides additional data to update the switch characterization tool to further refine the estimation of the switching time period (and optionally also determine which variables are most critical for a given situation).

[0083] An initial switch characterization tool can be pre-stored in memory 403 during the manufacturing of meter 400 for access by processor 402. For example, the initial switch characterization tool can be seeded during manufacturing based on characterization data (and possibly field data). The characterization data used to seed the initial switch characterization tool can come from a collection of meters being characterized. The initial switch characterization tool will be converted from general to specific to the actual meter 400 based on actual meter characteristics. Opening and closing of service disconnect switch 295 can be performed during manufacturing to provide first device-specific data for the switch characterization tool. The initial switch characterization tool pre-stored in memory 403 can be a lookup table (LUT), equation, or machine learning model.

[0084] Alternatively, the initial switch characterization tool can be generated by processor 402. In both examples, processor 402 is configured to update the switch characterization tool over time.

[0085] Figure 5 A flowchart of a method 500 for generating switch characterization tools is shown.

[0086] In step S502, processor 402 determines that the switching state of service disconnect switch 295 needs to be changed. Processor 402 can determine that the switching state of service disconnect switch 295 will change in several different ways. In one example, processor 402 can base its decision on the optical port of the meter (…). Figure 4 (Not shown) receives a command to determine whether to change the switching state of the service disconnect switch 295. In another example, the processor 402 may determine the state based on the response to selecting one or more buttons on the meter. Figure 4 (Not shown in the image) and receives a command to determine whether to change the switching state of the service disconnect switch 295. In another example, the processor 402 may determine whether to change the switching state of the service disconnect switch 295 based on a received command. The meter 400 may include a communication unit ( Figure 4(Not shown in the image) to allow receiving radio frequency transmissions from other meters and / or servers. In another example, processor 402 may determine whether to change the switching state of service disconnect switch 295 based on commands received via the communication unit.

[0087] In response to processor 402 determining that the switching state of service disconnect switch 295 needs to be changed, in step S504, processor 402 outputs a control signal to actuator 265. For example, processor 402 can output a control signal from connection 406 to actuator 265 to control the switching state of service disconnect switch 295a, and output a control signal from connection 410 to actuator 265 to control the switching state of service disconnect switch 295b (service disconnect switch 295b switches together with service disconnect switch 295b). Processor 402 is configured to record a timestamp (t) when the control signal is output to actuator 265 in memory 403. The timestamp (t) can be in the millisecond range.

[0088] In step S506, processor 402 records switch characterization data associated with service disconnect switch 295 in memory 403. The switch characterization data defines the state of service disconnect switch 295 when a control signal is output to actuator 265 at timestamp (t). For example, the switch characterization data may define the temperature of the environment surrounding meter 400 (determined based on the temperature signal received from temperature sensor 404). Alternatively or additionally, the switch characterization data may define the number of times the service disconnect switch 295 has been actuated since the manufacture of meter 400. Processor 402 may be configured to maintain a counter in memory 403 to indicate the number of times the service disconnect switch 295 has been actuated. This allows processor 402 to query memory 403 to determine the number of times the service disconnect switch 295 has been actuated. Alternatively or additionally, the switch characterization data may define the age of service disconnect switch 295. The age of the service disconnect switch 295 can be stored in memory 403, allowing the processor 402 to query memory 403 to determine the age of the service disconnect switch 295. The lifetime of the service disconnect switch 295 can be measured from the manufacturing date of the service disconnect switch 295. It should be understood that the lifetime of the service disconnect switch 295 can be measured in hours, days, weeks, etc.

[0089] In step S508, processor 402 monitors at least one load-side waveform of the meter on the connection between service disconnect switch 295 and the load-side output terminal to detect the actual switching time period between (i) the output of the control signal and (ii) a change in the switching state of the switch. For example, with respect to service disconnect switch 295a, processor 402 monitors at least one load-side waveform on the connection between service disconnect switch 295a and the first output terminal 240a. With respect to service disconnect switch 295b, processor 402 monitors at least one load-side waveform on the connection between service disconnect switch 295b and the second output terminal 240c. At step S508, processor 402 monitors the load-side voltage waveform and / or the load-side current waveform.

[0090] In step S510, the processor 402 uses the actual switching time period and switching characterization data to generate a switching characterization tool.

[0091] Specifically, in embodiments where the switch characterization tool is a LUT, in step S510, the processor 402 generates a LUT with entries including the actual switching time period and switch characterization data to indicate the actual switching time period measured when the service disconnect switch 295 operates under conditions defined by the switch characterization data. Once the meter is deployed and operational, the LUT will be supplemented based on the meter's real-time measurements.

[0092] In embodiments where the switching characterization tool is an equation or a system of equations, processor 402 generates an equation that defines the relationship between the actual switching time period and the switching characterization data. One or more equations can define multiple terms and coefficients (which can be updated as described later). In particular, a LUT can be simplified to an equation or system of equations with multiple terms and coefficients without requiring a LUT.

[0093] In other embodiments, the actual switching time period and switching representation data can be used as the first training data to generate a machine learning model.

[0094] In embodiments of the invention, for each subsequent switch actuation, the processor 402 uses and then updates the switch characterization tool. That is, each subsequent switch actuation provides additional data to refine the switch characterization tool.

[0095] As described above, the initial switch characterization tool can be pre-stored in memory 403 during the manufacture of meter 400 for access by processor 402.

[0096] Figure 6 This is a flowchart of the method for using and modifying switch characterization tools. Figure 6The process is executed by the processor 402 when the switch characterization tool is stored in the memory 403 and is accessible to the processor 402. For example, the switch characterization tool may have been pre-stored in the memory 403 for access by the processor 402 during the manufacture of the meter 400, or the switch characterization tool may have been generated by the processor 402 (e.g., using method 500).

[0097] In step S602, processor 402 determines that the switching state of service disconnect switch 295 needs to be changed. Processor 402 can determine that the switching state of service disconnect switch 295 will change in several different ways. In one example, processor 402 can base its decision on the optical port of the meter (…). Figure 4 (Not shown) receives a command to determine whether to change the switching state of the service disconnect switch 295. In another example, the processor 402 may determine the state based on the response to selecting one or more buttons on the meter. Figure 4 (Not shown in the image) and receives a command to determine whether to change the switching state of the service disconnect switch 295. In another example, the processor 402 may determine whether to change the switching state of the service disconnect switch 295 based on a received command. The meter 400 may include a communication unit ( Figure 4 (Not shown in the image) to allow receiving radio frequency transmissions from other meters and / or servers. In another example, processor 402 may determine whether to change the switching state of service disconnect switch 295 based on commands received via the communication unit.

[0098] In step S604, processor 402 uses a switch characterization tool stored in memory 403 to determine an estimated switching time period between (i) the processor 402 outputting a control signal to actuator 265 and (ii) a change in the switching state of service disconnect switch 295. Specifically, processor 402 detects switch characterization data defining the condition of service disconnect switch 295 and uses the switch characterization data and the switch characterization tool to determine the estimated switching time period. As described above, the switch characterization data may define one or more of the following: the ambient temperature of meter 400, the number of times the service disconnect switch 295 has been activated since meter 400 was manufactured, and the service life of service disconnect switch 295. That is, in step S604, processor 402 uses the switch characterization tool to look up the characterization of service disconnect switch 295 based on the current temperature, the number of times the switch has been activated, and / or the age of service disconnect switch 295.

[0099] As an example to illustrate the concept only, processor 402 can determine an estimated switching time period of 10 ms. That is, processor 402 estimates that under the current conditions, after processor 402 outputs a control signal to actuator 265, it will take 10 ms before the switching state of service disconnect switch 295 changes.

[0100] At step S606, processor 402 monitors waveforms. When service disconnect switch 295 is closed, processor 402 can monitor any one of the grid-side voltage waveform, grid-side current waveform, load-side voltage waveform, or load-side current waveform. For example, for service disconnect switch 295a, processor 402 can monitor the voltage or current on the connection between the first input terminal 220a and service disconnect switch 295a, or the voltage or current on the connection between service disconnect switch 295a and the first output terminal 240a. When service disconnect switch 295 is open, processor 402 can monitor the grid-side voltage waveform. For example, for service disconnect switch 295a, processor 402 can monitor the voltage on the connection between the first input terminal 220a and service disconnect switch 295a.

[0101] In step S608, processor 402 uses the monitored waveform and the estimated switching time period to determine the output time for outputting a control signal to actuator 265, such that the switching state of the switch will change when the waveform reaches a target point. That is, using the monitored waveform, processor 402 can estimate when the target point will occur (e.g., the zero-crossing point of the monitored waveform, or when the monitored waveform is at a 30-degree or 45-degree angle to the zero-crossing point), and then use the estimated switching time period to calculate in reverse when processor 402 should output the control signal. In some applications, the target point can be the zero-crossing point of the monitored waveform. In some applications, it may be desirable to avoid the switching state of the service disconnect switch changing when the waveform reaches the zero-crossing point of the monitored waveform, for example, when a high inductive load is present, as this could result in a much higher current than expected. In these applications, the target point can be set to be at least 20 degrees from the zero-crossing point, for example, at least 30 degrees, at least 40 degrees, or at least 45 degrees from the zero-crossing point.

[0102] In step S610, processor 402 outputs a control signal to actuator 265. For example, processor 402 can output a control signal from connection 406 to actuator 265 to control the switching state of service disconnect switch 295a. Alternatively or additionally, processor 402 can output a control signal from connection 410 to actuator 265 to control the switching state of service disconnect switch 295b. Processor 402 is configured to record a timestamp (t1) when the control signal is output to actuator 265 in memory 403. The timestamp (t1) can be in the millisecond range.

[0103] The processor 402 is configured to record the switch characterization data (detected at step S604) in the memory 403.

[0104] In step S612, the processor 402 monitors at least one load-side waveform of the meter on the connection between the service disconnect switch 295 and the load-side output terminal to detect the actual switching time period between (i) the output of a control signal occurring at timestamp (t1) and (ii) the change in the switching state of the switch occurring at timestamp (t2). For example, with respect to service disconnect switch 295a, the processor 402 monitors at least one load-side waveform on the connection between service disconnect switch 295a and the first output terminal 240a. With respect to service disconnect switch 295b, the processor 402 monitors at least one load-side waveform on the connection between service disconnect switch 295b and the second output terminal 240c. At step S612, the processor 402 monitors the load-side voltage waveform and / or the load-side current waveform.

[0105] Monitoring at least one load-side waveform allows processor 402 to detect when a change in the switching state of a switch occurs and record the timestamp of that change at timestamp (t2). For example, processor 402 can detect a change in the switching state of service disconnect switch 295 when the load-side voltage waveform increases from a non-zero voltage value (when the service disconnect switch is closed) or decreases to a zero voltage value (when the service disconnect switch is open). Processor 402 is configured to calculate the actual switching time period by determining the time difference between timestamp (t1) and timestamp (t2).

[0106] In step S614, the processor 402 modifies the switching characterization tool based on the actual switching time period. Specifically, the processor 402 modifies the switching characterization tool based on the actual switching time period and the switching characterization data.

[0107] Specifically, in embodiments where the switch characterization tool is a LUT, in step S614, the processor 402 modifies the LUT based on the actual switching time period and switch characterization data. Each actuation of the service disconnect switch 295 provides new data to the LUT. That is, during the operation of the meter 400, additional data is added to the LUT based on the meter's real-time measurements.

[0108] The LUT can be a multidimensional lookup table, where at least the cycle number, temperature, and prior information are inputs. As an example, the initial LUT can be pre-stored in memory 403 with 10 entries. After 100 operations of the service disconnect switch 295, the LUT may contain up to 110 entries. The prior information will be the 100 previous log entries when the 101st switching cycle occurs.

[0109] The initial LUT can include certain temperature data points paired with different numbers of switch actuations, such as -40, -20, 0, 25, 50, and 85°F, where the nominal delay is recorded in the LUT (i.e., the switching time period). This initial LUT is then updated accordingly to provide a more refined approach.

[0110] Additionally, in embodiments where the meter 400 is coupled to a communication network, the LUT stored on the meter 400 can be updated based on actual switching time period data received from other meters also coupled to the communication network (via the communication network). Alternatively or additionally, the LUT stored on the meter 400 can be updated via a firmware update prepared based on actual switching time period data measured by other meters.

[0111] In an embodiment where the switching characterization tool is an equation, in step S614, the processor 402 can modify one or more coefficients in the equation. That is, the processor 402 can modify the equation defining the slope based on general data from the manufacturing point, according to device-specific actual switching time period data, to adjust the intercept of the slope.

[0112] In an embodiment where the switch representation tool is a machine learning model, the actual switch time periods and switch representation data will provide further training data to supplement the previously used training data in order to retrain the machine learning model.

[0113] In embodiments where the switching representation tool is an equation or a machine learning model, the LUT (or at least the dataset) may be additionally stored in memory 403. For example, the operating log of the status of meter 400 and the associated actual switching time period data of the measurements may be stored in memory 403.

[0114] like Figure 6 As shown, method 600 is an iterative process that allows the switch characterization tool to be continuously updated (if necessary) after each actuation of the service disconnect switch 295. Understandably, the initial wear of the contacts of the service disconnect switch 295 will be more severe when using the initial switch characterization tool, but continuous learning will allow the processor 402 to refine the switching state of the service disconnect switch 295 at target points on the waveform monitored in step S606, and allow for reduced wear over time.

[0115] In embodiments of this disclosure, the switch characterization tool can also be updated via a dedicated update process (i.e., in addition to...). Figure 6 (Except for the process shown) to be updated. For example, the switch characterization tool can be updated via firmware or software updates. This update can be performed based on the characterization of the service disconnect switch 295 by the manufacturer of the service disconnect switch 295 and / or based on actual switching time period data observed by other operating meters.

[0116] While examples of switch characterization tools have been described above, it should be understood that these are merely examples, and embodiments of this disclosure are extended to other switch characterization tools that can be used to characterize the operation and updates of the service disconnect switch 295.

[0117] Although this disclosure has been described with reference to specific embodiments as described above, it should be understood that these embodiments are merely illustrative and the claims are not limited to those embodiments. In view of this disclosure, those skilled in the art will be able to make modifications and substitutions, which are considered to fall within the scope of the appended claims. Each feature disclosed or shown in this specification may be incorporated into any embodiment, either alone or in any suitable combination with any other feature disclosed or shown herein.

[0118] List of reference numerals

[0119] 100 kWh electricity meter

[0120] 105 load

[0121] 110 power supply line

[0122] 115 Transformer

[0123] 120a First Input Terminal

[0124] 120c second input terminal

[0125] 130 Measurement Circuit

[0126] 135a First Node

[0127] 135c second node

[0128] 140a First Output Terminal

[0129] 140c second output terminal

[0130] 145a Third Node

[0131] 145c fourth node

[0132] 150A First Current Transformer

[0133] 150C Second Current Transformer

[0134] 200 kWh electricity meter

[0135] 205 load

[0136] 215 grid

[0137] 220a First Input Terminal

[0138] 220c second input terminal

[0139] 230 Measurement Circuit

[0140] 240a First Output Terminal

[0141] 240c second output terminal

[0142] 260 power supply

[0143] 265 actuator

[0144] 270 analog front end

[0145] 275 digital circuits

[0146] 280G gate voltage sensing circuit

[0147] 280L Load Voltage Sensing Circuit

[0148] 290a First Current Sensing Circuit

[0149] 290c Second Current Sensing Circuit

[0150] 295 Service Disconnect Switch

[0151] 295a Service Disconnect Switch

[0152] 296a Service Disconnect Switch

[0153] 296a service circuit breaker contacts

[0154] 296b Service Circuit Breaker Contacts

[0155] 400 kWh electricity meter

[0156] 402 processor

[0157] 403 memory

[0158] 404 temperature sensor

[0159] 406 connection

[0160] 408 connection

[0161] 410 connection

[0162] 412 connection

Claims

1. An electricity meter, comprising: Power grid side input terminals and load side output terminals; A switch, the switch being coupled between the grid-side input terminal and the load-side output terminal; An actuator coupled to the switch, the actuator being configured to output a switching signal to the switch to change the switching state of the switch; and A processor is arranged to output a control signal to the actuator to cause the output of the switching signal; wherein the processor is configured to: The switching state of the switch is to be changed at a predetermined time. Using a switch characterization tool, determine the estimated switching time period between (i) the processor outputs a control signal to the actuator and (ii) the switch changes its switching state; Monitor the waveform of the meter; The output time of the output control signal is determined based on the waveform and the estimated switching time period, so that the switching state of the switch changes when the waveform reaches the target point. During the output time, a control signal is output to the actuator so that a switching signal is output from the actuator to the switch; Monitor at least one load-side waveform of the meter on the connection between the switch and the load-side output terminal to detect the actual switching time period between (i) outputting the control signal and (ii) a change in the switching state of the switch; and The switch characterization tool is modified based on the actual switching time period.

2. The electricity meter of claim 1, wherein, The waveform of the meter is the grid-side waveform present on the connection between the grid-side input terminal and the switch.

3. The electricity meter of claim 2, wherein, The processor is configured to monitor the grid-side waveform of the meter when the switch is in the closed state.

4. The electricity meter of claim 3, wherein, The grid-side waveform is the grid-side voltage waveform.

5. The electricity meter according to claim 3, wherein, The grid-side waveform is the grid-side current waveform.

6. The electricity meter according to claim 2, wherein, The grid-side waveform is the grid-side voltage, and the processor is configured to monitor the grid-side waveform of the meter when the switch is in the open state.

7. The electricity meter according to claim 1, wherein, The waveform of the meter is the load-side waveform present on the connection between the switch and the load-side output terminal.

8. The electricity meter according to claim 7, wherein, The load-side waveform is the load-side voltage waveform.

9. The electricity meter according to claim 7, wherein, The load-side waveform is the load-side current waveform.

10. The electricity meter according to any one of the preceding claims, wherein, The at least one load-side waveform of the meter includes one or both of the load-side voltage waveform and the load-side current waveform.

11. The electricity meter according to any one of the preceding claims, wherein, The actuator includes an electric motor.

12. The electricity meter according to any one of claims 1 to 10, wherein, The actuator includes a solenoid.

13. The electricity meter according to any one of claims 1 to 10, wherein, The actuator includes a relay.

14. The electricity meter according to any one of the preceding claims, wherein, The processor is configured to use the temperature in the environment of the electricity meter at the determined time to determine the estimated switching time period.

15. The electricity meter according to any one of the preceding claims, wherein, The processor is configured to use the age of the switch to determine the estimated switching time period.

16. The electricity meter according to any one of the preceding claims, wherein, The processor is configured to determine the estimated switching time period using the number of switch actuations performed by the switch.

17. The electricity meter according to any one of the preceding claims, wherein, The switch representation tool is a lookup table.

18. The electricity meter according to any one of the preceding claims, wherein, The switch characterization tool is an equation.

19. The electricity meter according to any one of the preceding claims, wherein, The switch representation tool is a machine learning model.

20. The electricity meter according to any one of the preceding claims, wherein, The target point is the zero-crossing point of the waveform.

21. A method for operating an electricity meter, the method comprising: At a predetermined time, it is determined that the switching state of the meter's switch is to be changed, and the switch is coupled between the grid-side input terminal and the load-side output terminal of the meter. Use switch characterization tools to determine the estimated switching time period between (i) outputting a control signal to the actuator coupled to the switch and (ii) a change in the switching state of the switch; Monitor the waveform of the meter; The output time of the output control signal is determined based on the waveform and the estimated switching time period, so that the switching state of the switch will change when the waveform reaches the target point. During the output time, a control signal is output to the actuator so that a switching signal is output from the actuator to the switch; Monitor at least one load-side waveform of the meter on the connection between the switch and the load-side output terminal to detect the actual switching time period between (i) the output of the control signal and (ii) the change in the switching state of the switch; and The switch characterization tool is modified based on the actual switching time period.

22. A non-transitory computer-readable storage medium comprising instructions for operating an electricity meter, the instructions causing the processor, when executed by a processor of the electricity meter, to: At a predetermined time, it is determined that the switching state of the meter's switch is to be changed, and the switch is coupled between the grid-side input terminal and the load-side output terminal of the meter. Use switch characterization tools to determine the estimated switching time period between (i) outputting a control signal to the actuator coupled to the switch and (ii) a change in the switching state of the switch; Monitor the waveform of the meter; The output time of the output control signal is determined based on the waveform and the estimated switching time period, so that the switching state of the switch will change when the waveform reaches the target point. During the output time, a control signal is output to the actuator so that a switching signal is output from the actuator to the switch; Monitor at least one load-side waveform of the meter on the connection between the switch and the load-side output terminal to detect the actual switching time period between (i) the output of the control signal and (ii) the change in the switching state of the switch; and The switch characterization tool is modified based on the actual switching time period.

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