Electricity meter and electricity meter anomaly detection method

Abstract

An electricity measurement unit (12) calculates a consumer electricity usage amount from a current value and a voltage value of a terminal fitting (14) of an electricity meter (11) and outputs electricity amount data which indicates the electricity usage amount. A temperature detection unit (31) outputs temperature data indicating the temperature of the inside of the electricity meter (11). The determination processing unit (32) determines that there is an anomaly of the terminal fitting (14) when the temperature data exceeds a prescribed temperature threshold value and the electricity amount data is not more than a prescribed electricity amount threshold value.

Description

Electricity meter and method for detecting abnormalities in the electricity meter

[0001] The present disclosure relates to a watt-hour meter, and more particularly to a technique for detecting heat generation due to an abnormality in a watt-hour meter.

[0002] Watt-hour meters, which calculate and measure the electricity used by consumers, are required to prevent damage to the watt-hour meters and the resulting damage to the consumers' electrical equipment.

[0003] For example, Patent Document 1 listed below discloses a watthour meter that outputs an alarm when it is detected that the temperature of the conductive parts and terminal parts of the watthour meter is above a certain value. Also, Patent Document 2 listed below discloses a watthour meter that measures the temperature inside the watthour meter and the temperature at a position closer to the outside of the watthour meter to determine whether the fire started from inside or outside when the watthour meter burns, and records the determination result.

[0004] JP 2010-19680 A JP 2018-72248 A

[0005] The main cause of heat generation and burnout in watt-hour meters is poor contact due to insufficient or loose screws in the terminals of the watt-hour meter. For this reason, when detecting temperature increases inside the watt-hour meter, a temperature sensor is typically placed near the terminals. However, because the terminals also generate heat when the consumer's electricity usage is high, a temperature sensor placed near the terminals cannot distinguish whether the cause of the temperature increase in the watt-hour meter is poor contact in the terminals or excessive electricity usage by the consumer, making it difficult to correctly detect heat generation due to poor contact in the watt-hour meter's terminals.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a technology that can detect heat generation caused by poor contact at the terminals of a watt-hour meter, distinguishing it from heat generation caused by electricity usage by consumers.

[0007] The electricity meter according to the present disclosure includes a terminal fitting to which a power line is connected, an electricity metering unit that calculates the amount of electricity used by a consumer from the current and voltage values ​​of the terminal fitting and outputs electricity energy data indicating the amount of electricity used, a temperature detection unit that outputs temperature data indicating the temperature inside the electricity meter, and a determination processing unit that determines that there is an abnormality in the terminal fitting if the temperature data exceeds a predetermined temperature threshold and the electricity energy data is equal to or less than the predetermined electricity energy threshold.

[0008] According to the method for detecting a temperature rise in a watt-hour meter disclosed herein, heat generation caused by poor contact in the terminals of the watt-hour meter can be detected separately from heat generation caused by the amount of power consumed by a consumer.

[0009] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0010] Fig. 1 is a configuration diagram of a watt-hour meter according to embodiment 1. Fig. 2 is a functional block diagram of a watt-hour meter according to embodiment 1. Fig. 3 is a flowchart showing a process for determining whether or not heat generation in a terminal fitting of a watt-hour meter is due to an abnormality in the terminal fitting, according to embodiment 1. Fig. 4 is a flowchart showing a process for determining whether or not heat generation in a terminal fitting of a watt-hour meter is due to an abnormality in the terminal fitting, according to embodiment 2.

[0011] <First Embodiment> Fig. 1 is a configuration diagram of a watt-hour meter 11 according to the first embodiment. The watt-hour meter 11 is a so-called smart meter, and includes a watt-hour meter unit 12 that measures the amount of power used by a consumer, a communication terminal unit 13 that periodically transmits the measured amount of power used to a host server, and terminal fittings 14 to which a power line that supplies power to the consumer is connected. The amount of power used measured by the watt-hour meter 11 is transmitted to the host server, allowing an administrator to know the amount of power used remotely.

[0012] The watt-hour meter 11 includes a housing 15 molded from, for example, resin. The watt-hour meter 11 also includes terminal fittings 14 including a service line side terminal fitting 14a for connecting a service line wiring from a distribution line and a home side terminal fitting 14b for connecting a wiring from a distribution board on the home side. In this embodiment, the watt-hour meter 11 is a single-phase three-wire watt-hour meter, and the service line side terminal fittings 14a include three terminal fittings 1S, 2S, and 3S for connecting a power transmission line, and the home side terminal fittings 14b include three terminal fittings 1L, 2L, and 3L for connecting a wiring leading to a distribution board.

[0013] Fig. 2 is a functional block diagram of the watt-hour meter 11. As shown in Fig. 2, the watt-hour meter 11 includes a voltage detection unit 21, a first current detection unit 22, a second current detection unit 23, a clock 24, a power calculation unit 25, a device control unit 26, a storage unit 27, and an external communication unit 28.

[0014] The voltage detection unit 21 detects the voltage value between the terminal fittings 1S and 1L and the voltage value between the terminal fittings 3S and 3L. The voltage values ​​detected by the voltage detection unit 21 are sent to the power calculation unit 25 as voltage value data.

[0015] The first current detection unit 22 detects the current value between the terminal fitting 1S and the terminal fitting 1L, and the second current detection unit 23 detects the current value between the terminal fitting 3S and the terminal fitting 3L. The current values ​​detected by the first current detection unit 22 and the second current detection unit 23 are sent to the power calculation unit 25 as current value data.

[0016] The clock 24 outputs time data indicating the current date, hour, minute and second to the device control unit 26 .

[0017] The power calculation unit 25 calculates the amount of power per unit time using the voltage value data acquired from the voltage detection unit 21 and the current value data acquired from the first current detection unit 22 and the second current detection unit 23. The amount of power calculated by the power calculation unit 25 is sent to the device control unit 26 as power amount data.

[0018] The device control unit 26 sends the power amount data acquired from the power calculation unit 25 and the time data acquired from the clock 24 to the storage unit 27. The storage unit 27 stores the power amount data and the time data received from the device control unit 26 in association with each other.

[0019] The device control unit 26 can request the storage unit 27 to send the stored power amount data and time data to the device control unit 26. When the storage unit 27 is requested to send the power amount data and time data, it sends the stored power amount data and time data to the device control unit 26. The device control unit 26 inputs the power amount data and time data received from the storage unit 27 to the external communication unit 28.

[0020] The external communication unit 28 transmits the power amount data and time data input from the device control unit 26 to the communication terminal unit 13 .

[0021] The communication terminal unit 13 includes a temperature detection unit 31, a device control unit 32, a storage unit 33, a wireless communication unit 34, and an external communication unit 35. The communication terminal unit 13 is also connected to a host server 41 of the communication terminal unit 13 via wireless communication.

[0022] The temperature detection unit 31 is a temperature sensor that periodically measures the temperature inside the watt-hour meter 11, specifically, the temperature around the communication terminal unit 13. The temperature detection unit 31 sends the measured temperature value to the device control unit 32 as temperature data.

[0023] The device control unit 32 sends the temperature data received from the temperature detection unit 31 to the storage unit 33. The device control unit 32 also sends the power amount data and time data received by the external communication unit 35 from the power meter unit 12 to the storage unit 33.

[0024] The device control unit 32 also functions as a determination processing unit that, when the terminal fittings 14 generate heat, determines whether the heat is due to an abnormality in the terminal fittings 14, such as poor contact, or due to excessive power usage by the consumer. If the device control unit 32 determines that the heat generated by the terminal fittings 14 is due to an abnormality in the terminal fittings 14, it outputs a terminal fitting abnormality notification indicating this. Details of this determination processing will be described later.

[0025] The storage unit 33 stores the temperature data, power data, and time data received from the device control unit 32. The device control unit 32 can request the storage unit 33 to transmit the stored power data, time data, and temperature data to the device control unit 32. When the storage unit 33 is requested to transmit the time data and temperature data to the device control unit 32, it sends the stored power data, time data, and temperature data to the device control unit 32. The device control unit 32 inputs the power data, time data, and temperature data received from the storage unit 33, as well as the terminal abnormality notification, to the wireless communication unit 34.

[0026] The wireless communication unit 34 is a communication unit that transmits the power amount data, time data, temperature data, and terminal abnormality notification input from the device control unit 32 to the upper server 41 by wireless communication.

[0027] The external communication unit 35 communicates with the external communication unit 28 of the power metering unit 12 , receives the power amount data and time data transmitted from the external communication unit 28 , and sends them to the device control unit 32 .

[0028] The upper server 41 receives the power data, time data, temperature data, and terminal abnormality notification sent from the wireless communication unit 34 of the communication terminal unit 13. The received data is presented to the administrator, allowing the administrator to know in advance which watt-hour meters 11 may be burned out.

[0029] In addition to functioning as a general electricity meter that measures the consumer's electricity usage, the electricity meter 11 also has the function of sending a terminal fitting abnormality notification to the upper server 41 when heat generation occurs due to an abnormality in the terminal fitting 14.

[0030] 3, a process by which the watt-hour meter 11 determines whether heat generation in the terminal fitting 14 is due to an abnormality in the terminal fitting 14 will be described below. This process is mainly performed by the device control unit 32 of the communication terminal unit 13.

[0031] The device control unit 32 acquires temperature data inside the watt-hour meter 11 measured by the temperature detection unit 31 periodically (e.g., every 5 minutes) (step S101). The device control unit 32 determines whether the temperature data exceeds a predetermined temperature threshold (e.g., 60°C) (step S102). If the temperature data does not exceed the temperature threshold (NO in step S102), the device control unit 32 determines that there is no abnormality in the temperature, and returns to step S101 to continue monitoring the temperature data.

[0032] If the temperature data exceeds the temperature threshold (YES in step S102), the device control unit 32 determines that a temperature abnormality has occurred and acquires power energy data for the same time period as the temperature data (i.e., power energy data linked to time data for the same time period as the temperature data) from the power meter unit 12 (step S103).The device control unit 32 then determines whether the acquired power energy data exceeds a predetermined power energy threshold (e.g., 500 Wh) (step S104).If the power energy data exceeds the power energy threshold (YES in step S104), the device control unit 32 determines that the heat generation in the terminal fitting 14 is due to excessive power usage by the consumer (there is no abnormality in the terminal fitting 14), and returns to step S101 to continue monitoring the temperature data.

[0033] If the power amount data does not exceed the power amount threshold (NO in step S104), the device control unit 32 determines that the heat generation in the terminal fittings 14 is due to an abnormality in the terminal fittings 14 (step S105), and transmits a terminal abnormality notification to the upper server 41 via the wireless communication unit 34 to notify the upper server 41 of the abnormality in the terminal fittings 14 (step S106). At this time, the device control unit 32 may transmit the power amount data, time data, and temperature data to the upper server 41 to present to the administrator.

[0034] The watt-hour meter 11 according to this embodiment can detect heat generation due to poor contact of the terminal fittings 14, distinguishing it from heat generation due to the consumer's power consumption. Furthermore, when the watt-hour meter 11 determines that the temperature rise inside the watt-hour meter 11 detected by the temperature detection unit 31 is due to an abnormality in the terminal fittings 14, it sends a terminal fitting abnormality notification to the upper server 41, allowing the administrator to quickly become aware of the abnormality in the terminal fittings 14. This makes it possible to prevent damage to the watt-hour meter 11 or the consumer's electrical equipment due to heat generation resulting from an abnormality in the terminal fittings 14.

[0035] In the watt-hour meter 11 according to this embodiment, the temperature is measured by a temperature detection unit 31 disposed in the communication terminal unit 13, and the temperature detection unit 31 measures the temperature around the communication terminal unit 13 that has risen due to the heat generated by the terminal fittings 14 convection within the housing 15 of the watt-hour meter 11. Because the position of the communication terminal unit 13 is far from the terminal fittings 14, which are the source of the heat, the communication terminal unit 13 is easily affected by the outside air temperature, which may make it difficult to accurately measure the temperature inside the watt-hour meter 11 that has risen due to the heat generated by the terminal fittings 14.

[0036] Therefore, the watt-hour meter 11 may be provided with a function for acquiring outside temperature data indicating the outside temperature in the area where the watt-hour meter 11 is installed, and the device control unit 32 may calculate the difference between the temperature data measured by the temperature detection unit 31 and the outside temperature data to capture only the temperature rise inside the watt-hour meter 11 and determine whether the temperature rise is due to an abnormality in the terminal fitting 14. Specifically, the device control unit 32 may subtract the outside temperature data from the temperature data measured by the temperature detection unit 31 and use this as the temperature data to compare with a predetermined temperature threshold. The outside temperature data for the area where the watt-hour meter 11 is installed may be, for example, data from the Japan Meteorological Agency available via the Internet, and is periodically transmitted from the upper server 41 to the device control unit 32 via the wireless communication unit 34.

[0037] There is also an advantage to arranging the temperature detection unit 31 in the communication terminal unit 13. If the power meter unit 12 and the communication terminal unit 13 in the watt-hour meter 11 are structured to be independent of each other, as in a general smart meter, it is possible to replace only the communication terminal unit 13. Furthermore, by replacing the communication terminal unit of a conventional smart meter that does not have a temperature detection function with the communication terminal unit 13 according to this embodiment, the effects of this embodiment can be obtained.

[0038] <Embodiment 2> Because the amount of electricity used by a consumer varies depending on the time of day, heat generation due to excessive electricity use by the consumer is usually temporary. On the other hand, heat generation due to an abnormality in the terminal fittings 14 is expected to continue for a long period of time. Therefore, in embodiment 2, a condition for determining that a temperature rise inside the watt-hour meter 11 is due to an abnormality in the terminal fittings 14 is that the temperature rise is continuous. Note that the configuration of the watt-hour meter 11 according to embodiment 2 is the same as that of embodiment 1 (FIGS. 1 and 2).

[0039] FIG. 4 is a flowchart showing a process performed by the watt-hour meter 11 according to the second embodiment to determine whether or not heat generated by the terminal fitting 14 is due to an abnormality in the terminal fitting 14 .

[0040] The flowchart in Fig. 4 is obtained by adding step S110 to the flowchart in Fig. 3. Since the other steps are the same as those in Fig. 3, only step S110 will be described here.

[0041] Step S110 is executed when step S102 is determined to be YES and step S104 is determined to be NO, i.e., when the temperature data measured by the temperature detection unit 31 exceeds the temperature threshold and the power amount data of the consumer is equal to or less than the power amount threshold. In step S110, the device control unit 32 determines whether the state of step S102 being YES and step S104 being NO has continued for a certain period of time (e.g., one or two days).

[0042] If the result of step S102 is YES and the result of step S104 is NO for a certain period of time (if the result of step S110 is NO), the device control unit 32 reserves the determination of whether the heat generated by the terminal fitting 14 is due to an abnormality in the terminal fitting 14, and returns to step S101 to continue monitoring the temperature data.

[0043] Thereafter, if the state of YES in step S102 and NO in step S104 continues for a certain period of time (YES in step S110), the device control unit 32 determines that the heat generation in the terminal fitting 14 is due to an abnormality in the terminal fitting 14 (step S105), and sends a terminal fitting abnormality notification to the upper server 41 via the wireless communication unit 34 to notify the abnormality in the terminal fitting 14 (step S106).

[0044] According to the second embodiment, the condition for determining that the temperature rise inside the electricity meter 11 is caused by an abnormality in the terminal fittings 14 is that the temperature rise is continuous, so that the accuracy of the determination can be expected to be improved compared to the first embodiment.

[0045] It should be noted that the embodiments can be freely combined, and the embodiments can be modified or omitted as appropriate.

[0046] The above description is illustrative in all respects, and it is understood that countless variations not illustrated can be envisioned.

[0047] REFERENCE SIGNS LIST 11 Watt-hour meter, 12 Watt-hour metering unit, 13 Communication terminal unit, 14 Terminal fittings, 14a Drop-in line side terminal fittings, 14b In-house side terminal fittings, 15 Housing, 21 Voltage detection unit, 22 First current detection unit, 23 Second current detection unit, 24 Clock, 25 Power calculation unit, 26 Device control unit, 27 Memory unit, 28 External communication unit, 31 Temperature detection unit, 32 Device control unit, 33 Memory unit, 34 Wireless communication unit, 35 External communication unit, 41 Upper server.

Claims

1. A watt-hour meter comprising: a terminal fitting to which a power line is connected; a watt-hour meter unit that calculates the amount of power used by a consumer from the current and voltage values ​​of the terminal fitting and outputs watt-hour data indicating the amount of power used; a temperature detection unit that outputs temperature data indicating the temperature inside the watt-hour meter; and a determination processing unit that determines that there is an abnormality in the terminal fitting when the temperature data exceeds a predetermined temperature threshold and the watt-hour data is equal to or less than the predetermined watt-hour threshold.

2. The electricity meter according to claim 1, further comprising a communication unit that, when the determination processing unit determines that the terminal fitting is abnormal, sends a terminal fitting abnormality notification indicating this to a higher-level server.

3. The watt-hour meter according to claim 1 or claim 2, wherein the determination processing unit acquires outside temperature data indicating the outside temperature in the area where the watt-hour meter is installed, and the temperature data obtained by subtracting the outside temperature data from the temperature data is used as the temperature data to be compared with the temperature threshold value.

4. A watt-hour meter as described in any one of claims 1 to 3, wherein the judgment processing unit judges that there is an abnormality in the terminal fitting when the state in which the temperature data exceeds the temperature threshold and the power amount data is equal to or less than the power amount threshold continues for a certain period of time.

5. A method for detecting an abnormality in an electric power meter, comprising: a step in which a power metering unit of the electric power meter calculates the amount of power used by a consumer from the current value and voltage value of the terminal fittings of the electric power meter, and outputs power amount data indicating the amount of power used; a step in which a temperature detection unit of the electric power meter outputs temperature data indicating the temperature inside the electric power meter; and a step in which a judgment processing unit of the electric power meter judges that there is an abnormality in the terminal fittings when the temperature data exceeds a predetermined temperature threshold and the power amount data is equal to or less than a predetermined power amount threshold.

6. The method for detecting an abnormality in an electricity meter according to claim 5, further comprising a step in which, when the determination processing unit determines that there is an abnormality in the terminal fitting, the communication unit of the electricity meter sends a terminal fitting abnormality notification indicating this to a higher-level server.

7. The method for detecting an abnormality in an electricity meter according to claim 5 or claim 6, wherein the determination processing unit acquires outside temperature data indicating the outside temperature in the area where the electricity meter is installed, and the temperature data obtained by subtracting the outside temperature data from the temperature data is used as the temperature data to be compared with the temperature threshold.

8. A method for detecting an abnormality in an electricity meter as described in any one of claims 5 to 7, wherein the judgment processing unit judges that there is an abnormality in the terminal fitting when a state in which the temperature data exceeds the temperature threshold and the power amount data is equal to or less than the power amount threshold continues for a certain period of time.

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